science teacher 2011 Featuring: (bio)diversity Microbial life on surfaces Life at high temperatures NZ’s marine biodiversity Conversing at home about science Alpine cress reveal evolutionary secrets Everything you need to know about Fungi Ecology at a crossroads? Advancing primary science Conversations at science/ education interface And more...
Number 128
ISSN 0110-7801
THE SCIENCE LEARNING HUB
www.sciencelearn.org.nz Explore the Science Learning Hub to find a wealth of resources for year 5–10 teachers including contemporary science stories, feature articles, people profiles, images, animations and video clips that showcase New Zealand’s world class science sector.
w w w . b i o t e c h l e a r n . o r g . n z Discover the processes, people, organisations and stories of our biotechnology sector through the Biotechnology Learning Hub - developed especially for New Zealand’s teachers.
NZ
science en nce nc ce ach cher he err teacher
contents
128
Editorial Advisory Group: Rosemary Hipkins, Chris Joyce, Suzanne Boniface, Beverley Cooper, Miles Barker and Anne Hume Editorial Address: lyn.nikoloff@xtra.co.nz
Editorial 2 From the President’s desk 3 Celebrating Rutherford
contents
NZST PublicationTeam: Editor: Lyn Nikoloff, Bijoux Publishing Ltd, Palmerston North Sub editor: Teresa Connor Typesetting and Cover Design: Pip’s Pre-Press Services, Palmerston North Printing: K&M Print, Palmerston North Distribution: NZ Association of Science Educators
Rutherford’s path to the nuclear atom 4 Biodiversity Biofilms: microbial life on surfaces 10
NZASE National Executive: President: Sabina Cleary Senior Vice-President: Lindsey Connor Treasurer/Web Manager: Robert Shaw Primary Science: Chris Astall Auckland Science Teachers: Carolyn Haslam Publications: Matt Balm Executive Member: Steven Sexton Executive Member: Gerard Harrigan
Life in extremely hot environments 12 Arthropod biodiversity in agriculture 15 New Zealand’s marine biodiversity 18 Diversity in native alpine cress 23
Mailing Address and Subscription Inquiries: NZASE PO Box 37 342 Halswell 8245. email: nzase@xtra.co.nz NZASE Subscriptions (2011) School description Secondary school
Roll numbers Subscription > 500 $240.00 < 500 $185.00 Area School - to be determined TBA Intermediate, middle and > 600 $240.00 composite schools 150-599 $90.00 < 150 $65.00 Primary/contributing schools > 150 $90.00 < 150 $70.00 Tertiary Education Organisations $240.00 Libraries $110.00 Individuals $50.00 Student teachers $45.00 Special Interest Group (includes access to secure sites): BEANZ, NZIC, STANZ, ESSE (was SCIPED) $20 per group Note: SIG fees are included all subscriptions except for individual members. Additional copies of the NZ Science Teacher Journal $32.06 per year for three issues Subscription includes membership and one copy of NZST per issue (i.e. three copies a year). All prices are inclusive of GST. Advertising: Advertising rates are available on request from nzst@nzase.org.nz Deadlines for articles and advertising: Issue 129: 20 December (publication date: 1 March, 2012) Issue 130: 20 April (publication date: 1 June, 2012) Issue 131: 20 August (publication date: 1 October, 2012)
The missing f-word: fungi 26 Diversity: Science Education Beyond poisoning possums ... 7 Ecology at a crossroads? 8 Conversing about science at home 34 Using pseudoscience to teach science 38 Science teaching in refugee camps 41 Science/Science Education Interface Conversation: a passion for the living world 22 Conversation: creative thinking and experimentation ... 40 Primary science Nature of science in action 30 Advancing primary science 33 Subject Associations
NZST welcomes contributions for each journal but the Editor reserves the right to publish articles it receives. Please contact the Editor before submitting unsolicited articles: nzst@nzase.org.nz
Biology 42
Disclaimer: The New Zealand Science Teacher is the journal of the NZASE and aims to promote the teaching of science, and foster communication between teachers, scientists, consultants and other science educators. Opinions expressed in this publication are those of the various authors, and do not necessarily represent those of the Editor, Editorial Advisory Group or the NZASE. Websites referred to in this publication are not necessarily endorsed.
Physics 45
Chemistry 44 ESSE 46 Technicians 48 Resources Book review 39, 47
F Front cover: Sponges and gorgonian octocorals at 68m depth north of Cape Reinga, photographed using NIWA’s Deep Towed Imaging System (DTIS) during a recent Ocean p Survey 2020 biogenic habitats’ voyage by RV Tangaroa. S Reproduced courtesy of MFish and LINZ. R
New New w Zealand Zea eala land la nd Association Asssoc ocia iati ia tion ti on of of Science Scie Sc ienc ie n e Educators nc Educat a or os
1
NZ
science teacher
editorial
128
Aspiring to excellence Recently, I attended a symposium where an organisation was talking about its pathway to a silver award in business excellence. To date, a diverse range of NZ organisations have achieved silver and gold business excellence awards including: Rio Tinto Aluminium (Bluff ), the NZ Navy and a healthcare provider. Yet, in spite of their diversity, all met the same prescribed criteria. And within science education there is a diversity of providers and yet all have the same aspiration to excellence.
In this issue... We bring to your attention the diversity of articles in this issue of the NZST. We hope you find something of value both professionally and practically, and that its content inspires you to aspire to excellence in science education. Students are not islands unto themselves, and parents can be useful in helping them to develop an interest in science, as Miles Barker and Claire Donaldson note (p.34). Alison Campbell enthuses about how pseudoscience can be a great context for teaching critical thinking skills (p.38); and Rob Julian writes about teaching science in a refugee camp (p.41). And for our primary sector colleagues there are two dedicated articles: one on the nature of science and the other on a primary science strategy (pp.30-33). This year we have been striking up a conversation with the science community. In this issue Ally Bull and Rose Hipkins talk with marine scientist, Dennis Gordon (p.22); and Anne Hume writes about her conversation with Eocene climate modeller, Duncan Ackerley (p.40). Did you know that this year is the centenary of Ernest Rutherford’s Nobel Prize? John Campbell has written a wonderful article celebrating Rutherford’s contribution to physics and notes that Rutherford’s achievements are: “Not bad for a young fellow who failed to get a school-teaching job in New Zealand.” (p.4). While many conservation programmes have been successful there is still some uncertainty about why some fail. Kevin Burns writes about the challenges facing ecology (p.7) and following on from this Rex Bartholomew discusses whether ecology is at a crossroads (p.8). Have you ever wondered about the microbial life on your teeth? Jon Palmer shares with readers how a better understanding of microbial life on biofilms, such as teeth, has transformed microbiology (p.10). In our geothermal areas, thermophilic bacteria thrive in temperatures in excess of 120°C. Hugh Morgan describes how these bacteria are helping scientists to better understand the evolution of life (p.12). NZ is dependent on agriculture and there has been an increasing demand for it to be sustainable. Louise Malone writes about the biodiversity of arthropods in two agroecosystems: pine plantation and kiwifruit orchard (p.15).
2
New Zealand Association of Science Educators
About 40% of marine species in NZ’s EEZ are endemic and it is vital we conserve this genetic diversity. Also, we are discovering new species faster than we can name them. Dennis Gordon’s article is a tour de force of NZ marine biodiversity and includes an excellent table of data for students to analyse (p.18). Peter Heenan describes the importance of studying the origin and evolution of the native alpine cress to gain a better understanding of adaptive radiation and speciation in NZ alpine plants (p.23). All too often fungi are omitted from school science programmes, yet life as we know it would not be possible without them. Peter Buchanan brings to your attention the missing f-word: fungi, and in so doing gives you a newfound respect for this often maligned group (p.26). This issue also features reports from: BEANZ – biology (p.42), chemistry (p.44), physics (p.45), and ESSE (p.46). There is also an illuminating article from science technicians in Christchurch who are being innovative and creative post-earthquake (p.48). Lindsey Conner, outgoing NZASE President, writes about the future of science education and how members can/must engage in the process (p.4).
And finally... I would like to extend a warm thank you to all the contributors – your generosity of spirit and commitment to science education is encouraging and most gratefully received. Thank you. I would like to extend an especial thank you to Rose Hipkins and Miles Barker, members of the NZST editorial review group, for the huge amount of planning they undertook to ensure that we were able to bring to your attention so many excellent science education articles. I would also like to acknowledge the work of the editorial review group, their generosity of spirit ensures the highest standard of article is published in the NZST. Thank you. And I extend a very warm thank you to the NZST production team; you are all great people to work with: Teresa Connor, Philippa Proctor and Raymond Jones. Thank you. With such a diverse range of articles in this issue of the NZST we are certainly aspiring to excellence. I hope you enjoy another rollicking great read. Happy summer holidays everyone. Kind regards
Lyn Nikoloff Editor, NZST
NZ
science teacher
impacting the future of science education
Science for Citizenship: 1. Assemble a working party through NZASE and RSNZ to create a definition of science for citizenship. This might include evidence-based decision making, inquisitiveness, curiosity, critical thinking, empathy, how scientific process works, risks and hazards, understanding the world around us, considering other views besides the traditional ‘Western’ view. 2. Work to ensure all science teachers have a common understanding on the Nature of Science (NoS). There is a need to tease out examples and possibilities for including aspects of NoS for all levels of the curriculum.
Systems Thinking: 3. There is a conflict between assessment and science education; there is a fragmentation of science caused by structural thinking that delimits science domain knowledge; we need to identify the levers for the necessary permissions to engage and explore and use an integrated approach to science education. 4. Establish a process for dialogue between the secondary schooling sector and the tertiary sector. 5. A recommendation for Ministry of Education, Ministry of Science and Innovation, RSNZ, NZASE to undertake a co-ordination of science education resources and initiatives.
Visioning as a Society: 6. Wherever possible, creating and highlight stories about NZ as a nation of scientists; we need high profile promotion of science as an integral part of our national identity. 7. A national conversation on Science Education. The greater populace needs to be engaged in this more in an effort to bring science to the fore in the media, and recognition of the importance of science in our daily lives. RSNZ should investigate strategies which might be
useful that other sectors have used to raise awareness about issues such as human rights, smoking etc. 8. A recommendation to RSNZ, NZASE, and the Office of the Prime Minister’s Science Advisor to work with the media to raise the issue of science education within the wider community.
fromthepresident
In a previous issue of the NZST, I discussed the importance of Sir Peter Gluckman’s document Inspiring Science and how it provided a beginning for conversations about what science education could, and should, be in New Zealand. The NZ Royal Society (RSNZ) has now held two forums in Wellington enabling many stakeholders including teachers, members of NZASE, Ministry of Education, Ministry of Science and Innovation, and NZCER personel, science advisors, science teacher educators, and other interested people to discuss their ideas. While the purpose was to engage in purposeful and informed visioning, the participants also came up with practical strategies to advance these. The secondary school forum grouped these under the themes of science for citizenship, systems’ thinking, visioning as a society and equiping teachers. Therefore, I have collated the main ideas from both forums and summarised these using these themes since there was overlap between the ideas from both forums.
128
Equipping Teachers: 9. A national focus on science teacher professional learning and development for primary and secondary sectors to bring about cultural change in every classroom – focus on NoS. 10. A recommendation to the Ministry of Education to re-evaluate the positions of Science Advisors or similar positions in the future to ensure teachers have professional development and assistance/advice when needed. 11. Expanding on the activities already available on TKI, a recommendation to MoE that a teaching and learning guideline be developed to unpack the Nature of Science from Levels 1 to 5. It was further recommended that this should be accompanied with sufficient professional development to ensure primary teachers have an understanding of the key concepts. 12. That further work be done regarding the place of Maori in science, and the unique contribution traditional knowledge makes in our school curriculum. 13. Recommendation to NEMP (or its replacement), RSNZ and NZAPSE to further work on the profiling of a Year 8 graduate and what they should have experienced during their schooling in science. 14. Recommendation to New Zealand Teachers’ Council to investigate the pre-service preparation for the teaching of science to identify minimal standards for effective primary science teaching and learning. 15. Recommendation to New Zealand Principals’ Federation, NZEI, RSNZ and the Office of the Prime Minister’s Science Advisor for a mechanism to recognise and reward primary science ‘champions’/effective primary science educators. 16. Work on developing new Levels 2 and 3 Achievement Standards which have more of a NoS flavour. These are very strong statements. Science teachers, as members of NZASE and the wider science education community, have been tasked to take up the above. It would be great to hear from you and your colleagues about how you can contribute to making these recommendations come to fruition. At the NZASE AGM this year we will be discussing short- and long-term planning and would welcome your suggestions. Noho ora mai Lindsey Conner President NZASE
New Zealand Association of Science Educators
3
NZ
science teacher
diversity: celebratingRutherford
128
Rutherford’s path to the nuclear atom Did you know that 2011 is the centennial of Ernest Rutherford’s discovery of the nuclear atom? Dr John Campbell, author of Rutherford’s biography, explains why all New Zealanders should be celebrating Rutherford’s achievements. Rutherford’s research at the Cavendish Laboratory By the age of 23, Ernest Rutherford had three degrees and completed two years of groundbreaking research in electrical technology and he was heading overseas to spend time at the Cavendish Laboratory, Cambridge University, thanks to an Exhibition of 1851 Science Scholarship. He chose Cambridge University because its director, J.J. Thomson, had written one of the books on advanced electricity which Rutherford had used to guide his research. This decision was fortuitous because it put him in the right place at the right time. Initially, Rutherford continued his work on the high frequency magnetisation of iron, developing his detector of fast current pulses to measure the dielectric properties of materials at very high frequencies, and to briefly hold the world record over which electric ‘wireless’ waves were detected. Thomson, or JJ as he was known, appreciated Rutherford’s experimental and analytical skills and so invited him to join in his own research into the nature of electrical conduction in gases at low pressures. Within five months of Rutherford’s arrival at Cavendish, the age of new physics commenced. Röntgen’s accidental discovery of X-rays and then Becquerel’s accidental discovery of radioactivity were announced. Rutherford used both to ionise his gases in an attempt to learn what it was that was conducting the electricity in an ionised gas. Very soon he changed to trying to understand radioactivity, with his research determining that two types of rays were emitted, which he named alpha and beta. Alphas were
easily stopped, a sheet of paper or the dead skin on a hand would do, whereas betas needed a millimetre or more of a metal heavier than copper to stop them. Meanwhile, Thomson continued mainly with the ionisation of gases. Two years after Rutherford’s arrival, Thomson carried out a definitive experiment which showed that cathode rays, the objects producing an electrical current in a discharge tube, were objects more than a thousand times less massive than the lightest atom. The electronic age and the age of sub-atomic particles had commenced, though mostly unheralded. (Thomson’s apparatus was the basis of glass–vacuum oscilloscopes and TV tubes for over 80 years, but is currently being replaced by LCD, LED, and plasma screens.) Rutherford was a close observer of Thomson’s discovery, and became an immediate convert to, and champion of, sub-atomic objects. Beta rays were quickly shown to be high-energy cathode rays (i.e. a high-speed electron). However, Rutherford had no future at Cambridge because after three years as a non-Cambridge graduate he was not eligible for a fellowship for another year, so he took a Chair of Physics at McGill University in Canada. (Cambridge changed its rules the following year; they knew what they had lost.) From then on, the world centre of radioactivity and particle research was wherever Rutherford was based.
Fuzzy beams At McGill, Rutherford showed that radioactivity was the spontaneous transmutation of radioactive atoms (Figure 1) and for this work he received the 1908 Nobel Prize in Chemistry. He also demonstrated that alpha particles were most likely helium atoms minus two electrons; and he dated the age of the Earth using radioactive techniques. In studying the nature of alpha particles, by being the first to deflect them
Figure 1: Uranium spontaneously decayed through many elements until it became stable lead. 4
New Zealand Association of Science Educators
NZ
science teacher 128
in magnetic and electric fields in beautifully conceived experiments, he observed that a narrow beam of alphas in a vacuum became fuzzy when either air was introduced into the chamber or it was passed through a thin sheet of mica. Alpha particles were Rutherford’s ‘baby’, having conceived them, and they featured in most of his research works. He stated at the time that to cause the scattering atoms had to be the site of incredible electrical forces. His journey into the atom had unknowingly begun. Rutherford returned to England in 1907 where he was appointed to the Chair of Physics at the University of Manchester. His first task was to establish a method for counting individual alpha particles. Rutherford was an expert in ionised gases, and he recalled that Townsend (an old friend from Cambridge) had said that: one ion if placed in a strong electric field ionised tens of thousands of atoms in a gas. This was an enormous magnifying effect. So with the assistant he had inherited, Hans Geiger, Rutherford placed a wire on the axis of a metal tube, pumped most of the air out of the tube, and placed a voltage between the wire and tube such that it wasn’t quite enough to cause a gas discharge. But it was primed ready to go (Figure 2). When an alpha particle entered the tube it produced many thousands of ions, each of which produced others as they were accelerated between the wire and tube and a spark discharge occurred. Thus, each alpha particle entering the tube gave a short pulse of electrical current which could be observed by the kick of a galvanometer and even recorded as a displaced spot of light on a strip of moving photographic paper. This device, the Rutherford-Geiger tube, had further minor improvements by Geiger and Mûller, and so today is known as the Geiger tube.
Fundamental constants With this individual alpha particle detector Rutherford was able to standardise sources of radioactivity. And the first unit of radioactivity was named in his honour, the rutherford (Rd): the amount of radioactive material which disintegrates at the rate of a million disintegrations per second. (This was later superseded by the curie and made redundant in 1957. The curie in its turn was superseded by the becquerel. One rutherford was a million becquerel.) Also using his detector, Rutherford accurately measured the charge on the electron and Avogadro’s Number. Such measurements were complicated by what he had noticed back in Canada, that alpha particles are scattered in a gas. So this scattering needed further study.
This model regarded the electrons as ‘the fruit’, scattered throughout a solid sphere of positive electrification, ‘the pudding’. Rutherford did not believe this scattering was multiple, and so once again he had to quantify the science to undo mistaken interpretations of others. Geiger was given the task of measuring the relative numbers of alpha particles scattered as a function of angle over the few degrees that Rutherford had measured photographically at McGill. Photography could not however, register single particles. Nor was the Rutherford–Geiger detector suitable for ‘quickly’ measuring scattered particles. However, the detector had, in part, been developed to determine whether or not the discovery by Crookes in 1903 of the ‘spinthariscope’ did register one flash of light for every alpha particle which struck a fluorescing (scintillating) screen. Geiger used monochromatic alpha particles in a vacuum tube to impinge on a metal foil and then on to a scintillation plate forming the end of the tube (Figure 3). A low power microscope, looking at about 1mm2 of the plate allowed the alphas to be counted. It was tiring work, waiting half an hour for the eye to adapt to the dark and then staring at the screen, unblinking, for a minute before resting the eye. It is said that Rutherford often cursed and left the counting to the younger Geiger. Another of Geiger’s duties was to train students in radioactivity techniques. It was Rutherford’s policy to involve undergraduates in a number of simple research projects, so Geiger reported to Rutherford that a young Manchurian undergraduate was ready for an investigation. So Rutherford set Ernest Marsden the task to see if he could observe alpha particles reflected from metal surfaces. This seemed unlikely, but beta particles did reflect. Marsden used the same detecting system as Geiger, but had the alpha source on the same side of the metal as the
diversity: celebratingRutherford
Figure 2: The Rutherford-Geiger detector. An alpha particle entering the tube caused a short pulse of electricity to flow between the wire and tube.
Scattering At this time a number of laboratories were studying the scattering of beta particles from atoms. The Cavendish Laboratory claimed that the large scattering angles for betas were due to many consecutive small angle scatterings inside Thomson’s ‘plum pudding’ model of the atom.
Figure 3: Geiger’s apparatus for determining the number of alphas (from A) scattered by a thin film (E) onto a scintillation screen (S). New Zealand Association of Science Educators
5
NZ
science teacher
diversity: celebratingRutherford
128
Figure 4: Marsden’s variation to determine if alphas (from A) were backscattered from a metal plate (R) to a scintillation screen (S). fluorescing screen, with a lead shield preventing alphas going directly to the screen (Figure 4). When Marsden reported that he saw about one in 10,000 alphas scattered at large angles, Rutherford (he later recalled) was astonished. It was as if a 15-inch naval shell had been fired at a piece of tissue paper and then bounced back. Geiger and Marsden published their measurements in July of 1909. Characteristically, Rutherford’s name was not listed as an author. As William Kaye, his laboratory steward, stated in a memoir many years later, Rutherford always gave full credit to his helpers.
The nucleus unveiled While Ernest Marsden concentrated on his exams his work was left fallow. Geiger continued obtaining more accurate statistics for alpha scattering from different materials and thickness of foils. It is recorded that one day Rutherford went into Geiger’s room to announce that he knew what the atom looked like. And in January 1911 Rutherford wrote to Arthur Eve in Canada: “Among other things I have been interesting myself in devising a new atom to explain some of the scattering results. It looks promising and we are now comparing the theory with experiments.” On 7 March 1911, Rutherford presented his idea at the Manchester Literary and Philosophical Society. He reported that Geiger’s experimental tests confirmed that the alpha rays scattered through large angles varied in angle according to his theory of a nuclear atom, in which almost all the mass of the atom was in a nucleus only a thousandth the diameter of an atom. If all the electrons in the atoms of the reader’s body were compressed into the nucleus, the reader would be the size of a grain of sand. A reporter present at the meeting wrote that Rutherford’s work “…involved a penetration of the atomic structure, and might be expected to throw some light thereon,” before concluding that “…we were on the threshold of an enquiry which might lead to a more definite knowledge of atomic structure.” Rutherford’s talk was published in the Manchester Literary and Philosophical Society’s Proceedings. It was also published in the May 1911 issue of the Philosophical Magazine in which Rutherford acknowledged Nagaoka’s mathematical consideration of a ‘Saturnian’ disc model of the atom. This model followed on from earlier work 6
New Zealand Association of Science Educators
by others, but he noted that it made no difference to the scattering if the atom was a disc rather than a sphere. Surprisingly, the nuclear atom created no significant scientific or public interest. Three nights later, Rutherford addressed the Society of Industrial Chemists on ‘Radium’ without mentioning the nuclear atom. Three weeks later, when addressing the Institution of Electrical Engineers on ‘The properties of alpha rays of radio-active matter’, he did mention that “he hoped very soon to form some reasonable view of the constitution of the atom itself.” Sir William Ramsay, in his Presidential address at the 1911 Annual General Meeting of the British Association for the Advancement of Science, did not mention the nuclear atom. Ramsay concentrated on his own discoveries, causing Arthur Schuster, who had stood down from the Physics Chair at Manchester on condition that it was offered to Rutherford, to write a letter to the editor of the Manchester Guardian pointing out which of those were actually Rutherford’s discoveries. Rutherford’s Nobel Prize in Chemistry of 1908 was too recent for physicists to nominate him again. It was to be 1922 before he was next nominated, unsuccessfully. To date, there have been 27 Nobel Prizes awarded for the discovery of, or theories linking, subatomic particles, but there was never one for the nuclear atom. However, there was a related one. At the end of 1911, Rutherford was the guest of honour at the Cavendish Annual Dinner, at which he was, not surprisingly, in fine form. The chairman, in introducing him, stated that Rutherford had another distinction: of all the young physicists who had worked at the Cavendish, none could match him in swearing at apparatus. It is recorded that Rutherford’s jovial laugh boomed around the room. A young Dane, visiting the Cavendish for a year to continue his work on electrons in metals, took an immense liking to the hearty New Zealander. He resolved to shift to Manchester and spend the rest of his year working with Rutherford. And so it was that Niels Bohr received the 1922 Nobel Prize for Physics for “his services in the investigation of the structure of atoms and of the radiation emanating from them.” Bohr had placed the electrons in stable orbits around Rutherford’s nuclear atom. Curiously, Rutherford’s nuclear atom has, like his other fundamental discoveries, attained that greatest of accolades ‘scientific obliteration’, whereby a scientist’s work is so well known and taken for granted that no one now sees a need to cite it. Not bad for a young fellow who failed to get a school-teaching job in New Zealand. For further information see John’s book “Rutherford Scientist Supreme” and www.rutherford.org.nz or contact: john.campbell@canterbury.ac.nz
Nobel Prize Centennial: Mme Marie Curie Awarded for the discovery of the elements polonium and radium The story of the life of Marie Curie is beautifully told by Susan Marie Frontczak, and excerpts can be found at: http://pubs.acs.org/cen/science/89/8921sci2.html. This is a great way to introduce your students to both the history of science and aspects of the nature of science.
New Zealand has one of the richest natural histories on Earth, and is potentially poised to resolve a centuries-old debate in ecology, as Dr K.C. Burns, School of Biological Sciences, Victoria University of Wellington explains: Alpine parrots, invertebrate mice and the world’s most primitive reptiles and frogs occur only in Aotearoa. Although much of our unique natural history has become extinct since the arrival of humans approximately 750 years ago, thanks in part to the dedicated efforts of conservation programmes, the tide seems to be turning on large-scale extinctions. Large-scale eradication programmes on offshore islands, ongoing mammal control on mainland islands and predator-proof fences are beginning to pay conservation dividends. This has led New Zealand to becoming a world leader in combating invasive species. And other countries, such as the United States and Canada, routinely look to us for help with their conservation problems. Yet despite these achievements, a far more complicated problem lies bubbling below the surface of conservation education, action and success. It is concerning that we are still mostly ignorant of how New Zealand ecosystems operate in isolation. This is, in part, because understanding the complexity of New Zealand’s natural history is exceedingly challenging. Yet we are not alone, and we share our ignorance of ‘pure ecology’ with most of the world. For example, mankind has an excellent understanding of objects millions of light years away, yet we know so little about why some of our ecosystem conservation efforts fail.
Clements and Gleason The roots of the modern scientific discipline of ‘pure’ ecology can be traced back to two scientists that worked in eastern North America in the early 20th century. Frederic Clements and Henry Gleason were united in their interest of plant communities, yet they were deeply divided over how ecological communities are put together. Clements argued that forests are assembled deterministically – competition and predation consistently produced predictable patterns in plant succession. Remarkably, Gleason came to the opposite conclusion, even though he worked on the same organisms in approximately the same place and time as Clements. Gleason argued that plant communities are assembled by chance from species that just happened to end up in the same spot as a result of seed dispersal. Today, most students of ecology are raised on a diet of niches and adaptations. Following in Darwin’s footsteps, we are taught that ecological communities are shaped by predictable, deterministic processes. More specifically, competition and predation weave co-occurring species together into a delicately-woven tapestry of coexistence. Although we understand evolution from a scientific perspective, there is actually very little evidence that ecosystems are consistently assembled from predictable, deterministic processes. In fact, ecologists are deeply divided over the issue. A century later, while the names of the scientists have changed, new terms have been coined to describe how
NZ
ecological communities might be structured, and both paradigms have been expanded to include animals. However, the argument between the relative importance of chance and determinism remains wholly unresolved.
Is there a law of ecology? Most pure ecologists would admit that there is more evidence for Gleason’s ideas – that ecosystems are structured more or less randomly – than what is commonly taught in classrooms. Don’t get me wrong, there is good evidence for the importance of deterministic processes such as competition and predation, but more often than not, simple stochastic models can reproduce the basic structural properties of ecosystems. The ‘species-area effect’ is widely considered to be the only true ‘law’ in ecology – species richness increases with sampling area across a wide range of spatial scales. But no one really knows why. Deterministic processes might be important. For example, bigger sampling areas can support bigger populations, which may be less susceptible to becoming extinct at the hands of competitors and predators. On the other hand, simple computer simulations that randomise the distribution of individuals through space can also generate the species-area effect. As a result, if they were alive today, both Clements and Gleason would likely claim that ecology’s most repeatable pattern is generated from the processes encapsulated by their respective paradigms.
128
biodiversity:ecologyandeducation
beyond poisoning possums: the science of ecology
science teacher
Future of ecology Clements and Gleason both conducted their research at a time when their respective scientific disciplines were ‘stuck’, and ecology is undoubtedly still ‘stuck’. So where does this leave the science of ecology? On the surface, things would seem to look pretty bleak. But I would argue the opposite. I am hopeful that we are on the cusp of breakthrough that will provide the road map to help us navigate through this sea of confusion. Like physicists living just before Newton and his laws of motion, the science of ecology is primed for a revolution, and there is no better laboratory than New Zealand to facilitate its development. For now New Zealand ecologists are comforted by our conservation achievements. But the more difficult problems – those that rely on a thorough understanding of the science of ecology – lay ahead. I would argue that a better understanding of ‘pure’ ecology is important in its own right, as are other scientific disciplines with no obvious practical applications. However, an understanding of how New Zealand ecosystems operate in isolation does have practical applications, and these applications are likely to become more and more important through time. For example, not all translocations to predator-free islands are successful, and it’s often difficult to know why. When translocated populations fail, what’s the reason? Competition? Predation? Or stochastic effects? Ecologists have been asking these questions for over a century, and the answers hinge on a better understanding of pure ecology. For further information contact kevin.burns@vuw.ac.nz New Zealand Association of Science Educators
7
NZ
science teacher
biodiversity:ecologyandeducation
128
Ecology at a crossroads? What are the (ecology) educational implications of Kevin Burns’ article entitled: Beyond Poisoning Possums: The Science of Ecology (found on the previous page in this issue)? Rex Bartholomew from the School of Education Policy and Implementation at Victoria University of Wellington, explains: Ecology and ecology education are not the same thing. When I began teaching in the 1970s Biological Science was the huge new textbook that introduced ecology to the school curriculum for the first time. The picture it presented was of a body of settled facts, and not much seems to have changed in our school textbooks since its publication. In his article ‘Beyond Poisoning Possums...’, Kevin Burns acknowledges the role New Zealand biology teachers have played in raising awareness of the uniqueness, and sad demise, of so much of our native flora and fauna. He goes on to point out that while recent NZ conservation technologies have improved the status of many of our endangered species, there is a more disturbing matter that the science education community has yet to fully grapple with. This is that fundamental ecological processes underpinning all biodiversity conservation, and sustainability programmes, are still being debated in the scientific community. Ecology is not as ‘settled’ as our textbooks suggest. I have been pondering the implications of the Burns’ article: how do we present the science of ecology, and how best can we present ecology as an active science? In recent years have we become complacent, ‘dumbing down’ the science of ecology? Have we limited ecology to superficial learning of traditional concepts – food chains, ecological niches, adaptations, zonation or successional patterns – in isolation from current scientific reality? Are our students’ field experiences disconnected from the theories that underpin them? I wonder how well we prepare our students for a contemporary understanding of ecological concepts and debates; and whether the curriculum or NCEA encourage this? The Burns’ article raises the issue of the long-standing debate regarding mechanisms driving the evolution and structure of ecological communities. I suspect the idea that ecology deals with complex interacting systems – systems that we are only beginning to understand – is not often discussed in class even at senior levels.
What is the scientific nature of ecology? For many years curricula, national assessments, and teaching resources have provided students with Clements’ (1916) view of directional, competitive, processes driving succession and ultimately producing stable ecosystems. Yet, as Burns points out, this view was being challenged almost immediately by ideas raised by Clements’ contemporary Gleason (1926). Clements’ position was that changes in ecological communities after disturbance are deterministic, that they follow a predictable path toward a known stable climax community; they are also autogenic, which means that early colonising plants modify their own environment rendering it suitable for new species to invade, and eventually out compete and replace them. In contrast, Gleason contended that community assemblages were more the result of chance aggregations of plants resulting from stochastic mechanisms, such as chance seed dispersal. 8
New Zealand Association of Science Educators
By 1973, Drury and Nisbert proposed a more complex mechanism where a range of chance factors – such as existing vegetation (initial floristic composition), the range of viable seed in the soil (seed-bank), dispersal strategies of different species, and differences in germination and growth rates – all acted in concert as drivers of succession. Burns reminds us that the mechanisms driving ecosystem species’ composition and distribution are still being elegantly debated in such distinguished scientific literature as Nature (Whitfield, 2002). There is currently a debate around the suggestion that: “… you don't need to invoke adaptation to explain biodiversity” (ibid. p.480), or by extension competition between individuals with different ecological niches. Ecologists Bell and Hubbell have proposed a ‘neutral model’ where it is possible to recreate patterns of biodiversity in ecosystems using only “…the birth and death of individuals, random dispersal, the overall population of individuals in the ecosystem, the total number of species and the origin of new species” (ibid. p480). Little was done to incorporate the concept of scientific debate about succession into ecology teaching in the 1970s, and that situation has not changed much in the intervening forty years. I wonder how many of our students are aware that there is, even now, debate about such fundamental concepts and theories in ecology?
NZC and the nature of (ecological) science That such fundamental theories are still being debated by ecologists, despite the practical success of our conservation efforts, is intriguing. At a time when the curriculum is nudging us to consider the ‘nature of science’ (Ministry of Education, 2007) alongside consideration of the tenets of our subject, how should we link ecological theories and principles to practical applications or research? I suspect underlying ecological theories and principles are usually taught as accepted fact, seldom challenged in class by students or teachers, and usually devoid of their evidential origins. The Level 7 and 8 curriculum statement requires that we provide opportunities for students to “understand that scientists have an obligation to connect their new ideas to current and historical knowledge and to present their findings for peer review and debate” (ibid.). It is my belief that the scientific debate, as described above, presents students with an ideal opportunity to contemplate such aspects of the nature of ecological science, and that theories depend on interpreted evidence. I am not suggesting that we deliberately sow doubt in the minds of students going off to sit examinations, but wonder about the educational consequences of presenting ecology as a science that has the core processes already fully understood? Supported by Bull et al (2010), Gluckman, in his 2011 report to the Prime Minister on science education in New Zealand, suggests we (science teachers) approach teaching with a dual purpose: “It is important to note that science education is not just for those who see their careers involving science but is an essential component of core knowledge that every member of our society requires.” This social imperative, together with the increased curriculum focus on the nature of science, may provide an opportunity to reconsider how we present the science of ecology.
Developing an NCEA opportunity?
So what should we expect an ecologically literate citizen to understand about the substantive concepts and investigative processes of ecology? I feel we need to do more to look at the nature of the evidence that underpins any theory, and how it can be interpreted in quite different ways – as exemplified by the debate between Clements and Gleason. This also raises the issue of how we link student practical investigation with theory. The design of basic scientific ecological investigations, especially those in the field such as using transects or quadrats, is well covered by senior biology teachers, and adequately supported by common texts. However, I suspect methods used to account for the more complex nature of fieldwork are not discussed as deeply. Too often I hear of biology teachers struggling to mount extended ecological field trips; which provide ideal opportunities for such discussions. How ecologists deal with replicate design, account for seasonal (even daily) variation in climate and weather when recording abiotic factors, deal with random site selection in difficult terrain or the effects of microclimate, may not be well contemplated by our students. I feel students should be learning about these issues in ecological research when considering concepts of scientific evidence (Gott, Duggan and Roberts, 2003) as part of the nature of science. It concerns me that students may not see the connection between their investigations and the substantive theories they are learning. For example, the widely held concepts of ecological niche and the competitive exclusion principle were largely based on controlled laboratory investigations of simple ecological systems such as paramecia communities on a Petri dish. Difficulties arise when we apply these principles to more complex natural communities. By encouraging students to reflect on the nature of the evidence that underpins the theories they learn, I suggest, a more scientific view of ecology. Similarly, I suggest we need to be more explicit about the way in which our current understanding of ecological theory influences our interpretation of evidence we gather from field and laboratory investigations. Are our students aware of how much they are influenced by the theory they learn when explaining mechanisms for the community or population patterns they investigate?
At a time when NCEA achievement standards are being aligned with the curriculum, I am hopeful that new ecological standards such as Biology 2.6 (Investigate a pattern in an ecological community) will encourage more than a superficial look at such patterns. Given the need for an informed public deciding on issues of sustainability, global warming, and conservation of biodiversity, it is disappointing that there is no NZQA assessment specific to ecological theories at either Year 12 or 13. However, since the ecology achievement standards are internally assessed, it is my hope that ecological principles may be expected to underpin Biology 2.3 (Demonstrate understanding of adaptation of plants or animals to their way of life), 3.3 (Demonstrate understanding of the responses of plants and animals to their external environment), and 3.5 (Demonstrate understanding of evolutionary processes leading to speciation). I suggest we are at a junction where curriculum change, NCEA alignment, and public concerns provide an opportunity to encourage in-depth study of contemporary ecological theory and research. Whether this happens will depend on how we biology teachers understand and value conversations with our students about the nature of ecological science. For further information contact: rex.bartholomew@vuw.ac.nz
NZ
science teacher 128
biodiversity:ecologyandeducation
How do you develop ecologically literate citizens?
References Bull, A., Gilbert, J., Barwick, H., Hipkins, R., & Baker, R. (2010). Inspired by science. A paper commissioned by the Royal Society and the Prime Minister’s Chief Science Advisor. Wellington: New Zealand Council for Educational Research. Burns, K. C. (2011). Beyond poisoning possums: The Science of Ecology. New Zealand Science Teacher, 128, p.10. Clements, F. E. (1916). Preface to plant succession: An analysis of the development of vegetation. Washington, D.C.: Carnegie Institution of Washington, Publication No. 242, pp.1-7. Gleason, H. A. (1926). The individualistic concept of the plant association. Bulletin of the Torrey Botanical Club, Vol. 53, No. 1 (Jan., 1926), pp.7-26. Published by: Torrey Botanical Society Article. Greenwood, T., Shepherd, L., & Allan, R. (2007). Year12 Biology 2007: Student resource and activity manual. BIOZONE international Ltd. Drury, W. H., & Nisbert, I.C.T. (1973). Succession. Journal of the Arnold Arboretum, Vol. 54, No. 3., 331-368. Gluckman, P. (2011). Looking ahead: Science education for the twenty-first century. A report from the Prime Minister’s Chief Science Advisor. Wellington, New Zealand.: Office of the Prime Minister’s Science Advisory Committee. Gott, R., Duggan, S., & Roberts, R. (2003). Concepts of Evidence. University of Durham, retrieved from: http://www.dur.ac.uk / richard.gott / Evidence/ cofev. htm Ministry of Education. (2007). The New Zealand Curriculum. Wellington. Learning Media Limited. Whitfield, J. (2002). Neutrality versus the niche. Nature, 417, 480-1.
continued from page 17
References Anon. (2011). Sanctuary Marlborough Sauvignon Blanc receives carbon life cycle certification. 9 Jun 2011. http://www.foodworks.co.nz/3-10-760/ news/Sanctuary-Marlborough-Sauvignon-Blanc-receives-carbon-life-cyclecertification Boutin, C., Baril, A., & Martin, P.A. (2008). Plant diversity in crop fields and woody hedgerows of organic and conventional farms in contrasting landscapes. Agriculture Ecosystems & Environment, 123, 185-193. Convention on Biological Diversity (CBD) (2010). Secretariat of the Convention on Biological Diversity. Global Biodiversity Outlook 3. Montreal. 94 pp. Clothier, B.E., S. Green and M. Deurer. 2010 Reducing the production footprints of horticultural products – (1) Water footprint. Proceedings of the Workshop “Farming’s Future: Minimising footprints and maximising margins. Fertiliser & Lime Research Centre, Massey University, 10-11 February 2010. Costanza, R., dArge, R., deGroot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., Oneill, R.V., Paruelo, J., Raskin, R.G., Sutton, P., & vandenBelt, M. (1997). The value of the world's ecosystem services and natural capital. Nature, 387, 253-260. Deurer, M., Clothier, B.E., Pickering, A., & Cleland, D.J. (2008). Carbon footprinting for the kiwifruit supply chain – draft report on reduction opportunities. Report prepared for New Zealand Ministry of Agriculture and Forestry, August 2008. 29 pp. Ehrlich, P.R. & Ehrlich, A. (1981). Extinction: the causes and consequences of the disappearance of species. Random House. 305 pp. Hole, D.G., Perkins, A.J., Wilson, J.D., Alexander, I.H., Grice, I.V. & Evans, A.D. (2005). Does organic farming benefit biodiversity? Biological Conservation, 122, 113-130. Jeanneret, P., Baumgartner, D.U., Freiermuth Knuchel, R., & Gaillard, G. (2008). Integration of biodiversity as impact category for LCA in agriculture (SALCA-Biodiversity). In: 6th International Conference on LCA in the Agri-Food
Sector, Zurich, November 12–14, 2008 Zurich. Louette, G., Maes, D., Alkemade, J.R.M., Boitani, L., de Knegt, B., Eggers, J., Falcucci, A., Framstad, E., Hagemeijer, W., Hennekens, S.M., Maiorano, L., Nagy, S., Serradilla, A.N., Ozinga, W.A., Schaminee, J.H.J., Tsiaousi, V., van Tol, S., & Delbaere, B. (2010). BioScore - Cost-effective assessment of policy impact on biodiversity using species sensitivity scores. Journal of Nature Conservation, 18, 142-148. Moller, H., MacLeod, C.J., Haggerty, J., Rosin, C., Blackwell, G., Perley, C., Meadows, S., Weller, F. & Gradwohl, M. (2008). Intensification of New Zealand agriculture: implications for biodiversity. New Zealand Journal of Agricultural Research, 51, 253-263. Pawson, S.M. & Emberson, R.M. (2000). The conservation status of invertebrates in Canterbury. Department of Conservation, Wellington, New Zealand, 16 pp. Schnitzler, F-R., Burgess, E.P.J., Kean, A.M., Philip, B.A., Barraclough, E.I., Malone, L.A., & Walter, C. (2010). No unintended impacts of transgenic pine (Pinus radiata) trees on above ground invertebrate communities. Environmental Entomology, 39, 1359- 1368. The Economics of Ecosystems and Biodiversity (TEEB) (2009). TEEB - The Economics of Ecosystems and Biodiversity for National and International Policy Makers – Summary: Responding to the Value of Nature. Todd, J.H., Ramankutty, P., Barraclough, E.I., & Malone, L.A. (2008). A screening method for prioritizing non-target invertebrates for improved biosafety testing of transgenic crops. Environmental Biosafety Research, 7, 35-56. Todd, J.H., Malone, L.A., McArdle, B.H., Benge, J., Poulton, J., Thorpe, S., & Beggs, J.R. (2011). Invertebrate community richness in New Zealand kiwifruit orchards under organic or integrated pest management. Agriculture, Ecosystems and Environment. in press DOI: 10.1016/j.agee.2011.02.2007 UNEP. (2010). UNEP news release, 29 April 2010. World governments fail to deliver on 2010 biodiversity target. http://www.unep.org/Documents.Multilingual/ Default.asp?DocumentID=620&ArticleID=6547&l=en&t=long
New Zealand Association of Science Educators
9
NZ
science teacher
biodiversity:biofilms
128
biofilms: microbial life on surfaces Biofilms are found on living tissues, teeth, indwelling medical devices, water supply systems, oil pipelines, food contact surfaces, to name a few; and are populated with microorganisms which gain three key benefits from them, as Jon Palmer, Institute of Food and Human Nutrition, Massey University explains: For many years, microbiologists have studied microorganisms in the planktonic state or freely suspended in a liquid phase. However, in the last 30 years a transformation has taken place in microbiology. Today it is believed 95–99% of all microorganisms, in natural environments, live attached to surfaces within a structure termed a biofilm.
What are biofilms? The most common definition describes biofilms as dense aggregates of microbial cells embedded in extracellular polymeric matrix composed of polysaccharide, DNA and protein attached to a surface. The life cycle of a biofilm is characterised by the attachment of planktonic cells to a surface, followed by cell division and production of extracellular polymeric matrix to adhere cells irreversibly to a surface. Further cell division and biofilm expansion results in the formation of a mature biofilm structure as outlined in Figure 1. Individual cells or groups of cells can detach from the biofilm structure to contaminate the bulk fluid passing by or reattach further along. The physical structure of the biofilm can range from a bacterial monolayer (1–5 micrometers) to several millimetres or more in thickness. Figure 1 represents a classical biofilm structure; however, the structure can vary depending upon the type of nutrients present and their concentration, environmental conditions such as pH, temperature, oxygen levels, mechanical factors such as shear forces and the composition of the surface and types of microorganisms present. Biofilms form on a wide variety of surfaces including living tissues, teeth, indwelling medical devices, water supply systems, oil pipelines, food contact surfaces, as well as an array of natural aquatic systems. In most natural environments a biofilm is not the domain of one species alone, but is invariably a multispecies community; several authors have even gone as far as describing a biofilm as a multicultural community or ‘a city of microbes’ much like our own cities as an analogy, (Nikolaev and Plakunov, 2007).
Figure 1: Typical biofilm structure, outlining the different stages of biofilm development. 10
New Zealand Association of Science Educators
Within this biofilm structure, microorganisms are not randomly distributed but are organised to best meet the nutritional and environmental conditions of each species present within the biofilm. An example of the importance of the spatial distribution of bacteria within a biofilm is illustrated by microbial communities found within dental plaque or oral biofilms. During oral biofilm formation, certain oral bacteria are early colonisers that directly adhere to teeth or periodontal tissue; this is followed by late colonisers that adhere to the early colonisers. Within an established oral biofilm specific bacterial species are often found located together, which confer adherence or growth advantages to each species within the biofilm structure. Which bacterial species dominates the biofilm is generally a function of the relative growth rates of each species present. However, a shift in the nutrient profile or environmental conditions could allow different species to dominate or co-exist within a biofilm. One example of this was reported by Raskin et al. (1995) where the addition of sulphate to an anaerobic biofilm resulted in a rapid increase in sulphate reducing bacteria within the biofilm.
What benefits do microorganisms gain from living attached to a surface? Well, according to Darwin’s theory of evolution, any action that causes an increase in the population will help with species’ proliferation. Therefore, we need to ask the question how does biofilm formation help in bacterial proliferation? Especially when bacterial cells growing within a biofilm generally have a reduced rate of growth compared with bacterial cells in a broth culture growing planktonically. Consequently, there must be some advantages for the bacteria imparted by the biofilm mode of growth.
Advantage 1: Defence The first advantage gained by bacteria growing within a biofilm structure is defence. Defence from shear forces produced by cleaning fluids in food processing industries, or blood flow during an infection. Bacteria within biofilms demonstrate greater resistance to antibiotics and cleaning chemicals than their planktonic counterparts. Medical biofilms are also more resistant to phagocytosis as well as antibiotics. This increased resistance to phagocytosis and antibiotics is considered one possible reason infections can persist inside a host for many years resulting in countless chronic infections over time e.g. Cystic fibrosis. In environmental ecosystems, bacterial cells within a biofilm are more resistant to grazing from protozoa and snails. This reduced vulnerability of biofilms to chemicals and predators is not completely understood, but likely to depend on two important characteristics of biofilms: extracellular polymeric matrix, and heterogeneity of the bacterial cells within the biofilm. After the initial contact with the surface, bacteria start producing fibres as depicted in Figure 2. These fibres become thicker with time and develop into the biofilm extracellular polymeric matrix. The important role of extracellular polymeric matrix, composed of polysaccharides, DNA and protein in biofilm structure is
NZ
science teacher 128
biodiversity:biofilms
Fibre production to anchor the bacterial cell to the surface
Figure 2: Fibre production after cell attachment. illustrated by the noticeable increase in alginate production, a precursor for polysaccharide production during the early stages of biofilm formation in Pseudomonas aeruginosa (Hentzer et al. 2001). Some evidence suggests extracellular polymeric matrix may limit the ability of antimicrobial chemicals to penetrate deep into the biofilm structure, providing protection for bacterial cells deep within the biofilm. However, more recently it has been established that bacterial cells growing within a biofilm demonstrate a high level of heterogeneity, with some cells exhibiting a high metabolic rate, while other cells are effectively metabolically dormant. The differences in metabolic rates between individual cells within a biofilm could be due to variation in diffusion, pH, oxygen levels and nutrient concentrations. Nevertheless, virtually all antimicrobial chemicals are far more effective against actively growing cells. Common antibiotics such as Penicillin are only effective against growing cells and have little to no effect on metabolically dormant cells that can exist within biofilms.
Advantage 2: Favourable niche The second advantage may pertain to the need for bacteria to remain in a favourable niche. In environmental ecosystems where availability of nutrients can be low, nutrient concentration tends to be highest near the surface, encouraging bacteria to attach to surfaces and take advantage of the nutrient concentration gradient. In human and animal bodies many parts are nutrient rich and environmentally stable, in terms of water availability, pH and oxygen concentration. This tends to make the body an appealing place for many bacteria to live, and can be a driving force for bacteria to remain fixed in place by forming a biofilm. Pathogenic and commensal bacteria have evolved a number of strategies to ensure continual survival on their host organism. One key strategy is the range of surface proteins produced by bacteria that permit cells to attach to a variety of host extracellular proteins such as fibronectin, fibrinogen, and elastin. Staphylococcus aureus is particularly notable for the abundance of MSCRAMMs (microbial surface component recognising adhesive matrix molecules) it produces that allow it to attach to a wide range of tissues within the host organism, such as the mouth, throat, nose, skin and hair follicles. On the other hand, bacteria whose main domain is the gut, such as E.coli produce surface proteins designed to allow the bacterial cell to preferentially attach to the gut lining of warm-blooded animals.
Advantage 3: Biofilm community The third advantage relates to the community created within a biofilm structure. Some of the benefits bacteria gain from living within this community include less exposure to antimicrobial chemicals and variations in pH for most of the population of the biofilm. One evolutionary hypothesis is that biofilms should be regarded as an early version of multicellular organism. Evidence to support this theory lies in the observation that bacteria secrete substances referred to as auto-inducing signals, which can influence gene expression within a bacterial population and may be the main way that bacteria communicate with each other. However, the fundamental difference between a liver cell or brain cell from an animal and bacterial cell is that a liver cell or brain cell has to undergo a process of differentiation and at present, cannot be converted back or changed to another cell type. Bacterial cells do not undergo a differentiation process and cells removed from a biofilm quickly change gene expression to suit the needs of the bacterial cellâ&#x20AC;&#x2122;s new environment, whether that form is in the biofilm or planktonic mode of growth. The biofilm is also an ideal environment for the exchange of genetic information from cell to cell, in what is termed horizontal gene transfer. The main mechanism of this genetic transfer is either plasmid DNA or phage DNA. This increase in gene transfer within biofilm cells compared with planktonic cells is thought to play an important role in the exchange of antibiotic resistance genes, especially in biofilms inhabiting the gut of warm-blooded animals.
In conclusion... It is obvious that bacteria gain a number of benefits from growing within a biofilm structure. However, the question remains: do the bacteria communicate and co-ordinate within biofilms for the benefit of the biofilm as a whole, or are they simply reacting to their environment independent of one another, has yet to be answered by microbiologists. For further information contact: J.S.Palmer@massey.ac.nz
References Hentzer, M., Teitzel, G.M., Balzer G.J., Heydorn, A., Molin, S., Givskov, M., & Parsek, R. (2001). Alginate overproduction affects Psesdomonas aeruginosa biofilm structure and function. Journal of Bacteriology, 183, 5395-5401. Nikolaev, Y.A., & Plakunov V.K. (2007). Biofilm-â&#x20AC;&#x153;City of Microbesâ&#x20AC;? or an analogue of multicellular organisms? Microbiology, 76, 149-163. Raskin, L., Amann, R.I., Pulsen, L.K., Rittmann, B.E., & Stahl, D.A. (1995). Use of Ribosomal RNA-based molecular probes for characterization of complex microbial communities in anaerobic biofilms. Water Science and Technology, 31, 261-272.
New Zealand Association of Science Educators
11
NZ
science teacher
biodiversity:thermophillicbacteria
128
life in extremely hot environments Thermophilic bacteria live in extremely hot environments, and studying them has led to a greater understanding of life at more normal conditions, as Hugh Morgan, of the Thermophile Research Unit at the University of Waikato, explains: Thermal environment Hot springs have long held a natural fascination due to their sometimes spectacular colours, their association with geysers and sulphurous odours and frequent claims of their ability to cure ailments and illnesses. Geothermal activity, of which hot springs are one of the more prominent features, is commonly associated with tectonic plate boundaries. New Zealand straddles one of these boundaries where the Australian tectonic plate is overriding the Pacific plate, producing a fault line that runs most of the length of the country. Hot springs along the line of this fault can be broadly divided into two groups. The most common type is that which contains alkaline chloride water. This reflects a mixing of groundwater (derived largely from rainfall) with some tectonic water from the Earth’s crust. These springs typically have a neutral to slightly alkaline pH, are clear with little suspended sediment, and often have a high silica content which might precipitate out on cooling – the silica sinters of the Pink and White Terraces and the area surrounding Champagne Pool at Waiotapu are examples of silica deposition from such pools. The second group of pools are the acidic, often sulphurous pools. Here the water is largely tectonic, initially containing high concentrations of sulphur or sulphides. When this water nears the surface and mixes with oxygen and bacteria in the spring the sulphur compounds are oxidised to sulphuric acid which lowers the pH. The acid produced can release clays and minerals from the surrounding soil which frequently makes the water turbid – mud pools are really an extreme example of these acid pools, where the clays and minerals released form a thick suspension. Figure 1 is an illustration of the pH distribution of 158 hot pools with temperatures above 65°C in the Taupo Volcanic Zone. While pH is a major property of hot pools, pools with the same pH and temperature can still differ considerably with respect to other features e.g. chemical composition, flow
rate, sulphur and sulphide content, organic material in the form of twigs or leaves falling into the pool. What this means is that hot pools exhibit considerable habitat diversity, and where we find habitat diversity then evolution can produce biological diversity. But the habitat must be relatively constant for an extended time period to allow evolutionary adaptation to the environment. This variation in the chemical and physical characteristics of a pool is reflected in the microbial diversity, and is not always predictable. Figure 2 illustrates the differences in thermophile diversity of two pools by the simple method of inserting clean microscope slides in the pool water for a period of time, and then observing slide colonisation under a phase contrast microscope. In Fig. 2(a) rapid colonisation of a mixed culture from a pool in Kuirau Park, Rotorua (pH 8.1, temp 95°C) has occurred after only 48hrs: after a few days the microbes are so numerous that microscopy cannot differentiate the layers of cells. In contrast, Fig. 2(b) illustrates the lack of microbes in Champagne Pool, Waiotapu (pH 5.5, temp 74°C). Even after several weeks’ immersion the slide had few colonising microbes and no evidence of growth was observed – this environment has a low bacterial biomass and biodiversity, even though the organic carbon content (the substrate on which bacteria grow) is greater than that of the Rotorua pool. Thus, even though the Kuirau Park pool might appear more extreme, this is not reflected in microbial content.
(a)
(b)
Figure 1: The pH distribution of 158 pools with temperature above 65°C in the Taupo-Rotorua thermal district. 12
New Zealand Association of Science Educators
Figure 2: Colonisation of glass microscope slides immersed in hot pools. (a) immersed in a pool at 95°C, pH 8.1 in Kuirau Park, Rotorua for 48hrs. (b) immersed in Champagne Pool, Waiotapu (temp 74°C, pH 5.5) for 9 days. Images viewed under phase contrast x1000.
Thermophiles and hyperthermophiles As the name suggests, thermophiles are heat loving microbes. Most bacteria can grow over an approx. 30–35°C spread of temperature between their minimum and maximum temperatures for growth1. The optimum temperature for growth (the temperature at which they grow best) always lies closer to the maximum. To categorise growth in response to temperature it is usual to compare the optimum growth temperature of different species. Generally, species with an optimum growth temperature above 65°C are called thermophiles, those species with an optimum above 85°C are frequently referred to as hyperthermophiles. The temperature of 65°C is convenient since above this temperature no eukaryotic life (in the form of fungi, algae or protozoa) exists, it is an entirely microbial world, much like all of Earth for the first 2–3 billion years of its existence (Fig. 3).
has increased from 75°C to the current 122°C; there is no certainty that this will not increase further over the next 40 years as our knowledge of these organisms expands. Practically all the known species that have temperature optima for growth above 100°C have been isolated from deep sea hydrothermal vents. These are hot springs deep in the ocean (often 2km below the surface) with water temperatures in excess of 200°C. The water does not boil and form steam because of the huge pressure exerted by sea water at these depths. This raises an interesting question: if habitats exist on Earth where the temperature is constantly above 200°C, why do no life forms exist that grow above 122°C? Is it because we have not yet managed to detect or culture them, or is there a temperature above which life cannot survive? If the latter is true, then what is it that limits life to a temperature of 122°C. As yet, biochemical studies have not demonstrated convincing reasons for this limit based on the stability of proteins, nucleic acids, membranes or metabolic co-factors. There are some other intriguing features regarding the highest temperatures for growth. All microbes with temperature optima above 100°C belong to the Archaea. The Bacteria have a more limited distribution; the bacterial species with the highest growth temperature (Aquifex pyrophilus) has a maximum temperature of 95°C. It is interesting to question why, for instance, no Bacteria grow above 95°C, no eukaryotic algae grow above 60°C (Fig. 3), while archaea encounter no problems growing at much higher temperatures? Additionally, temperature interacts with other features of the environment in limiting growth. The highest growth temperatures are always found in thermal waters at pH values close to neutral. In the low pH acid pools the highest temperature at which life has been recorded is around 80°C, and mud pools, which are often at low pH with the temperature fluctuating between ambient and boiling as the mud circulates within the pool, appear to be sterile.
NZ
science teacher 128
biodiversity:thermophillicbacteria
There are also man-made thermal environments which can be colonised by thermophiles normally found in pools. Hot water cylinders and central heating systems can be ideal habitats for the growth of thermophiles (particularly if the water is not chlorinated); the fact that you might drink this water and not suffer any infection is because thermophiles are not pathogenic – our body temperature is simply too cold for them to grow. Compost heaps are another environment where temperatures up to 75–80°C have been recorded, and not surprisingly, thermophiles are the cause of these higher temperatures and are responsible for the breakdown of organic material in the compost.
Why study thermophiles?
Figure 3: The maximum temperature for growth for different groups of microorganisms. The highest optimum temperature for each group is shown by the temperature on the bar. The black arrows indicate the optimum temperature spans for designating microbes either thermophiles or hyperthermophiles
Life at high temperatures The microbial world consists of two distinct evolutionary lineages, the Bacteria and the Archaea. There are major differences in cell organisation, structure and biochemistry between these groups. The Archaea have a profusion of species which have adapted to extreme environments, and they are the dominant group among the hyperthermophiles. There has always been an interest in the ‘Guinness Book of Records’ for the highest temperature at which life exists. Most microbiologists define life’s existence as the ability to grow i.e. replicate and divide, at a particular temperature rather than just survive for a period. By this definition the record holder is an archeal species called Methanopyrus kandleri which grows at a temperature of 122°C. However, over the last 40 years the highest temperature for growth
1. Because they are there. We have always explored our environment and extreme environments that hold the prospect of discovering extreme life forms. These extreme life forms bring a greater focus to our understanding of life at more normal conditions. Until the discovery of hyperthermophiles, cell membranes were always viewed as being composed of lipid bilayers, yet the hyperthermophiles have membranes which are lipid monolayers. The study of thermophiles has altered our understanding not only of membrane structure, but protein and enzyme thermostability, nucleic acid stabilisation and co-factor substitution. As we begin to explore other planets in our Solar System, an intriguing question is the possibility of life being present or having existed on them. While surface temperatures of our close planetary neighbours appear to be either too hot or too cold to sustain life as we know it, below the surface conditions can be quite different. In the depths of some South African gold mines temperatures of above 55°C are common, and thermophilic bacteria are abundant2. There is now evidence that well below the Earth’s surface there is a unique ecosystem composed largely of thermophiles which is long lived and is not dependent on the Sun as the energy source for life3,4. Not surprisingly, NASA has had a continuing interest in studies on extremophiles; if they exist on other planets there are concerns that they should not be unwittingly introduced to Earth on returning space flights. New Zealand Association of Science Educators
13
NZ
science teacher
biodiversity:thermophillicbacteria
128
14
Figure 4 : Universal phylogenetic tree derived from comparative rRNA gene sequences (16S rRNA for Bacteria and Archaea, 18S rRNA for Eukarya). 2. Because they might represent the earliest form of life, from which all other life evolved. The advent of DNA sequencing technologies has allowed the sequencing of many genes, and more recently complete genomes of bacteria. By comparing variation in sequences of the same gene found in many different species, it is possible to construct evolutionary trees, called phylogenies, for those genes. The gene that is most commonly used for this purpose is the 16S ribosomal gene. This gene codes for a piece of RNA which is an integral part of every ribosome. All bacteria (indeed, practically all forms of life) contain ribosomes to make their proteins, so the 16S gene is found in all species of bacteria. Figure 4 shows a phylogenetic tree for the 16S gene sequence of just a few key species of Bacteria and Archaea. The base of the tree represents the nucleotide sequence of the 16S gene of the common ancestor of all Bacteria and Archaea. This is a computer-generated sequence which is our best approximation of what the original 16S gene sequence might have been when life on Earth emerged, possibly 3.5 billion years ago. We have no way of confirming this sequence directly, since there are no molecular fossils of any life forms from that time. The tips of the branches of the tree, which contain the 16S gene sequences of the named species, represents the present, so the tree attempts to encapsulate the whole 3.5 billion years of evolution. The length of the line from the common ancestor to a named species indicates the amount of change in the genes’ sequence over this time period – long lines mean a lot of mutations (to adapt to large changes in the environment), short lines mean fewer mutations (because the environment has changed little). Interestingly, all the species with the shortest lines are thermophiles or hyperthermophiles (Aquifex, Thermodesulfobacterium, Thermotoga for Bacteria and Thermococcus, Pyrolobus, Methanopyrus for Archaea), which is interpreted as indicating the environment in which these life forms emerged was similar to that of a hot pool. So life on Earth could have begun in a hot environment, possibly in hydrothermal vents deep under the ocean, and from there as Earth cooled other environments were colonised. Not all gene trees give the same picture, and so this hypothesis on the origin of life is still being debated; whole genome sequence comparisons might provide a more conclusive answer, but for thermophiles there is evidence of substantial lateral gene transfer (the swapping of genes between species) which makes the sequence comparison difficult to interpret. 3. Because their enzymes are thermostable and may have applications in biotechnology. Enzymes are the protein catalysts of the cell. They are New Zealand Association of Science Educators
involved in all of the cell’s metabolism and are responsible for the digestion of substrates (or food) that is supplied to the cell, as well as the building of new cell material. At any one time, a cell may be producing up to 1,000 different enzymes. Some of these enzymes with desired catalytic properties have been purified and are used in industrial applications e.g. starch hydrolysis, food processing, production of diet sweeteners, tanning and leather softening, and enzyme sales represent a billion dollar industry. Enzymes produced from mesophilic or moderate temperature organisms lose their activity quite rapidly and this makes them expensive to use. Frequently, there would be advantages in running industrial processes at higher temperatures but the rapid loss of enzyme activity is a restriction. Not surprisingly, enzymes from thermophiles are viewed as an alternative, because they have evolved to be stable at high temperature. Thermophiles contain the equivalent thermostable version of all the enzymes found in mesophilic cells. Many enzymes from hyperthermophiles growing above 100°C can withstand several hours in boiling water before losing their activity. For example, the cellulase isolated from an archaeal isolated from a hot spring at 95°Cwas most active at a temperature of 109°C and retained activity for several hours, properties which might be beneficial in bioethanol production from cellulosic biomass5. Applying these enzymes to industry does not rely solely on thermostability since there are a range of other properties an enzyme must possess to meet an industrial process. A spectacular example of a thermophilic enzyme being applied to biotechnology is the DNA polymerase enzyme purified from Thermus aquaticus. This bacterium was one of the first pure cultures to be isolated from a hot pool in Yellowstone National Park, and has an optimum temperature for growth of 70°C.The DNA polymerase is commonly referred to as Taq polymerase and is used in the polymerase chain reaction (PCR). PCR is a means of amplifying single strands of DNA several million fold, so that sufficient DNA copies can be produced for further analysis e.g. sequencing, cloning. Molecular biology, forensic science, genome sequencing, epidemiology and food safety have all been revolutionised by the use of PCR and Taq polymerase. The application of Taq polymerase to biotechnology is interesting in that the thermostable enzyme did not replace a mesophilic enzyme in an existing process – PCR was possible solely because of the thermostable nature of the Taq enzyme. Future applications where the process is also built around the properties of the thermostable enzyme, rather than an existing process being adapted to use a thermostable enzyme, will likely result in greater innovation and rewards. For further information contact: hwm@waikato.ac.nz continued on page 22
As calls for sustainability in food production increase, entomologists, farmers and food marketers are showing a greater interest in understanding, preserving and utilising biodiversity in agroecosystems, as Louise Malone, Plant & Food Research, explains: Why worry about biodiversity? Quite simply, because we are losing it. The Convention on Biological Diversity’s 2010 report ‘Global Biodiversity Outlook 3’ notes that nearly a quarter of all plant species are threatened with extinction, that the abundance of vertebrate species fell by one third between 1970 and 2006, and that crop and livestock genetic diversity continues to decline. It also states that, although there has been some slowing of the loss of tropical forests and mangroves, coral reefs, wetlands and salt marshes are still in serious decline. If this loss of species and habitats does not concern you, consider how much we humans rely on biodiversity. Biodiversity underpins the functioning of ecosystems and we depend on these for food, fibre, medicines and fresh water. We rely on biodiversity to support the pollination of crops, filtration of pollutants, for protection against natural disasters, and for recreational and cultural benefits. Threats to global biodiversity were first officially recognised at the 1993 Rio Convention on Biological Diversity (CBD) and signatories to this convention, including New Zealand, made a commitment to preserve biodiversity. In 2002, the goal to ‘achieve a significant reduction in the current rate of biodiversity loss by 2010’ was set. Sadly in 2010, the International Year of Biodiversity, our collective global failure to reach this goal was acknowledged.
What about New Zealand? In 2000, New Zealand’s ‘Biodiversity Strategy’ set goals for 2020 to preserve native species and ecosystems, to manage productive landscapes sustainably, and to maintain genetic diversity of important introduced species. Because this plan was already in place, we had no specific response to the CBD’s 2002 agreement to halt species loss by 2010. However, we received good press internationally in 2010 for saving the New Zealand Black Stilt from extinction (UNEP news release, 29 April 2010). There are now 200 stilts in the wild, whereas in 1981 there were only 23. The fact that we had driven these once common birds nearly to extinction was not mentioned. In 2007, our Ministry for the Environment issued its ‘state of the environment’ report; the next is due in 2012. Selected indicators for New Zealand biodiversity were: area of native land cover, distributions of the Lesser Short-tailed Bat, kiwi, Ka¯ka¯, Ka¯kako, Yellowhead, Wrybill, and Dactylanthus (a parasitic flowering plant). Of these species, only the kiwi is likely to be found in productive environments (i.e. pine plantations).
What has this to do with agriculture? Links between agriculture and biodiversity have been made most strongly in European countries, where arable crops and agricultural landscapes predominate, and farmland is considered part of ‘Nature’. Hedgerows, field margins and the crops themselves are seen to have key roles in biodiversity maintenance. Accordingly, the
NZ
‘Streamlining European 2010 Biodiversity Indicators’ project generated measures of biodiversity that included birds, butterflies, ‘high value farmland’, nitrogen balance, area under organic farming (although this was later questioned) and area under “biodiversity supportive agri-environment” (payment) schemes. New Zealand’s situation is very different. We have extremely high levels of endemism – over 90% of species in the major insect orders are endemic, i.e. occur only in New Zealand (Pawson & Emberson, 2000)–many species are endangered, and we have relatively little knowledge of the roles (if any) of agroecosystems in preserving indigenous biodiversity. Saving large iconic species such as birds from extinction and preserving unique habitats have understandably taken precedence.
Economics enters the biodiversity picture In reviewing the state of global biodiversity in 2010, the CBD observed that in spite of conservation efforts, the pressures on biodiversity had continued to increase. This report was the first in recent times to link increasing human population and consumption by humans to biodiversity loss explicitly. It also recognised the potential power of economic instruments to drive changes in human behaviour that could help to reduce that loss (CBD 2010). Clearly, confining our biodiversity preservation efforts to government departments with environmental responsibilities only would not be sufficient to halt species’ losses. Making biodiversity a high priority for all decision making and economic sectors would be required to meet the CBD’s aims. The term ‘ecosystem services’, to describe the free provision of fresh water, crop pollination, soil quality, biological control of pests, erosion control and other benefits to agriculture from nature was first coined by Ehrlich & Ehrlich in 1981. No economic value was placed on these services and they were assumed to be in endless supply. In 1997, Constanza and colleagues attempted to place a value on these services and estimated that the ‘natural capital’ of the United States was worth US$16 to 45 trillion per year. The term ‘triple bottom line’, embracing economic, environmental and social values, became commonplace over the following decade. By 2005, concerns about climate change resulted in the Kyoto Protocol for the reduction of greenhouse gases and led to the first example of an economic market for an environmental attribute: the carbon market. At the 2007 Potsdam G8+5 meeting, The Economics of Ecosystems and Biodiversity project (TEEB) was launched. In 2009, its first report (for national and international policymakers) recommended rewarding biodiversity benefits through payments and markets via: ‘greening the supply chain’ via product certification, green public procurement, standards, labelling and voluntary actions, reforming harmful subsidies, addressing threats to biodiversity through regulation and pricing, adding value through protected areas, and investing in ecological infrastructure (TEEB 2009). Business and biodiversity were starting to appear together in the same sentences.
128
biodiversity:arthropodsandagriculture
arthropod biodiversity in agriculture
science teacher
A biodiversity footprint While the carbon footprint of a tray of New Zealandproduced kiwifruit (Deurer et al. 2008) and a bottle of Sauvignon Blanc (Anon 2011) have now been estimated, New Zealand Association of Science Educators
15
NZ
science teacher
biodiversity:arthropodsandagriculture
128
and techniques for calculating water footprints have been published (Clothier et al. 2010), we have yet to see a standard definition of a biodiversity footprint. One may not be far away, however. GlobalGAP (Good Agricultural Practice) standards list on-farm conservation plans as a “minor must” and there are scientists exploring ways in which to incorporate biodiversity impacts into product life cycle assessments (Jeanerret et al. 2008; Louette et al. 2010). A biodiversity footprint that could be applied to products, activities, services, nations and individuals might shift the onus for behaviour change away from governments and on to producers and consumers. This could have quite far-reaching implications for New Zealand agriculture. Major exporters in our horticulture and arable industries have already recognised that New Zealand, as a producer of relatively high-cost foods, must anticipate consumer requirements and exceed international standards for environmental stewardship1. Research to better understand biodiversity in New Zealand’s farms, plantation forests and orchards is required to support these efforts.
Biodiversity in NZ agricultural systems Understanding the biology and control of pest arthropod species has inevitably taken precedence over other entomological research in New Zealand’s primary productive sectors. Integrated pest management (IPM) programmes introduced into horticulture over the last few decades have ensured a widespread understanding of the importance of ‘beneficials’ (arthropods that are pollinators of crops or natural enemies of pests). These contributors to ‘on-farm biodiversity’ are probably the best understood, and some recent incidents have illustrated how vulnerable (and important) these organisms can be, e.g. outbreaks of woolly apple aphids after a new insecticide inadvertently affected its natural enemy, and the loss of biological control of pests on tomatoes now that broad-spectrum insecticides have to be applied to control the newly arrived tomato potato psyllid. Compared with applied research to solve pressing pest problems, there has been little work to investigate on-farm biodiversity in the broader sense in New Zealand. The Agricultural Research Group on Sustainability (ARGOS)2 has been examining the environmental, social and economic sustainability of New Zealand farming systems (kiwifruit, lowland and highland sheep/beef and dairy farms) since 2003. In a recent publication, ARGOS researchers noted “a critical lack of research and monitoring of robust indicators of biodiversity in production landscapes in New Zealand” (Moller et al. 2008). As part of a research programme to assist with environmental risk assessment of new biological control agents, transgenic plants and nanomaterials, Plant & Food Research has developed the ‘Eco Invertebase’ – a database of biological and ecological information on 1300 different invertebrate species found in pastures, pine forests, kiwifruit and apple orchards in New Zealand. New information from recent faunal surveys conducted in pine plantations (Schnitzler et al. 2010) and kiwifruit orchards (Todd et al. 2011) has been added to the database and it continues to grow. The Eco Invertebase was initially developed to help with a difficult step in environmental risk assessment – choosing ‘representative’ non-target species for testing the biosafety of new agri-technologies, such as transgenic plants. Every receiving environment has hundreds of potential non-target arthropod species, but only a subset of these 1
2
16
‘Growing a New Future’, HorticultureNZ strategy, www.hortnz.co.nz; ‘Apple Futures’, PipfruitNZ , www.pipfruitnz.co.nz; and ‘Sustainable Winegrowers NZ’, www.nzwine.com/swnz/ http://www.argos.org.nz/
New Zealand Association of Science Educators
can be tested in the laboratory before the decision to release the new plant (or not) must be made. Jacqui Todd and co-workers (2008) developed an automated screening method that applies a set of selection criteria to all the species in the database simultaneously and produces a ranked list of test subjects from the appropriate receiving environment (e.g. pasture, pine forest). Those species most likely to be exposed and affected by the new plant, most valued (native, iconic, etc.) and easiest to work with, appear at the top of the list. Although the database was established for this purpose, it is becoming a valuable record of New Zealand’s agricultural arthropod biodiversity, and is being used in several new research projects.
What affects biodiversity in agricultural systems? Arthropod biodiversity in pine trees Arthropod biodiversity in a stand of transgenic and non-transgenic pine trees (grown in a field trial in Rotorua) was assessed over a two-year period. The field trial was designed to assess the potential environmental impacts of trees genetically modified to express an antibiotic resistance marker gene, nptII, and various genes expected to alter the trees’ reproductive structures (e.g. cones) (Schnitzler et al. 2010). Two arthropod classes (Insecta and Arachnida), 16 orders and 321 recognisable taxonomic units (RTUs), both introduced and endemic, were represented among the 26,446 arthropod specimens collected by beating tree branches in this study (E. Burgess, pers. comm.). There were no significant differences in species abundance (numbers of individuals of each RTU), species richness (numbers of RTUs), Simpson’s diversity (the probability that two individuals drawn at random from a community will belong to the same RTU), or species composition (which RTUs were where) among the transgenic and control trees. Thus it was shown that the genetic modification had no impacts on aboveground invertebrate communities in this field trial. However, there was a significant effect of sampling date (collections had been made in October and April between 2006 and 2008) on total invertebrate communities, suggesting that specimen abundance and species’ richness changed over time without significant interactions between treatments (transgenic or not) and sampling dates (Schnitzler et al. 2010) (Fig. 1). Faunal surveys like this one provide us with baseline data so we can begin to build an idea of what ‘normal arthropod biodiversity’ looks like in New Zealand’s productive landscapes. Arthropod biodiversity in kiwifruit orchards In another recent large study (Todd et al. 2011), Jacqui Todd collected arthropods in pitfall, pan and intercept traps in twenty different ‘Hayward’ (green) kiwifruit orchards in the Bay of Plenty on three occasions: October 2007, January and March 2008. With collaborator and ARGOS researcher, Jayson Benge, Jacqui had selected ten pairs of orchards to study; each pair comprised one orchard using organic practices and another in close proximity, with similar geographical features and similar weather conditions, which used integrated pest management (IPM) practices. The aim of this study was to determine aboveground arthropod taxonomic richness in kiwifruit orchards and to see if there were differences in taxonomic composition that could be attributed to the two orchard management systems (organic or IPM). In total, 602 taxa were identified in all samples from the orchards: 471 of these were found in the IPM orchards and 516 in the organic orchards. The two orchard types had 385 taxa in common. On each sampling occasion, significantly more taxa were collected from the organic orchards, confirming similar findings in European and Canadian farms growing arable crops (Hole et al. 2005; Boutin et al. 2008), suggesting that
NZ
science teacher 128
organic farming practices in general might support a greater number of different species than the alternatives. Although the proportions of native to non-native arthropods varied considerably from orchard to orchard, they were statistically similar for the two types of orchard (38% in organic vs 21% in IPM), suggesting that both orchard management types can support native arthropod biodiversity. When the species were sorted into functional groups – herbivores, predators, parasitoids, omnivores and fungivores – organic orchards were seen to have consistently and significantly greater numbers of species in each group, except for the detritivores. This suggests that the organic orchards could support a greater diversity of ‘ecosystem service providers’ such as predators and parasitoids than IPM orchards. As herbivores were also more diverse on organic orchards, the potential for pests to occur might also be greater. Greater plant diversity (understorey and shelterbelts), creating a greater diversity of niches, and the application of different types of agrichemicals on organic orchards compared with IPM orchards, may explain the observed differences in arthropod biodiversity. As Schnitzler had found in the pine plantation study, Jacqui Todd found that sampling date accounted for a large amount of variation in the species collected from kiwifruit orchards. Clearly the ‘normal’ state of arthropod biodiversity in agroecosystems is a dynamic one, capable of quite large fluctuations in population numbers and significant recovery from perturbations. Even within the certification guidelines for ‘organic’ and ‘IPM’ fruit production systems, there is still room for variation in the volumes and types of compounds applied for pest control, mulching and mowing practices, composition of shelterbelts, girdling, pruning, and other plant and property management practices that could affect on-orchard arthropod biodiversity. Further research is now under way to try to look at the relationships, if any, between particular orchard
Figure 2: Taking sweep net samples of arthropods from pine trees. Photograph courtesy of Libby Burgess.
biodiversity:arthropodsandagriculture
Figure 1: Multidimensional scaling plots showing similarity in total invertebrate species among treatments (five transgenic pine tree lines and control trees) but differences among sampling occasions. Each point on the graph represents the invertebrate community found on an individual pine tree on one sampling occasion. The plot is based on non-standardised square root-transformed abundance data and binomial deviance dissimilarity.
Figure 3: Collecting invertebrates from pan traps set in a kiwifruit orchard. Photograph courtesy of Tim Holmes. management practices and the amounts and types of arthropod biodiversity in kiwifruit orchards. If strong correlations are found with particular practices, then this could form the basis of new decision-making tools for growers wishing to improve biodiversity without compromising fruit production and quality. Although Todd’s study used paired orchards to try and reduce the influence of landscape factors, such as biogeographical characteristics and neighbouring land uses, there is no doubt that these are also important in determining biodiversity in orchards, and current research to understand this is also being carried out by David Logan, Garry Hill and colleagues at Plant & Food Research in Te Puke.
Finally... As we gain a better understanding of arthropods and their ecological functions in New Zealand agroecosystems, including the dynamics of their populations, their mobility and their trophic interactions, we are better placed to make good decisions to support sustainability in food production, and to find ways for this to complement and support conservation efforts. For further information contact: louise.malone @plantandfood.co.nz continued on page 9 New Zealand Association of Science Educators
17
NZ
science teacher
biodiversity:marine
128
New Zealand’s marine biodiversity Scientifically, there’s more to marine life than fish. In New Zealand we are discovering new species faster than we can name them, and our marine biodiversity has many special attributes, as Dr Dennis P. Gordon, from NIWA, explains: Hands up if you’ve ever seen one – a comb jelly, peanut worm, spoon worm, lamp shell, horseshoe worm, goblet worm, arrow worm, mud dragon, penis worm, or acorn worm. Don’t be surprised if the answer is no – many professional zoologists have never laid eyes on some of them. Yet each is the common name for an entire phylum of animals, respectively Ctenophora, Sipuncula, Echiura, Brachiopoda, Phoronida, Kamptozoa, Chaetognatha, Kinorhyncha, Priapulida, and Hemichordata. They are exclusively marine and all of them can be found in New Zealand waters. The reason they are not often seen is that none of these groups has many species and they are largely hidden from view. The largest of them in terms of numbers, the Brachiopoda (lamp shells), has only about 350 species worldwide. Horseshoe worms (Phoronida) number only ten species. The rest have numbers in between. Comb jellies and arrow worms are ocean-going creatures that are mostly transparent. The other wormy groups are buried in mud or sand; mud dragons are microscopic. Little-known they may be, but all have their ecological roles and are important to science in terms of what we can learn from them (Figures 1 and 2). When we think of marine life we tend to think of the well-known things we can eat, easily see, and readily catch: fish and shellfish, crabs and lobsters, seaweeds and barnacles, and sea stars and sea urchins. Some of these, such as barnacles, trouble us because they also choose to settle on our boats and marine installations, and, as adults and larvae, get carted about on vessel hulls or in ballast water and may become biosecurity problems. The problem of alien species also means that our marine biodiversity is slowly increasing, as foreign-sourced species get added to our biota. Which raises the question: how many marine species are there in our Exclusive Economic Zone (EEZ)?
New Zealand’s marine species inventory We now know for the first time how many species occur in our marine, freshwater and terrestrial environments, thanks to a decade-long project, involving 227 taxonomists in 18 countries, to inventory all of life through all of time in New Zealand. Three volumes (two published, one in press)1,2,3 review our biodiversity and list all known species, the names of which are being captured for the New Zealand Organisms Register – an online infrastructure funded by the TFBIS (Terrestrial and Freshwater Biodiversity Information System) programme administered by the Department of Conservation – that is under development. So, how many marine species do we have, and how do the numbers compare with biodiversity on land and in fresh waters? Furthermore, how does New Zealand’s marine biodiversity compare with that in other parts of the world? Table 1 summarises all the data presently available to us. From it we can see that we have almost 17,000 marine species in our EEZ, i.e. just over 30% of the entire biota, with the balance of species comprising about 60% terrestrial and 18
New Zealand Association of Science Educators
10% freshwater. And our marine life makes up almost 7% of known marine species globally. Of that ~17,000, about 4320 species are known-undescribed species in collections. Estimates of yet-undiscovered diversity in the EEZ range from 13,000 to 50,000 additional species (not including bacteria); hence we may have ~17,000–54,000 species or more to name. The uncertainty concerning how many species yet to name centres on parasitic and commensal protists, parasitic myxozoans and nematodes, and free-living nematodes. Thus, at the present rate of new species descriptions – currently averaging less than 100 per year – it will take more than 170–500 years to complete the task of naming our remaining marine life.
Classifying marine life Table 1 partitions all of life into six kingdoms according to a scheme developed by Professor Tom Cavalier-Smith of Oxford University, comprising a single prokaryote kingdom (Greek pro-, before, and karyon, nucleus) in which a cell nucleus is lacking (Bacteria), and five kingdoms of eukaryotic (eu-, true) organisms with a cell nucleus. The 1990 three-domains scheme [Bacteria, Archaea (archaebacteria) and Eukaryota] of American microbiologist Carl Woese is rejected by Cavalier-Smith on ultrastructural, biochemical, molecular, and paleontological grounds)4. The most basal eukaryote kingdom is Protozoa. It is paraphyletic, in that it includes the ancestors of the other kingdoms. It comprises forms that were ancestrally rigid zooflagellates on the one hand, and ancestrally heterotrophic (non-photosynthetic) amoeboflagellates on the other, and includes such forms as euglenoids, trypanosomes, amoebas, collar flagellates, Giardia, and some other zooflagellates. As presently narrowly defined, kingdom Protozoa is restricted to largely uninucleate, mostly phagotrophic, unicells without cortical alveoli (flattened sacs under the cell membrane), central capsules or branching pseudopodia. Ciliates, the shelled foraminiferans and radiolarians, dinoflagellates, and the parasitic sporozoans, now all belong, along with water moulds, and the golden and brown seaweeds and diatoms, to kingdom Chromista, united by molecular and ultrastructural criteria. The plant kingdom in the 21st century is restricted to glaucophytes, green and red algae, and land plants. True fungi include not only the familiar chytrids, pin moulds, Ascomycota, Basidiomycota and lichenised forms, but also the parasitic microsporidians. Excluded from kingdom Fungi are the water moulds and downy mildews as well as the plasmodiophoras, labyrinthulid slime nets, and thraustochytrids (all Chromista). Most of these have marine representatives.
Outstanding features of our marine biodiversity Our present-day marine biodiversity is a consequence of New Zealand’s geological and biological history, latitudinal spread, diversity of seafloor relief and long geographic isolation. The EEZ is one of the largest in the world (in the top 10), spans 30° of latitude from the subtropics to the Subantarctic, and includes undersea ranges, volcanoes, plateaus, canyons, and plains, and a trench 10 km deep. The New Zealand coastline is also very long. Estimates range from 15,000 to 18,000 km, the exact length being confounded by the fractal quality of inlets, headlands, spits, bays, harbours, fiords, sounds, and estuaries.
was found in sunken wood from 1100 m-deep canyons off the Wairarapa coast and off Hokitika. At bathyal depths (1000–4000 m), New Zealand’s sea-cucumber (Holothuroidea) fauna is remarkably diverse, comprising a third of the world’s known species of orders Elasipodida and Molpadida. New Zealand’s fish fauna of 1387 species constitutes a globally unique mix of widespread (semi-cosmopolitan), Indo-Pacific, Australasian, sub Antarctic and endemic taxa. Approximately half the species are widespread and about 19% are endemic. Currently, 148 species of cartilaginous fishes are represented in New Zealand waters, comprising a diverse group of sharks, skates, rays and relatives. About 90% of New Zealand’s fishes are bony fishes or teleosts (1233 species). Families that give New Zealand a distinctive ‘fishy’ character include the coastal triplefins
NZ
science teacher 128
biodiversity:marine
Our EEZ has high species numbers of some groups of marine organisms relative to known global diversities5. These include carnivorous sponges (Cladorhizidae), rock sponges (‘Lithistida’) and glass sponges (Hexactinellida), certain gorgonian octocoral families, black corals (Antipatharia), hydrocorals (Stylasteridae), several genera and families of gastropod and bivalved Mollusca, as well as monoplacophorans and chitons. Compared with the tropics, New Zealand’s echinoderm fauna is not exceptional, but most orders are represented, the most speciose of which are the brittle-star order Ophiurida and sea-star order Valvatida; the latter includes the crown-of-thorns sea star, which is found at Raoul Island on the Kermadec Ridge. The New Zealand sea-star fauna also includes the first-discovered species of Concentricycloidea (sea daisies), Xyloplax medusiformis, which
Table 1: New Zealand’s known (totals for described and known-undescribed species) and estimated-unknown eukaryote diversity1,2,3. Kingdom/ Phylum
Common name
No. of marine species
No. of terrestrial 1 species
ANIMALIA Porifera Ctenophora Cnidaria Platyhelminthes Dicyemida Gastrotricha Gnathifera Mollusca Brachiopoda Phoronida Bryozoa Kamptozoa Sipuncula Echiura Annelida Orthonectida Nemertea Xenacoelomorpha Echinodermata Hemichordata Tunicata Chordata Chaetognatha Tardigrada Onychophora Arthropoda Kinorhyncha Loricifera Priapulida Nematoda Nematomorpha PROTOZOA CHROMISTA PLANTAE FUNGI 4 BACTERIA TOTALS
animals sponges comb jellies corals, jellyfish, etc. flatworms, flukes, tapeworms dicyemid worms gastrotrich worms rotifers, etc. snails, clams, squid, etc. lamp shells horseshoe worms bryozoans goblet worms peanut worms spoon worms bristleworms, leeches, etc. orthonectid worms ribbon worms acoel flatworms sea stars, sea eggs, etc. acorn worms, etc. sea squirts, salps, etc. vertebrates, etc. arrow worms water bears velvet worms crustacea, insects, mites, etc. mud dragons corset worms penis worms round worms horsehair worms protozoans chromist algae, pseudofungi green and red algae, plants true fungi bacteria, bluegreen ‘algae’
13,402 744 19 1112 322 6 4 44 3813 50 3 953 12 26 7 792 1 29 2 623 7 192 1427 14 5 0 2930 45 4 4 211 1 42 2640 698 60 79 16,921
19,546 0 0 0 137 0 0 2 910 0 0 0 0 0 0 207 0 6 0 0 0 0 264 0 0 34 17,446 0 0 0 540 0 333 471 5395 6811 272 32,828
No. of No. of freshwater species in 1 species all environments (corrected for overlap) 2179 5 0 14 78 0 1 484 96 0 0 8 0 0 0 55 0 4 0 0 0 0 96 0 3 83 0 1242 0 0 0 9 4 197 1277 1086 315 356 5410
34,927 749 19 1126 537 6 5 530 4819 50 3 961 12 26 7 1054 1 39 2 623 7 192 1787 14 88 34 21,418 45 4 4 760 5 527 4635 7119 7049 702 54,959
Undiscovered Approximate New Zealand number of marine species described (minimum of marine range of species estimates) globally 37,890 211,880 510 8370 12 190 2 1230 10,705 790 11,680 50 109 25 434 85 661 430 59,670 5 386 3 10 300 5900 25 193 5 150 15 175 760 13,721 3 25 140 1285 40 401 45 7468 4 118 195 3146 835 18,010 25 128 100 183 10 0 26,600 56,380 30 209 10 32 4 19 5600 12,115 2 5 >670 800 4685 23,010 810 7190 15,000 500 unknowable 5800 5 59,055 249,180
1
Some organisms inhabit freshwater and terrestrial environments during their life cycle, so there is some overlap in these two columns Mostly myxozoan parasites of fishes Including terrestrial species, as these occur in seepages and films of water 4 Bluegreen bacteria (bluegreen ‘algae’) and cultured bacteria only 5 Not including bacteria 2 3
New Zealand Association of Science Educators
19
NZ
science teacher
a)
Figure 1: (a) Ercolania sp., a minute sea slug (Mollusca) from Cook Strait (Geoff Read, NIWA); (b) Saccoglossus otagoensis, a small acorn worm (Hemichordata) from Cook Strait. (Geoff Read, NIWA); (c) Priapulopsis australis, a penis worm (Priapulida), from Whangateau Harbour (Richard Taylor, University of Auckland); (d) Branchiomma curtum, a bristleworm (Annelida), from the Wellington south coast (Geoff Read, NIWA).
b)
biodiversity:marine
128
c) d)
(Tripterygiidae), clingfishes (Gobiesocidae), right-eyed flounders (Pleuronectidae), whitebaits (Galaxiidae), and sleepers (Eleotridae). Thanks to intensive exploration of fishing grounds during the past thirty years, plus the technology that has allowed sampling in deeper waters and new methods of collecting in shallow water, there has been a dramatic increase in knowledge of fish diversity, such that the number of known fish species from the EEZ has doubled over the past 15 years and continues to increase at a rate of about 20 species per year, about half of which are new to science. The current estimate of undiscovered fish diversity in the EEZ is around 760 species5. Out of a total bird fauna of 286 species, New Zealand has 122 that may be classified as marine or maritime, i.e. spending all or almost all of their time feeding in those environments. Almost three quarters of the world’s penguin, albatross, and petrel species, and half of shearwater and shag species occur or have occurred in the New Zealand EEZ (some Holocene extinctions). Six species of penguins still nest in the EEZ and the hoiho (yellow-eyed penguin) represents a monotypic endemic genus. Seven of the 12 species of albatross (Diomedeidae) that currently breed in the EEZ are endemic to the New Zealand region. Among marine mammals, nearly half the world’s cetaceans have been recorded in the EEZ, in other words, 43 species and subspecies. There are nine species of baleen whales, including the great whales (Balaenopteridae), such as the blue, fin, sei, Bryde’s, minke, and humpback, plus the southern right whale (Balaenidae) and pygmy right whale (Neobalaenidae). There are 17 members of the dolphin family (Delphinidae), including two subspecies of endemic Hector’s dolphin (Cephalorhynchus hectori). Of the 17, ten occur permanently and five are extralimital stragglers from tropical waters. There are 12 species of beaked whale (Ziphiidae). They are rarely seen at sea and are known mainly from stranded specimens. Three species of Physeteridae occur: sperm, pygmy sperm, and dwarf sperm whales. Three species of pinnipeds are regularly seen on the mainland and sub Antarctic islands: the New Zealand fur seal Arctocephalus forsteri and, to a lesser extent and mainly in the south, the endemic New Zealand sea lion Phocarctos hookeri and the southern elephant seal Mirounga leonina. There are about 900 species of macroalgae, including at least 109 that are new to science and undescribed, mostly red seaweeds (Rhodophyta), including an exceptional number of karengo species, i.e. Porphyra-like and related 20
New Zealand Association of Science Educators
to the algae used for wrapping sushi. There are also many unnamed species of sea lettuce among the green algae (Chlorophyta). As for the brown seaweeds (Ochrophyta), of the five known species of the bull-kelp genus Durvillaea, which is restricted to the Southern Hemisphere, four are present in New Zealand and three of them are endemic.
How do we compare with other parts of the world? Thanks to the very large EEZ, New Zealand’s marine species diversity compares very well with that elsewhere. While we don’t come close to the total biodiversity of the world’s marine-biodiversity hotspot (the Coral Triangle), our diversity exceeds that region in the diversity of specific genera, families and orders and is comparable to some other temperate regions. For example, the figure of 12,601 described marine species for New Zealand compares with 12,915 described species for the South African EEZ, but their figure of 7590 known-undescribed species exceeds our 4320 such species. A more interesting comparison can be made with the European region. Though the ERMS (European Register of Marine Species) region is 5.5 times larger in area than the New Zealand EEZ, it has only twice as many species6. The ERMS region encompasses the area bounded by 26° N latitude and the Mid-Atlantic Ridge to the North Pole and Russia north of the Urals and includes the Mediterranean and Black Seas. Species diversity for the most intensively studied phylum-level taxa in New Zealand (Cnidaria, Mollusca, Brachiopoda, Bryozoa, Kinorhyncha, Echinodermata, Chordata) is more or less equivalent to that in the ERMS region. For example, we have 1387 fish species compared to Europe’s 1349 species, 3813 mollusc species to their 3353 species, and 50 Brachiopoda to their 18. The implication is that, when all other New Zealand phyla are equally well studied, whether the phylum is large or small in species number, total marine diversity in the EEZ may be expected to equal that in the ERMS region. In the meantime, it appears that total species numbers per phylum in European waters could be a useful proxy of what to expect for the poorly studied groups in New Zealand.
Alien species To date, 177 marine species are considered to be alien in New Zealand5. This number comprises only naturalised species that have successfully bred and spread in ports and harbours, possibly more than once. Among marine animals, the phyla most represented are Annelida (32 species, all but
a)
d)
NZ
science teacher
c)
one polychaetes), Arthropoda (28, mostly malacostracan crustaceans), Bryozoa (24, mostly cheilostomes), and Cnidaria (23, mostly hydroids). Among macroalgae are 12 species of red seaweeds and 11 species of brown seaweeds. Vessel hulls have transported far more species successfully than ballast water.
Threats to marine biodiversity The threats to New Zealand’s marine biodiversity are several, including fishing, mining, chemical pollution, coastal nutrient and sediment input, habitat loss, aquaculture, invasive species, harmful algal blooms, and climate change. Fishing effects include overfishing, habitat modification or destruction, bycatch depletion, and diminishment of ecosystem services because of biodiversity loss. A single commercial trawler can easily disturb 10 km2 in a single day’s fishing, sometimes repeatedly in the same area over the course of a year. New Zealand has been predominantly an agricultural economy, and some of the principal pollution problems result from the transfer of nutrients from animal wastes and fertilisers into coastal waters, especially those that are semi-enclosed, added to which is municipal sewage and industrial effluent in some areas (particularly during flood events). Soil erosion, caused by forest removal and agriculture, along with land-contouring for housing developments, has led to considerable amounts of sediment entering the coastal environment. In some areas, reef sponges, kelp forests, weed beds and fish nursery grounds have been lost because of increased sediment. Nutrient input from terrestrial runoff has been suggested as contributory to some harmful algal blooms, including red tides. Finally, global warming and ocean acidification are expected to affect calcification in all marine organisms that have calcium carbonate skeletons, including larval and adult and free-living and sessile animals, shelled protozoans, and calcareous algae.
Why do we need to know our marine biodiversity? There are many reasons. Beyond the obvious aspect of curiosity and the human proclivity to categorise things, there are practical benefits. About 40% of our marine species appear to be endemic, i.e. found only in the EEZ. We have relatively high numbers of species, genera and families that are unique to our region and, in terms of their
128
biodiversity:marine
Figure 2: (a) Eunice laticeps, a bristleworm (Annelida) from the Wellington region (Geoff Read, NIWA); (b) Marphysa capensis, a bristleworm (Annelida) from Island Bay, Wellington (Geoff Read, NIWA); (c) Amblyosyllis granosa, a bristleworm (Annelida) from the Wellington region (Geoff Read, NIWA); (d) Clavularia novaezealandiae, a small octocoral (Cnidaria) from Island Bay, Wellington (Dennis Gordon, NIWA).
b)
scientific value and the preservation of genetic diversity, New Zealand has a global responsibility to conserve them. These taxa contribute to the scientific criteria for establishing marine reserves; knowing what is widespread, representative, rare, unique, or threatened helps us to decide where and what to protect. In ecological surveys, and in determining the consequences of fishing methods (such as what is caught as bycatch), we also need to know the names of species. Many marine organisms are sources of significant biochemicals that are cytotoxic, anti-cancer, antibiotic, antiviral, biocidal, or useful in cosmetics. Accurate identification of species is crucial in natural-products research. A number of microalgal species, both native and alien, are toxic, causing a range of effects (amnesia, paralysis, gastrointestinal upsets, even death) if people ingest wild shellfish that have been feeding on harmful algal blooms. And then there is the problem of marine-fouling species and being able to identify what is native and what is introduced. Early recognition of alien status is an important line of defence – if it occurs at or soon after introduction, eradication or control measures may be able to be implemented, and it is also easier to determine the means of arrival and source of the immigrant species. In short, human health, aquaculture, fisheries, conservation, biosecurity, and science generally, all benefit from knowing our species. For further information contact: d.gordon@niwa.co.nz
References 1
2
3
4
5
6
Gordon, D.P. Ed. (2009). New Zealand Inventory of Biodiversity. Volume 1. Kingdom Animalia: Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press, Christchurch. Gordon, D.P. Ed. (2010). New Zealand Inventory of Biodiversity. Volume 2. Kingdom Animalia: Chaetognatha, Ecdysozoa, Ichnofossils. Canterbury University Press, Christchurch. Gordon, D.P. Ed. (2011). New Zealand Inventory of Biodiversity. Volume 3. Kingdoms Bacteria, Protozoa, Chromista, Plantae, Fungi. Canterbury University Press, Christchurch. Cavalier-Smith, T. (2010). Deep phylogeny, ancestral groups and the four ages of life. Philosophical Transactions of the Royal Society, B, 365, 111-132. Gordon, D.P., Beaumont, J., MacDiarmid, A., Robertson, D., Ahyong, S. (2010). Marine biodiversity of Aotearoa New Zealand. PLoS ONE, 5(8), e10905, 1-17. Costello, M.J., Emblow, C. & White, R. Eds (2001). European Register of Marine Species. A check-list of the marine species in Europe and a bibliography of guides to their identification. Patrimoines naturels, 50, 1-463.
New Zealand Association of Science Educators
21
NZ
science teacher
conversationscience/scienceeducationinterface:marinediversity
128
a passion for the living world This article explores the science/science education interface, drawing on a conversation between Dennis Gordon from NIWA and Ally Bull and Rosemary Hipkins from NZCER. Prior to the meeting, Rose and Ally read the draft of Dennis’s article that appears in this issue of NZST (pp.). We were interested in finding out which ideas in the article Dennis thought were important for all secondary students to know about. We were also keen to find out what Dennis thought students should gain from school science in the ideal world, but we also wondered about what experiences or early influences had encouraged him to take up a career in science. Was there a teacher or an aspect of school science that had set him on this path? We sent him these questions in advance and his reaction to them was interesting. Dennis replied that our questions had prompted him to think deeply because he hadn’t really reflected on some of the issues we raised. This made us think that one value of these conversations is raising awareness among scientists of the way in which the work of science educators is different from theirs, although obviously not unrelated.
Stirring the imagination with vivid images Our conversation with Dennis covered many interesting topics, but the overwhelming impression we took away with us was just how passionate he is about his subject – and according to Dennis this passion began at school. In fact, he began a recent article in the New Zealand Geographic with these words, “Thank you, Mount Albert Grammar School. That’s where it all started – in the fifth form, with a collection of preserved animals and Ralph Buchsbaum’s two-volume paperback classic, Animals Without Backbones.” Retrieving his much-read copies off the bookshelf, Dennis quickly found a photo of a woman with elephantiasis and commented on how much this and other images had intrigued him as a school boy. Rose similarly recalled staring in fascinated horror at a geology book with a photo plate of a tsunami from which one person was narrowly escaping on a steep hillside – with others presumably not so lucky. This made her wonder about how often we find spaces to engage those vivid image-based imaginings and questions.
Feed an interest in science This sense of the wondrous and bizarre came through again in the examples that Dennis picked out as we were privileged to have a quick look around NIWA’s extensive collection of species. For Dennis, “It is impossible to be bored in science.” (How many of us or our students would agree?) This doesn’t mean that science is always exciting – in fact he pointed out that before patterns can be seen there is a need to collect enough data and this is often routine, monotonous work. What keeps his interest alive during these phases is the possibility of discovery. Dennis thinks the main purpose of school science is to “feed an interest.” He argues that young children are hardwired to be inquisitive and school should feed this to make it a lifelong disposition. “We should never stop asking questions.”
Using ready-made data sets This made Ally think that if we really want to engage students in science perhaps it is time to question how much routine data collection students really need to do 22
New Zealand Association of Science Educators
themselves, and whether there are ways we could better use existing sets of data to stimulate curiosity. In his article, Dennis presents a great deal of data. For example, he compares European waters with New Zealand. Although the European zone is more than five times the size of the New Zealand zone, it has only twice as many species. Why might that be? What is the same or different about the regions? How do we know which species are where? How does the current estimate of undiscovered fish diversity in New Zealand compare with different places? How is this estimate arrived at? By carefully examining the table in the article, what patterns emerge? What questions might these generate? As well as stimulating question-asking, ready-made data sets could be used to support students to think about how we interpret what we see in more reliable ways. This is an important understanding for the Nature of Science. The Understanding about science achievement objective of the curriculum at both Level 5 and Level 6 states, “Students will understand that scientists’ investigations are informed by current scientific theories and aim to collect evidence that will be interpreted through processes of logical argument.”
New discoveries in classification As a taxonomist, Dennis continues to be excited by the possibility of making a discovery that will prompt a rethinking of an aspect of the classification system. Indeed, in his article he briefly explains a monumental and quite recent change in theoretical thinking about the relationships between different groups that come broadly within the major kingdoms of life. While some contexts are just too hard to give students that active sense of meaning-making at the cutting edge, classification does seem like a very accessible context in which to do this. For further information contact: Ally.Bull@nzcer.org.nz continued from page 14
References 1. Brock Biology of Microorganisms 12th ed, Madigan, Martinko, Dunlap and Clark. Pearson International Edition 2009. While this is a general microbiology text book, Thomas Brock is regarded as the father of modern studies on thermophiles and the text still has relevant sections on thermophiles. In particular, pages 157-165, 368-373, 494-515 provide extensive background to the current article. 2. Gihring, T.M., D.P. Moser, L.-H. Lin, M. Davidson, T.C. Onstott, L. Morgan, M. Milleson, T.L. Kieft, E. Trimarco, D.L. Balkwill, & M.E. Dollhopf. (2006). The distribution of microbial taxa in the subsurface water of the Kalahari Shield, South Africa. Geomicrobiol. J., 23,415-430. 3. Gold, T. (1992). The deep, hot biosphere. Proc. Natl. Acad. Sci. USA, 89, 6045-6049. 4. Lin, L.-H., P.-L. Wang, D. Rumble, J. Lippmann-Pipke, E. Boice, L.M. Pratt, B.S. Lollar, E.L. Brodie, T.C. Hazen, G.L. Andersen, T.Z. DeSantis, D.P. Moser, D. Kershaw, & T.C. Onstott. (2006). Long-term sustainability of a high-energy, low-diversity crustal biome. Science, 314, 479-482. 5. Graham, J.E., Clark, M.E., Nadler, D.C., Huffer, S., Chokhawala, H.A., Rowland, S.E., Blanch, H.W., Clark, D.S. & Robb, F.T. (2011). Identification and characterization of a multidomain hyperthermophilic cellulase from an archaeal enrichment. Nature Communications, 2, 375.
NZ
and North American genera Arabis, Braya, Cardamine, Nasturtium and Sisymbrium, as they appeared morphologically similar to species from these genera. The genus Pachycladon was described by Hooker (1867) to accommodate P. novae-zelandiae. A global study of the Brassicaceae by Schulz (1924, 1936) resulted in the erection of the The genus Pachycladon is a New Zealand native two new endemic New Zealand genera alpine cress that belongs to the cabbage family Cheesemania and Ischnocarpus. Species (Brassicaceae). Among its relatives are such In the field at a assigned to these two genera are now placed well-known vegetables as radish (Raphanus Pachycladon in Pachycladon (Heenan et al. 2002), but prior datalogger site, sativus), Chinese cabbage (Brassica rapa), to this happening Cheesemania, Ischnocarpus Ohau Skifield, Barrier cabbage and broccoli (Brassica oleracea), the and Pachycladon were not considered to have Range. Note the plant condiments black mustard (B. nigra), white a close relationship. Schulz placed Cheesemania of P. fastigiatum mustard (Sinapis alba) and black pepper in the tribe Arabideae and Ischnocarpus and above my head. (Sinapis sp.), and the popular summer-flowering Pachycladon in different subtribes of the garden plants Allysum and Iberis. Other genera of the tribe Sisymbrieae. Much of this confusion arose because Brassicaceae with New Zealand native species include emphasis was placed on fruit and seed characters that are Cardamine (7 species, many others undescribed), Lepidium labile, and therefore are not reliable indicators of taxonomic (8 species, several undescribed), Notothlaspi (2 species), and relationships. Rorippa (2 species, maybe 3). Phylogenetic analyses of DNA sequence data over the There are nine species of Pachycladon endemic to the South last decade have provided new insights into relationships Island and one species (P. radicatum) found only in the of species assigned to Pachycladon, Cheesemania, and mountains of Tasmania. Pachycladon species are perennial Ischnocarpus (Mitchell and Heenan 2000; Heenan et al. 2002; herbs that exhibit considerable morphological and Joly et al. 2009). These studies have shown the three genera ecological diversity and they mainly grow on shaded rock form a monophyletic clade of closely related species with bluffs in alpine regions of the South Island. low sequence divergence (2.6%) (see Figure 2). The New Zealand species form three distinct groups based Following the DNA studies, a reassessment of morphological on morphological characters and habitat preferences, characters, and the generation of fecund interspecific and vary from being generalists to specialists (Heenan hybrids between species from each of the three genera and Mitchell 2003) (Figure 1). Species’ relationships (Heenan 1999; Yogeeswaran et al. 2011), Pachycladon and a number of their main distribution, habitat and was recircumscribed in 2002 to include species placed in morphological features are illustrated in Figure 2. Cheesemania and Ischnocarpus (Heenan et al. 2002). Four species of Pachycladon are listed as New Zealand The recent taxonomic research has not only been threatened species (de Lange et al. 2009). Pachycladon exile, confined to defining the genus Pachycladon, and three P. stellatum and P. fasciarium are listed as Nationally Critical new species have recently been described. These include and P. cheesemanii is Nationally Vulnerable. These species Pachycladon stellatum (as Cheesemania stellata) and P. exile are adversely affected by habitat modification and invasion (as Ischnocarpus exilis) in 1999 and Pachycladon fasciarium by introduced weeds. in 2009 (Heenan & Garnock-Jones 1999; Molloy et al. 1999; The natural diversity of Pachycladon and a close relationship Heenan 2009). The other species of Pachycladon were to the lab-rat of the plant world, the model plant thale cress named and described intermittently from 1864 through to (Arabidopsis thaliana), have resulted in the emergence of 1957. Pachycladon as a system to study speciation and adaptive What are the species? radiation in New Zealand alpine plants.
Origin and evolution of the alpine Pachycladon is being used to study speciation and adaptive radiation in New Zealand alpine plants, as Peter Heenan, Allan Herbarium, Landcare Research, explains: Introduction
Taxonomic history Pachycladon has a taxonomic history that reflects botanical discovery and exploration in New Zealand. Several of the species now assigned to Pachycladon were first named and described in the late 1800s and early 1900s by European botanists who placed them in the familiar European
128
biodiversity:alpineplants
diversity in native alpine cress
science teacher
Group 1: Polycarpic generalists
Two species, P. exile and P. cheesemanii, are defined as ‘polycarpic generalists’ as they are polycarpic (flower and fruit for several years), have woody caudices, short aerial branches, exhibit heterophylly, have slender, terminal inflorescences, terete siliques with a single row of seeds, and seeds are without wings.
Figure 1: Pachycladon enysii monocarpic flowering plant (a) and a single rosette with hairy leaves (b); P. wallii polycarpic flowering plant (c) and a large plant with many rosettes and some inflorescences in fruit (d); P. cheesemanii flowers with narrow petals (e) and leafy rosette (f). New Zealand Association of Science Educators
23
NZ
science teacher
Origin of Pachycladon
biodiversity:alpineplants
128
Figure 2: Phylogeny of Pachycladon showing species’ relationships (on left) and important distributional and morphological characters showing various species’ groupings. Pachycladon cheesemanii is the most widely distributed species occurring in the eastern South Island, where it grows from near sea level (10m) to mountaintops (1,600m) and it is a substrate generalist occurring on greywacke, Haast schist, and basaltic and andesitic volcanic rocks. The closely related Pachycladon exile has a restricted distribution in northern Otago and it is known with certainty from only three low-altitude (<500m) sites comprising calcareous substrates such as limestone and volcanic rock.
Group 2: Polycarpic, schist specialists This group comprises P. novae-zelandiae and P. wallii, which are polycarpic and with lobed leaves, lateral inflorescences, short and laterally compressed siliques with seeds in two rows, and seeds with or without wings. These two species occur in the southern South Island and mainly on Haast schist. Pachycladon novae-zelandiae occurs on rocky outcrops and fellfield between 1,000 and 2,000m, and P. wallii is found on rocky outcrops and bluffs between 1,100 and 1,900m.
Group 3: Monocarpic species The five species in this group are monocarpic (plants flower only once then die after fruiting), have a stout and soft caudex, serrate leaves, stout terminal inflorescences, long and laterally compressed siliques with two rows of seeds, and seeds have wings. They mainly grow on shaded, rocky bluffs in the alpine zone. Of these, Pachycladon latisiliquum is a northwest Nelson endemic growing in a narrow latitudinal range and at an altitude of 1,000-1,750m on a wide variety of rock types including granite, sandstone, marble, limestone, and volcanics. Pachycladon fasciarium is a limestone specialist that is endemic to Marlborough. The other three species are restricted to greywacke rocks in the Southern Alps. Pachycladon enysii occurs throughout the Southern Alps from 975m to 2,500m above sea level and is one of the highest altitude plant species in New Zealand. In contrast, Pachycladon fastigiatum has a lower altitudinal range (900-2,050m) and disjunct populations in the northern and southern parts of the Southern Alps, being absent from the high mountains of the central Southern Alps. It has been suggested that this distribution reflects its extirpation from this area during the last glacial maximum some 15-25,000 years ago, whereas P. enysii survived in-situ during the glacial periods (Heenan and Mitchell 2003). Pachycladon stellatum is restricted to a small geographic area in southern Marlborough, where it occurs on greywacke bluffs at a relatively low altitude (900-1,400m). Further information on the biogeography and distribution of Pachycladon species can be found in Heenan & Mitchell (2003). 24
New Zealand Association of Science Educators
A phylogenetic DNA study using multiple, single-copy, nuclear gene markers (CHS, PRK, MS, CAD5 and MtN21) of four Pachycladon species confirmed an allopolyploid origin for the genus (Joly et al. 2009). This means that Pachycladon was originally formed as a result of hybridisation between two different ancestral species, and this hybrid stabilised and subsequently diversified into 10 species. Interestingly, Pachycladon has retained two copies of each of the parental genomes, and it shares these with the Australian genera Arabidella, Ballantina, and Stenopetalum which are also allopolyploid (Mandakova et al. 2010a). Furthermore, the relationship of each of the parental genomes has been revealed. One genome copy of the Australian genera and Pachycladon is closely related to the Asian Crucihimalaya and the North American Boechera, and the second genome copy is related to the Asian genera Sophiopsis and Hedinia (Joly et al. 2009; Zhao et al. 2010). Chloroplast DNA markers that are maternally inherited have also been studied, and these have shown that the mother of the original hybrid that gave rise to Pachycladon was the genome most closely related to Crucihimalaya. Using molecular clock divergence estimates of the DNA sequence data it has also been possible to infer that the two genome copies in Pachycladon diverged about 8.18mya, but that the hybridization event that led to the formation of Pachycladon occurred between 1.61–0.8mya (Joly et al. 2009). Chromosome painting, using the Ancestral Crucifer Karyotype as a template for chromosome evolution, has also confirmed the allopolyploid origin, as in Pachycladon each haploid set of chromosomes (n = 10) comprises two copies of each genome (Mandakova et al. 2010b). The ancestral and primary allopolyploid probably had 16 haploid chromosomes (n = 16), but through subsequent genome reshuffling this reduced to n = 10 haploid chromosomes. This reduction in number occurred mainly through chromosome ‘fusions’ that occurred by inversions, translocations and centromere inactivation/loss. The molecular clock dates of 1.61–0.8mya for the formation of Pachycladon are congruent with the geological history of the formation of the Southern Alps and associated glacial periods during the early Pleistocene. The major geological and ecological changes at that time have probably been the stimulus for the evolution and rapid radiation of Pachycladon in a dynamic new alpine environment. How may have this have occurred? Allopolyploids have the advantage of possessing two or more genome copies which allows the plants to tolerate major changes at both the gene and genomic levels. The two copies of a gene in an allopolyploid could allow selective advantages in speciation and adaptation.
Gene expression and plant evolution The recent origin of Pachycladon, as well as its ecological and morphological diversity, means it is ideal to study the genetic processes underlying plant speciation and evolution. Additionally, the close relationship between Pachycladon and the ‘lab-rat’ Arabidopsis thaliana enables the use of the latter’s genomic resources to provide an understanding of the processes involved in plant development and evolution. It is now accepted that major changes in plant form can be accomplished by changes in a few key genes (e.g. Doebley & Lukens 1998), but there is still much to learn about the mechanisms most important to morphological and ecological diversification during plant speciation (e.g. Mitchell-Olds 2001). For example, is selection on a small number of key genes sufficient for plant speciation? Pachycladon can be used to better understand plant
Glucosinolates and herbivore protection Analysis of glucosinolate genes involved in plant defence against herbivores showed differential expression of two myrosinase-associated genes: ESP in P. enysii and ESM1 in P. fastigiatum (Voelckel et al. 2008, 2010). These genes predict that P. enysii and P. fastigiatum would differ in the formation of glucosinolate breakdown products. In line with the up-regulation of ESP in P. enysii and ESM1 in P. fastigiatum, plants of P. enysii produced nitriles and those of P. fastigiatum produced isothiocyanates following glucosinolate hydrolysis. The significance of these results is that Arabidopsis thaliana plants producing isothiocyanates are more toxic to generalist herbivores than plants producing nitriles. Therefore, it seems that P. fastigiatum is better protected against herbivores than P. enysii (Figure 3). Given the differential expression of ESP and ESM1 genes, a characterisation of the genetic architecture of the ESP gene cluster and the ESM1 gene in Pachylcadon is being undertaken.
Habitat and ecophysiological studies The alpine species of Pachycladon generally grow above treeline in the crevices and ledges of steep (slope > 72°), shaded and south-facing rock bluffs that are often surrounded by scree slopes. Plant communities inhabiting these alpine bluffs face unique environmental challenges, such as low temperature and light. To better understand these habitats, micrometeorological stations were installed in the mountains of the South Island at populations of P. stellatum (1380m alt.), P. fastigiatum (1730m alt.), and P. enysii (1800m alt.) (Bickford et al. 2011).
NZ
science teacher 128
Figure 3: Pachycladon enysii being browsed by an alpine grass hopper. P. enysii produces glucosinolate nitriles and these do not provide as good herbivore resistance as P. fastigiatum has with isothiocynates.
biodiversity:alpineplants
speciation processes and to identify some of the key genes that may be involved in these processes. Wild populations of two of the greywacke alpine specialists, P. enysii and P. fastigiatum, were investigated for differences in gene expression using messenger RNA microarrays from A. thaliana (Voelckel et al. 2008). An important finding of this study was that 634 genes were differentially expressed between P. enysii and P. fastigiatum. In P. fastigiata 310 predominantly hormone- and stress-response genes were up-regulated, and another 324 genes were up-regulated in P. enysii. In P. fastigiatum the genes that were up-regulated include, for example, response to stress, response to cold, cold acclimation, response to biotic stimulus, response to desiccation and response to water deprivation. Their up-regulation may either be a consequence of the different environmental conditions experienced by P. fastigiatum compared to P. enysii during the sampling period, or be real species-level differences that result from different selection pressures over many generations. A second glasshouse gene-expression study also revealed differential expression of genes involved in the interconversion of carbon dioxide and bicarbonate, water use efficiency and other stress-related genes in P. cheesemanii, P. exile and P. novae-zealandiae (Voelckel et al. 2010). This study suggested that the three species diverged in physiological processes that affect carbon and water balance in addition to divergence in glucosinolate metabolism. These two gene expression studies suggest that biotic drivers, such as plant-herbivore interactions, are likely to be as important as abiotic drivers in the diversification of Pachycladon. For example, genes involved with glucosinolate biosynthesis were found to be differentially expressed between P. enysii and P. fastigiatum. Glucosinolates are important compounds in Brassicaceae and they give the distinctive taste to many vegetables.
Remarkably, plants of Pachycladon growing on shaded alpine bluffs at these three sites generally receive as little as 100–200µmolm-2 s-1 of photosynthetically active radiation (this equates to only 5–10% of full sunlight). The mean annual air temperatures are 1.1°C for P. enysii, 3.0°C for P. fastigiatum and 5.5°C for P. stellatum, and reflect the different altitudes of each site. Mean annual soil temperatures were similar to the mean annual air temperatures at the three sites. At the P. enysii site, 203 out of 365 days (55%) were ‘ice days’ where the temperature did not rise above 0°C for a 24-hour period. The question arises as to how do Pachycladon species grow successfully in this unique alpine bluff habitat? The growing season at the three alpine sites of P. enysii, P. fastigiatum, and P. stellatum appears to be limited by low air and soil temperature and reduced levels of photosynthetically active radiation. It is possible that for Pachycladon species growing in the shaded alpine bluff habitats their plant leaf temperatures are mainly regulated by air temperature and not by incident radiation. Unpublished research suggests that variation in carboxylation efficiency and photosynthetic rates vary between Pachycladon species, with the highest rates of carboxylation efficiency occuring in the high alpine species (C. Bickford pers. comm.). Comparative studies on physiological parameters such as photosynthetic carbon and light response curves, stomatal and mesophyll conductance, water use efficiency and carbon isotope discrimination found P. enysii, P. fastigiatum and P. cheesemanii to differ markedly in these parameters (C. Bickford pers. comm.). This means the high alpine species are able to grow efficiently for the short periods when the resources (suitable soil and air temperature and sunlight) they require are available. The field data from the micrometeorological stations located at the habitats of three alpine species of Pachycladon along with ecophysiological studies will to lead to a better understanding of the adaptation of these species to their unique shaded alpine bluff habitats. Furthermore, integrating gene expression and ecophysiological studies are likely to further reveal adaptation and specialisation of Pachycladon species. An example of this could be integration of water use efficiency and differential expresion of carbonic anhydrase genes. For further information contact: HeenanP@landcareresearch.co.nz continued on page 29 New Zealand Association of Science Educators
25
NZ
science teacher
biodiversity:fungi
128
the missing f-word: fungi There is an estimated fungal biodiversity in NZ of 20,000–24,000 species, of which only 7,500 are recorded. Yet fungi are functionally important to life as we know it as Peter Buchanan from Landcare Research in Auckland explains: What is the largest living organism known? Here are some clues: it’s not the blue whale, it covers over 9km2, weighs between 7,000 and 35,000 tons, is a member of the second largest Kingdom of Life, is neither an animal nor a plant – although of the two is more closely related to animals – and is at least 1900 years old! Its name is Armillaria ostoyae, a root-rot and mushroom-forming fungus from Oregon, USA1, related to one of New Zealand’s most common mushrooms known as harore (see later). Fungi are an often surprising, mega-diverse group of organisms and are critical components of biodiversity in all land environments; they are also present in freshwater and oceans. Fungi are a major kingdom of life, completely separate from the Animals and Plants. Biodiversity, beyond the bacteria and archaea, is often oversimplified as ‘fauna and flora’, but many decades have elapsed since the Fungi were recognised as a distinct kingdom related to animals. Appropriate terminology, however, has often been slow to catch up. New Zealand is rich in fungi, with a vast number of endemic species (occurring only in New Zealand). Most of our fungi have yet to be recorded. On the basis of comparisons with countries where fungi are well known, we estimate a New Zealand fungal biodiversity of 20,000–24,000 species, of which we have recorded to date about 7,500. If you aspire to name species new to science, the study of fungi is a stimulating area to be in, and is very accessible to amateurs and professionals. If you seek to understand how ecosystems function, the multiple roles of fungi are key ingredients – including contributing several of the ‘ecosystem services’ that biodiversity provides of direct necessity and benefit to humanity. Attempting to summarise a kingdom of organisms estimated to number 1.5 million species will necessarily involve generalisations. Amongst such mega-diversity exceptions abound, but in my examples I will try to focus on fungi of particular relevance to New Zealand. Our research on New Zealand’s native and introduced fungi is based on their ecological, cultural, biosecurity, food, medicinal, and conservation importance.
Ecological roles of fungi Fungi are functionally important in New Zealand’s ecosystems, and globally, because of their key interactions with plants, animals including humans, and other life forms, as well as with soils, water, and dead organic matter. Three of the important functional roles of fungi are: decomposers, parasites, and mutualists. 1. Decomposer fungi Decomposer fungi are responsible for nutrient recycling, converting dead plant, animal, and fungal matter to simple organic compounds by enzymatic digestion. Most fungi are composed of living networks of branched fine threads 1
26
http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev3_033146.pdf
New Zealand Association of Science Educators
(‘hyphae’, collectively forming a ‘mycelium’), and they can be thought of as expansive plumbing systems within soil, leaf litter, and wood. Fungal hyphae secrete digestive enzymes into their immediate surroundings, and absorb digested materials, moving these through the hyphal network to achieve growth and thereby seek further sources of food. They act in conjunction with bacteria and invertebrates; fungal decomposition of wood can make it more palatable to invertebrates. Decomposer fungi are readily seen in compost heaps, on fallen trunks and branches, as moulds on stale foods, and in gardens on wood-chip mulch. A common native fungus that has adapted to the human-engineered wood-chip mulch is the basket fungus, known to Ma¯ori as ko¯purawhetu¯ (Figure 1). You might smell this ‘stinkhorn’ fungus before seeing it as its spores are formed in a smelly slime intended to attract flies for dispersal.
Figure 1: Basket Fungus – Ileodictyon cibarium, known to Ma¯ ori as ko¯purawhetu¯. A native member of the stinkhorn fungi, with its spores dispersed by flies attracted to its slimy spore mass smelling like rotten meat. This species has adapted well to growth on wood-chip mulch on urban gardens, and can occur in quantity. Photograph courtesy of Ross Beever.
2. Parasitic fungi Parasitic fungi affect most plant species, those under cultivation as well as native species. With the New Zealand economy based on plant production (from grasses to vegetables, fruit crops, and timber trees) the economic costs for control of parasitic fungi affecting these plants are substantial. Current concern in native forests is addressing the dieback disease of kauri, caused by a fungus-like organism in the ‘plant destroyer’ genus Phytophthora. A related species, P. infestans on potato, was responsible for the Irish potato famine (1845-1852) that resulted in a million deaths in Ireland and emigration of a similar number of Irish. Parasitic fungi also directly affect animals too, with fungal diseases such as facial eczema of sheep, and thrush and dandruff in humans. 3. Mutualistic fungi Mutualist fungi are those that associate closely with other organisms for reciprocal benefit. One conspicuous group are those fungi (about 20% of all fungi) that form lichens, partnering with various species of green algae or cyanobacteria.
NZ
science teacher 128
biodiversity:fungi
Figure 2: Bootlace fungus – Armillaria novaezelandiae, known to Ma¯ori as harore. The mushrooms are edible, common in late autumn to early winter on many different kinds of dead wood. This species is also a parasite of living trees including young pines and mature kiwifruit vines, if infected dead material is present in soil adjacent to living plants.
Figure 3: New Zealand $50 banknote, featuring the skyblue mushroom Entoloma hochstetteri, known to Ma¯ori as werewere-kokako. The Ma¯ori story is that the kokako rubs its cheek (wattle) against the mushroom to gain the vivid blue colour. E. hochstetteri is a favourite subject for photographers and makes for a dramatic sight on the forest floor.
Photograph taken during icy conditions by Peter Buchanan.
Photograph courtesy of Peter Buchanan.
Lichens are known by their fungal name, with the fungus forming the bulk of the tissue while the microscopic algae provide the capability to photosynthesise. Rocks, pavements, and power poles can thus be colonised by lichens, all substrates inhospitable for growth by fungi or algae on their own. A less visible mutualism is the widespread relationship between mycorrhizal (‘fungus-root’) fungi and plant roots, a belowground feature of most species of vascular plants. Mycorrhizas assist plant growth as well as the plant’s resistance to drought stress and disease. Such associations are thought to date back to the first colonisation of land by marine plants, with fungi already present on land. In a mycorrhizal association, the fungal hyphae extend beyond the root to absorb minerals and water, some of which is then available to the root, while the fungus receives a portion of the carbohydrates manufactured in plant leaves and translocated to the root. Radiata pine seedlings, for example, are grown in nurseries supplemented with forest soil so that transplanted seedlings carry already established mycorrhizas on their roots. In native beech and tea tree forests, it is the native mycorrhizal fungi that are the dominant species forming mushrooms on the forest floor during autumn and spring.
In association with different host plants and substrates, A. novaezelandiae is atypical in performing three different ecological roles: as a decomposer fungus decaying fallen wood and dead roots and forming a characteristic large-pocket rot; as a parasite of many living plants including young radiata pines and kiwifruit; and as a mutualist forming a mycorrhizal relationship with ‘huperei’ (the black orchid, Gastrodia cunninghamii). For the latter, Armillaria provides a link via its hyphae and rhizomorphs for carbohydrates to move from its host tree to the non-photosynthetic orchid. The animal parasite, Cordyceps robertsii – vegetable caterpillar fungus or awheto, was used by Ma¯ori as a source of pigment for ta-moko or tattooing, and occasionally as a food. The fungus infects and mummifies the large caterpillars of two native moth species, and from the head of the buried caterpillar grows to form a stick-like reproductive stage, extending about 15cm above ground in order to release its spores into the air currents. Its use as a tattooing pigment reportedly followed preparation as a powdered charcoal mixed with animal fat or mahoe berry juice. The edible hakeka or wood ear is common in forests and urban bush, and was eaten by Ma¯ori though not necessarily as a food of choice. It was, however, a source of revenue for Ma¯ori and others to support the successful export “fungus trade” to China. Established by Chew Chong, a famous businessman honoured in the New Zealand Business Hall of Fame, the trade was based on widespread collection and drying of this fungus, yielding vast quantities. Two thousand tons dry weight was reportedly shipped to China over 12 years from 1872 to 1883. Today, with artificial cultivation of wood ear widespread in Asia and field collection here comparatively expensive, New Zealand now imports this fungus from Asia. The New Zealand $50 banknote, probably the only banknote in the world to feature a mushroom, relates a Ma¯ori story connecting the sky-blue Entoloma mushroom – werewere-kokako – to the kokako bird (Figure 3). Set against a backdrop of Pureora Forest where both species occur, the kokako is said to rub its head against the mushroom to gain its vivid blue wattle.
Cultural importance Judging by the number of words reportedly used for different fungi, Ma¯ori use of fungi was probably extensive in early times. Unfortunately, there has been more recent loss of oral transfer of knowledge from elders to mokopuna. Many Ma¯ori names can no longer be matched to a fungal species name. Nevertheless, about 12 species are known to have special relevance. Armillaria novaezelandiae (harore, related to the gigantic A. ostoyae referred to earlier from Oregon) was widely eaten by Ma¯ori. Abundant fruiting of this mushroom (Figure 2) in late autumn to early winter was considered a tohu (sign) of an impending lean winter season for other kinds of food. Harore has also been adopted as the most appropriate Ma¯ori word to represent all fungi as a Kingdom, as in: “Nga¯ Harore o Aotearoa” (The Fungi of New Zealand), also the title of a series comprising five volumes on New Zealand fungi. In English, harore is commonly called the ‘bootlace mushroom’ because of the black, bootlace-like ‘rhizomorphs’ by which the fungus grows along infected roots and through soil seeking food sources.
Biosecurity As an isolated island nation with high levels of trade and passage of people, our borders are vulnerable to incursion of unwanted plant and animal diseases, pests, and weed New Zealand Association of Science Educators
27
NZ
science teacher
biodiversity:fungi
128
species. Biosecurity at the border is thus a priority, to protect both cultivated and native plants, animals, and fungi, with strict procedures to prevent arrival of potentially infected materials. MAF diagnosticians detect and identify intercepted species of concern, and specialist mycologists (fungal scientists) provide research to optimise the accuracy and speed of diagnosis and management responses. These mycologists also research the diversity of New Zealand’s native and introduced fungi, contributing multiple benefits including the ability to recognise when interceptions are new organisms. Introductions of non-parasitic fungi are also a threat to New Zealand. Recent examples of ‘fungal weeds’ include the orange-pore fungus, Favolaschia calocera, that has spread through native forests from Auckland to southern Westland since the late 1960s, and the mycorrhizal Amanita muscaria (fly agaric) that has jumped hosts from pines and oaks to native beech, potentially competing with native mycorrhizal fungi. Some managed new introductions of parasitic fungi, however, may be desirable to control plant weeds such as old man’s beard and blackberry. Importation of these biocontrol fungi is tightly regulated by the Environmental Protection Agency. As parasites specific to a target weed, their role can replace the costs and toxicity of chemical weed control.
well as cyclosporine from Tolypocladium inflatum used in organ transplants to reduce rejection of the new organ.
Fungal conservation Along with most other groups of organisms, survival of many species of fungi is threatened by a combination of habitat destruction, biodiversity loss, pollution, and climate change. Fungi are included in New Zealand’s threat classification lists, although strategies to conserve our most threatened species and even to fully recognise all species under serious threat are only now under development. Currently, 62 species of fungi are listed in the highest Department of Conservation threat category of ‘Nationally Critical’, 43 are listed in lower threat categories, and about 1100 are listed as data deficient reflecting a lack of information on which to base informed decisions. Only a subset of fungi have been assessed for threat status, mainly the macrofungi – those forming reproductive structures visible to the naked eye –but also some microfungi where these are specifically associated with a single threatened plant or animal host. As an example of a Nationally Critical fungus, Ganoderma sp. “Awaroa” (Figure 4), yet to be formally named, is a large bracket fungus known from only three specimens collected on pukatea trees in the Waikato between 1969 and 1972, and not seen since. Might it have gone extinct?
Food and medical importance Edible mushrooms are an economically important food in New Zealand and globally. Harvest of wild mushrooms is uncommon in New Zealand, except for the common field mushroom, and edibility or toxicity of most of our native fungi is unknown. Commercial production is largely of the button mushrooms, Agaricus bisporus and A. bitorquis, distinct from the field mushroom and harvested at different stages of maturity and hence size (viz. buttons, cups, and flats). Commercial cultivation of button mushrooms is an exacting and demanding process, with production concentrated in large farms equipped with climate control and rigorous hygiene protocols. Some specialty mushrooms such as oyster mushrooms (Pleurotus pulmonarius) and shiitake (Lentinula edodes) are also cultivated locally on hardwood sawdust, retailing fresh at much higher prices than Agaricus. Oyster mushrooms also lend themselves to demonstrations of mushroom development in the classroom (see resources below). Much higher value edible mushrooms include the truffles. Research by scientists at Plant & Food Research engineered truffle mycorrhizas on oak and hazel seedlings that were then sold for managed plantings throughout New Zealand. Harvesting of the buried truffles requires detection by a sensitive nose as provided by a specially trained truffle dog. Local prices of $3,000 to $4,000 per kg are very attractive, but success in production has varied widely across planted truffle orchards. Other introduced edible mycorrhizal fungi also offer potential commercial revenue, including the saffron milk cap (Lactarius deliciosus) recently planted with pines in the Gisborne region, and the cep (Boletus edulis) harvested under mature oak trees in Christchurch. Of course, microscopic fungi such as the Saccharomyces yeasts, and the mould fungi Aspergillus and Penicillium, are essential organisms in industrial-scale production of common foods and beverages including bread, wine, beer, cheese, Marmite, and soy sauce. Products made of the meat substitute ‘Quorn’ are popular in Europe, manufactured from mycoprotein from the fungus Fusarium venenatum. Medicinal mushrooms are a thriving business particularly in many Asian countries, and fungi have contributed many compounds of medical importance such as the Penicilliumderived antibiotic penicillin and antifungal griseofulvin, as 28
New Zealand Association of Science Educators
Figure 4: Dried specimen of Ganoderma sp. “Awaroa” (PDD 29835), a Nationally Critical threatened fungus, awaiting formal description. The specimen illustrated is 34cm across, and one of only three known specimens of this species, last collected in 1972 on pukatea from Waikato. Photograph courtesy of Peter Buchanan.
Relevance to curriculum The importance of fungi in New Zealand and globally needs to be appropriately reflected in education curricula, and there is great potential for this to receive further development in New Zealand. Fungi are occasionally mentioned in the curriculum, and might be intended for inclusion under the word ‘microorganisms’. As a term, microorganisms is typically applied to a vast assemblage of organisms that are of microscopic size, including the bacteria, archaea, microscopic algae, microscopic fungi including the unicellular yeasts, protozoa and (in some definitions) viruses. As such, it covers the microscopic members of both prokaryotes and eukaryotes, and for the latter includes plants, animals, and fungi. Most fungi are not microorganisms, even though their hyphal structure typically comprises microscopic elements. In the same way, most plants and animals are not microorganisms, even though plant and animal cells are themselves microscopic. With an emphasis on the biology of New Zealand organisms, the Living World strand of the New Zealand Curriculum is, as stated in the Achievement Aims for Ecology, Life Processes and Evolution: “…about living things
Resources for the teaching of fungi deserve better dissemination and availability. Those known to me and currently available are listed below. For further information, contact: BuchananP@LandcareResearch.co.nz Footnote: Peter and colleagues at Landcare Research in Auckland manage two national collections of fungi – PDD: containing 90,000 dried specimens of fungi, and ICMP: holding 8,000 living strains of fungi, mostly under liquid nitrogen. Acknowledgments: I thank Carolyn Haslam, Faculty of Education, The University of Auckland, for assisting me to understand elements of the New Zealand Curriculum. I acknowledge funding from Ministry of Science and Innovation through the Defining New Zealand’s Land Biota Biosystematics contract.
NZ
science teacher 128
biodiversity:fungi
and how they interact with each other and the environment. Students develop an understanding of the diversity of life and life processes, of where and how life has evolved, of evolution as the link between life processes and ecology, and of the impact of humans on all forms of life.” (Italics my own). The strand is appropriately inclusive in intent. Living World objectives for Levels 1 to 3 address all ‘living things’ or ‘plants, animals and other living things’, but for Levels 5 to 7 (e.g. life processes) I note that the wording defaults to ‘plants and animals’ or to ‘plants, animals, and microorganisms’. The new Achievement Standards, Science 1.11 and Biology 1.3, are intended to specifically include fungi. There are also several examples of Biology Achievement Standards where fungi can serve as relevant organisms for practical work and study including: Biology 3.1 (Carry out a practical investigation into an aspect of an organism’s ecological niche with guidance): e.g. fungi on wood-chip mulch; plant diseases such as kauri dieback; bread mould; edible mushrooms such as oyster mushrooms. Biology 2.4 (Investigate an interrelationship or pattern in an ecological population or community): e.g. lichens; fungi on wood-chip mulch; plant associations of mushrooms; decomposition rates of different foods. I suggest that Biology 3.4 (Describe animal behaviour and plant responses in relation to environmental factors) could be more inclusive since the criteria applicable for animals and plants (i.e. orientation, timing, interspecific relationships…) are equally relevant for fungi. Among Achievement Standards, # 90462 and # 90463 are, respectively: ‘Describe diversity in the structure and function of animals’; and and ‘Describe diversity … of plants.’ Ironically, # 90464 is not ‘Describe diversity …of fungi.’ Instead, it is: ‘Describe cell structure and function ….Cells will include: plant cells, animal cells, and unicellular organisms.’ effectively excluding most fungi!
References Fuller, R., Buchanan, P.K., & Roberts, M. (2004). Ma ¯ ori Knowledge of Fungi/ Ma¯tauranga o Nga¯ Harore. In E.H.C. McKenzie (Ed.) – see below. Pp.81-118. Hall, I., Buchanan, P., Wang, Y., & Cole, A.L.J. (1998). Edible and Poisonous Mushrooms, an Introduction. New Zealand Institute for Crop & Food Research, Christchurch. McKenzie, E.H.C. (ed.). Introduction to Fungi of New Zealand. Fungi of New Zealand/Nga¯ Harore o Aotearoa, 1, 1- 498. Parsons, S., Blanchon, D., Buchanan, P., Clout, M., Galbraith, M., Ji, W., Macdonald, J., Walker, M., & Wass, R. (2006). Biology Aotearoa: Unique Flora, Fauna and Fungi. Pearson Education New Zealand, Auckland. Ridley, G., & Horne, D. (2006). A Photographic Guide to Mushrooms and other Fungi of New Zealand. New Holland Publishers, Auckland.
More fungal resources http://www.sciencelearn.org.nz/Science-Stories/Microorganisms/Fungi Anonymous 2004. Moulds Are Fungi – Structure, Function, and Interrelationships. Ministry of Education, Building Science Concepts no. 53. (Level 3-4) Internal Assessment Resource, Science 1.11A ‘Fermented Food’ http://www.14u.co.nz (edible mushroom kits for schools) http://www.clarku.edu/faculty/dhibbett/TFTOL/ (teaching lessons) http://science.lotsoflessons.com/fungi.html (teaching lessons) Collect and learn about fungi at the Fungal Network of New Zealand’s (www. funnz.org.nz) annual New Zealand Fungal Foray, now in its 26th year – and open to all.
continued from page 25
Acknowledgements The research discussed here is part of a collaborative research programme that is lead by Dr Peter Heenan (Landcare Research) and Prof. Peter Lockhart (Massey University). Important collaborators in this research have included Drs Claudia Voelckel, Anthony Mitchell, Cilla Luo, Ross Bicknell, Simon Joly, Martin Lysak, Terri Mandakova, Chris Bickford, Matthias Becker, Nicole Grunheit, Oliver Deusch, Paul Haynes, and Krithika Yogeeswaran. Funding for this research has been provided by New Zealand Marsden Fund, New Zealand Ministry of Science and Innovation, Feodor-Lynen Postdoctoral Fellowship from the Alexander-von Humboldt Foundation, Natural Sciences and Engineering Research Council of Canada, Czech Academy of Science and the Czech Ministry of Education, Landcare Research and Massey University.
References Bickford C.P., Hunt J.E., & Heenan P.B. (2011). Microclimate characteristics of alpine bluff ecosystems of New Zealand's South Island, and implications for plant growth. New Zealand Journal of Ecology, 35, 273-277. de Lange P.J., Norton D.A., Courtney S.P., Heenan P.B., Barkla J.W., Cameron E.K., Hitchmough R., & Townsend A.J. (2009). New Zealand extinct, threatened and at risk vascular plant list. New Zealand Journal of Botany, 47, 61-96. Doebley J., & Lukens L. (1998). Transcriptional regulators and the evolution of plant form. Plant Cell, 10, 1075-1082. Heenan P.B. (1999). Artificial intergeneric hybrids between the New Zealand endemic Ischnocarpus and Pachycladon (Brassicaceae). New Zealand Journal of Botany, 37, 595-601. Heenan P.B. (2009). A new species of Pachycladon (Brassicaceae) from limestone in eastern Marlborough, New Zealand. New Zealand Journal of Botany, 47, 155-161. Heenan P.B., & Garnock-Jones P.J. (1999). A new species combination in Cheesemania (Brassicaceae) from New Zealand. New Zealand Journal of Botany, 37, 235-241.
Heenan P.B., Mitchell A.D. (2003). Phylogeny, biogeography, and adaptive radiation of Pachycladon (Brassicaceae) in the mountains of South Island, New Zealand. Journal of Biogeography, 30, 1737-1749. Heenan P.B., Mitchell A.D., Koch M. (2002). Molecular systematic of the New Zealand Pachycladon (Brassicaceae) complex: generic circumscription and relationships to Arabidopsis s. l. and Arabis s. l. New Zealand Journal of Botany, 40, 543-562. Hooker J.D. (1867). Handbook of the New Zealand flora. Reeve, London, UK. Joly S, Heenan P.B., Lockhart P.J. (2009). A Pleistocene intertribal allopolyploidization event precedes the species radiation of Pachycladon (Brassicaceae) in New Zealand. Molecular Phylogenetics and Evolution, 51, 365-372. Mandakova T., Joly S., Krywinski M., Mummenhoff K., & Lysak M. (2010a). Fast diploidization in close mesopolyploid relatives of Arabidopsis. Plant Cell, 22, 2277-2290. Mandakova T., Heenan P.B., & Lysak M.A. (2010b). Island species radiation and karyotypic stasis in Pachycladon allopolyploids. BMC Evolutionary Biology, 10, 367. doi:10.1186/1471-2148-10-367. Mitchell A.D., & Heenan P.B. 2000. Systematic relationships of New Zealand endemic Brassicaceae inferred from rDNA sequence data. Systematic Botany, 25, 98-105. Mitchell-Olds T. (2001). Arabidopsis thaliana and its wild relatives: a model system for ecology and evolution. Trends in Ecology and Evolution, 16, 693-700. Schulz O.E. (1924). Cruciferae-Sisymbrieae. Das Pflanzenreich IV 105 (Heft 86): 1-388. Schulz O.E. 1936. Cruciferen. In A. Engler and H. Harms (Eds.), Die Nat€ urlichen Pflanzenfamilien 17b, 2nd edn, pp. 227-658. Leipzig, Engelmann, Germany. Voelckel C., Heenan .P.B., Janssen B., Reichelt M., Ford K., Hofmann R., & Lockhart P.J. (2008). Transcriptional and biochemical signatures of divergence in natural populations of two species of New Zealand alpine Pachycladon. Molecular Ecology, 17, 4740-4753. Voelckel C., Mirzaei M., Reichelt M., Luo Z., Pascovici D., Heenan P.B., Schmidt S., Janssen B., Haynes P.A., & Lockhart P.J. (2010). Transcript and protein profiling identify candidate gene sets of potential adaptive significance in New Zealand Pachycladon. BMC Evolutionary Biology, 10, 151. Yogeeswaran K., Voelckel C., Joly S., & Heenan P.B. (2011). Chapter 14 Pachycladon. In C. Kole (Ed.), Wild Crop Relatives: Genomic and Breeding Resources, Oilseeds, DOI 10.1007/978-3-642-14871-2_14, Springer-Verlag Berlin Heidelberg. Zhao B., Lui B., Tan D., & Wang J. (2010). Analysis of phylogenetic relationships of Brassicaceae species based on CHS sequences. Biochemical Systematics and Ecology, 38, 731-739.
New Zealand Association of Science Educators
29
NZ
science teacher
primaryscience
128
nature of science in action This ‘Nature of Science in Action’1 article focuses on ‘Communicating in Science’2 and provides examples of activities that can be used in the classroom to support the teaching of the four strands within Nature of Science, as Chris Astall explains: Developing children’s scientific attitudes, their understanding of ideas about science, what science is and how scientists work, is central to the New Zealand Curriculum (NZC)3. The Nature of Science (NoS) is the core strand of the NZC and the major contexts for developing these ideas about NoS are provided in the other four strands: Living World, Planet Earth and Beyond, Physical World and the Material World.
Kirwee Model School Teachers at Kirwee Model School (KMS) have been exploring how they can develop children’s understanding of the Nature of Science through authentic contexts. With the 2011 National Primary Science Week falling at the start of Term 2, the school took the opportunity to have science as the focus for the whole of the term. There was a science rotation one day each week for 5 weeks (see Table 1). The cycle was then repeated for another 5 weeks with the Junior and Senior rotations swapping. Each rotation was for one hour. Table 1: Five weeks’ rotations for the science day at Kirwee Model School Junior Paper making
Yr 1
Yr 2
Yr 3
Kitchen chemistry
Yr 2
Yr 3
Yr 1
Electricity
Yr 3
Yr 1
Yr 2
Yr 4
Yr 5
Yr 6
Senior Dyes Water cycle
Yr 5
Yr 6
Yr 4
Worms
Yr 6
Yr 4
Yr 5
Communicating in Science Using examples of what NoS could look like (Bruce & Astall, 2009)4, the six teachers and Principal of the school identified two ideas within each aspect of the NoS strand that they would, as a school, focus on teaching. For the ‘Communicating in Science’ aspect, these were ‘Communicating Careful Observations’ and ‘Building Scientific Vocabulary’. The teachers then worked together to develop a KMS rubric for each aspect. When planning the science 1
2
3
4
30
The first article in this series explored ideas to teach the ‘Understanding about Science’ strand within the Nature of Science. Astall, C. (2011). The nature of science in action. New Zealand Science Teacher, 126, 43-42. The second article in the series looked at the ‘Investigating in Science.’ Sexton, S. (2011). Nature of science activity. New Zealand Science Teacher, 127, 41-42. At Level 1/2: Build their language and develop their understandings of the many ways the natural world can be represented. At Level 3/4: Begin to use a range of scientific symbols, conventions, and vocabulary. Engage with a range of science texts and begin to question the purposes for which these texts are constructed. Achievement aims and objectives can be found at: http:// nzcurriculum.tki.org.nz/Curriculum-documents/The-New-Zealand-Curriculum/ Learning-areas/Science/Science-curriculum-achievement-aims-and-objectives Ministry of Education, The New Zealand Curriculum, Learning Media, Wellington, 2007, pp28-29 From Bruce, W., & Astall, C. (2009). Thinking about the nature of science? New Zealand Science Teacher, 122, 46.
New Zealand Association of Science Educators
unit, teachers ensured that these two aspects of ‘Communicating in Science’ were explicitly planned for, that they were clearly connected to the context and that they were linked to an investigation. What follows are examples of how two teachers integrated the ’Communicating in Science’ strand of NoS into their science teaching.
Example 1: Paper Making Paula (Year 1 teacher) developed a science unit around the context of paper making. Children explored the properties of a range of different paper. They then made their own recycled paper and finally, tested some properties of their paper and compared and contrasted it to other types of paper. Paula used a number of activities from the Making Better Sense of the Material World resource5. Communicating Careful Observations Paula focused specifically on Communicating Careful Observations. At the start of each lesson she introduced the KMS rubric that the teachers had developed (see Figure 1). In Paula’s classes, the children were shown that using a ‘table’ is just one way of organising their observations. Children were encouraged to provide evidence of observations within their table in a number of different forms. They were able to draw, write, include samples of paper and take photos. They were then expected to report back to the class what they had found. This provided the children with rich examples of different ways of communicating their observations. Paula commented: “I liked the fact that that we [teachers] had written a range of ideas [for communicating observations] on our rubric because initially all I could think of was to draw or write what they saw! I also found the rubric incredibly helpful when providing feedback to the children about their observations and to get them to peer and self-assess their work”. The younger children were introduced to a flowchart to share the process of making their own paper (Figure 2). Paula modelled this using the interactive whiteboard, with children choosing the most appropriate photo to place on the flowchart. Paula provided more photos than spaces on the flowchart and this led to great discussion about which photos represented what actually happened. More discussion and decision making took place as the children worked as a group and placed photos onto a class flowchart. Paula did find that when teaching children the range of ways to communicate observations she had to adapt the templates and develop more specific, challenging success criteria for the older children which resulted in those children producing higher quality work. Paula commented: “I structured lessons slightly differently for each age group – making the younger children's sessions more hands-on, group observations (rather than individual or pairs) and templates that required no writing. With the older children I expected them to work more independently and I gave them more explicit success criteria and reflection time. The most 5
‘The Science Toolbox’ lists a variety or resources that can be used to support science teaching in the classroom. http://www.minedu.govt.nz/NZEducation/ EducationPolicies/Schools/PublicationsAndResources/ScienceToolbox.aspx
NZ
science teacher 128
primaryscience
Figure 1: The KMS rubric for ‘Communicating Careful Observations’, one aspect from ‘Communicating in Science’. useful tool for me was the rubric we made on Communicating and Sharing Observations, I used this every session and the children seemed to grow in understanding as we got to the end of the unit. I also used the interactive whiteboard to set the scene at the start of each lesson and provide some interaction with the learning goals and prior learning”. With the older children, Paula used a jigsaw activity that allowed the children to record their observations in four different ways. They used flowcharts, drawings, videos (iPod Touch or Flip video) or writing (description or report). At the conclusion of the jigsaw activity Paula used the rubric (Figure 1) to allow the groups to self-assess and then they peer reviewed one another. By allowing the children time to see the other types of communication and reflect on the type of information, type of data gathered, ease of collection and communication style, the children were more able to select and make choices about the method of communication they would like to use for their next investigation. Paula noted that: “It was interesting to talk to the children and ask them about their favourite way of recording observations and about which way would suit different tasks.” This process also gave Paula the opportunity to reinforce the idea that science must be able to withstand peer review and to encourage the use of argument and scepticism when sharing science ideas. To do this children need to be able to argue their point, maybe using evidence and, more importantly, be prepared to review and revise their ideas if they don't withstand peer review. When asked to review her work with the children over the term, Paula commented: “I think with thorough planning and support…this has been my most successful science unit yet! I am confident in using a variety of ways of communicating observations and feel that I have managed to teach these methods to a range of children effectively. I have enjoyed using the resources that we have been provided with and the rubrics that we have come up with together. I have been challenged to be organised and well resourced each week and I think that I have lifted the expectations of my teaching as well as the children's learning. I believe the children have learnt a lot about science and about their learning through the use of these resources [rubrics] and the provision of such exciting hands-on experiences throughout the school. I have evidence
that the quality of the children's observations has improved, especially in the senior level.”
Example 2: Dyeing to try it! Karen (Year 3 teacher) had developed a unit based around dyes. Her focus was the book by Dr Zuess ‘Green Eggs and Ham.’6 The series of five lessons culminated in the children creating and tasting green eggs! The children created their own vegetable dyes, tested the effectiveness of the dyes on different fabrics, looked at how to get dyes to stick to the fabric (using a mordant), explored food products that contain dyes and also looked at colour changing dyes. Karen used a range of activities from the Making Better Sense of the Material World resource.
Building Scientific Vocabulary Karen’s focus for her teaching was on Building Scientific Vocabulary (see Figure 3). While planning her lessons, she also made careful use of the rubric that the KMS staff had developed. “I also tried all the experiments at home first. When writing my plan, I focused on the specific learning outcomes (making careful observations and building scientific vocabulary) with an emphasis on providing opportunities for students to be hands-on and engaged. During the sessions we used a variety of thinking maps, worksheets and ICT to record observations. An area in the classroom was set aside for equipment and a wall display exclusively for science. During each session students were encouraged to refer to the KMS rubrics and prompted to extend their thinking and justify their answers/ ideas with evidence.” To help focus the children on using scientific vocabulary, Karen developed a word wall of terms and words that she had identified as ‘scientific’ as well as ones that the children had identified. Karen was able to look at those words that may cause confusion because they had both an everyday as well as a scientific meaning. Karen noted: “This week with the senior students I felt more confident applying student centred lessons more so than with the juniors. The students enjoyed learning some new scientific vocabulary – we have started a word wall. The children were keen to independently experiment to see if their dye bath 6
Dr Seuss (1960). Green Eggs and Ham. USA: Random House.
New Zealand Association of Science Educators
31
NZ
science teacher
provide purposeful hands-on activities which relate directly to the learning outcomes. During discussions students are using scientific vocabulary (such as acids, alkaline, mordants…) in context. I believe that I have met my goal – a better understanding of the NoS and student engagement in purposeful hands-on activities – whilst also receiving effective NoS instruction.”
primaryscience
128
Using rubrics
Figure 2: Year 1 children making choices as they construct a flowchart to show the process of making their paper. would work on other fabrics. It was great at the end of the lesson to have helpers and time for clean up! I think my next step is to build my own understanding of scientific vocabulary e.g. mordants and hydrophilic.” Karen was able to use the rubric to help guide the children towards using their science vocabulary in a variety of situations. As part of their digital science portfolio, the younger children created a PhotoPeach7 slideshow celebrating their work. This was enriched with children’s descriptions of the science activities. Here, Karen was able to use the rubric to assess the progression of the children. When asked about the impact of using the rubrics within her science teaching, Karen commented: “I have enjoyed watching the children develop their ability to communicate their learning ‘scientifically’ against the KMS rubrics (seedling/ sapling/tree). My next step is to work towards providing a range of ways in which the children can record their understandings. I am now more confident in providing student centred learning opportunities in science. I am now more aware of how to use simple equipment/resources to
As KMS will have another science focus during Term 4, the teachers will continue to work with the rubrics to support the children’s learning. As one teacher remarked: “The rubrics have made the development of skills in this area more explicit and I will use them to better direct my planning next time.” The Principal at KMS, Sarah Wiki-Bennett, explained how the rubrics have supported teaching and learning within the Nature of Science: “I was a little bit dubious at first because we have had our learners’ qualities for some time…the seed, sapling, tree scenario…so using the rubrics has never taken off to the extent that the science ones have. [Recently] my appraisee was here and when he spoke to the students to get their perspective about the way they gauge their learning, they spoke about using the seed, sapling and tree and I know they have only ever done this in science! Clearly it has made an impact on them but it is also coming through to the parents, because [they are using the rubrics for] goal setting for the next six months. One of the children said it [rubric] was really good because when you see where you are all you do is read the next stage and just figure out a way, with your teacher, how to move from one [stage] to the other. They have been really good maps for children and teachers to use, as it has created pathways and is quite effective. More explicit teaching has happened around teaching and using a range of communication methods [Communicating in Science]. Using the rubric to help construct and scaffold their understanding and learning, students were able to see for themselves on the rubric which level they were. I believe we now have a good model of how to facilitate student learning around communication.” If you would like further information about the KMS Project, please contact Chris at: chris.astall@canterbury.ac.nz
Figure 3: The KMS rubric for ‘Building Scientific Vocabulary’, one aspect from ‘Communicating in Science. 7
32
http://photopeach.com/
New Zealand Association of Science Educators
advancing primary science – a strategy NZ
science teacher 128
The Royal Society of New Zealand (RSNZ) is concerned that science teaching and learning in primary schools does not have the emphasis that it should. There are a number of reasons for this, but one that has been identified is that many primary teachers are not confident with science concepts. This lack of confidence may come from their own limited educational experiences in science, a concern they won’t have the background knowledge to answer student questions, or the perception that science involves carrying out ‘experiments’ using unfamiliar equipment. In his 2011 report Science Education for the 21st Century1, Sir Peter Gluckman wrote, “If teachers are not able to answer children’s questions at primary school with confidence and enthusiasm, then children detect that lack of confidence and enthusiasm and that spirit of enquiry can be lost.”2 While we recognise that teachers will not have all the answers, we want to avoid the situation described above by supporting primary teachers in building their confidence in such a way that allows them and their students to feel the same in science as they do in other subject disciplines. The RSNZ’s Advancing Primary Science strategy looks to raise the profile of science teaching and learning in primary schools in a variety of ways.3
Working in partnership The RSNZ has historically worked collaboratively with the NZASE and the most recent initiative, Curious Classrooms, is a collaboration between the Todd Foundation, local science providers and the Auckland Science Teacher Association (ASTA). This involves giving primary school children in South Auckland exploring hands-on science experiences. At the same time, ASTA provides professional learning opportunities for the teachers and providers to ensure these events are not limited to the one-off experience. Ian Kennedy, Director of the National Science and Technology Roadshow Trust, has been engaged by the Todd Foundation to develop the processes and to oversee the implementation of the initiative. Another exciting initiative was the launch in May 2011 of the first National Primary Science Week. Teachers from over 300 schools attended workshops held in a variety of locations. Corporations assisted in the production of teacher and student material, as well as support for posting experiments and forums online. As Dr Di McCarthy, Chief Executive of the RSNZ said, “We hope that this focus on science will help primary school teachers gain confidence in teaching science, and find ways to get young people buzzing about science.”
Teaching resources In 2009, the RSNZ commissioned the Making the Most of Science articles which looked at the importance of effective and exciting science teaching. This series was published in the September and October issues of the New Zealand Education Gazette. The RSNZ provides a number of online resources4: • Alpha series – information leaflets designed to support 1 2 3 4
http://www.royalsociety.org.nz/media/Science-education-PDF-version.pdf Pg 4, Science Education for the 21st Century http://www.royalsociety.org.nz/organisation/about/aps/about/ All resources found at http://www.royalsociety.org.nz/
•
•
•
• •
the learning of the science curriculum (check out the Harakeke and NZ Frogs issues) The BP Challenge – students work in teams and are required to design and develop solutions to problems using easily resourced materials (ideal for practising the Key Competencies) Primary CREST awards – activities designed to motivate primary students and develop an interest in science and technology Gamma series – discussion papers based on current issues that emerge in the media and become part of public debate (check out the Dirty Yucky Hands issue) Heads Up and CRESTlet – daily postings of interesting links to a wide variety of resources Science Teacher Announce – a notification service of science events.
primaryscience
The Royal Society of New Zealand is supporting Primary Science teaching, as Jessie McKenzie explains:
Working alongside teachers To support teachers’ professional learning the RSNZ administers two fellowship programmes5. Endeavour Teacher Fellowships – a two-term programme of professional learning designed to give teachers cutting edge knowledge in their subject discipline, to develop leadership capacity and to support excellent teachers in providing high quality teaching and learning programmes Primary Science Teacher Fellowships – a programme intended to create primary sector curriculum leaders in science. Teachers are placed in a scientific organisation for a period of two terms allowing them to observe and learn more about the processes of science and science research. These teachers participate in curriculum development workshops and leadership programmes that are designed to improve their ability to lead science education in their school upon their return.
Supporting science education In May 2011, the RSNZ convened a group of primary science educators and representatives of relevant organisations to host a Forum on Primary Science Education for the 21st Century. The aim was to generate a set of recommendations for the advancement of primary science that would be passed on to the RSNZ Education Committee. A process is being developed to identify, recognise and celebrate, ‘champions’ of primary science education. RSNZ and NZAPSE are planning the 2012 National Primary Science Week as well as the primary section of the SciCon 2012. In conjunction with TRCC two primary science conferences are being planned for 2013.
So, what can you do?6 Join your local science network, subscribe to Heads-Up and Science Teacher Announce, use the Primary CREST materials (all free), explore the links, keep up to date with current ideas and research, share resources and/or send your ideas for advancing primary science education to: AdvancingPrimaryScience@royalsociety.org.nz By working together, we are collectively able to advance primary science education in New Zealand. For further information contact: jessie.mckenzie@royalsociety.org.nz
5 6
Information found at http://www.royalsociety.org.nz/programmes/ See http://www.royalsociety.org.nz/ for further information
New Zealand Association of Science Educators
33
NZ
science teacher
diversity:parentingandschoolscienceeducation
128
conversing about science at home Using three case studies, Claire Donald (University of Auckland) and Miles Barker (University of Waikato) explore parenting and school science education. Parents’ influence on the science education that their children are receiving at school rarely features in science teachers’ journals. Perhaps we science teachers are ambivalent about parents’ roles; while we like to think that parents are working with us on a common educational enterprise, we also see ourselves as professionals with privileged expertise. However, from the parents’ point of view, the messages they get about what is going on in their children’s school science can be something of a mystery – tantalising, inscrutable, sometimes uplifting and sometimes worrying. And for parents, who are well-intentioned but who nevertheless feel they are ‘outsiders’ in this situation, there is a challenge here: How should they respond? In this article we present case studies of three children engaging in school science education at three different levels: primary, intermediate, and high school. Josh (of course that is not his real name) is a sparky 7 year-old in a semi-rural primary school whose wild enthusiasms about everything from rockets to robots frequently bewilder his patient parents. Mei-Chun is an 11 year-old at a rural primary school whose parents listen to her sometimes ecstatic, sometimes confusing accounts of a school-led project about sustainability. Rajev, 13 years old, tosses his bag in the corner of the kitchen and holds forth to whoever will listen on the ups and downs of his science learning in a large, urban secondary school. All three youngsters were born in New Zealand; and their parents, who all migrated to New Zealand well before the children were born, care deeply about their future. The case studies document snippets of ‘bring home conversation’ between the children and their parents. First, however, we shall take a step back and suggest that there may be a spectrum of at least five basic roles that parents play in their children’s science education. We then reflect on the three cases in light of these roles. Next, we draw some conclusions about what we see as the key question for this article, namely: How might parents respond to their children’s ‘school talk’ about their learning in science to best support their interest and motivation to achieve? To do this, we cautiously draw out what seems to us to be very laudable features of the content and style of the parents’ responses. Finally, we offer some more general thoughts about the roles of parents at large in science education.
2.
3.
4.
Five roles of parents in science education To establish and clarify the role of our three sets of parents, we place this in the context of five (often very overlapping) roles: 1. Parents as official teachers Primarily, this entails home schooling (Katz, 1996). In New Zealand, these parents must obtain approval for their programme submitted to the Ministry of Education. Science may be one of the two subjects per year for which materials can be uplifted from Te Aho o te Kura Pounamu (the Correspondence School). The Education Review Office currently carries out a tiny number of discretionary reviews of these programmes in homes. Writing about the British context, Solomon (2003, p.219) notes that “at home the children’s 34
New Zealand Association of Science Educators
5.
participation becomes far more relaxed and personal, just as discussion with their parents is more fluent than at school.” Parents as empathisers These parents rely on schooling to anchor their children’s science education but nevertheless, they are active listeners who, in home conversation, persistently try to unravel the soundings they perceive from school science. Not necessarily owning a comprehensive knowledge of science content themselves, but with a feel for inquiry processes generally, they do what they can to interrogate, support and promote what appears to be going on in school science. Research as to how this actually happens, that is, the focus of the present article, is scant. Ash (2003) comments that: “looking at dialogue is not new to classroom research” – the classic study of Edwards and Mercer (1987) initiated much of this – “but it is relatively new to informal research settings.” And ‘informal’ science learning – in museums, science centres, science trails, etc. – is usually still assumed to be teacherfacilitated (Braund & Reiss, 2004; Hofstein & Rosenfeld, 1996). The research on informal science learning rarely mentions home dialogue (see Dierking & Martin, 1997; Rennie & Feher, 2003; Rennie, 2007). Parents as resource providers Very media-aware, these parents set up family visits to exhibitions, museums, zoos, etc. and the families are likely to be involved in community conservation projects and groups. Some research reports on how families converse in museums (Ash, 2003) and other venues (Dierking & Falk, 1994), and the part that information and communication technology plays in such homes (Wellington & Britto, 2004). Parents as enforcers These parents see their role only as ensuring that tasks prescribed at school, especially homework, are rigorously pursued, but they do not necessarily engage with the specifics of the children’s science learning. This relationship is currently being researched (Tapper, 2011) and the virtues of adopting “a fierce, achievementorientated parenting style” (Laugesen, 2011) of parent/ child dialogue have recently been debated in media worldwide. Parents as absenters These parents have little or no influence on their children’s science education. The seriousness of this is underscored by Heyneman’s (1997) finding, based on research in 29 countries: that in countries such as Holland, Australia, Scotland and England only 25–35% of school science achievement is attributable to the school
environment; home factors were far more influential. Most of what our children learn is not in formal education settings (Boshier, 2009). We now present the three case studies, documented as 11 vignettes – snippets of conversations which the parents saw as significant and memorable, and which they recorded, diary-fashion, soon after.
Case study 1: Josh Josh is a 7-year-old, Year 3 student at a semi-rural primary school. These two vignettes took place in the first week of Term One. In this first vignette, Josh (J) has run inside for dinner. His mum (M) dusts pine needles off his back; he’s been climbing trees again. His dad (D) and his 12-year-old sister (S) are already sitting at the table: J: Dad, did you know if it weren’t for plants we’d all be exTINCT!!? D: Yes. S: And without bees we’d also be extinct. D: Maybe. J: No! S: Yes! The plants are pollinated by the bees. If there’s no pollination there won’t be any more plants… M: Well, flowering plants. J: No way! The plants wouldn’t die without bees! Look, that plant doesn’t have flowers (pointing to some trees outside), and (looks at the lawn outside) grass doesn’t have flowers. They don’t need bees. S: Josh, most of the plants we eat for food have flowers. J (munching on a carrot): Carrots don’t have flowers. D: Well Josh, I know we don’t see them often in the veggie patch, but carrots are flowering plants. The second vignette occurred a few evenings later when Mum was reading a bedtime story about dinosaurs to Josh: M: Remember what you said after school today about there still being dinosaurs in New Zealand? J: Yes. M: Are any of them in this book? J: No, our dinosaurs are crocodiles and alligators and… what’s that other one again? M: Tua…ummm… J: Tuataras! M: That’s it. Then there’s a pause… J: Why aren’t they in this book? M: Don’t know. Want to look for them in the other dinosaur books in the school library tomorrow? J: Nah – I wanna play soccer with Connor and Tyler. M: Hmm – do you think they looked the same way back then? J: The tuatara? M: Mmm… J: Why, would it look different? M: Just wondering – look how different the Earth looked in those days. J: Mum, how does the person who drew those pictures in my book know what it looked like when the dinosaurs were here? There were no people around then. M: Now that’s another good question, Josh. We’ll have to wait ‘til tomorrow. (She stretches over and switches off Josh’s light.)
Case study 2: Mei-Chun Mei-Chun is an 11-year-old, Year 6 primary school student. This vignette occurs in the context of Mei-Chun’s school receiving a Green-Gold award for sustainability. Mei-Chun
NZ
science teacher
Case study 3: Rajev Rejev is a 13-year-old Year 9 student at a large urban secondary school. The following eight vignettes, captured through one year at secondary school, have as their point of departure an incident near the end of Rajev’s final year at intermediate school. One evening at home over a cup of Milo, Rajev was mulling over his subject choices for the coming year. He suddenly asked: “What is ‘science’?” His parents were horrified. How could he be near the end of Year 8 and not know what science is? Put on the spot, his father suggested: “It’s a study of the world and how it works. Surely you do this at school?” “Nah,” Rajev replied, “Well sort of – we do things in ‘Topic’ twice a week, like water or sustainability or flying. No one talks about ‘science’.” Unravelling this mystery – what ‘science ‘ is – turned out to be a major theme of Rajev’s (R) and his mum’s (M) ongoing discussions during the following year at secondary school. In our first vignette, early in term one, Rajev appears to be quite despondent: R: Science is boring. We just sit in this room and Mr X talks endlessly and writes on the whiteboard. I wanna DO things with experiments and make things explode and stuff. M: What are you doing at the moment? R: Ah, the basics, lab safety – that sort of stuff. We had to draw a test tube – duh! But two weeks later, Rajev comes home excited about something in science: R: We did our first experiment today! We worked in groups, measuring temperature change in the yellow and blue parts of a flame – which heats water faster? We recorded our results. [Rajev goes into lots of details about which knobs to turn and all the equipment] …The blue flame didn’t heat it nearly as fast as I thought it would. However, in our third vignette (later in the first term), Rajev New Zealand Association of Science Educators
128
diversity:parentingandschoolscienceeducation
Vignettes from three case studies
delivers a speech about what it means to be a green kid in a sustainable school. In part, this involved a project on water quality in the local Okatipu stream, a place where Mei-Chun has spent much of her childhood hunting for eels and walking the dog. The next day, before school, Mei-Chun (Me) and her mum (Mu) are at home preparing a fish tank for Mei-Chun’s new pets: two goldfish called ‘Fish’ and ‘Chips’. Me: The water needs to be colder Mum. When we did the water testing at Okatipu stream we learned that the colder the water, the more air in it, so there will be more good bugs. Mu: Does warm water have less air in it? Me: Yes. Mu: Why? Me: I don't know how it works. The water testing man said the colder the water, the more good bugs there were in the stream 'cause there was more air in it for them to breathe. Mu: What are ‘good bugs’? Me: Umm, insects, snails… Mu: Are snails bugs? Me: "NO! (Pause.) Can I move my fish tank into Len’s room? He's got a shady spot where the water won’t warm up too much for ‘Fish’ and ‘Chips’. However, there was no time left now and off Mei-Chun went, to jump on her bike and ride to school – over the Okatipu stream.
35
NZ
science teacher
diversity:parentingandschoolscienceeducation
128
36
is still frustrated: R: Science was good today. M: Why? R: We didn’t do anything. M: Is that good? R: Yes. No science in the science period is better than doing science – we just draw stupid test tubes. But, surprisingly, a few days later there’s a complete change. Rajev texts his mum on his way home from school: “Osmium is heavy!” When he gets home he barges in and starts jabbering loudly over mum’s shoulder as she sits working at the computer: “Mum, Google osmium. It’s amazing! The heaviest mineral on Earth.” (He adds lots of detail...) In our fifth vignette, one afternoon as the first term draws to a close, Rajev has an interesting acknowledgment: R: Science was semi-decent today, Mum. M: Oh? What happened? R: We got to work with microscopes for the first time. M: What did you do look at? R: Onion cells and things. M: Did you see them clearly? R: Yeah! But it was more interesting looking at other stuff. We broke off some pieces of rubber and put those under. You could see these crystal-type things like those highly-magnified sand grains we saw in the movie about flooding in the desert last week. And we put fresh pencil sharpenings under the lens. You could see the actual fibres! We tried to look at the lead tip of a pencil but it was too big for the magnification to work. Paul put a piece of his skin under. Gross! There were these black lines like scratch marks on it. What were they from? M: I don’t know. Did you look at your cheek cells by scraping your nail inside your mouth like we did last year with Granddad’s old microscope? R: No. We only had to look at onion cells. But everyone got bored with that and was crowding round our microscope. So they blocked the light we needed for the mirror and we couldn’t see our other stuff. M: (remembering when she did this at high school): Next time see if you can look at your cheek cells. You’ll need to stain the water droplet on your slide with something like iodine before you put the cover slip on. R: Huh? Slide? Cover slip? What’s that? M: Isn’t that what you used to mount the onion cells? R: Nah! We just put our stuff straight onto the black stage thing. It’s not clear if this next vignette, at the beginning of the second term, represents a step backwards or a step forwards: R: Today I had the best science lesson I’ve had all year (speaking sincerely). M: Really? What did you do? R: Read the text book. M: Huh? What was Mr X doing? R: Oh I dunno. Rambling on about something. M: Weren’t you supposed to be listening? R: I was. Whenever he told us to write something down I did. Then I carried on reading. It’s the first time I’ve understood the stuff. M: What are you learning about? R: Atoms and atomic numbers and that sort of stuff. Particle nature of something or other...the atomic number of calcium is 12. M: What does that mean? R: There are 12 protons in the nucleus. M: Protons?
New Zealand Association of Science Educators
R: You get protons, neutrons and electrons in the atom’s nucleus. Yesterday Mr X asked us how many protons nitrogen had...without teaching us a thing! How were we supposed to know? He always does that. Asks us a question about stuff he’s never taught us. M: Isn’t he just checking what you know about a new topic before he starts teaching you? R: No. He just talks for ages and makes us write things. At least reading the text book keeps me awake and I can understand stuff for the first time. As the second term gets under way, science is at the bottom of Rajev’s list of favourite subjects, along with Technology. Nevertheless, in this seventh vignette, he relates a gleeful story: R: We had fun in science today. We played with dry ice. We were supposed to put it in little film canisters and put the lid on and point it to the wall and watch it pop off – to ‘explain how the gas expands and all that kind of stuff’. Then we stretched a balloon over the top and watched it blow up. Then Mr X put meths in a beaker and freeze-cooled the meths. M: Why? R: I dunno I wasn’t watching. I was trying to light containers of meths with pieces of paper, matchsticks and leaves dipped in meths. In the meantime, Mr X dipped leaves in freezing meths and froze the leaves. That was boring ‘cause nothing was on fire or exploding. After that we got the canisters and dry ice and filled two with water. We waited till it was bubbling, then pointed it at the beaker cabinet. M: Did anything happen? R: Nah not really. M: What are you learning about? R: Dunno. Particle expansion or something. Then we were given gloves to hold dry ice. We put five pieces of dry ice into each finger, filled it with water and waited for the freezing gas, and pointed it at someone. It was fun! They’d get covered in it. Finally, from the third term: R: We had fun in science today. We got asked questions about energy. The teams who got the right answers got to shoot the other team with rifles. We beat the other guys 2-1! M: So you got your questions right? R: Must’ve. M: What were they about? R: Dunno. I was right at the back. I shot Alex at 10 metres with my rubber band when Mr X wasn’t looking. Pretty good shot, huh? M: Yeah. What kind of energy was that? R: Aah Mum! (Pause.) Ah! Kinetic! You see? I WAS listening!
Some conclusions We believe these three case studies can be instructive because they suggest some ways in which parents can construct conversations at home which might help to bridge the gap between the mysterious other world of their children’s school science and the parents’ own desire to support their children’s interest in science and their motivation to succeed. Reflecting on the five roles that parents may play in their children’s science education – as outlined above – it appears to us that one of these five roles, ‘parents as empathisers’ predominates in all three cases of the parents’ conversations with Josh, Mei-Chun and Rajev teachers. Of course we also see instances of these parents as teachers, and providing resources. Whatever frame of reference we may use, there are five positive features of these parents’ contributions to the conversations:
Two final thoughts 1. Classroom teaching How might these data encourage us as teachers of science? On a very general (and perhaps rather pious) level, the pivotal place of home conversations certainly would encourage us towards achieving scientific literacy as a major goal for our science teaching – that is, the promoting of a population of future parents who can genuinely augment and support what we offer
students at school. In more practical terms, however, we all need to remember that the home and the science classroom are entitled to their own autonomy, even privacy, and insensitive intrusions either way can be counterproductive. Having said that, and acknowledging that the parents in this study were not chosen to be typical or representative, we would hope that teachers feel encouraged, supported and even inspired by reading these conversations. However, exactly how these synergies between school and home may be pursued is probably best left up to individual teachers, science departments and schools. These case studies, nonetheless, suggest to us that science conversations at home are powerful learning opportunities. Indeed, these conversations offer fruitful avenues between school and home for science students to engage with and extend their experience of science in authentic contexts. 2. Parenting Of course, empathising parents don’t just empathise in science matters. In fact, they may not have any personal affinity with science. They are well aware of the demands also being made on their children’s learning in English, maths, Maori, and so on. What is important, however, is that they will have some feel for the place and power of inquiry in teaching generally (Ministry of Education, 2007, p.35), for lifelong learning (Barker, 2010), and for the notion of literacy in informal learning (Lucas, 1983). Armed with these notions, their children’s tales from school science will be seen as a springboard for family learning. As Oliver Sacks (2001, p.10) recalled of his family: “It was our business, the family business, to ask questions, to be ‘scientific’.” For further information contact: c.donald@auckland.ac.nz
NZ
science teacher 128
diversity:parentingandschoolscienceeducation
1) The parents are respectful of their children’s comments and listen to them carefully (they are not remote or dismissive). They think deeply about the comments and they immediately build them into conversation and discussion at the time. 2) Sometimes the parents will explain or ‘teach’ something to the child; on other occasions they will deliberately hold back and encourage their child to develop the thought or idea with more questions, or by pointing out some detail, unnoticed before. They know when not to pre-empt children’s answers or put words in their mouths. They hold back and let their children speak more. 3) The parents try to engage with the topic or phenomenon at the child’s level of understanding and interest. There is seldom closure. More often there’s an invitation to do more or follow up. Sometimes the parents suggest something that the child goes back to school with, such as looking for something in the school library, or looking at something else under the microscope. 4) The parents enjoy their children’s discoveries and share in the excitement of their learning and celebrate with them. 5) The parents are aware of the bigger picture of their children’s growing awareness and understanding of their world, and how their school learning fits into this bigger picture. Their children, on the face of it, attach about as much significance to their ‘bring home stories’ as they do to the leftover sandwich crusts in their lunch boxes. But their parents take opportunities, when their children are receptive, to use their children’s ‘bring home stories’ as windows onto this bigger picture, that they can look out onto together, and share views across the generations. Claxton (2008) could have been commenting on the role of parents as empathisers when he wrote (p.170): “If parents are open-minded and inquisitive, the chances are that those traits will rub off on their children. If the family debates interesting subjects around the dinner table, and people listen to each other respectfully, and disagree graciously, then younger brothers and sisters, voracious voyeurs and eavesdroppers that they are, will pick up those habits too.” As we have said, there is of course enormous overlap between the five roles we have described. ‘Resourceful’ parents (in our sense) are most likely to be the ones who are the most empathising conversationalists. Again, for many parents, the world of school science may actually be accessed directly and often: they go on school field trips, they contribute to classroom goings-on by offering to come in and tell stories, or bringing some item of interest into the class, or donating a book on the topic or sending resources directly to the teachers (while delicately negotiating authority and parameters of professional practice). At home, they may contrive their own resources: files of what their children build or draw or say, photos, videos, and hence create an accessible record for the children to return to and reflect on.
References Ash, D, (2003). Dialogic inquiry in the life science conversations of family groups in a museum. Journal of Research in Science Teaching, 40(2), 138-162. Barker, M. (2010). Lifelong science learning. New Zealand Science Teacher, 123, 32-36. Boshier, R. (2009). Why is the Scholarship of Teaching and Learning such a hard sell? Higher Education Research and Development, 28 (1), 1–15. Braund, M. & Reiss, M. (Eds.) (2004). Learning science outside the classroom. London: RoutledgeFalmer. Claxton, G. (2008). What’s the point of school? Rediscovering the heart of education. Oxford: Oneworld Publications. Dierking, L.D., & Falk, J.H. (1994). Family behaviour and learning in informal science settings: A review of research. Science Education, 78, 57-72. Dierking, L.D., & Martin, L.M.W. (Eds.) (1997). Informal science learning [Special issue]. Science Education, 81(6). Edwards, D., & Mercer, N. (1987). Common knowledge: The development of understanding in the classroom. London: Routledge. Heyneman, S. (1997). Economic growth and international trade in educational reform. Prospects, 27(4), 501-30. Hofstein, A., & Rosenfeld, S. (1996). Bridging the gap between formal and informal science learning. Studies in Science Education, 29, 87-112. Katz, P. (1996). Parents as teachers. Science and Children, 33(10), 47-49. Lucas, A.M. (1983). Scientific literacy and informal learning. Studies in Science Education, 10, 1-36. Laugesen, R. (2011). Achieving child, controlling mother. New Zealand Listener, February 12th, 16-20. Ministry of Education (2007). The New Zealand curriculum. Wellington: Learning Media. Rennie, L. (2007). Learning science outside of school In S.K. Abell & N.G. Lederman (Eds.), Handbook of research on science education. Mahwah, NJ: Lawrence Erlbaum, pp125-167. Rennie, L.J., & Feher, E. (Eds.) (2003). Informal education [Special issue]. Journal of Research in Science Teaching, 40 (2). Sacks, O. (2001). Uncle tungsten: Memoirs of a chemical boyhood. London: Picador. Solomon, J. (2003). Home-school learning of science: The culture of homes and pupils’ difficult border crossing. Journal of Research in Science Teaching, 40 (2), 219-233. Tapper, L. (2011). Letters: A for achievement. New Zealand Listener, February 19th, 6. Wellington, J. & Britto, J. (2004). Learning science through ICT at home In M. Braund & M. Reiss, Learning science outside the classroom, pp. 207-223. London: RoutledgeFalmer.
New Zealand Association of Science Educators
37
NZ
science teacher
diversity:pseudoscienceandscienceteaching
128
using pseudoscience to teach science Pseudoscience can provide an excellent context for teaching students about the nature of science as Alison Campbell, Department of Biological Sciences at the University of Waikato, explains: We live in a time when science features large in our lives, probably more so than ever before. It is important that people have at least some understanding of how science works, not least so that they can make informed decisions when aspects of science impinge on them. Yet pseudoscience seems to be on the increase. While some argue that we simply ignore it, I suggest we use pseudoscience to help teach the nature of science1. The New Zealand Curriculum (MoE, 2007) makes it clear that there's more to studying science than simply accumulating facts: Science is a way of investigating, understanding, and explaining our natural, physical world and the wider Universe. It involves generating and testing ideas, gathering evidence – including by making observations, carrying out investigations and modeling, and communicating and debating with others – in order to develop scientific knowledge, understanding and explanations (p28). In other words, studying science also involves learning about the nature of science: that it is a process as much as, or more than, a set of facts. Pseudoscience offers a lens through which to approach this.
1. Check the information Students should be encouraged to think about the validity and reliability of particular statements. They should learn about the process of peer review. They should ask: has a particular claim been peer reviewed; who reviewed it; where was it published? There is a big difference between information that's been tested and reviewed, and information (or misinformation) that simply represents a particular point of view and is promoted via the popular press (and Internet). 'Cold fusion' is a good example. Cold fusion was a claim that nuclear fusion could be achieved in the laboratory at room temperatures. The claim was trumpeted to the world via a press release, but was subsequently debunked because other researchers tried, and failed, to duplicate its findings. Thus checking the source of the information is vital. There is a hierarchy of journals, with publications such as Science considered prestigious, and publications such as Medical Hypotheses considered less so. The key distinction between these journals is the peer review process. For example, papers submitted to Science are subject to stringent peer review processes (and many don’t make the grade), while Medical Hypotheses seems to accept submissions uncritically, with minimal review. By considering the source of information students can begin to develop the sort of critical thinking skills that they need to make sense of the cornucopia of information on the Internet. When viewing a particular Internet site they should ask (and answer!) questions about the source of the information: has it been subject to peer review (you could argue that the Internet is an excellent 'venue' for peer review, but all too often it's simply self-referential), does it fit into our existing scientific knowledge, and do we need to know anything else about the data or its source? 1
38
I recommend Jane Young’s excellent book: The uncertainty of it all: understanding the nature of science.
New Zealand Association of Science Educators
2.
Analyse the information
The following example is excellent for a discussion around both evolution and experimental design, in addition to the nature of science. There is an online article entitled Darwin at the drugstore: testing the biological fitness of antibiotic-resistant bacteria (Gillen & Anderson, 2008) where the researchers tested the concept that a mutation conferring antibiotic resistance rendered the bacteria less ‘fit’. Note: There is an energy cost to bacteria in producing any protein, but whether this renders them less fit – in the Darwinian sense – is entirely dependent on context. The researchers used two populations of the bacterium Serratia marcescens: an ampicillin-resistant lab-grown strain, which produces white colonies, and a pink, non-resistant ('wild-type') population obtained from pond water. 'Fitness' was defined as 'growth rate and colony "robustness" in minimal media.' After 12 hours' incubation the two populations showed no difference in growth on normal lab media (though there were differences between 4 and 6 hours) but the wild-type strain did better on minimal media. It is difficult to know whether the difference was of any statistical significance as the paper's graphs lack error bars and there are no tables showing the results of statistical comparisons. Nonetheless, the authors describe the differences in growth as 'significant'. The authors concluded that antibiotic resistance did not enhance the fitness of Serratia marcescens: wild-type [S.marcescens] has a significant fitness advantage over the mutant strains due to its growth rate and colony size. Therefore, it can be argued that ampicillin resistance mutations reduce the growth rate and therefore the general biological fitness of S.marcescens. This study concurs with Anderson (2005) that while mutations providing antibiotic resistance may be beneficial in certain, specific, environments, they often come at the expense of pre-existing function, and thus do not provide a mechanism for macroevolution (Gillen & Anderson, 2008). Let us now apply some critical thinking to this paper. Your students will be familiar with the concept of a fair test, so they will probably recognise fairly quickly that such a test was not performed in this case because the researchers were not comparing ‘apples with apples’. When one strain of the test organism is lab-bred and not only antibiotic-resistant but forms different coloured colonies from the pond-dwelling wild-type, there are a lot of different variables involved, not just the one whose effects are supposedly being examined. In addition, and perhaps more tellingly, the experiment did not test the fitness of the antibiotic-resistance gene in the environment where it might convey an advantage. The two Serratia marcescens strains were not grown in media containing ampicillin! Evolutionary biology predicts that the resistant strain would be at a disadvantage in minimal media. This is due to it using energy to express a gene that provides no benefit in that environment, making it short of energy for other cellular processes. And, as I commented earlier, the data do not show any significant differences between the two bacterial strains. Also, the authors work at Liberty University, a private faith-based institution with strong creationist leanings, and the article is an online publication in the ‘Answers in Depth’ section of the website of Answers in Genesis (a young-Earth
creationist organisation). This is not a mainstream peer-reviewed science journal. This does suggest that a priori assumptions may have coloured the experimental design. Your students should learn how to recognise 'bogus' science (also read my blog on this topic2). To begin with, students should scrutinise information presented via the popular media (including websites) and ask: why is this happening? Another warning sign is the presence of conspiracy theories. One conspiracy theory worth discussing relates to the validity of vaccination programmes: “Is vaccination really for the good of our health, or the result of a conspiracy between government and 'big pharma' to make us all sick so that pharmaceutical companies can make more money selling products to help us get better?” Dr A. Kalokerinos is often quoted on anti-vaccination websites as saying: My final conclusion after forty years or more in this business is that the unofficial policy of the World Health Organisation and the unofficial policy of ‘Save the Children’s Fund and almost all those organisations is one of murder and genocide. They want to make it appear as if they are saving these kids, but in actual fact they don’t. This quote is a good example of how conspiracy theorists often use an argument from an ‘authority’. Yet it is easy to pull together a list of names with PhD or MD after them to support an argument. Try giving your students a list of names of ‘experts’ and see if they can work out their field of expertise. Recently, New Zealand schools received a mail out from a group called ‘Scientists Anonymous’ offering an article purporting to support ‘intelligent design’ rather than an evolutionary explanation for a feature of neuroanatomy. The article was authored by Dr Jerry Bergman. A search of the literature indicates that Dr Bergman has made no recent contributions to scientific literature in this field, but he has published a number of articles with a creationist slant. So Dr Bergman cannot really be regarded as an expert authority in this particular area. Similarly, it is well worth reviewing the credentials of many anti-vaccination ‘experts’ – the fact that someone has a PhD by itself is irrelevant; the discipline in which that degree was gained, is important. Observant students may also wonder why the originators of the mail out feel it necessary to remain anonymous. Students need to know the difference between anecdote 2
http://tinyurl.com/3q5vwhh
NZ
science teacher
Finally… If students can learn to apply these tools to questions of science and pseudoscience, they will become better equipped to find their way through the maze of conflicting information that the modern world presents, regardless of whether they go on to further study in the sciences. For further information contact: acampbel@waikato.ac.nz
References Gillen, A.G. & Anderson, S. (2008). Darwin at the drugstore: testing the biological fitness of antibiotic-resistant bacteria. http://www.answersingenesis.org/ articles/aid/v2/n1/Darwin-at-drugstore (access date August 3 2011) Ministry of Education (2007). The New Zealand Curriculum (online). http:// nzcurriculum.tki.org.nz/Curriculum-documents/The-New-ZealandCurriculum (access date August 2 2011) Young, J. (2010). The uncertainty of it all: understanding the nature of science. Triple Helix Resources Ltd www.biologyresources.co.nz 10:23 Campaign (2011) http://www.1023.org.uk (access date 22 August 2011).
Each topic begins with an analogy. For example, to explain why metals are better conductors than non-metals, a domino analogy is used such that a row of dominoes falls faster than a row of books. ‘Emptying a bathtub with teacup’ is the analogy used to explain the heart and circulatory system. This topic also includes information such as how a red blood cell passes through the heart over 1200 times a day. The book is divided into the following sections: physics, chemistry, biology, astronomy, Earth science, human body, and technology. I strongly recommend this book to all teachers of science because it is refreshingly innovative in its use of analogy, it has plenty of accessible facts and it is a great read at a great price!
New Zealand Association of Science Educators
bookreview
book review A Bee in a Cathedral: And 99 Other Scientific Analogies Author: Joel Levy Publisher: Allen and Unwin ISBN: 9781742376493 RRP: $29.99 (published 1 August 2011) Reviewed by Lyn Nikoloff The Bee in a Cathedral: And 99 Other Scientific Analogies is 221 pages of scientific principles and facts that will keep even the most reluctant reader interested with its exciting layout and use of diagrams. There are 100 science analogies in this book, one for almost every science unit in Years 7 to 11. Each of the topics has a double-page spread. There is a sense of fun in the page layout with great diagrams, plenty of facts and figures, and enough text to whet the student’s appetite and spur them on to find out more.
128
diversity:pseudoscienceandscienceteaching
3. Verify the information
and data. Humans are pattern-seeking animals and we do have a tendency to see non-existent correlations where in fact we are looking at coincidences. For example, a child may develop a fever a day after receiving a vaccination. But without knowing how many non-vaccinated children also developed a fever on that particular day, it's not actually possible to say that there's a causal link between the two. Another important message to get across to students is that there are not always two equal sides to every argument, not withstanding the catchcry of "teach the controversy!" This is an area where the media, with their tendency to allot equal time to each side for the sake of ‘fairness’, are not helping. Balance is all very well, but not without due cause. For example, apply scientific thinking to claims such as the health benefits of homeopathy. Homeopathy makes quite specific claims concerning health and well-being. How would you test those claims of efficacy? What are the mechanisms by which homeopathy – or indeed any other alternative health product – is supposed to have its effects? Claims that homeopathy works through mechanisms as yet unknown to science don’t address this question, but in addition, they presuppose that it does actually work. Students will have some knowledge of the properties of matter and the effects of dilution, and senior classes may be aware of Avogadro’s number. They could apply this to the claim that homeopathic remedies become more effective at higher and higher dilutions, something that, if correct, would overturn our understanding of basic chemistry and physics. The 10:23 Campaign (2011) – in which people take ‘overdoses’ of homeopathic remedies – is a humorous way of highlighting the improbability of such claims.
39
NZ
science teacher
conversationscience/scienceeducationinterface:eoceneclimatemodelling
128
40
conversation: creative thinking and experimentation in science Anne Hume, Waikato University, enjoys a conversation with Duncan Ackerley (NZST Issue 127) about what motivates scientists to explore the past to better understand the future and in the process illuminates the nature of science. In Issue 127 of the NZST, Duncan Ackerley, James Renwick, Mathew Huber, and Chris Hollis wrote an article entitled “Modelling Eocene Climate”. As I read the article on the modelling of the climate in the Eocene period of Earth’s history, I couldn’t help but be impressed by our ability (as humans) to use indirect evidence to visualise and convincingly recapture a past that we were never a part of! The intellectual drive to attempt and achieve such endeavours is also impressive but why do scientists do it? What possesses scientists to delve into a very deep past on Earth to recreate former environments in which humans were non-existent and to devise complex mathematical models that represent these prehistoric times? Is it just innate curiosity, or is there something else of worth to be gained? The motivation must be very strong because time and the elements have surely transformed, even destroyed, much of the more obvious forms of evidence. In my conversation with Duncan Ackerley, one of the co-authors of the Eocene article and a former climate scientist at NIWA, I voiced some of the views expressed above and invited Duncan to comment in terms of what he thought was significant for teachers and students of science to understand about his work. He responded with genuine enthusiasm and as we talked Duncan revealed insights into the intense interest scientists have in the past and the reasons why. Duncan explained that developing tools that enable prediction of future climate is vital for identifying the effects of the current global warming trend. As the large majority of the scientific community now accepts this trend is being accelerated by human activity, such as greenhouse gas emissions, it is essential that scientists inform world societies of the consequences of such continued action with convincing and graphic evidence. Climate modelling is now providing that data and building pictures of a world future, which we ignore at our peril if human society, as we know it, is to survive. From my previous geology studies I recalled the adage "the present is the key to the past", which was first coined by Charles Lyell and based on the uniformitarianism principle of James Hutton (the father of geology). I asked Duncan about the continuing relevance of this principle to climate modelling. He pointed out that the highly sophisticated models that climate scientists develop today are based on observations of current processes, and identification of a myriad of variables within the Earth System that interact and influence the nature of climate at any given point or place in time. The complex mathematical equations that form the basis of these climate models are calibrated using
New Zealand Association of Science Educators
directly measured data from the present day, and like other hypotheses in science, these models must be tested and evaluated as tools capable of predicting future climate changes. Since it is impossible to test the model using data obtained from the future, scientists like Duncan turn to the past for answers. In this sense the modelling work in the Eocene past can be viewed as ‘the key to the future’. Duncan was keen to share the idea that he and his colleagues see the geological past as a giant ‘laboratory’ that holds vast stores of data that can be used to test their hypotheses (in the form of models) about climate processes. Development of the models typically involves teams of scientists drawing on international experience and research from a wide range of knowledge domains. The methodology has a very ‘trial and error’ element to it, but what is so powerful in the testing and evaluation of these models for climate prediction is the ability to compare the values of climate variables generated by the models at given points and places in the deep past with those of proxy data. The power of proxy data, like oxygen isotopes and biomarkers which are representative of the target variable in a given environment, is that they can be directly measured, unlike the target variable. This deductive line of reasoning in these ‘experiments’ in the past provides vital information to the scientists about the viability of their models for predicting future climate events and environmental changes. Close matches indicate the model may be a potentially useful predictive tool – any mismatches and it’s back to the drawing board! Duncan commented that it was often at this phase that creative thinking and that spark of genius are most needed – sometimes it may come from unrelated fields but someone in the team can see a link. I sensed Duncan wasn’t too devastated by recent problems with their Eocene modelling but looked forward to the challenge of finding the missing piece to the jigsaw! My conversation with Duncan confirmed that re-creation of the deep past does indeed require complex detective work, persistence and much innovative thinking. The motivation to engage in this intricate and multi-faceted science comes from the need to find solutions to real-life environmental problems of great significance to humanity. His description of the role of models and how they are developed gives real insights into how scientists work and the nature of the knowledge they construct. Footnote: On reading my article above, Duncan commented that my ‘missing piece to the jigsaw’ observation: “Really hits the nail on the head, that is, don't be upset about a negative result, use it as a driver to improve upon the experiment, which is what science is all about and something that teachers can really instill upon their students.” For further information contact: annehume@waikato.ac.nz
During a visit to see my daughter Katie, who works for the Curriculum Development Project (CP) along the Thai-Myanmar Border, I was invited to deliver science teacher workshops at the Mae Sot and Mae La refugee camps, writes Rob Julian, Victoria University, Wellington. There are 150,000 to 200,000 Myanmar and Karen refugees in camps along the Thai-Myanmar Border with many escaping political, religious, or ethnic persecution in Myanmar (formerly Burma). Visitors to the camps require a permit from the Thai authorities.
The refugee camps have an extensive network of schools providing education for children up to senior levels, and education is highly valued by students and parents. It has even been suggested that parents in Myanmar villages send their children to the camps so that they can attend schools. I was invited to present a three-day workshop at the Mae La camp and a two-day workshop at a school in Mae Sot. The workshops were a joint venture with the CP (funded by the USA) and the Karen Refugee Committee Education Entity, plus ZOA Refugee Care, a Dutch charitable institution.
NZ
along the Thai-Myanmar Border to tell me which bottle will hit the ground first, but no one spoke. So I asked for a show of hands in response to my queries and the majority indicated that the heavier one would hit the ground first. After both the bottles hit the ground at the same time there was some consternation with some teachers suggesting that I had not dropped them from a high enough height. Eventually they reasoned that gravity pulled with twice the force in order to get the heavier bottle to fall with the same acceleration. However, the main purpose of the demonstration was to get them thinking, talking, and arguing, rather than sitting and expecting me to teach them science. We also discussed the “Monkey and the Hunter” problem. A hunter with no sights on his rifle aims along the barrel at a monkey hanging from a branch 100 metres away. When the monkey sees the flash of the rifle being fired he lets go of the branch and drops. Will the bullet hit the monkey? The teachers rolled marbles horizontally off the table several times and simultaneously dropped another marble from the same height. They also got measurements to plot parabolic graphs of the projectile motion of the marble. We investigated Newton’s laws of motion by blowing a marble across the desk with a straw, and noticed that the marble accelerated with a constant force; and Hooke’s Law by suspending plastic bottles from rubber bands adding cupfuls of water and measuring the extension on their paper measuring rules and plotted mass (number of cups) versus extension. From their graphs the teachers were able to measure an unknown mass. Similarly, red cabbage juice was used for acid/base chemistry (Figure 1), vinegar and baking soda were used for chemical reactions, and we studied the insects, spiders and plant life found in the camp (we even came across a scorpion industriously crossing the main road in the camp!).
128
diversity:scienceteachinginrefugeecamp
science teaching in refugee camps
science teacher
Teaching science with few resources In the camps science classes usually have more than 60 students in them, with many teachers lacking a science background and equipment. There are no bunsen burners, metre rules, masses, ammeters, voltmeters, measuring cylinders, or chemicals – no equipment, only eager students sitting expectantly at desks. Consequently, science lessons are mainly ‘book learning’ and the teachers do what they call ‘dry experiments’ which is to say, they talk about them. In order to encourage student-teacher interaction, I focused on the social constructivist Predict/Observe/Explain (PEO) technique, such as “which bottle will hit the ground first?” To answer this particular question, I suspended two bottles from rubber bands to demonstrate that gravity pulled on the full bottle with twice the force. Then, standing on a table in the bamboo classroom, I held a one litre plastic bottle full of water in one hand, and a similar bottle half-full of water in the other. I invited the 34 science teachers from camps
Figure 1: Acid-base chemistry using red cabbage juice. We finished the workshop by investigating how many teachers could stand on an inverted table resting on inflated balloons – answer: 12 teachers. At the end of the two workshops, I was presented with a very handsome Karen ethnic robe and one of the teachers read out a poem she had written: “Our leader has been so good to us…I want to be the best teacher I can be to make my leader proud of me.” Finally... A workbook and science toolkit based on the workshops is currently being prepared for dissemination to all the camp and border schools. But funding of this resource is a challenge for the Curriculum Development Project. For further information contact: rob.julian@clear.net.nz New Zealand Association of Science Educators
41
NZ
science teacher
biology
128
Nurturing the seed for lifelong learning Written by BEANZ members: Jacquie Bay (Liggins Institute, The University of Auckland and The National Research Centre for Growth and Development ), Kate Rice (University of Otago) and Terry Burrell (Onslow College). Since its establishment in 1999, the Biology Educators’ Association of New Zealand has supported biology teachers at all levels, providing a voice for biological sciences’ education within the New Zealand Association of Science Educators, and more broadly in the public arena. Now in our second decade, we are challenged with meeting the needs of 21st century learners in an environment where the biological sciences continue to grow rapidly and increasingly impact the daily lives of citizens, and the social and economic potential of Aotearoa-New Zealand. This is an exciting time as we align the biology we teach with the immense changes that have taken place in the discipline, the challenges and opportunities afforded by the new curriculum, and the new resources we have available to enrich our teaching. The BEANZ Biolive2011 Conference provided a forum for educators and scientists to share knowledge and engage in discussion and debate regarding appropriate ways to support the development of teaching and learning environments that will foster lifelong learning for all students – whether they are in primary, secondary or tertiary education. The seed of potential that sits within each child, if nurtured, will see them mature to contribute to the growth and development of our communities and our nation. The consistent theme brought together by keynotes and session speakers alike, was the need to explore and develop more appropriate ways to nurture the seed of potential within our rangatahi, and allow each new generation to develop the capacity to become active participants in societies where complex science collides daily with our individual and community physical, social, environmental, economic, mental and spiritual wellbeing.
Scientific literacy for the 21st century In order to function as contributing adults in 21st century societies, young people need to develop the capacity to engage with complex socio-scientific issues such as climate change, the use of biotechnologies, sustainable food production, energy sources, disease epidemics etc. This means that they need to be able to “use scientific knowledge and skills to make informed decisions about the communication, application, and implications of science….” (Ministry of Education 2007 p.28). Participation and attainment data emphasises the need to establish the foundation for these skills and understanding in science early in schooling. “In 2009, 81 percent of Year 11 took part in at least one NCEA science subject usually a general science course. In Year 12, 48 percent and Year 13, 37 percent of students participated in at least one science subject; either biology, chemistry or physics.” (Ministry of Education 2010). Of course, attainment is only achieved by a proportion of these students. For Biology, participation in 2009 was 25% in Year 12 and 21% in Year 13; attainment (defined as achieving 14 42
New Zealand Association of Science Educators
or more credits in biology) was achieved by 47% of participating Year 12 students and 55% of participating Year 13 students (ibid). This means that only about 12% of all students are achieving in Biology at Year 13. It is therefore essential that lifelong learning capability to support ongoing development of scientific literacy is established through effective building blocks in primary and early secondary education, and supported by continued tertiary and community education opportunities. The centrality of development of scientific literacy in curricula worldwide has been driven by the interaction between complex science and daily life that has occurred increasingly over the past 50 years. The Organisation for Economic Co-operation and Development (OECD) defines scientific literacy as ‘the capacity to use scientific knowledge, to identify questions and to draw evidence-based conclusions in order to understand and help make decisions about the natural world and the changes made to it through human activity’ (OECD, 2003). Paradoxically, many of the significant environmental, economic, social and health challenges facing our communities have been brought about by advances in technology, but primarily require science and technology in order to find solutions (Gluckman, 2011a). The complexity of these issues is reflected in the change seen in science itself, from the linear model of question, investigation and answer to more frequently a ‘complex, non-linear and dynamic’ model of science that ‘almost never produces absolute answers but serves to elucidate interactions and reduce uncertainties’ (Gluckman, 2011b p.50). This level of complexity and uncertainty adds significant challenge to the development of teaching and learning environments where students can explore concepts of science within contexts of relevance, in order to develop functional scientific literacy. However, the complexity also clarifies the need for education to focus on development of understanding of science as a dynamic process, equipping our young people to engage in issues of science throughout their lives.
Relevance to 21st century youth The world of 21st century rangatahi is very different to the world that their parents, teachers and grandparents grew up in. It is a media rich world defined by complex social networks and open access to vast arrays of information. To youth, Facebook, Google, Wikipedia and Web-capable phones are not new; they are what they have grown up with. To succeed in this media rich world young people need to develop curiosity, the ability to access and analyse information, critical thinking and problem solving skills, creativity, communication skills, resilience and adaptability, networking and collaboration skills. They will change jobs multiple times and will need to learn and apply new skills throughout their lives. They will make decisions about the use of science and technologies that are as yet undefined, and as with many of today’s socio-scientific issues, underpinned by complex science that is beyond the understanding of the majority of the population. This all means that the education that they deserve and require, must by nature be very different to the education of
Nurturing the seed Nurturing the seed to realise functional scientific literacy within our communities. The placement of the Nature of Science strand as the overarching and unifying strand in the science learning area within the New Zealand Curriculum (MoE, 2007) has established the right for teachers to build learning environments that nurture the development of scientific literacy. It allows teachers to place emphasis on the understanding of science as a socially valuable knowledge system, and a dynamic process that interacts with society. Combining this with development of key concepts of science from within the context strands potentially equips students to apply understanding of science to decision making at a personal, family and community level. We learn within the context of our experience and our being. Each individual brings to the learning environment a range of scientific, social and cultural experiences that they have encountered throughout life. Therefore, in order to nurture growth and development, we must recognise, explore and endeavour to understand the notions, experiences and cultural precepts that our students, their families, our school communities and we as teachers bring to the learning journey. Science, science education and science education research are human social activities carried out inside cultural and institutional frameworks (Lemke, 2004). As teachers we interact with each of these cultures, however, the majority of citizens do not. For most of our students, their families and communities, perceptions of the culture of science are developed from snapshot views, often experienced through mass media, both fictional and real. The combination of the complexity of science, often conflicting views of societal ‘authorities’, and personal concerns relating to potential personal and community impact of an issue may create confusion and potentially distrust of science. Observing our communities as they try to make sense of the risk of potential further earthquakes in the Canterbury region this year has borne testament to this. Attempting to understand science when you have not been able to explore the culture of science could be compared to trying to learn to play a sport by reading about it and watching DVDs of games, without actually playing the sport yourself! Therefore, as teachers we need to create environments where our students are able to enter, and using the scaffolding we provide, explore the culture of science. This enables the student to, over a period of time, bring these experiences alongside their personal life experiences, world view and cultural setting, and construct a personal perception of science based on experience. This may challenge the perceptions of science that the student has previously developed through home, school or media such as CSI-style television programmes, however, these experiences in fact provide students with a tool to measure their understanding, allowing them to explore and challenge their previous conceptions of science. An important part of nurturing the seed is providing experiences that encourage the student to develop the desire to participate in scientific enterprises, and the opportunity to become competent so that they and others recognise their scientific identity. These experiences enable the student to start to construct their own identity as a person who can engage with, and in, science. Therefore, to
address the now commonly held belief that ‘young people need an understanding of how scientific enquiry is conducted to help them appreciate the reasoning which underpins scientific claims’ (Miller and Osborne 1998, p.2011), we need to move away from the often content-laden, assessmentdriven teaching programmes and provide students with experiences where they can interact with the culture of science, and develop the skills and competencies that will enable them to transfer their understanding of science concepts between contexts. Scaffolded experiences where students interact with science, alongside development of understanding of the nature of science will assist students in building the skills required to engage with science in the context of their community (see Figure 1).
NZ
science teacher 128
biology
their parents and grandparents. They require educational environments that foster the development of lifelong learning skills and competencies, which they can apply over a range of contexts.
Figure 1: Engaging with science.
In conclusion... The challenge that we face as educators is that the nature of the education we should be providing in the compulsory sector is very different to that of the past and difficult for many in our community to understand. It is the responsibility of professional educators to assist communities to understand the educational needs of young people, and support the development of learning environments that build scientific literacy either to equip students to participate in society, or to form the building blocks on which further development can occur for students who proceed to tertiary science education. Kaua e rangiruatia te ha¯ o te hoe; e kore to¯ ta¯tou waka e u¯ ki uta. Do not lift the paddle out of unison or our canoe will never reach the shore. For further information contact: j.bay@auckland.ac.nz
References Gluckman, P.D. (2011a). The wider roles of science and innovation. New Zealand Science Review, 68, 1, 49-51 Available from: http://www.scientists.org.nz/files/ journal/2011-68/NZSR_68_1.pdf Gluckman, P.D. (2011b). Towards better use of evidence in policy formation: a discussion paper. Office of the Prime Minister’s Science Advisory Committee: Wellington. Available from: http://www.pmcsa.org.nz/wp-content/ uploads/2011/04/Towards-better-use-of-evidence-in-policy-formation.pdf Lemke, J. (2004). Articulating communities: Sociocultural perspectives on science education. Journal of Research in Science Teaching, 38, 296-316. Ministry of Education (2007). The New Zealand Curriculum for English-medium teaching and learning in years 1-13. Wellington: Learning Media Ministry of Education (2010). Participation and Attainment in the National Certificate of Educational Achievement in Science. Available from http:// www.educationcounts.govt.nz/statistics/schooling/ncea-attainment/ ncea-achievement-data-roll-based/participation-and-attainment-in-thenational-certificate-of-educational-achievement-in-science Miller, R., & Osborne, J. (1998). Beyond 2000: Science Education for the Future. King’s College, London. OECD (2003). The PISA 2003 Assessment Framework –Mathematics, Reading, Science, and Problem Solving Knowledge and Skills, OECD: Paris, France. Available from http://www.oecd.org/dataoecd/46/14/33694881.pdf
New Zealand Association of Science Educators
43
NZ
science teacher
chemistry
128
chemistry news Written by Suzanne Boniface Classifying chemical reactions
A
Chemical reactions may be classified according to different criteria, such as: the nature of the species transferred during a reaction, visible changes that occur, or the nature of the atomic arrangement that occurs during the reaction. A simple classification based on the number and nature of the reactants and products and the type of transformation that is needed to convert the reactants to products can be used to classify most chemical reactions. Reactions can be classified as decomposition, combination, displacement and exchange. 1. Combination: elements or simple compounds come together to form a single more complex compound. More than one reactant joins together to form only one product – 2 or more particles combine to form only 1 particle. e.g. S(s) + O2(g) SO2(g) A
+
B
A
B
2. Decomposition: a compound breaks apart into either elements or less complex compounds. One reactant visibly becomes two products – 1 particle breaks into 2 (or more) particles. This is the opposite of combinations. e.g. CuCO3(s) CuO(s) + CO2(g) A
B
A
+
B
3. Displacement: a single element replaces another element in a compound. This means that there will be an element and a compound in the reactants, and a different element and a compound in the products. Often the elements will be metals, but the action of a metal on an acid to release hydrogen gas is also an example of a displacement reaction.
National Secondary Schools Quiz A number NZ Institute of Chemistry Branches have been running regional quizzes for secondary schools for a number of years now. These have proved to be lots of fun and popular with students. In 2011, the winners of the regional competitions were invited to a National Competition to help celebrate International Year of Chemistry (IYC). This event was organised by the Wellington Branch of NZIC on 5 July and was hosted by Dr Rob Keyzers. The six regional teams (23 boys and one girl) were from: James Hargest College (Invercargill); St Paul’s Collegiate School (Hamilton); Burnside High School (Christchurch); Macleans College (Auckland), Palmerston North Boys’ High School; and Wellington College. There were six rounds of nine questions containing material from the senior syllabus and beyond. Some were lighthearted but all encompassed chemistry as the central science.
44
Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g)
e.g.
Level 1 Science AS90947 and Level 1 Chemistry AS90934
New Zealand Association of Science Educators
+
B
C
A
C
+
B
4. Exchange: atoms or groups of atoms are exchanged between two compounds. For ionic compounds the exchange reaction will be recognised when the ions are swapped between the dissolved compounds, and one of the products is insoluble and precipitates out. e.g. BaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2NaCl(aq) A
B
+
C
D
A D
+
B
C
Many more complex reactions can be classified as a sequence of two or more of the above reactions e.g. an exchange reaction for which one of the products is unstable will be followed by a decomposition reaction. When hydrochloric acid and limestone (calcium carbonate) react, carbon dioxide is produced. This could be considered in two steps, exchange followed by decomposition. Exchange: CaCO3(s) + 2HCl(aq) CaCl2(aq) + H2CO3(aq) Decomposition: H2CO3(aq) H2O + CO2(g) Overall reaction: CaCO3(aq) + 2HCl(aq) CaCl2(aq) + H2O + CO2(g) This simple classification allows students to explain their observations of chemical reactions using their understanding of what is happening at the ‘molecular’ or submicroscopic level of particles and link these to the symbolic level of formulae and equations. As their understanding of the particles involved in reactions becomes more sophisticated, so too will their explanations and they will find new ways of classifying chemical reactions such as proton or electron transfer, nucleophilic or electrophilic substitution.
Competition was tight with the top two places only being separated by less than 2 marks. The results were: First: Macleans College; Second: St. Paul’s Collegiate School, and Third: Burnside High School. The complete prize package was generously provided by Agilent Technologies with the all members of the winning team and school receiving $300; second prize was $200 for each member of the team and school; and third prize was an MP3 player for each competitor.
Global Water Experiment It is not too late to get involved in the Global Water Experiment. Go to: http://water.chemistry2011.org/web/ iyc and sign up so that your students can collect and contribute NZ data to the global database. For more information about IYC events visit: http:/yearofchemistry.org.nz/ and http://www.chemistry2011.org/
NZ
science teacher
more physics activities
128
Physics @ Yahoo Answers Renowned physicist, Richard Feynman commented on the variety of ways in which students prefer to engage with his subject. While formal lectures, demonstrations, practicals, problem solving, tutorials, group discussion, textbook reading, investigations etc. have their devotees, he found it impossible to satisfy all students with a single mode of instruction. He decided to offer every approach in every course so that most students will find something in which they can succeed. With this idea in mind, you might like to try the following as part of your homework schedule. Yahoo Answers (answers.yahoo.com) is a free forum where questions posted are answered by anyone who feels so inclined. The Physics section of the forum is used by students worldwide to have their homework questions answered by retired teachers, clever students and various crackpots. First, get your students to register using passwords that you assign them and then you can set tasks using the forum. Knowing the students’ email and passwords you can monitor their progress at any time. Beyond meeting ‘course compliance’ requirements no evaluation should be attempted because copying and pasting answers is too easy for those who choose to meet the minimum standard. However, the main purpose is to offer just one more route to get students to engage with physics. Here are some ideas for the site: 1. Answer 10 questions that require use of Newton’s Laws of motion. Note: The forum gets up to 500 physics
questions every day – so there are always plenty to choose from. 2. Submit 5 questions of your own devising and evaluate any answers that are given. Note: there is a comment space for questioners to say ‘thank you’ etc. 3. Survey the questions that are asked in a day looking for the most popular topics, or the topics that attract the most answers. 4. Set a race for the first student to reach Level 2.
Filling the gaps We all show our science classes 50ml of water added to 50ml meths and explain the resulting 98ml of mixture to be the result of the different molecules slotting into ‘the gaps’. Now try this: 1. On a level surface place a small clean plastic cup on a paper towel. Add water to the cup until the meniscus bulges above the rim (and be prepared for discussion about surface tension). 2. Drop icing sugar as gently as possible onto the water surface. I tapped a teaspoon full of it just above the surface and even when big lumps dropped in the meniscus held, and 3 teaspoonsful vanished into the liquid without any obvious increase in volume. I didn’t establish how much sugar is required to cause an overflow – that could be a fine science fair investigation – but it is amazing to see how much mass will fit between the molecular gaps. And it’s fun!
chemistry
New Zealand team wins 4 medals at the 2011 International Chemistry Olympiad. The 2011 New Zealand Chemistry Olympiad team of high school students Thomas Fellowes (Christ College, Christchurch), Kailun Wang (Auckland Grammar School, Auckland), Andy Chen (Macleans College, Auckland) and Jade Leung (St Cuthbert’s College, Auckland) returned from the 43rd International Chemistry Olympiad held in Ankara, Turkey on 9-18 July with 4 well-earned bronze medals. This again ranks New Zealand in the top 50% of the countries competing. The mentors who travelled with the team, Dr David Salter (The University of Auckland) and Dr Suzanne Boniface (Victoria University of Wellington), said that the team’s result was an outstanding achievement and reflected the hard work and dedication that each student made between April and July in training for this competition. The students were supported to attend the International Chemistry Olympiad by the Talented Student Travel Award, funded by the Ministry of Science and Innovation and administered by the Royal Society of New Zealand, along with sponsorship from The MacDiarmid Institute, Douglas Pharmaceuticals, ABA Books and The University of Auckland Science Faculty.
physics
Written by Paul King
Andy, Kailun, Thomas and Jade with their medals.
New Zealand Association of Science Educators
45
NZ
science teacher
ESSE
128
Earth and space science – Years 12 and 13 It is essential with the problems facing planet Earth that students have a chance to study the Earth System and its intimate relationship with the Solar System. The new Y12 and 13 subject, Earth and Space Science (ESS), develops Earth, ocean, atmosphere and space concepts in local, national, international and astronomical contexts by studying interesting and relevant topics underpinned by relevant content. Students can take ESS in Years 12 and 13 even when they have done no Planet Earth and Beyond (PEB) topics in Year 11. The ESS standards have considerable flexibility and can be used to assess a number of interesting courses. Below are possible courses in Earth and Space Science, Geology, Marine Science and Astronomy.
Earth and Space Science Y12 Learning Activities •
Carry out an investigation showing the relative energy from the Sun at different times of the day, or over two or three seasons • Find a local telescope and look at nebulae, stars of different colours, planets, and open and closed clusters • Relate different star colours and masses to their life cycles • Find out how the planets in our Solar System formed • Use models, diagrams, photographs, and texts to demonstrate the key processes within the geosphere such as the importance of tectonic plate movement • Go on a field trip to a local geological feature and study the relationship between the type of rocks and the feature • Use models, diagrams, photographs, and texts to demonstrate the causes of extreme events such as volcanoes, hurricanes and tsunamis • Understand how the heat energy from the Sun and the centre of the Earth drive important Earth cycles and processes such as ocean circulation Possible assessments: ESS: 2.1, 2.3, 2.5, 2.6, 2.7
Earth and Space Science Y13 Learning Activities •
•
• •
• •
•
46
Understand that human activities are unbalancing the cycles of the Earth system with significant consequences for all parts of the Earth system Learn about some of the space probes that have visited different parts of the Solar System, not only other planets and moons, but also asteroids and comets Describe how to detect bodies such as Kuiper Belt Objects and extrasolar planets Study various techniques such as tree ring dating, and ice core data, from glaciers or Antarctica, as indications of climate fluctuations and geological history Sunspot cycles and solar flares and the effects on modern communications How Polynesians discovered and navigated around Pacific Islands using astronomy and knowledge of ocean currents Explain the role of the ocean in absorbing excess carbon dioxide and the effect on the ocean’s acidity on ocean ecosystems
New Zealand Association of Science Educators
•
Use models, diagrams, photographs, and texts to demonstrate the key processes within the atmosphere such as the formation of winds • Illustrate how the transmission, reflection, absorption, and scattering of all types of electromagnetic radiation and sound can aid exploration of Earth and space systems Possible assessments: ESS 3.2, 3.3, 3.4, 3.6, 3.7
Geology Y12 Learning Activities • • •
Carry out an investigation on sedimentation Explore an issue such as how the dinosaurs died Go on a field trip to a local feature to study the type of rocks of the feature • Use models, diagrams, photographs, and texts to demonstrate the importance of tectonic plate movement • Relate plate tectonic and rock cycle processes in New Zealand contexts • Use models, diagrams, photographs, and texts to demonstrate the causes of extreme events such as volcanoes, hurricanes, earthquakes and tsunamis Possible assessments: ESS: 2.1, 2.2, 2.3, 2.5, 2.7
Geology Y13 Learning Activities •
Investigate a local area to study past evidence for geological events in rock outcrops or road cuttings • Use techniques such as modelling and satellite images to see geological features obscured by erosion and vegetation • Understand that human activities are unbalancing the cycles of the Earth system with significant consequences for all parts of the Earth system • Study various techniques such as tree ring dating, and ice core data from glaciers or Antarctica, as indications of climate fluctuations and geological events • Explain the role of the ocean basins in directing the great ocean currents • Use models, diagrams, photographs, and texts to demonstrate the key processes within the atmosphere such as the formation of winds Possible assessments: ESS 3.1, 3.2, 3.3, 3.4, 3.6
Marine Science Y12 Learning Activities • •
• •
• •
Use techniques such as modelling and satellite images to study temperature differences in the ocean Explain the role of the ocean in absorbing excess carbon dioxide and the effect on the ocean’s acidity on ocean ecosystems Carry out an investigation into the effect of weak acid on seashells Use models, diagrams, photographs, and texts to demonstrate how tectonic plate movement has formed the ocean basins Go on a field trip to a local coastal area and study the relationship between the type of rocks and the shoreline Research why the ocean is so important to life on the whole planet
• •
Marine Science Y13 Learning Activities • •
Explore how the oceans distribute heat around the world Learn how gases such as carbon dioxide are exchanged between atmosphere and ocean • Understand how the oceans help cycle carbon by chemical and biological means • Learn about the importance of phytoplankton in the production of oxygen and the cycling of carbon • Investigate the effects on marine life of the oceans becoming less alkaline (more acidic) • Carry out an experiment of the effect of weak acid on marine shells • Understand how sediment cores can be used to discover past climate changes • Experiment on how well sound travels through water and relate this to how marine animals such as whales echolocate and communicate over vast distances Possible assessments: ESS 3.1, 3.2, 3.3, 3.4, 3.6
Astronomy Y12 Learning Activities •
•
Carry out an investigation showing the relative energy from the Sun at different times of the day or over two or three seasons Explore the problems humans would have to overcome to undertake long space flights
•
Have an astronomy evening to look at nebulae, stars of different colours, planets, and open and closed clusters • Use models, diagrams, photographs, and texts to represent the stages in the birth, life and death of stars, and the energy transfers and transformations involved • Find out the characteristics of different stars and planetary systems • Observe and track the movement of selected planets over a period of time • Use models, diagrams, photographs, and texts to represent the characteristics of planetary systems and their formation from protoplanetary disks around young stars • Research the problem of space debris • Explore how heat moves and travels outwards in planet Earth, the Sun and stars by convection and radiation Possible assessments: ESS: 2.1, 2.2, 2.4, 2.6, 2.7
NZ
science teacher
Astronomy Y13 Learning Activities •
Investigate the conditions on other planets and moons that may mean primitive life could exist on them • Explore the forms such life may take • Find out how exoplanets are found around stars • Learn how electromagnetic waves and sound assist exploration of the Solar System and Universe • Research the benefits and drawbacks of space exploration to humans using both manned and unmanned probes Possible assessments: ESS: 3.1, 3.2, 3.5; PHY: 3.2 For further information contact: jenny.pollock@ncg.school.nz
The book is obviously Australian in origin but attempts have been made to make it more relevant to a New Zealand audience. Some illustrations include New Zealand images, but there is still enough for it to have a distinct Australian feel, the food webs with gum trees, wombats, echidna and dingoes being a classic example. New Directions in Science Workbook Level 1 (Wignall, Wales, Robinson and Dixon) and Year 11 Science Workbook NCEA Level 1 (Gary Hunt) both focus on providing a workbook for Year 11 NCEA Science students, identifying particular achievement standards around which they base their chapters. As would be expected they both cover typical Biology, Chemistry and Physics topics although only Hunt’s workbook has a chapter dedicated to Earth Science. The workbooks largely provide small portions of theory followed by a series of questions and each workbook has a smattering of practical activities for students. If pushed to choose one over the other to use with students I’d opt for Hunt’s workbook for the layout and coverage. Learning objectives are given at the beginning of each chapter which help students know what they need to be learning and the layout visually appeals to me. That said, the New Directions workbook comes with a CD which includes notes, photos and animations which create a point of difference, even if a little uninspiring in construction. At the end of the day preference will come down to the teacher using the workbooks, and interestingly both books are published by Pearson, so either way, the publisher wins. New Zealand Association of Science Educators
bookreviews
book reviews Pearson Skills: Science and Inquiry 1, by Greg Laidler et al, Pearson, ISBN: 9781442545854, RRP: $34.99 New Directions in Science Workbook Level 1 (Book + CD) (3 Ed), by Anne Wignall et al, Pearson, ISBN: 9781442530904, RRP: $29.99 Year 11 Science Workbook NCEA Level 1 (2 Ed) by Gary Hunt, Pearson, ISBN: 9781442539259, RRP: $29.99 Reviewed by: Craig Steed, Freyberg High School, Palmerston North Pearson’s Science and Inquiry 1 is most suited for Years 9 and 10 Science students, although the authors claim it has relevance for Years 11-13 to refresh students’ knowledge of the skills they learned in Years 9 and 10. The book is divided into chapters that cover laboratory skills, data skills, experiment skills then subject specific biology, Earth science, chemistry and science research skills. Physics’ skills are incorporated into the data skills’ chapter which is largely dedicated to measuring and graphing. The chapters are fairly text heavy and each section of the chapter usually has three quarters or more dedicated to the theory behind the skill being covered, followed by two or three skill review questions. If you’re looking for a book that offers easy access to the theoretical side of a range of science skills then this book provides an option. It is not a typical workbook with lots of questions or activities, but teachers could creatively use the text to develop lessons as there is enough information contained within to allow students to use it in jigsaw activities, or as a resource to draw information from and use innovatively.
128
ESSE
Explore how life adapts to the deep ocean Use models, diagrams, photographs, and texts to demonstrate the causes of extreme events such as volcanoes, hurricanes and tsunamis Possible assessments: ESS 2.1, 2.3, 2.4, 2.5, 2.7
47
NZ
science teacher
sciencetechnicians
128
48
Christchurch, but not as we knew it! Fellow technicians from Christchurch are coping with the extraordinary circumstances forced on them by the earthquakes and aftershocks. We invited technicians to share their stories with us, writes Beryl McKinnell, President of STANZ. Annette from Shirley Boys’ High School writes: The February quake was the end of life as we knew it at Shirley Boys’. The buildings were shaken, liquefaction bubbled around and into the buildings, drains, carpet, and over everything that fell onto the floor during the shaking. Our house was without water and power for about twelve days. Water tanks were placed around the streets, but the water had to be boiled. The sewerage system was (and is still not) in usable condition and Portaloos were delivered to every street in the eastern suburbs. The next saga was the delivery of the ‘chemical toilet’, which is effectively a St Andrews College - Chapel being held up. camping toilet that needs emptying into a tank halfway down our street. Before they arrived it was a hole in the afternoon from 1:15–2 p.m. in the unused labs. Our students garden! We are still using the chemical toilet nine months start at 1 p.m. and finish at 5:35 p.m. with the same timetable later as the sewerage system in the east is munted! structure. Both schools have a 20-minute break after period 3. Papanui High came to our rescue, but the logistics of Being from a solo technician school, I am really enjoying the getting 1500 pupils from the east side of the city to the company of Jane and Colleen. We have great discussions northern side posed some problems for the Ministry of about the education system, earthquake problems, world Education. It takes 17 buses, on different routes, to bring our situations – as well as doing some work! It is lovely to have boys to and from school each day. The parking problem was someone to talk to and work with. solved by using a company just down the road. And Jane and Colleen concur: “Having Allison here has been Alan at Papanui High School starts his day at 7 a.m. ready a real bonus for us – she is easy to work with and assists us for the 8 a.m. start to the pupils’ day. But he does get to go and our teachers.” home early in the afternoon, so he can catch up on a few Robin from St Andrew’s College writes: I live on the ZZZs. For me, it means that I don’t have to get up at 6.30 good side of town and our house only has minor cracking; a.m., but on the other hand, it means that I am finishing liquefaction has only produced mini volcanoes on the lawn. work at 6:30 p.m. (in the dark). I have to tidy up and put At school we are fortunate to have a new science building, stuff away after our staff finish teaching at 5:45 p.m. so that built to hold up the old one in case of an earthquake. Papanui can have a clean start in the morning. It is late It has withstood the major ones and the 5000+ smaller when I finally get to eat. aftershocks. The chemicals all remain upright behind wires There is a lot of pressure on rooms and gear, although and very little glassware has broken. The skeleton survived the two schools are totally separate, and teaching staff its quick trip to the floor and the fish their tsunamis. We are and pupils do not really even see, let alone bump into, fortunate in this broken city. each other. The computer systems and phone systems are The kids shovelled the silt from the fields, and grounds’ staff separate. Keeping labs topped up and checking gear is an worked tirelessly to have them up and running for winter issue, because there is no “after school” time. In the main we sports. They are now being worked on again after the 13th are using Papanui’s gear which has meant that I have had to June aftershock. It was an awesome sight to see the field find where it all is. It is just like starting over again. erupting in fountains of silt and water when we were all out The great thing is that we Techies are able to have some there as buildings and trees swayed in the aftershocks. company and collegiality as we are the ones whose times The surrounding streets are also filled with silt and need overlap. What did they say about the loneliness of the long careful negotiation. The sewage and water were off for distance runner? There are now three of us on the same weeks in February. Our sewage still goes into big tanks, stretch of road. emptied daily as the mains are slowly repaired. Remember, Allison from Avonside Girls’ High School writes: There this is the good side of town. are nineteen labs at Burnside High, and Avonside Girls’ Our four-storey classroom block is being reinforced with High (AGHS) uses ten of them, so the AGHS staff enjoy a huge amounts of steel and concrete. The timetable has lab to themselves. At first I thought nineteen labs – yikes! – been changed many times, but classes continue as usual. compared to our seven, but of course we only use ten. We We all lack sleep and live on our nerves at times, but the have been made very welcome by all the science staff here winter has been kind, so far, and we take one day at a time. and resources are willingly shared, which certainly makes the situation a lot easier. Finally ... Our thoughts are with the courageous folk of Christchurch as they go about their business trying to bring Burnside High starts at 8 a.m. and finishes at 12:35 p.m., a new ‘normal’ to their lives. – Beryl McKinnell there are five 45-minute periods with five minutes between classes and the Years 12 and 13 students have a class in the
New Zealand Association of Science Educators
National NZIP Conference
CONSTANZ ‘11
The 15th National NZ Institute of Physics Conference
The Science Technicians’ Association of NZ Conference 2011
17-19 October 2011
10 to 12 October 2011
Victoria University, Wellington
John McGlashan College, Dunedin This Conference will appeal to all school science technicians, and also some technicians from tertiary institutions (such as Polytechnics)
Energise your physics teaching with three days of ideas, stimulation and interactions!
For further information contact: Margaret Woodford - Conference Convenor, Margaret.Woodford@kvc.school.nz or
For further details visit: www.nzip.org.nz
CONSTANZ ‘11 Anne-Marie Pulham - Secretary, ampulham@kavanagh.school.nz
NECTIONS
SCICONnections is the NZASE biennial conference
Making Connections 1 to 4 July, 2012, Auckland Enjoy four days of profesisonal development Making connections with: curriculum, IT, primary, secondary, scientists and more ...
For further information visit: www.nzase.org.nz or email Conference Convenor: c.haslam@auckland.ac.nz
Subscriptions 2012 Invoice to be sent October 2011
NZASE, PO Box 37 342, Halswell, 8245. Website: www.nzase.org.nz Email address: nzase@xtra.co.nz