Let's Do Science 5 – Text Book A

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Prr i ma P mary 5 Textbook

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Aligned to the Next Generation Science Standards

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P mary 5 Prr i ma 2 Textbook

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The 5E Model – Guided Inquiry

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The Let’s Do Science series is based on the Biological Sciences Curriculu Curriculum riculu Study (BSCS) 5E teaching and learning instructional model. The he 5E E model is centered on the idea that students understand science concepts oncepts pts best by using prior knowledge to pose questions and find answers rs through hrough guided inquiry.

This hands-on approach, integrated with engineering ng g and design skills, sk s has students learn science by doing science. Teachers chers guide the llearning process and are able to assess student performance evaluating student mance ce by evalua explanations and the application of newly acquired quired d knowledge knowledg knowled and skills.

Engage

The Engage phase of the 5E model provides videss students with w the opportunity to demonstrate their prior knowledge and understanding of the topic or understand concept. Students are presented with which serves to h an n activity or question q motivate and engage students as they hey begin the llesson. Teachers identify and correct any misconceptions and d gather data dat from students which will guide informed teaching and learning. earning. ng Essential to stimulating and students is the use of mixed media d engaging gaging stude st such as colorful photos, illustrations found throughout the trations tions and diagrams d textbooks and activity books.

Let’s Science also includes extensive bo boo t’s Do S digital resources such narrated videos, interactive lessons, virtual labs, h as narra nar id slideshows and more. re.

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Explore

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This phase encourages exploration of concepts and skills through gh handshan on activities and investigations. Students are encouraged to work togethe together red learning earn and apply various process skills while gaining concrete, shared ch students experiences. These experiences provide a foundation for which epts.. This studentstuden can refer to while building their knowledge of new concepts. centered phase comes before formal explanations and d definitions of tthe concept which are presented by the teacher.

Explain

This phase follows the exploration phase and iss more ore teacher-directed. teacherteache Students are initially encouraged to draw on their learning experiences and earning ex e oncept ept through explanations e demonstrate their understanding of the concept and he opportunity pportunity to t demonstrate discussion. After the students have had the their understanding of the concept, the formal e teacher cher then introduces in definitions and scientific explanations. also clarifies any s. The teacher eache al erged during the th Explore phase. misconceptions that may have emerged

Elaborate

In the Elaborate phase, students nts refine ne and consolidate co c their acquired knowledge and skills. Opportunities for students to further rtunities nities are provided pro apply their knowledge and skillss to new situations in order to broaden si and deepen their understanding rst ng g of the concept. Students may conduct additional investigations, share information and ideas, or apply their ns, sh shar orm knowledge and skillss to other ther disciplines. disc d

Evaluate

This final phase se includes cludes both formal form and informal assessments. These can include concept models, journals as well as more traditional cept maps, physical phys ummative ative assessm assess forms of summative assessment such as quizzes or writing assessments. e encouraged to review and reflect on their own learning, and Studentss are on theirr newly wly acquired knowledge, kn understanding and skills.

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Let’s Do Science Let’s Do Science is based on the United States Next Generation Science Standards (NGSS). The series consists of full-color textbooks and full-color activity books for Grades K to 6.

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Wallac

Let’s Do Science engages students with a highly visual al presentation of the disciplinary core ideas in the textbooks xtbooks books and places an emphasis on applying scientific knowledge nowledge ledge using NGSS practices through numerous scientific tific investigations. Let’s Do Science sees engineering ring ass an essential element of science education and tightly d as such is tight integrated into both the textbooks and activity ctivity books.

The Let’s Do Science textbooks include e the following ffeatures:

Amphibians

The word amphib term which mean to their unique life amphibians, begin land. Amphibians fertilization, and h

There are three m Frogs are amphib They often have s legs for moving a Toads are similar often have drier a

European tree frog

moor frog with eggs

Think Deeply

eld In the Field

Topic-related questions for group discussion aimed at deepening students’ understanding of the topic.

ande Fleming Sir Alexander

ian and sicia hysicia phys hp Scottish w s a Scott wa Alexander Fleming was i A Sir enicillin g the drug pe ing covering for discov own fo ogist, best kno microbiologist, microb teria. acteria c used to killl ba tibiotic antib st effective ant – the first e stigating the sti vestiga ming was inv m Flemin 8,, Fl 928, atory in 1928, oa abo In hiss labor g from ci. On returning er Sttaphylococc eria er bacte rttiess of the bacteria operties proper properties ng in a e growin teria bacte noticed that bacteria ng not Flemin Fleming d id holiday, y ho m ly fam a fami e n llium,, a type Penici Pen u Peni y the fungus illed by kille ing kille eing dish were be di petri d pet petri d. mold mol off m

bacteria d that the b bserved He obs g the ding nd ounding y surrou e ately immedi nd that an le a lle lled lled, killed fungu had been ki fungus away were aw fa err away b cteria farth e ba the y usly ny” he famou unny” funny” ’ss fu at’s m . “Tha ma normal sistant. o his asssista ar ed to remark

o the ed to y led scovery scover discover ’ss di ing’s min Flemin iotic ntibiotic he antib en of the me lopment lo develo was a wa e yw cover cove he h discover The llin. T cillin. penic gh for the kthrough bre kthrou medicall brea medica ses il y illnes ny o many ntt of ment treatm ern y, moder Today ia.. Today, ia bacteria y ba d by ed caused ga using ted using tested ar still te oticss are antibiotics s similar o simil ho method pen d pe ed vere ov discov

Engineer It!

Goes beyond inquiry uiry by encouraging students udents to design, model and build utions to to engineer solutions oblems. defined problems.

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I W or. When for g fo lo looki lookin ot looking e is not hat one findss wh times find “One sometimes nly c 28, I certai 28, 1928 er 28, eptember September wn on Sep wn daw ke up justt after d ke woke scoveriing tthe discoveri y dis icine by medicine e all me nize nize revolution n plan to revolutio didn’t th that u su suppose I t Bu But B er. kill a eria acteri b ba r o or ibiotic, rld s first antibiotic, world’ m g. emin Flemin Alexander Fle actly what I did..“ – Sir Al exactly wass ex

A Closer Look Arthropod Life Cycles

iv ec iv rece g rrecei F Flemin d wo ard his ha for h fo es inc o erie disco discov gy o olog siol Ph sio in Phy

After hatching, most arthro pods do not resemble their parents. The young, called larvae, go through a series of chang es in a process called metamorphosis.

During metamorphosis, a larva goes into an inactive pupa stage. When an arthropod emerges has all of the characterist from the pupa, it ics of its parent.

31 The life cycle of a mosqu ito goes through four distinc egg, larva, pupa and t phases – adult. The organism looks, feeds and moves differently in each stage stage.

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raft of eggs

egg

In the Field

Inspirational sc sciencerelated to ated professions p stir interest rest in sciencerelated careers.

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A Closer Look

Invokes enthusiasm in science by presenting interesting topics beyond the syllabus.

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aquatic larva

Amazing Fact!

ce’s flying frog

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Interesting facts to bui build interest and enthusiasm. nthusiasm.

Did You Kno Know?

tadpoles

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bian comes from a Greek ns ‘double life’. This is due cycle which, for many ns in water and moves on to reproduce sexually by external atch from eggs.

Salamanders are amphibians that are similar in appearance to lizards. They have long, slender bodies with a tail. Caecilians are limbless, worm-like amphibians. Most live underground.

spotted salamander

Most amphibians get the oxygen they need using lungs to breathe in air. Many amphibians are also able to take in oxygen through their moist skin.

main groups of amphibians. bians we are most familiar with. short bodies with powerful hind about on land and in water. in appearance to frogs, but and rougher skin.

Extra ra information to t build students’ dents’ knowledge know se of the cu base current topic.

Try This!

Optional ptio hands-on activities to be conducted activ in groups or at home.

Some poison dart frogs carry their young on their backs to a source of water.

What are the characteristics of amphibians?

AB Activity 3.12

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Science Words

12.

Use the words to comp lete the sentences. biotic factors abiotic factors individual population community

producer consumer primary consumer secondary consumer tertiary consumer

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decomposers food chain food web energy pyramid

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An animal that feeds

An animal that feeds

on prima ary r consumers

.

is a

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An is a model th that shows how much energy is available at each level in an ecosy stem em.

Review

1.

break down organic mater ial and absorb the broken down remains.

1.

List three biotic fact ctors you would d expect to find in a tropica rainforest ecosystem l tem.

2.

A is an organism that gets energy by eating other organisms.

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List three abiotic factor s you ou would w ld expect to find in rainforest ecosystem. a tropical

3.

A

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An animal that feeds

is an organism that make s food through photosynthe sis. on secondary consumers is a .

5. A single organism in an ecosystem is called an .

6. All of the organisms in an ecosystem are called .

7. All of the non-living things in an ecosystem are called .

8. All of the organisms of the same kind that interact and reproduce within an ecosystem make up a .

3.

4.

Draw and label a simple diagram to show how ow an individual, a popula and a comm com unity in a grassl pop tion and ecosystem. m Wha What hat at role does each ea organism play in a desert ecosy osyste stem?

(a) a) hawk h

Think Deeply

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on a producer ce is a

Mosquitoes are insects that can spread diseases to humans. Female Anophe eles le mosquitoes can spread the disease malaria which wh infects more than 200 00 million people every year. How H can learning about the he life cycle of Anopheles mosq squitoes help control the spre pread of malaria?

(b) rattles ra nake

5.

What does a food web

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How is an energy pyram

7.

8.

(c) c) b brittlebrush

(d) wood rat

show?

id different from a food d web?

Explain how all of the food wi within an Arctic Ocean Oc ecosystem can be traced back ack to the energy in sunligh t.

Riley thinkss most of the mater m ial for plan ant growth comes from Do you think Riley is cor the soil. correct? Explain your yo answer.

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A female Anopheles mosqu ito feeding on human blood.

AB Activity

Links students to the Let’s Do Science Activity Book at the appropriate juncture.

Discussion

Topic-related questions and situations for class discussion to build a deeper understanding of topics.

emerging adult eme

aqu quatic pupa

Go Online!

Watch a video about Watc the life cycle of a mosquito on cyc the NGScience website.

N QuickCode: V1J4

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Review

Topical questions at the end of each chapter for formative assessment.

Science Words

Lists the essential science vocabulary covered in each chapter.

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Contents

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Unit 1 - Diversity of Life

What Are Organisms?

Classifying Organisms Kingdoms What’s Inside Cells? ganization Cell Organization Review

Unit 2 - Plants

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Classification n of Plants turess Plant Structures cless Plant Life Cycles Review

Unit 3 - Animal nimal Classification Cl on Classificatio assificat ls Classification of Animals Invertebra Invertebrates Verte Vertebra Vertebrates Review R

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2

4 10 15 24 27 29

32 34 4 40 48 59

60 62 63 78 93

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Unit 4 - Energy in Ecosystems What Is an Ecosystem?

Energy in Ecosystems osystems Matter in Ecosystems w Review

Unit 5 - Earth’s Land nd and Water Structure ure of the he Earth Ea Earth’s Landforms Land The e Hydrosphere ydrosphe Review w

96 100 110 113

114 116 120 126 140

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Science Skills

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Scie Scientists Scien ask questions about the world d aroun around them. the m To find the answer to these e questions, estions, scientists use special skills to collect, and scie en ollect,, analyze an interpret data. They communicate things in nte unicate ate the thing thin they th find out.

Let’s look at how you ou can use these thes the skills so you can be a scientist entistt too.

Observing ng

You make when you gather e observations bservations w information using your ation about something som senses. how something es. You u can observe obse looks, ks, feels, eels, sounds, sound smells or tastes.

Scientists entists often use tools and instruments that at allow them the to observe things closely. Such Suc tools include hand lenses, microscopes and telescopes. microsco microscop It is important to accurately record your im observations in a way that can be easily se understood by others. You can make notes, and create charts and tables. You can also draw and label diagrams. dr

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Comparing and Classifying

Scientists compare the things they observe.

To compare means to observe the properties erties or characteristics of two or more thingss and d es. identify their similarities and differences.

Classification is the process of placing cing ng things into in nto o groups based on similarities in their heir properties or o characteristics. Objects around classified d us can an be clas sified by the properties of the materials they hey are made of. o Organisms can be classified by their features, es, such as the th presence or absence of a backbone.

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du ca tio Measure

Measuring g is an n important importan science skill. It allows you your observations. ou to o quantify yo y Distance, volume, mass and ce, time, me, volume perature perature are some so som quantities that temperature n be measured. can measure you often need To mea asure accurately, ac as rulers, beakers, to o use ttools such s thermometers and stopwatches. thermo her ome me

Make a Model Ma Scientists often construct models to predict, test and observe real-life phenomena. p Models can be physical objects, such a model of a miniature wind turbine to simulate electricity generation or a model of the Earth’s surface to simulate weathering and erosion.

Models can also be in the form of diagrams. A food web diagram is a model that shows the flow of energy in an ecosystem. A map is a diagrammatic model of an area of land or water.

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Infer

You infer when you make a guess about something based on what you know or what you observe.

If you see footprints in the snow, you can infer that an animal has passed d by b after the last snowfall.

wit If you discover an animal jaw bone with large canine teeth, you can infer nferr that the animal likely ate other animals. mals.

Communicate

sh sho or tell other You communicate when you show people what you find out. on can an be in the form of a written Communication plays or an oral presentation. report, visuall displays

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Scientific Method

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Scientists ask questions based on observations bservation rvation of the world around them. To find the answers to their questions, they carry out ut tests ts and investigations following the scientific ientific ific method.

Why is it useful for scientists to follow the same scientific method?

The scientific method is a logical set of steps ste that is followed to help guide investigation. It also e an n investigation investigati helps to ensure the investigation carried out vestigation ation is ca car fairly and in a manner understood er that hat can be u and repeated by other scientists.

Make Observations servations vation

The scientific fic method ethod begins begin by making observations world around you. ons about the w may in one area grow You m ay y observe that plants p faster fas ster and d taller than plants in other areas.

You u may m notice that tha you feel hotter in a darker-colored darker-colored dar d ker-colored shirt than a lighter-colored shirt.

You that ice melts faster in a Yo ou may observe obs cup c made mad of one material than a cup made another material. of anot Such observations lead you to ask Su questions about why these things occur. q ques

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Ask Questions

Asking questions helps you to define the investigation. Your investigation should be designed to find the answer to your questions.

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You can also use prior knowledge and experiences to provide possible answers to your questions.

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Before a science investigation begins, it’s important to ask questions about what you would like to find out.

Why does warm warm m water w wa err cool fasterr in in a met me m metal etal a cup thann in a foam fo m cup? ccu

Do plants grow taller when fertilizer is added to soil?

Why do amphibians live near water?

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Make a Prediction Ma M

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On Once nc you have asked questions based sed on your yo observations, it’s time to make a prediction ob bse iction and form fo or a hypothesis. A hypothesis sis is a statement statemen about what you think your investigation a nvestigation stigation will w show.

A hypothesis is more re than just a guess. gu g It is a statement based you d on knowledge knowle already have orr things ngs you have observed in the past.

Based on past you B ast gardening experience, ex may m predict ct that plants will w grow faster and taller talle in humus-rich mus-rich rich potting soil than in sandy soil.

Based you may Ba ase on n a previous investigation, inv in already metal is a better conductor of already know now that me heatt compared or plastic. These past mpared to wood w experiences you predict the results of xperiences ences can help h an investigation. investigation nvestigatio

Why is it important to write a procedure that can be easily followed by others?

Plan n and Carry Out Investigation an In

Once you have stated your hypothesis, it’s time and conduct an investigation that will test to op plan a your p yo prediction. In planning your investigation, you should include all the materials you will need and a procedure that clearly shows the steps a an you y will take to conduct the investigation.

Your materials and procedure should be written in a way that allows the investigation to be easily followed and repeated by others. In your procedure, include the data you will collect and the way it will be recorded.

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Variables An important part in a science investigation on n are variables. A variable is any factor thatt can be controlled or changed during the investigation. There are three main variables – the independent variable, the dependent variables and the controlled variables.

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The independent variable is the one condition in the investigation that you can change. Usually it is the thing that is being tested. If you were investigating which ch h he materials are good conductors of heat, th the independent variable would be the type pe o of material.

The dependent variable is the factor actor or that you measure or observe. The dependent nd variable should change due to changes hanges in the th independent variable.

In an investigation on materials mate that are good conductors of heat, the dependent va variable he e depen dep could be temperature ure of water in a cup. You would expect the temperature mperature of the water to change as you ou change ange the independent indep in variable – the type e of material materia the cup is made of.

Imagine conducting an investigation about the growth rates of different seedlings.

What would be the independent variable?

What would be the dependent variable?

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Imagine you were carrying out an investigation into the effect of temperature on plant growth. What would be your controlled variables?

The controlled variables are variables that do not change during the investigation. igation Controlled variables could include the type ype and size of a container, the source ce and nd temperature of water and the types es of instruments used to take measurements. asurements. ements.

The purpose of the controlled ed variables variab is to ensure that the only influence nfluence on changes in your observations ations ons is due to tthe independent variable.

Collecting g and nd Recor Recording Data Make observations vations ons and collect coll colle data as stated in your our procedure. ocedure. The T data should be d in an organized organize way that can be recorded nd understood by b others. read and Often, recorded in a visual manner, ften, en data ata is reco such uch as charts, graphs g and diagrams. Data can also be e entered into computer software en which it easier to analyze and hich ch can make m present p nt the th data.

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Analyze and Interpret Data

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Once your observations have been accurately recorded, it’s time to analyze and interpret the data da ata to see if your hypothesis is supported.

You analyze when you look closely at recorded data. You look for patterns to help explain your results. A pattern is when data repeats in a predictable way.

You interpret when you understand and explain what the data means. In interpreting g data, you use your prior knowledge, experience, rience, ce,, identifie fie ed d and skills to explain patterns and trends identified in the analysis of the data.

An important part of analyzing and d interpreting iss to check the accuracy of the data ta collected. ollected. If there th are inaccuracies or inconsistencies cies in n the data, data you may need to adjust your procedure repeat cedure ure and rep repe the investigation.

Draw a Conclusion usion sion

By analyzing and interpreting nterpreting rpreting your you data, d clusion. on. Your conclusion co conclu you reach a conclusion. is a he data ata collected. collecte Your Yo conclusion summary of the ate the he accuracy of your prediction. should indicate usion should state stat whether w Your conclusion your hypothesis sis was supported o or not supported.

R

urr hypothesis w was no If your not supported, you may cide e to form a ne new hypothesis h decide and plan and conduct investigation.

If your hypothesis onductt a new invest ondu in upported, you may wish to do further upp supported, was su stigations sti gatio to confirm c investigations the results or improve racy of the data collected. rac the accuracy

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Communicate

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The final f step in a science investigation tion is to c communicate your findings to others. co ers.

This you to share what you This allows a ou have ve discovered and also allows others dis d rs to assess the th accuracy of your investigation. estigatio estigation.

The people you communicate your mmunicate municate you results with may wish to conduct conduc a similar investigation ation n and compare comp results. They may also wish to conduct further investigations estigations ations to find fin out more.

If they do, they’ll communicate their y’ll also com results so others r rs can learn lea lear from their investigations in ationss too.

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Scientific Method Flowchart Make Observations

Ask Questions

Construct Hypothesis hesis

Plan and nd Conduct Investigation stigation

Analyze ze and Interpret Data Dat

Form a Conclusion

Hypothesis pothesis Not No Supported

Hypothesis Supported

Communicate Results

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Science Safety ty

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In the Laboratory y

Follow these safety rules es when in your yo science laboratory or when hen carrying out any science investigation. igation. gation.

Do not enter the e laboratory w without a teacher.

Follow your our teacher’s eacher’s instructions. ins in If you have or are ve any questions quest unsure ure off what to do, d raise your hand and nd ask sk your teacher. teac Do not eat, dr dri drink, play or run in the th laboratory. laborato

Wash W your yo hands with soap when entering en nterin and before leaving the laboratory.

Dry your hands properly, lab ab b bor especially if you will be working es sp s with electrical equipment. If any wi w chemical or hazardous material gets ch on your hands, inform your teacher immediately. im Wear W appropriate safety gear when carrying out scientific investigations. ca Safety gear includes a lab coat, safety Sa goggles and gloves. Tie long hair back go and do not wear open-toed shoes. an Be careful when handling sharp tools or working with burners and hot substances. su

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Do not panic if an accident occurs.

Be aware of eyewash stations, fire ty extinguishers, exit doors and other safety equipment and procedures in case of an emergency.

Keep your workspace clean and organized. Report any spills or breakages to your teacher. Clean up any spills straight away and dispose of the cleaning products safely.

When cleaning up, ensure all materials and substances go into the correct bin or container. Do not pour any liquid down the sink unless your teacher has instructed you to do so. o.

Look after the equipment you use and return it to its proper location in the e same condition you received ed it.. Wipe your workstation down after fter use. use

In the Field

Make sure you are e accompanied ccompanie by an adult when on field other ield trips or doing doin ot activities outside schoolyard. de of the schoolyard schoo On long trips, ps, make sure you take t enough water and food. B Bring Brin insect repellent nt iff necessary.

Try This!

Create a poster of the rules to be followed in your science laboratory or classroom.

Display the poster in a place for everyone to see.

On sunny sunny days, take tak Su Sun protection such shirt, hat as a long-sleev long-sleeved sh and sunscreen sunscreen.

Do nott tou touch pl plants, animals or other organismss un unless instructed to do so by your teacher.

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Diversity of Life How do scientists determine if something is an organism?

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In this chapter you will ...

• identify the needs and characteristics of allll organism organisms.

nisms in tthe six kingdoms.

• describe and provide examples of organisms elles.

• describe cells and list cell organelles.

• explain how cells are organized.

How do scientists cientists classify organisms into groups? organ

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What parts rts can be found fo inside th functions? a cell? What are their

Go Online!

Access interactive content relating to this topic on the NGScience website. ngscience.com

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What Are Organisms? sms Classification is an important partt off science. It is the process of observing rving and placing things into groups oupss based e. One way on characteristics they share. gss is is as living livin things thin th scientists classify things and non-living things. s.. A living liv ving th thing hing iis an organism. mething hing to be classified c In order for something as an organism, m, scientists ntists look closely at its characteristics functions. stics and functio All organisms: nisms:: • are made of one o orr more cells.

•o obtain bta tain in and d use use energy.

• repr pro roduce. reproduce.

• rrespond espo pon nd to changes. row row • gr grow.

What characteristics and functions of the deer let scientists know it is a living thing?

AB

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Activity 1.1

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Cells

Organisms come in a great variety of shapes pes and sizes, and can be found in all areas of ebas, s, the Earth. Some, like microscopic amoebas, scope are so small, we need to use a microscope hale, can to see them. Others, like the blue whale, reach lengths of over 25 meters – that’s hat’s about as long as a basketball court!

From microscopic amoebass to giant blue whales, all organisms are made e of cells. cells Cells C are the smallest units within an n organism that can carry out life processes. esse They are often esses. referred to as the ‘building of life’. uilding ng blocks block blo

Some organisms, diatoms s, like e parameciums, parameciu and bacteria, are made up of only a single cell.

They are unicellular Others, like cellular ular organisms. organisms organis most of the you are familiar e plants nts and animals anim with, are made They are called e up of many cells. c multicellular ellular ar organisms. organisms.

amoeba

Did You Know?

Cells were first discovered in 1665 by the English scientist Robert Hooke. When observing cork under a microscope, he noticed a series of small boxes which he called ‘cells’.

Humans mans are multicellular multicellula organisms. Scientists multice estimate stimate that our ou bodies bod are made up of trillions of different cells that tha all play a role in helping our bodies es fu function.

AB

Activities 1.2 – 1.3

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Goshawk feeding on a Eurasian magpie.

House Sparrows feeding ding ng on a raspberry cane.

Obtaining and d Using sing Energy Ene

Plants are organisms that use the energy in sunlight to produce food.

All organisms need d energy ergy to carry carr car out life processes. Life processes rocesses esses include includ growth, reproduction and nd the he repair and an maintenance of structures. Some like many e organisms, organism organis animals, use move their body parts e energy ergy to mov or to move ve from om place to t place.

Different energy in ent organisms obtain o different erent ways. Plants Plan are organisms that photosynthesize hotosynthesize synthesize – they capture light energy and from m the Sun an a convert it into food. The food throughout the plant. ood d is distributed distribu distrib Animals o obtain energy by eating other An A organisms. Fungi obtain energy by breaking orga organis down and absorbing the remains of organisms. dead org

AB

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Activity 1.4

Reproduction All organisms are able to reproduce. This means they are able to make more of their own kind. There are two main types of reproduction – sexual reproduction and asexual reproduction.

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Sexual reproduction involves two parents. Each parent produces a special reproductive cell which join together to form a single cell. This process is called fertilization. The offspring that develops from the fertilized cell will have characteristics from both parents.

Asexual reproduction involves only one e parent. parent nt The offspring are genetically identical ical cal to the ms reproduce eproduce parent. Most unicellular organisms asexually. Bacteria and many other unicellular organisms reproduce by dividing ding into two identical daughter cells.

AB

Activity 1.5

Parameciums reproduce by dividing into two identical daughter cells.

Go Online!

Some simple organisms, such as yeast and freshwater hydra, reproduce asexually by budding. Find out more on the NGScience website.

QuickCode: D6S9

Lions and other mammals reproduce sexually.

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Growth h and nd Development Deve Organisms ms grow row and develop de as they get older. All off the stages in an organism’s life om first entering enteri the world, growing – from rger ger and developing develo develop larger new parts, to reproducing oducing you young of its own make up its life cycle.

When the sex cells from a flowering plant are fert fertili fertilized, the fertilized cell develops iinto a sseed. Under the right conditions, the sseed eed will germinate and start to grow. It w will grow leaves and start to make its own ffood food. It will eventually develop flowers and fruits and go on to produce new plants of ffrui tth the same kind.

W When multicellular organisms grow, tthey usually change in size and shape.

T The number of cells that makes up their b bodies increases.

U Unicellular organisms also grow and change shape as they get older. c T They usually get larger in size before rreproducing by dividing.

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Re ga le du ca t When an eagle spots prey, it responds by diving and catching it.

Response to Change

An eagle flies high in the sky. It uses its keen n sense of sight to search for fish in the e lake below. When it spots a fish, it dives down and catches it in its sharp talons.

Spotting the fish in its environment ment nt is an example of a stimulus. The way y the th he eagle he respo respon acted when it spotted the fish sh iss a response. o stimulilii in n their All organisms respond to environment. uses A stimulus is any change nge that causes cau an organism to act in n a certain way. wa ay The way an organism rganism ism reacts to the th h stimulus is called alled d a response. response Generally, Ge an organism sm willl respond in a way that increasess its chances of survival. sur surv

Amazing Fact!

Pea plants have specialized stems, called tendrils, that curl and twine around the objects they touch as they grow. How does this response help the pea plant survive?

tendril

pea plant

A stimulus in mulus could be a change ch light, chemical ht, temperature, sound, sou changes environment or hanges to an e enviro contact ontact w with other organisms.

AB

Activity 1.6

9

Classifying Organisms nism Earth is home to a great diversity rsity of of organisms. To organize and gain gain n a better better ms, scientists sc cientiistss understanding of organisms, pss b ased on ase on the th he classify them into groups based features they share. The he process process cess o off naming and classifying ing ng organisms organi org nisms iis called taxonomy.

u

nd tthe he w orrlld use us the Scientists around world same system off c classification. mo lass ssificatio This allows od escriib be o rga scientists to describe organisms in a ay. Th T his enables enable them to easily precise wa way.

This heir k nowledge and discoveries. now share their knowledge How is classifying organisms useful?

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Activity 1.7

The broadest and most general group of organisms are called kingdoms. There are six kingdoms recognized by scientists: • • • • • •

10

ancient bacteria bacteria protists fungi plants animals

ga le du ca tio n

All of the organisms in each kingdom share basic characteristics or traits. The chart below shows some shared characteristics of the organisms within each kingdom.

The Six Kingdoms of Life fe

Ancient Bacteria

• unicellular • no nucleus • decomposers • can move from place to place

R

Fungi

multicellular • un unicellular nicellula and multicellu ular • nucleus eus • decomposers posers • cannot move from place to place

Bacteria

• unicellular • no nucleus cleus • decomposers mposers • can move from place to place p

Pla Plants

• multicellular • nucleus • producers d • cannot move from place to place

Protists

• unicellular and multicellular • nucleus • producers and consumers • some can move from place to place

Animals

• multicellular • nucleus • consumers • can move from place to place

11

ed uc ati on

By looking closely at the characteristics of organisms, scientists are able to classify them sify th et’s take ake a lo into smaller and smaller groups. Let’s look oking g at how a at this classification system by looking tiger is classified.

Kingdom – Animalia

Re ga

Phylum m – Chordata Chord

Class – Mammalia

12

ed uc ati on

Order – Carnivora ivora

Family – Felidae

Re ga

Genus nus – Panthera Panth

S nthera tigris Species – Panthera Sp

13

Think Deeply Occasionally tigers are born with white fur instead of orange. How could scientists tell if they belong to the species Panthera tigris?

Tigers belong to the kingdom Animalia An which includes all animals. Att the next e ne rs is the classification level for tigers nima in phylum Chordata. All of the animals ckbone one – they’r this phylum have a backbone they’re all vertebrates.

Ma Mam Below a phylum is the class Mammalia. he class ass Mamm All animals in the Mammalia are mammals. Mammals get their mals that ge energy by eating animals g mostly other ot o vores. s. They are classified are carnivores. err a rder Carnivora.

C together ass the order Within is the family hin the th he class he class Carnivora Ca Felidae. members of this family are elid dae e. A e.

Allll mem me emb cats – tigers, lio lions, lynx and domestic cats Within the cat family are the ats too. Withi big cats – tigers, lions and leopards. ttig These animals belong to the genus ani Panthera.

Panther The smallest unit of classification is a species. A species is a group of similar sp organisms that are able to reproduce young of the same species. yo All species are given a two-part scientific name. The first part of the name is the organism’s genus. The second part of the name is called the specific name. The scientific name for tigers is Panthera tigris.

14

Kingdoms Bacteria

Re ga le du ca ti

Bacteria (singular bacterium) are amongst the simplest and oldest organisms on Earth.

All bacteria are unicellular microorganisms and most can only be seen using powerful microscopes. Bacterial cells do not have a nucleus.

Bacteria are divided into two kingdoms – eubacteria and archaebacteria.

escherichia bacteria escherich escherichi

Eubacteria can be found in all natural environments – in the air, in water and soil and even in the bodies of other organisms, nisms, including humans. Archaebacteria a live in extreme environments such as the he deep ocean floor, volcanic vents and hot springs.

Bacteria reproduce asexually lly whereby an individual bacterium dividess to form two identical daughter bacteria. er Reproducing producin in this way allows bacteria to reproduce rap rapidly. o reprod repr

streptococcus bacteria

Bacteria can cause infections e diseases seases and inf in plants, animalss and d people. Salmonella S Salmo and E. coli are bacteria cause food teria that c can ca poisoning in people ople and some som animals. a Bacteria can helpful. Many organisms an also o be helpfu M need bacteria cteria ia to help them get the nutrients they need. eed. Bacteria in your stomach help you to get ett nutrients from the food you eat.

Bacteria classified by the shapes of acteria are ofte often cla their bodies such as rods, spirals heir unic unicellular bod and spheres. phere pheres.

spirilla bacteria

15

Re ga le du ca tio

Kelp are multicellular protists. otists. ts. They can grow to lengths of over 50 meters. le s.

Protists Pr P

Vorticella are unicellular aquatic organisms often found attached to plants and rocks.

Did You Know?

Protists do not have many characteristics in common.

They are classified together as they do not fit clearly into any of the other kingdoms.

Slime molds are decomposers. They ey breakdown akdo dead organic matter er and absorb the remains. mains. s.

16

Protists are organisms anisms sms that belong belo to the kingdom Protista. sta. They hey come com in a diverse range nd sizes. izes. Most protists, p pr of shapes and like diatoms, orticellas, are a unicellular. There euglenas and vorticellas, are also multicellular pro protists, such as the giant kelp and nd slime molds. me protists otists are p Some plant-like, such as diatoms and euglenas, an and are able to photosynthesize. and obtain energy by Others ers are animal-like anim a feeding organisms or by absorbing eding ding on other ot o nutrients nts from fr fro their environment. Amoebas are unicellular protists that engulf and feed on other un unice organisms such as algae and bacteria. organ organism reproduce asexually. But some Mos protists Most pr multicellular protists have more complex m multic cycles. life c

AB

Activity 1.8

Fungi Fungi (singular fungus) include organisms such as mushrooms, puffballs and molds.

ga le du ca t

Most fungi are multicellular and reproduce by releasing microscopic spores into the air. New fungi grow from the spores. Yeasts are unicellular and reproduce asexually by budding whereby a small bud forms and splits to form a new daughter cell.

Fungi are decomposers – they get the energy er erg e gy y they need by breaking down the remains ns of other organisms and absorbing the organic rganic c matter. In doing so, they play an important ortant ant role in ecosystems by returning nutrients to o the soil.

Some fungi can cause diseasess in plants, pla animals and people. Fungi can helpful an also so be helpf helpfu to people in many ways. Many any mushrooms mushroom are important food sources. Yeast ast iss used in the t preparation of bread and nd cheese. se

The medicine penicillin, antibiotic, is cillin, an important import impo obtained from the notatum. e fungus ngus Penicillium Penicill What are e the characteristics charac of fungi??

fly agaric mushroom growing on the forest floor

Go Online!

Mycorrhizae are microscopic fungi found in soil. They play an important role in helping plants take in water and nutrients. Discover more about mycorrhizal fungi on the NGScience website.

QuickCode: X2T6

AB

Activity 1.9

bracket rackett fungus growing on a log

17

A Closer Look

What Is a Virus?

You might know of viruses as the microscopic germs that can cause us n to get sick. Unlike microscopic organisms such as bacteria, viruses are not alive. They are not made of cells, they cannot obtain orr store energy and they can only replicate when inside the cells of other organisms.

A virus is a strand of genetic material surrounded by covering. It y an outer c can invade and take over the cells of all types of organisms, animals rganisms, from fr and plants to microorganisms including bacteria. The cell that tha is invaded by a virus is called a host cell.

Once inside a host cell, the virus releases itss genetic material and instructs ma the host cell to replicate it many times. Hostt cells can replicate millions of copies of a virus in just a few hours. Once replicated, replicate the host cell bursts open and the newly replicated viruss is released. E Each new virus can go on to invade other host cells.

AB

18

Activity 1.10

Think k Deeply Deepl

ed uc ati on

Most viruses are harmless to people, but some can cause us to get sick. Viruses can cause illnesses such as the common cold, the flu, cold sores and chicken pox.

We get sick from a virus when it infects or kills many of our cells, causing an immune response from our bodies. Often, the virus will infect cells in certain parts of the body. The common cold, for example, is caused by a rhinovirus that affects the nose and throat. The runny nose and sore throat you get when you have a cold is your body’s immune system fighting the infection. n.

Many viruses can only replicate at specific c temperatures. A fever is your immune system’s em’s response to fight the virus by increasing ng your ur body temperature.

What things gs did people do to e spread of Covid-19?

C slow the Why were these measures necessar necessary?

envelope

genetic material

R

ga

In 2020, there was a global spread ad of a virus called Covid-19. This virus infected ted the he lower airways and lungs. People infected fected ted with Covid-19 Cov had symptoms such as a dry cough, difficulty diffic dif breathing lungs. reathing and mucus in the lung ungs ngs. ngs gs.

An arti A artist’s impression of the coronavirus that causes Covid-19. co corona

19

Plants Pla F rom tiny mosquito ferns to giant sequoia sequo uoia ia From trees, tr ree plants can be found in all sshapes, hape pes, sizes sizes and a nd colors. Plants can be found d in in all all areas al areas of of tthe he Earth – in icy tundras, dry ry deserts deserts and and in i and salt water too. ffresh r Plants are multicellular ular organisms organisms that get the energy gy tthey hey need need by by photosynthesizing.

Photosynthesis is the ing. P hotosy synth th process by which energy, hich llight ight e nerg erg water and carbon dioxide are used c xid de a re u sed to to produce stored chemical energy c energy iin n tthe he fform or of glucose. The glucose is stored by and used to g lu sttored b y the the plant p carry As primary producers c ar outt life life processes. processes. A in in all al ecosystems, osy os ystem ms, plants plants are important food sources sour es ffor fo or many many other ma oth organisms.

Amazing Fact!

Re ga

The tallest trees on Earth are a type of sequoia called coast redwoods. They can reach heights of up to 115 meters (377 ft). With the e thickest bark of all trees, s, they are also immune ne to most diseases.

20

eg al ed uc ati o Flowering plants and conifers are vascular plants. nts. ts

Plants can be classified in different ways.

One way scientists classify plants is by the presence or absence of vascular tissue.

Vascular tissue are internal tube-like structures in the roots, stem and leaves that at transport water, nutrients and food around nd the plant.

Think Deeply Thin

Imagin you discover a new Imagine spec species of plant in a forest.

How could you determine if it is a vascular plant or a nonvascular plant?

Plants with vascular tissue are called ed d vascular plants. Flowering plants, s, conifers onifers and ferns are vascular plants.

Plants without vascular tissue ue are re called non-vascular plants. Without out structures structure to o transport water, nutrients ts and food, ood, nonnon vascular plants are usually sually ually smaller ssm in size than vascular plants. and s. Mosses, ses, liverworts liver liv nd d hornworts are non-vascular n-vascular ascular plants. plan

liverwort

What are the characteristics charact of plants? s?

mosses es growing rowing on rocks in a stream

21

ga le du ca tio

macaw

rock lobster lobs lob

Animals

Millions of different diffe t kinds ds of animals anima anim live on Earth. They can ca be found in the freezing hottest They can be poles to the ho ottestt deserts. Th found in bodies bodie ie es of fresh and salt water and underground in a great undergroun und too. t o. They come co diversity of shapes o sha apes and ssizes.

meerkat

Unlike get e plants, ants, which whic w g the energy they need by photosynthesizing, animals feed on other photosynthesizi synthesizi organisms nisms to get the energy they need.

Most ost st animals have body parts that enable them to move t mo from place to place. Animals m also als have sense organs to take in information about th the world around them. Their sense organs allow them to move in response to organ al changes around them. Animals also move cha change about in search of food, to escape from danger ab or to find a mate. blue pit viper

red-eyed tree frog red-eye

22

jellyfish

African elephant

Within the animal kingdom, scientists divide animals into two main groups based on the presence or absence of a backbone.

Re ga le d

Animals that have a backbone are classified as vertebrates. Many of the he animals we are most familiar with, like mammals, birds, reptiles, amphibians phibia bia ans and fish are vertebrates.

Animals without a backbone e are re classified classsified ified d as invertebrates. They account ount nt for about ab bo bou out 95 percent of the animals Some ome om als on Earth. arth. So invertebrates, like worms rms ms and an jellyfish, sh have soft bodies. Others, like insects nsectss and crustaceans, cr ceans, have a hard outerr covering vering called an exoskeleton. The e exoskeleton skeleton provides provid pr protection and water loss. d often en helps to prevent prev Without a backbone bone or internal inte interna skeleton on of bones, invertebrates smaller nvertebrates tebrates are generally gen ge aller in size than vertebrates. ertebrates. brates.

What ar are the characteristics of animals? anim

AB

locust

Activity 1.11

23

What’s Inside Cells?

Re ga le du ca tio n

Plants and animals are multicellularr organism organisms. ganism They are made up of cells of many ny different ifferent es and ssize kinds and come in a variety of shapes sizes. en suited to the The shape and size of a cell iss often organism function it performs for the organism.

Did You Know?

The English scientist, Robert Hooke, was the first person to observe cells. He did so in 1665, when looking at a slice of cork under a microscope he made.

Shortly after, Antonie Philips van Leeuwenhoek, a selftaught scientist, made a more powerful microscope and became the first person to observe unicellular organisms.

Most plant and animal cells ls have the same ssa internal parts, called organelles. rganelles elles.. Each organelle has a specific role in n helping ping the cell cel to function as a whole system. m. Let’ss take a look loo at the parts of an animal cell..

Animal Cells lls

The outermost ermost part of an a animal cell is the cell membrane rane ane – a thin layer lay that surrounds the cell. la The main n function of the cell membrane is to regulate interactions that occur between the gulate the interac intera cell ell and nd its external extern environment. It controls the that go in and out of the cell. substances stances ttha

Amazing Fact!

The human body is made up of trillions of cells of which there are about 200 different kinds. Cells are continuously reproducing. g Every day, billions of cells ells die and are replaced by new cells.

Inside the c cell is the cytoplasm. The cytoplasm is watery substance that holds the cell organelles aw wa for the cell nucleus. It helps to protect the except fo excep organelles and also gives the cell its shape. organ organelle nucleus is often referred to as the control The n Th center of the cell. It controls all of the internal cent cell activities and processes such as growth and c ce metabolism. At the center of the nucleus is the nucleolus which is where ribosomes are made.

Mitochondria (singular mitochondrion) are often referred to as the powerhouses of the cell. They release the energy from digested foods.

24

ca tio n

The Golgi apparatus is the organelle that packages and transports proteins for delivery to different destinations within the cell.

Did You Know?

K

The endoplasmic reticulum (ER) is an organelle attached to the nucleus. Its main function is to produce proteins for the rest of the cell. The protein is made in ribosomes, which are small, round organelles on the surface of the ER.

Animal al cells are generally plant cells. As smaller than pla they cell wall, they hey lack a cel irregular in shape are also irre compared to plant cells.

Vacuoles are storage spaces for water, wastess and other cellular material. nucleus

nucleolus

cell membrane membran vacuole

Re

Golgi apparatus

endoplasmic reticulum endopla endoplas end ribosomes) (with rib

mitochondrion

cytoplasm

Wh organelles can be found in animal What cells? What are their functions?

25

Plant Cells

vacuole

ed uc ati on

Like animal cells, plant cells have a cell mem membrane, nucleus, mitochondria, ER and ribosomes. osomes. mes. Plant cells also have vacuoles, but they larger ey are usually la lar than the vacuoles in animal cells. ells. Like animal cells, the organelles in plant cells float in the cytoplasm. cytop cyt

cell wall

cell membrane

plant cells with chloroplasts

Think Deeply Halle viewed unicellular protists under a microscope and noticed they contained chloroplasts. What can she infer about how they obtain the energy they need?

Plant cells are different from rom om animal cells ce in that they have a cell wall – a rigid gid structure structur that surrounds the cell membrane. function of embrane. brane. The main m the cell wall is to provide rovide e support and protection.

Many plant cells contain chloroplasts. ells also so contai Photosynthesis esis takes place in the chloroplasts.

Chloroplasts which is a green asts contain chlorophyll ch chlo pigment ntt that captures the energy from sunlight.

AB

hloroplast p pla chloroplast

Activities tivit 1.12 – 1.13 n nucle nucleolus

nucleus

Re g

mitochondrion

cytoplasm cytopla

26

Golgi apparatus

endoplasmic reticulum (with ribosomes)

In what ways are plant cells similar to animal cells? How are they different?

Cell Organization

Re ga le du ca tio n

Multicellular organisms are made up of many different kinds of cells. The cells are organized in a way that allows them to work together to perform specific functions.

A group of similar cells that work together to perform m the same function forms tissue. Muscle is an example mple e of tissue. Muscle is made of groups of muscle cells. lls.

muscle ce cell

Tissues work together too. A group of tissues that work together to perform a specific function n forms orms an organ. The heart is an organ made up p of different tissues. The function of the heart is to pump ump p blood around the body.

Organs working together to perform rm m a specific function form an organ system.. The e circulatory system is comprised of the heart vessels. art and nd blood v ve

muscle tissue

All of the organ systems working orking ng together togeth make an organism. Within a tiger the skeletal muscular eletal system, syst system, circulatory system, tem respiratory tem, ratory system and other systems all work together to help the tiger move rk togethe togeth about and carry out ut life e processes. processe

AB

Activity 1.14

body bo bod syst systems sys of a tiger

heart (organ)

27

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. organism cells unicellular organism multicellular organism sexual reproduction asexual reproduction virus

vascular plants non-vascular plants vertebrates invertebrates organelles photosynthesis

1.

Plants produce their own food through the process of

2.

are animals with a backbone. ne.

3.

are animals withoutt a backbone.

.

4.

An organism made of just one cell is a

5.

e than one cell c is a An organism made of more

6.

A over cells.

7.

are the e smallest units within an organism that can carry out life processes. s.

8.

A living thing g is called an

.

is a strand off genetic material that can invade and take

.

9.

do not contain con vascular tissue.

10.

contain vascular tissue.

11.

R roductio that involves fertilization is called Reproduction

12.

Reproduction involving just one parent is called Repr

13.

The parts of a cell are called

28

.

.

.

.

Review List five characteristics of organisms.

Re ga le du ca tio n

1.

2.

True or false. (a) Animals are unicellular organisms. (b) Animals cells do not have a cell wall. (c) Photosynthesis takes place in the nucleus of a cell. (d) Ferns and mosses belong to the same kingdom. dom.

3.

What is a virus?

4.

Describe and provide an example of a decomposer. composer.

5.

Copy and complete the tables.

(a)

Plant Classification lassificatio

Type of Plant

Description

Examples

Vascular Plants Non-vascular Plants

(b)

Animal Classification

Type of Animal

Description

Examples

tebrates Vertebrates

Invertebrates

6.

What is chlorophyll?

Where is it found? chlorop

7.

Draw diagram to show how cells are organized within a D aw a labeled labe vertebrate animal. verte

29

In the Field

Sir Alexander Fleming “One sometimes finds what one is not looking for. When en I woke up just after dawn on September 28, 1928, I certainly ta ainly didn’t plan to revolutionize all medicine by discovering ng the the ose e tthat ha at world’s first antibiotic, or bacteria killer. But I suppose was exactly what I did.“ – Sir Alexander Fleming.

Sir Alexander Fleming was a Scottish physician an and nd the drug penicillin pe enic nici microbiologist, best known for discovering the – the first effective antibiotic used to kill bacteria. ba acteria.

In his laboratory in 1928, Fleming wass investigating inv vesstig igating the th properties of the bacteria Staphylococci.

On from ococc ci.i. O n returning retur eturn a family holiday, Fleming noticed that in a hat bacteria bact bacter eria growing g petri dish were being killed by the a type he fungus fungu us Penicillium, Peniic c of mold.

30

ti ca

He observed that the bacteria immediately surrounding the fungus had been killed, and that ha at at the bacteria farther away were ere usly us normal. “That’s funny” he famou famously remarked to his assistant.t.

Fleming’s discovery led to o the the e antibiotic a tic development of the penicillin. The discovery co overy ry was w a medical breakthrough hrough fo ffor or tthe he treatment of many man ny illnesses illln ne ess sses es caused by b bacteria.

Today, modern acteri eriia. T od da ay, y, mo antibioticss a are using re still tested teste te ed du sin a method Fleming d similar sim miillar to how how Fle em discovered ve ered d penicillin. penicil enicillin. in . em ming received receiived m a awards Fleming many for ffo or his his hard d work wo w ork and an scientific discoveries the Nobel Prize d isco scoveries riess including iinclu n ud in Physiology Physiolog gy or or Medicine in 1945.

31

Plants

Re ga le du ca tio n

2

In this chapter you will ...

• describe some ways in which plants can be classified. sified.

al and external extern • construct an argument that plants have internal owth, behavior beha structures that function to support survival, growth, and reproduction. p • describe and compare the life cycles of flowering plants, mosses and ferns.

What characteristics ristics do scientists observe to o classify plants? pla

32

ed uc a

How do a plant’s internal al and external structures support port its survival, growth and reproduction? production

Go Online!

Re

Access interactive content relating to this topic on the NGScience website. ngscience.com

Wha are the stages in the life What cycle of a flowering plant? c

33

Classification of Plants nt Scientists have discovered, named and d classif classified about 400,000 different kinds of plants. nts. Each eciess are year, about 2,000 new plant species er understan discovered. To organize and better understand ationships between betwe betw plant structures and the relationships plants, scientists classify them groups. One hem into groups way plants are classified or d iss as vascular vascula plants p non-vascular plants.

Re ga le du ca tio n

Try This!

One way scientists classify plants is by the shape and edges of their leaves.

In small groups, use a hand lens to observe and classify the plants in your schoolyard by tthe shape and edges ges of leaves. g lea

Vascular plants have ve vascular ascular tissue tiss tissu – internal, tube-like structures res to transport water, minerals ughout ut the plant. plant Non-vascular and food throughout ve vascular tissue. t plants do nott have Why is it important importa to name plants? classify and na

Go Online!

AB

Activity 2.1 Activit

Discover more about the classification of plants on the NGScience website.

QuickCode: W8S9

Plant Kingdom

Non-vascular Plants Non

Mosses

34

Liverworts

Hornworts

Re ga le du ca tio n Moss spores are held in capsules.

Plants can also be classified by how they reproduce. Non-vascular plants and ferns do not ot produce seeds – they are seedless plants. They hey reproduce from spores. The spores are typically pically ly made of just one cell. Each spore is capable ble of developing into a new organism. In mosses, ses spores are contained in a capsule. In ferns, spores are usually located on the underside nderside of the fronds in clusters called sori.

Gymnosperms, such as conifers ers and d firs, are cone-bearing plants. They reproduce eproduce oduce from seeds held in cones. Angiospermss are e flowerin flowering plants.

They reproduce from seeds that hat at develop develo in flowers and are held in n fruits. fruit fru

fern sori

AB Activity 2.2

V Vascular Plants

Ferns

Gymnosperms

Angiosperms

35

Non-vascular Plants N N Non-vascular plants do not have vascular tissue – xylem and d phloem, througho to transport substances throughout the plant. They also lack stems ck roots, ste and leaves.

liverwort

To T survive without ut vascular tissue, non-vascular plants no ants are small sma and live close the cllos to the ground. und. They absorb a water wate and nutrients nts they need ne from their environment.

The enviro on e water then the travels within the plant plant by b moving ng from one o cell to the next.

Mosses, liverworts hornworts are nonliive rts and horn vascular plants. pla Non-vascular plants have rootNon-vas like structures called rhizoids that tha anchor them in place. They can c often be seen carpeting the moist forest floor, clinging to rocks near streams and growing on tree trunks.

moss

36

Mosses and liverworts have tiny leaf-like parts called leaflets which are just one cell thick.

Most photosynthesis occurs in the leaflets.

du ca tio n

Did You ou Know?

Kn

Non-vascular plants are seedless plants.

They reproduce from single-celled microscopic spores held in a part called the capsule.

When the capsule opens, the spores are spread by water and wind to new places. Under the right conditions, new plants will grow from the spores.

Non-vascular ular plants we were the first plants nts to grow on land.

Scientists discovered tists have disc fossil evidence of o liverworts growing on land 473 million ago. years ago

AB Activity 2.3 A

What are the characteristics of non-vascular plants?

A Closer Look

Parts of a Moss Plant

capsule sporophyte

seta

Re

foot

eaflets leaflets

gametophyte

rhizoids

37

Vascular Plants Vas Va

Re ga le du ca tio n

Vasc Vascular cu plants are plants that have e tubebetissue to transport substances like vascular va ubstances anc th hro throughout the plant. There are re two o main types of vascular tissue – xylem tty m and phloem. phloe phlo Xylem transports waterr and nutrients X nutrients, usually from the roots tss to the upper rregions of the plant. Phloem m transports food ffo from the leaves to all partss of the pla plant.

The cells in vascular are rigid and ular tissue a provide plants ants with support, suppo suppor allowing them to grow taller plants. aller than non-vascular non-v

Vascular V Va ar plants ants can be further classified based ba as on whether they the produce seeds and where whe ere the he seeds form form.

bracken ferns

Think Deeply

Fern Ferns ns and d horsetails horsetai are seedless vascular plants.

They The hey ey reproduce eproduce fr ffrom spores.

Wha are the primary functions of What xyle xylem and phloem?

Many ferns are able to grow in low-light environments.

What adaptation allows them to do this?

Vascular Plants

Seedless Plants

Ferns

38

Horsetails

Plants that reproduce from seeds are called seed plants. The two main types of seed plants are gymnosperms and angiosperms.

Re ga le du ca t

Gymnosperms are non-flowering plants. They reproduce from seeds, but do not produce flowers or fruits. The seeds are usually held in reproductive structures called cones.

Common gymnosperms include conifers, rs,, cycads and ginkgos.

Angiosperms are flowering plants. They y produce seeds that are held in the ovaries ries ie of ies flowers. As the seed develops, the ovary ary forms rms a protective fruit around the seeds. Angiosperms ngiosperms are the most diverse group of plants. nts. s. More than 300,000 different species have been n named and classified. All grains, fruits and vegetable plants are angiosperms. As are tulips, sunflowers, sunflo oaks and maples.

What are the characteristics char of vascular plants?

Gymnosperms reproduce from seeds held in cones.

Did You Know?

The term ‘gymnosperm’ comes from Greek words meaning ‘naked seeds’ as the seeds are not enclosed in ovaries.

Go Online!

Learn about the life cycle of gymnosperms in a video on the NGScience website.

QuickCode: R2Y5

Seed Plant Plants

Gymnosperms osperms

Angiosperms

AB Activity 2.4

39

vascular tissue

Plant Structures

uc ati on

Roots

Find a weed in your garden and d try to pull pul it from the soil. You’ll notice that it takes akes a lot of o force. If the weed is big enough, ugh, you may not n be able to pull it out at all. Holding lding ding the weed ffirmly o a in the ground are roots. All of the roots of plant make up the root ot system. stem. In most mo vascular plants, the root system The root em iss underground. undergrou system has three main n functions: functions • take in waterr and the soil. d minerals from f • hold the plant ant in the soil.

• store food. d.

root hair

epidermiss

root hair

The T outer layer of a root is called the epidermis.

Attached to the epidermis are tiny roots hairs which are just one cell thick. The root hairs absorb water and minerals which are transported from the root to the upper parts of the plant. root ca cap

At the tip of a root is a root cap. It helps to protect the root as it grows down into the soil.

40

In the center of a root is vascular tissue. Xylem vessels transport water and minerals to the upper parts of the plant, called the shoot system. Food is transported to all parts of the plant, including the roots, in phloem vessels.

Re ga le du ca ti

phloem

xylem

root hair

idermis mis epidermis

root section

Plants can have different roots that hat help them in different ways. Some roots are branch out e shallow ow and b br ots, called fibrous fib to cover a large area. These roots, roots, ts off water when whe w help the plant to take up lots it rains.

Other plants have one main ma root, called calle a taproot, which grows deep into to the he soil. so This T helps to reach water deeper in the e soil. oil.

Some plants have above ground, ave roots that grow gr called aerial roots. roots ts.. An epiphyte epiphy is i a plant that grows on another plant, of trees. Many t, often on the trunks t ferns and orchids Their aerial roots ids are epiphytes. epiphyt epiph take in rainwater water and water wate vapor from the air. Some epiphytes able to take in moisture through ytes are also a theirr leaves. leave What ar are the primary functions of roots? o

AB

Activities 2.5 – 2.6

41

A Closer Look

Mangroves

ati o

Mangroves are plants that grow in intertidal regions in coastal areas. An intertidal region is submerged with salt water during high tides and exposed to the air during low tides. Mangroves have a number of adaptations that allow them to survive in this ever-changing environment.

The soil in which mangroves grow is soft and nd low in oxygen. To survive in such soil, many ny mangroves have stilt roots that prop up p the the plant and prevent the shoot system from rom being bein in g submerged during high tides.

Go Online!

ga

Learn more about mangrove adaptations to intertidal environments and their importance to ecosystems in a video on the NGScience website.

QuickCode: F5Q2

AB Activity y 2.7

42

nd Plant cells, including those in underground roots, require oxygen. Normally, oxygen en can an be taken in through pockets of air in n the soil.

However, the soil where mangroves es often grow has insufficient spaces for air and is very ver low in oxygen. To adapt to this low-oxygen low-oxyg environment, some mangroves ves have specialized specia root structures called pneumatophores. umatophores atophores.. These T vertical structures stick up p out ut of the soil so and enable the mangrove root up root system system to take t oxygen from the atmosphere. mosphere.

Re ga l

Another unique adaptation can adaptatiion n of mangroves m be seen in their life of many life cycle. cy yc cle le. The seeds s mangroves g germinate to grow erminate ate and d begin b while still attached plants. Once tached to to the the parent p developed, d, the the sseedlings eedlings fall away. The seedlings float and d are are dispersed dispersed to new places by the tidal flow off w water. ow o ater.

43

al ed uc ati o

Trees have strong and d thick hick woody stems. stem

Stems

The stem is usually y the e part of the t plant that connects the he roott system to t the upper portions of the e plant. ant.

One function ion of the stem is to provide support and hold d up the e leaves. This T allows the leaves to spread ead out and take in more sunlight.

A tomato plant has a green and flexible soft stem.

Some me plants have hav green stems that are thin and can more easily than others. They n bend m are herbaceous stems. Herbaceous e called herb their green color from chloroplasts stems ems get tthe in n the cells. Vegetable plants such as tomatoes, atoe beans, peppers and herbs have atoes s stems. soft would not be able to support the A soft so stem s weight of the extensive shoot system of a w weigh tree. Trees are plants with thick, strong stems tree covered in protective bark. They do not bend co easily. These stems are called woody stems.

Many shrubs also have woody stems. Woody stems are usually brown in color. The cells in woody stems do not contain chloroplasts.

What are the differences between herbaceous stems and woody stems?

44

Stems contain vascular tissue that transports substances throughout the plant. Xylem vessels transport water and minerals from the root system to the leaves. Phloem vessels transport food from the leaves to all parts of the plant. xylem

epidermis

phloem

stem section ction

ga l

Some plants use their stems forr storage. storage Bamboo and sugarcane ne sstore food od in their stems. Many cacti store water in their stems.

R

What are the main functions funct of the stem?

AB

Activities 2.8 – 2.9 45

L Leaves

cuticle

epidermis

ati on

Leaves together with the stem form m the e shoot shoo system of a plant. Leaves are the food d factories for the plant. They are highly specialized carry ecialized ed to carr out photosynthesis. They are often n flat, broad and branch out in all directions. ons. This enabl enables them to absorb as much sunlight unlight as possible, possi which is the essential source urce ce of energy needed n to produce food.

palisade layer

vein

phloem

Re ga l

stoma st sto stom

Think Deeply eply

Generally, stomata open n during the day and close at night. What could uld be a reason for this?

day

46

night

xylem

leaf anatomy

Running through the center of the leaf is a vein Ru containing xylem and phloem. co conta The T top of a leaf is a layer of cells called the Th epidermis. A waxy covering on the epidermis, called the cuticle, helps to prevent water loss due to evaporation.

On the underside of a leaf are many tiny openings called stomata (singular stoma).

Air, including the carbon dioxide needed for photosynthesis, enters the leaf through the stomata.

Inside the chloroplasts, light energy absorbed by the green pigment chlorophyll combines carbon dioxide and water to produce sugar and oxygen.

The sugar provides the plant with the energy it needs to carry out life processes. The sugar is transported from the leaf to all parts of the plant nt through phloem vessels.

The oxygen produced during photosynthesis esis iss released into the air through the stomata. ta.

AB

Go Online! e!

du ca tio n

Below the epidermis is a layer of cells called the palisade layer. Cells in this part of the leaf contain many chloroplasts. Photosynthesis takes place in chloroplasts.

Observe how ow substances substanc move into to and out of o leaves in an animated video vide on the website.

NGScience webs P8Q1 QuickCode: P8Q

Think T h Deeply

Wha energy transformation What takes place during the tak process of photosynthesis?

Activities 2.10 – 2.12

Re g

sunlight

water ater

oxygen

su ugar ug sugar

carbon dioxide

During photosynthesis, plants use the energy in sunlight to convert water and carbon dioxide into sugar and oxygen.

47

Plant Life Cycles Like all organisms, plants produce young ng of their own kind – they reproduce. Different erent types p s. Let’s take ta of plants reproduce in different ways. a lo loo giosperms, perms, ferns look at the life cycles of angiosperms, and d mosses.

Re ga le du ca tio n

Pollen grains sticking to the body of a bee.

A Angiosperm Life e Cycle

A Angiosperms are plants. They e flowering owering plan reproduce by sexual reproduction. This al reproduc means a male needs to unite with ale sex cell need a female sex cell. Male se sex cells are called sperms. They ey are located locat locate in pollen grains on the anther ther of a flower. flower Female sex cells are eggs e which are stored store in the ovary of a flower. wer.

Did You Know?

Animals that help to pollinate flowers are called pollinators.

They play a vital role in the production of many of the crops humans rely on forr food. Common pollinators rs include insects such as honeybees, butterflies, flies, beetles and hoverflies. flies. Many bird and bat at species are also pollinators. rs.

Forr an a angiosperm ngiosperm to reproduce, pollen grains from to be transferred to the fro om o m the anther need n stigma s ma st stigm stig m of a flower fflow – a process called pollination.

This his can occur occu occ within the same flower, and also between een two tw flowers of the same kind.

When a pollen grain lands on the stigma, it produces a tube, called a pollen tube. The pollen produ tube ube grows gro from the stigma, through the style to the Inside the ovary are ovules. Each ovule th ovary. ov contains an egg cell. cont A sperm cell moves from the pollen grain on the stigma, through the pollen tube to the ovary.

When the sperm cell reaches an ovule, it fuses with the egg cell. This joining of the sex cells is called fertilization.

What are some ways pollen can move from flower to flower?

48

ed uc a

Following fertilization, the flower petalss fall p away and the ovule begins to develop into a seed. The ovary of the flower swells to form a protective fruit. Once developed, the seeds need to be dispersed to new places. This can occur when animals feed on fruits or when seeds and fruits stick to their bodies. Fruits and seeds can also fall away and are carried to new places by wind or water.

In its new location and under the rightt conditions, the seed will germinate and nd d grow into an adult plant.

What are the stages in the life ife cycle of an angiosperm?

AB Activity 2.13

petal

As seeds develop, the ovary of the flower swells to form a protective fruit.

stigma

style er anther

pollen tube

stamen

pistil

ffi iila lla ame ame ent nt filament ovule

R

ovary sepal sep

49

Angiosperm Life Cycle The filament and anther make up the stamen. The filament produces pollen grains.

2

Pollen is released into the air or carried away by pollinators such as birds and insects.

ga le du ca ti

1

n

A Closer Look

2

3

Pollen lands on the surface of the stigma.

Each pollen grain grows a pollen tube which extends down into the style.

4

Male reproductive cells, called sperm m cells, are guided down the pollen tube, through the style to the ovary.

5

Fertilization occurs when a sperm erm cell unites u with a female sex cell, called d an egg cell. c

1

50

4

Re ga le du ca tio n

3

5

6

The fertilized cell begins to develop velop into a seed as the ovary swells to form m a protective protectiv fruit.

7

Once developed, the seeds to new ds are spread sp places and will grow row into new ew plants. pl

6

7

51

Fern Life Cycle F

ca tio n

Fe Ferns are seedless plants that reproduce oduce ce from sspores. Their life cycle is also different erent nt from seed see plants in that it involves two distinct stinct phases phase – an asexual phase and a sexual xual phase.

In the asexual phase, spores clusters pores res form in clu on the underside of mature ature ture fern fronds. fron frond The spores are held in cases ses called sporangia. spora Once the spores are O e developed, veloped, the sporangia breaks open and the by br he spores pores are dispersed di d wind and moving w g water. ater.

Re ga

ed

fern spores in sporangia

mature sporophyte

52

sporangia

sporophyte

ed uc ati on

Under the right conditions, a single spore will germinate and grow into a heart-shaped plant called a gametophyte. Root-like rhizoids anchor the gametophyte to the ground. The gametophyte has both male and female parts.

Sperm cells make their way from the male part to the female part and fuse with female egg cells. The fertilized egg cell develops into an embryo. It eventually grows larger than the gametophyte and becomes a sporophyte. The ase sporophyte produces spores and the two-phase life cycle repeats.

spores ess released re eleased

Re ga

gametophyte

fertilizati fertilization

53

Moss Life Cycle M

ed uc ati on

Like ferns, mosses are seedlesss plants ants with wi a life cycle that involves both h asexual exual and sexual reproduction.

In the asexual phase, spores produced pores are prod produ and held in a capsule. e. When the capsule cap breaks open, the spores into ores es are released release relea the t air. They are spread pread to new places pla by the right b wind or moving g water. ater. Under th conditions, a single and cond e spore re will germinate germ grow gro ow into a leafy y gametophyte. metophyte.

moss capsules

spores released

sporophyte

54

Go Online!

Learn more about the t life cycle of mosses osses and other ot non-flowering ing plants on o the NGScience nce website.

QuickCode: Co L4H9 L4H

ed uc ati on

The gametophyte has male and female parts. Fertilization occurs when a sperm cell from the male part fuses with an egg cell in the female part. The fertilized egg will develop into a new moss sporophyte. The sporophyte will produce spores held in capsules and the life cycle continues.

In what ways is the life cycle of mosses similar to the life cycle of ferns?

AB Activity 2.14

leafy gametophyte gam

germinating spore

R

ffertilization ertilization ilization

55

Vegetative Reproduction

ati on

A Closer Look Some plants are able to produce new plants from a fragment ment of the parent plant or a specialized reproductive structure. re. ativ ative This process is called vegetative reproduction. Vegetative reproduction is an asexual process and the offspring are genetically identical to the parents.

Re g

Strawberries have flowers and can reproduce sexually. They can also produce new plants from modified stems called runners. Runners grow out from the strawberry plant, usually just beneath the surface of the soil.

They eventually develop their own roots and begin to grow.

The roots hold the new plant in the soil and the runner dries up and breaks away.

How ow is vegetative veg reproduction different from reproduct sexual reproduction?

56

ti

ca

potato plant growing from tuber

Potatoes can also reproduce vegetatively. The e part of a potato plant we eat is a modified stem m called a tuber. New plants develop from buds on o the sides of the tuber. As they grow, they y use se the th he e starch stored in the potato for energy.

Bryophyllum is a plant that can reproduce produce roduce from plantlets on its leaves. Plantlets are structures re tiny ny structure growing on the edges of the leaves. eaves. The plantlets plant grow roots while still attached d to o the parent plant.

Eventually the plantlets drop p to the grou ground and grow into new plants.

plantlets growing on the leaf of a bryophyllum plant

Think Deeply The offspring produced through vegetative reproduction are genetically identical to the parent plant.

How could this be useful in agriculture?

AB Activity 2.15

57

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. xylem phloem gymnosperms angiosperms fibrous roots

1.

taproot aerial roots herbaceous stem woody stem vegetative reproduction on

are shallow roots that branch out to cover a large area.

2.

e soil is called calle a A single main root that grows deep into the

3.

A green stem that can bend is a called a

4.

e is called a The thick, strong stem of a tree

5.

Asexual reproduction from partt of a plan plant is called

.

.

.

6.

are above ground und roots.

7.

are cone-bearing ring plan plants that reproduce from seeds.

8.

are plants nts that tha produce flowers.

9.

Vascular tissue that water and nutrients from the roots to hat transports transp the upper regions ons of the plant is called .

sue that tra 10. Vascular tissue transports food from the leaves to all parts of the alled . plant is called

58

.

Review List two kinds of seedless plants.

Re ga le du ca tio n

1.

2.

Why are non-vascular plants usually shorter in size compared ared to vascular plants?

3.

How are gymnosperms similar to angiosperms in n terms of how they reproduce? How are they different?

4.

List two kinds of gymnosperms.

5.

List two kinds of angiosperms.

6.

Chelsea observed a small plant under a microscop microscope and noticed it did not have vascular tissue. What can she e infer about abo how the plant reproduces?

7.

In a forest, Wyatt spots a tall plant spores on the underside of its ant with spo fronds. What type of plant did Wyatt spot? spot

8.

True or false. (a) Phloem transports water ter from the roots to the leaves. (b) In most plants, s, photosynthesis p nthesis mainly takes place in the leaves. (c) Ferns and gymnosperms reproduce from seeds. mnosp (d) Most trees have ve woody stems.

9.

What do plants need to ph photosynthesize?

10. What gas iss released iinto the air during photosynthesis?

11.

List two spores are dispersed to new places. o ways moss spo

12.

Draw a simple labeled diagram to show the process of pollination.

13. what occurs when an egg cell in the ovule of a plant 3. Describe w is fertilized. fer 14.

Describe two functions of fruits.

59

Animal Classification

Re ga le

ti

What characteristics do scientists look at when they classify animals?

n

3

W What are the main groups invertebrates? of inv

In this is chapter chapt you will ...

• listt and describe the characteristics of simple invertebrates. lis and d • list describe the characteristics of complex invertebrates.

• list and describe the characteristics of vertebrates.

60

What are the main groups of vertebrates?

Go Online!

Access interactive content relating to this topic on the NGScience website. ngscience.com

61

Classification of Animals m

ed uc ati on

Scientists classify animals into two main n groups. group Many of the larger animals you are re most familiar familia es are animals anim with are vertebrates. Vertebrates bians, s, reptiles, birds b with a backbone. Fish, amphibians, ates. Humans are ar a and mammals are vertebrates. vertebrates too – we’re mammals. ammals. mmals. n Earth, th, about 9 Most of the animals on 95 percent, vertebrates tebrate are animals that are invertebrates. Invertebrates do not have a backbone. kbone. e. Sponges, Sponges jellyfish, sea stars, snails and insects invertebrates. nsects cts are inve inver Animal Kingdom om

Re ga

Vertebrates

62

Invertebrates

What is the main difference between vertebrates and invertebrates?

AB

Activity 3.1

Invertebrates Go Online! e!

Re ga le du ca tio n

Invertebrates are the largest group of animals.

They have no backbone or internal skeleton.

Without the support and protection of bones, many invertebrates are smaller in size than vertebrates, although many large invertebrates can be found in the ocean.

Many invertebrates have soft, flexible bodies with a tough outer covering for protection and to reduce water loss. Most invertebrates reproduce sexually with the young hatching g from om m eggs. The young often look very different from cularly their parents. Some invertebrates, particularly arthropods, undergo changes in body y form m as they grow – a process called metamorphosis. morpho morphosis.

Sponges

C Cnidarians id i

Discover the e great diversity of invertebrate brate animals in a video on the NGScience NGScienc website.

W5 QuickCode: W5E4 QuickCode

Think Deeply Thin

Why a are many invertebrates in the ocean much larger in si size than invertebrates on land?

AB

Activity 3.2

Worms

Invertebrates

Echinoderms hinoderms oderms

Mollusks

Arthropods A rthropods

63

Sponges Sponges are some of the world’s d’s oldest and simplest animals. The They are multicellular organisms, but do not have hav body parts, tissues or organs. gans. Their asymmetrical bodies es consist of one o or more tubes with an n opening at the th top.

An asymmetrical body does not n have any lines of symmetry. live try. Most sponges sp in the ocean, but some live in fresh water environments.

e

barrel sponge

Sponges are filter-feeders. feeders. They Th pump sea water through the holes in their bodies called t pores. As water moves through the pores, thro bacteria and tiny particles particl are taken up from the water ass food. Sponge Sponges do not move about and rely on a continual flo flow of water through their bodies to food and oxygen and to o obtain fo remove rem mo wastes.

pore ore

64

Collar cells help to move water through g the sponge p g and take in food.

Go Online!

Watch a video o on the th life cycle of sponges onges on the NGScience website. webs QuickCode: ode: E1K7

ca tio n

Sponges usually reproduce sexually, but some reproduce asexually by budding. Budding is the process in which a new organism develops from an outgrowth on the body of the parent organism. Once developed, the offspring detaches as a new organism that is genetically identical to its parent.

Did You Know?

A scientist that specializes in the study stu of animals called a zoologist. A is calle zoologist that specializes oolo the study of sponges is in th called a spongologist.

AB

Activity 3.3

tube sponge

65

ffan an coral

Cnidarians Amazing Fact!

Cnidarians are animals als that live in aquatic environments. Mostt can be fou found in the ocean, but some also live in water. Jellyfish n fresh w are cnidarians with soft jelly-like bodies. jelly ies. They rly stages of their life ife cycle spend the early attached floor d to the sea floo and are free-swimming ree-swimming as adults.. Jellyfish sh have h tha at are e used to tentacles that catch ch prey. prey rey.

eg a

Jellyfish range in size from just a few centimeters to several meters in length. The largest of all jellyfish is the lion’s mane jellyfish, or the giant jellyfish. It has a bell with a diameter of up to two meters (6.5 ft) and tentacles that can stretch for more than 30 meters (98 ft).

ti

brain coral

jellyfish h

Corals are cnidarianss that spend their lives attached to the ocean cean floor or other underwater surfaces. Some om corals get the energy they need from algae living within their tissue. Others have a series of tentacles that are used to catch small organisms floating by their anchored bodies.

66

ti

soft coral

sea anemone nem

Most cnidarians reproduce sexually, whereby sex cells are released and are fertilized in water. Some corals are also able to reproduce e asexually by budding. Unlike sponges, cnidarians have radial symmetry. This means ans their bodies are arranged around a central point with more than one line of symmetry. mmetry.

Re ga l

A unique characteristic of cnidarianss a are stinging cells called cnidocytes. Cnidocytes contain a toxin and are used to stun and capture prey. They are also used defense ed for def against predators. Some me jjellyfish produce produ toxins that are harmful to people. ple.

What are re the characteristics cha off cnidarians? cnida id darians?

cnidocyte

AB

Activity 3.4 67

Worms Worm Wor

Re ga le du ca tio n

Worm m is the general name given to animals mals from three different groups – flatworms, th tworms, rm roundworms and segmented rou un ed worms. ms. Worms Worm are long a multicellular and typically ically y have a lon tube-like body and no tu o limbs. All worms worm wo have bilateral symmetry.

Organisms with metry. Organism bilateral symmetry metry try have a body bod with a bo single plane of symmetry divides mmetry which wh it into two mirror or images.

Most worms ormss reproduce sexually, although reproduce asexually. gh some ome can rep

Fuchsia flatworm

Amazing Fact!

Nematodes are considered to be the most abundant animals on earth. About four out of every five animalss on Earth is a nematode!

They range in size from microscopic parasites sites to giant marine ne ribbon worms which can an reach lengths of o over 50 0 meters.

68

Flatworms, called platyhelminths, Fla worms F ms,, also calle are are simple mple le worms with wi w a soft, flat body.

They y can c be found in salt water, fresh water, and damp Many flatworms da amp am p land environments. enviro are parasitic. organism lives in or on para pa p asitic. sitic. A parasitic para par another nother er organism. organism Most flatworms have a body cavity ty with only onl one opening. Food enters the body y opening openin and waste leaves through the same e opening. openi Roundworms, also called nematodes, are Rou Round more advanced than flatworms. They have a adv tubular systems with openings at both ubu digestive d ends. live in a range of different en Roundworms R environments.

Many are parasitic and can cause envir illnesses and diseases in other organisms. i illne microscopic roundworms

Earthworms live in moist soil.

ed uc a

Segmented worms, also called annelids, are the most advanced of the three worm groups. They get their name from their bodies which are divided into an n segments. Segmented worms have organ systems including circulatory, digestive e and an nd d nervous systems.

Re g

d in most wet Segmented worms can be found environments, including underground ground nd and in the tth ocean. Common segmented worms ms include earthworms, leeches and bristle worms. ristle e worms

l leech

In what ways are flatworms, roundworms and segmented worms roundworm similar? In what ways are they different?

AB

Activity 3.5 A

bristle worms

Did You Know?

Many leeches are hematophagous which means they feed on the blood of other animals.

69

sea cucumber uc u cum umb

Echinoderms Ech h ms sea urchins

Amazing Fact!

Sea S ea sstars, brittle e sstars, tars, ssea ea u urchins rch and sea cucumbers are echinoderms. c ucum a re e chinoderm All echinoderms live in the o ocean, warm tropical reefs to cean, ffrom rom w a the icy arctic Most rctic poles. poles. M ost echinoderms have radial symmetry and ymme ym metry a nd rreproduce sexually.

However, ever, some some me can can also reproduce asexually.

Re ga

When injured, some species of sea stars and brittle stars are able to regrow parts of their body. This process is called regeneration. Some species can even regrow their entire body from just one severed limb!

Go Online! lin

Discover the fascinating ating world worl of echinoderms in a video on the NGScience ence website.

QuickCode: de: T8C8

70

Sea stars and many other echinoderms have five-part radial symmetry.

i

brittle star

Echinoderms produce a hard internal na al structure called an endoskeleton which which gh, spiny spiny gives their outer covering a rough, appearance.

sea star tube feet

Echinoderms move about using off using a ssystem yst stem o tube feet. This allows them tto crawl oc rawl sslowly lowly on on the ocean floor.

AB

ga l

What are the characteristics haracterist of echinoderms? ms?

Activity vity 3.6

71

Mollusks

blue dragon nudibranch

Did You Know?

Nudibranchs are a diverse group of soft-bodied sea slugs. They are well-known for their bright colors and are often given fancy names such as dancers, clowns and dragons. About 3,000 different nudibranchs have been named and classified.

du ca tio n

Mollusks are animals with soft bodies, es, often with a hard outer covering called a mantle. man Most mollusks live in the ocean, with some ome living on land or in fresh water.r. Common mmon mollusks include octopus, squid, quid, clams, snails snai sn and slugs.

The soft body of mollusks and usks contains tissues tiss organs to carry out life They have ife processes. Th digestive, respiratory ry and nd circulatory circulato systems.

Most mollusks have ave a specialized specialize mouth structure called d a radula adula which is a series of tiny teeth used ed for scraping food fo particles into the mouth.

Molluskss also have a muscular organ, called a m foot, which ch is used to move about. eye e

upper tentacle (ocular)

shell lower tentacle (olfactory)

R

mouth

tail

foot

72

parts of a garden snail

ati o

A common characteristic of mollusks is a mantle in the form of a shell. Snails and limpets are examples of mollusks with one shell. Clams and scallops have two shells which are hinged on one side. This allows the shell to open and close. All mollusks have bilateral symmetry.

All mollusks reproduce sexually which involves the fertilization of male and female sex cells.

What are the characteristics of mollusks?

giant clam

squid

Go Online!

octopus

Cephalopods are a group of mollusks that includes octopuses, squid and cuttlefish. The animals in this group are thought to be the most intelligent of all invertebrates. Their large and well-developed brain makes them very efficient predators. They are known to use tools and have demonstrated advanced learning and problemsolving abilities in laboratory environments. Watch a video about these fascinating creatures to find out just how smart they are!

QuickCode: U6G2

AB

Activity 3.7 73

ed uc ati o blue swimmer crab

blue crayfish

Arthropods

Amazing Fact!

Some arthropods have specialized internal structures that produce venom. The venom is a type of poison that is injected by a bite or sting into other animals.

It can be used to kill prey or for protection against predators. Wasps, bees, spiders and scorpions are often venomous.

eastern rn lubber bbe grasshopper hopper p

Arthropods are the e most ost diverse a and numerous group of animals. s. They ey make up over 80 percent of all known species eciess of animals on Earth. They live in all areass of the he Earth – from the deep ocean to hot, ot, dry y deserts and a moist tropical rainforests. s.

Common include mon aquatic arthropods arth crustaceans staceans ans such as a crabs, shrimp and lobsters.

Terrestrial arthropods include insects, spiders, rrestrial al arthrop millipedes. tickss and millipe

honeybee bee

A Arthropods have a hard outer body covering called an exoskeleton. Made of chitin, the exoskeleton supports and protects the animal’s body and can also help reduce water loss.

Arthropods have paired limbs on each side of their segmented bodies. Some arthropods have modified limbs in the form of claws or wings.

74

Re ga le du ca tio n giant hairy scorpion

tick

An exoskeleton does not bend easily. To move about, arthropods have many joints which allow w them to bend parts of their bodies.

eir Without an internal skeleton to support their bodies, arthropods are usually small in size.

Aquatic arthropods, such as crabs and d lobsters, sters, are often larger than land arthropods ds as they are able to use the surrounding water for or support.

Arthropods have organs and body systems fo for digestion, breathing, circulation reproduction. on and reprodu They also have a variety off different ferent sense sen organs, such as eyes and antennae. tennae. nnae All arthropods have bilateral and ateral symmetry sy reproduce by sexual al reproduction. eproductio

European garden spider

Try This!

Use a hand lens to observe insects in your schoolyard.

Describe the structures each insect has. Discuss the function of the structures with your classmates.

What characteristics teristics do all arthropods share? In what ways are a they different?

AB

Activities ctivities 3.8 – 3.9 giant mil millipede

pill bug

75

Arthropod Life Cycles

ca tio n

A Closer Look After hatching, most arthropods do not resemble their parents. rents.. The young, called larvae, go through a series of changes in a process ocess called metamorphosis. During metamorphosis, a larva a goes into an inactive pupa stage. When an arthropod emerges from om the pupa, it has all of the characteristics of its parent.

The life cycle of a mosquito goes through four distinct nct phases – egg, larva, pupa and adult. The organism looks, ks, feeds eds and moves m differently in each stage.

raft of eggs

g

egg g

aquatic larva

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ca tio n

Think k Deeply

Mosquitoess are insects in that can spread read diseases disease to humans. ns. Female Anopheles mosquitoes can spread the which e disease malaria ma more than 200 million infects mo every year. How can people eve about the life cycle of learning a Anopheles mosquitoes help Anoph control ntr the spread of malaria?

A female Anopheles mosquito feeding on human blood.

emerging adult

Go Online! aquatic pupa

Watch a video about the life cycle of a mosquito on the NGScience website.

QuickCode: V1J4

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Re ga le du ca ti surgeonfish

Fish

Vertebrates ates es

hammerhead shark

Did You Know?

Scientists have classified and named about 70,000 different species of vertebrates. Here’s how many are in each of the main vertebrate groups: fish – 30,000 species amphibians – 9,000 reptiles – 13,000 birds – 11,000 mammals – 7,000

Vertebrates are animals tha that have a backbone and an internal usually made of bone. ernal skeleton, u

The skeleton vital organs such eleton eton helps to protect p as the e brain, ain, heart and an a lungs. It also provides support which allows vertebrates pport and structure structu struct to much larger than most o reach ach sizes mu invertebrates. rtebrates All vertebrates have bilateral symmetry. rtebra Vertebrates are classified into five main groups – Vertebra Verteb reptiles, birds and mammals. fish, amphibians, amp a

Amphibians

green een tree frog

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fire salamander

du ca tio

common box turtle

Chinese inese nese water dragon drago

Reptiles

Birds

Vertebrates

blue tit

oriole

Mammals Mam Mamm mmals

R

tiger cub

AB Activity 3.10

grey long-eared bat

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lampreys

A school of trevally.

Fish Cold-blo Fish are cold-blooded animals that live in water.. Cold-blooded means their body temperature is not regulated d and varies var with the temperature of the environment. Fish range ange in size from just a few millimeters to several meters. Most ost fish reproduce re sexually by external fertilization whereby eby eggs and an sperms are released into and fertilized in the water. er There are three main groups of fish sh – jawless fish, cartilaginous fish and bony fish.

great white shark

Jawless fish are the oldest and simplest group of fish that include lampreys and hagfish. They do not have jaws and feed by sucking their food. They have long cylindrical bodies and a skeleton made of cartilage.

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A variety of bony fish inhabit coral reefs.

Cartilaginous fish include sharks, rays and skates. They have an internal skeleton made of cartilage. Cartilage is strong and flexible. It provides support and protection and enables many cartilaginous fish to grow larger than n other types of fish.

Bony fish have an internal skeleton made of bone. They include many of the fish you are most familiar with including salmon, tuna and an swordfish. Sea dragons and eels ls are also bony fish.

The body of fish is well-adapted to life in water.

-ada They have a streamlined shape shape, fins and a tail that allows them to move about a and change direction easily. Bony fish usually have a body covered in scales which also h helps them glide through water. Scales provide protection. cales also p

moray eel

Amazing Fact!

Leafy sea dragons have leaf-like appendages that allow them to achieve almost perfect camouflage amongst the seaweed in which they live. They have no known predators and spend all day sucking up prey using their long pipe-like snout.

Re

Fish have a specialized respiratory system with resp gills. As water the gills, they take in ter flows over th oxygen en which passes passe into the bloodstream.

What are the characteristics o of fish?

AB

Activity 3.11

Southern stingray

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A Closer Look

ati on

How Do Gills Work?

Fish and many other aquatic animals have special internal structures called gills. Gills allow animals to take in the oxygen they need from water. They also remove carbon dioxide and release it back into the water. This process of taking in and removing gasess iss called gas exchange.

du

ed on the Gills are soft, branching organs,, usually located overs. side of a fish’s head and protected under gillll covers.

Gas exchange occurs when water enters a fish’s h’s mouth and and moves through the gills.

eg a

direction of water flow

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blood vessels

du ca tio n

Gills are made of soft oft tissue t called filaments. As water enters the gills, it washes ashes over the filaments.

Each filament ment contains a network k of tiny blood vessels ve called capillaries. water apillaries. As w washes capillaries, hes over the ca dissolved sssolved ved oxygen is taken into dioxide the blood lood and carbon c is removed re emoved from fro the blood and released relea eleased ed back ba bac into the water.

Re ga l

gill filament

oxygen-rich n-ric ch blood d

direction irection of of water flow wa w

capillaries

oxygen-poor blood

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Wallace’s flying frog g

Amphibians The word amphibian comes omes from a Greek term which means ‘double ub life’. lif ’. This Th is due ycle which, for f many to their unique life cycle a moves on to amphibians, beginss in water and land. Amphibianss reproduce sexually by external fertilization, and hatch from eggs. re three main groups g There are of amphibians. e amphibians amphibian we are most familiar with.

Frogs are They often bodies with powerful hind en have short sh legs for moving about on land and in water. a ds are sim Toads similar in appearance to frogs, but n have d often drier and rougher skin.

European tree frog

moorr frog with eggs

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ca t

tadpoles

Salamanders are amphibians that are similar in appearance to lizards. They have long, slender bodies with a tail. Caecilians are limbless, worm-like amphibians. Most live underground.

Most amphibians get the oxygen they ey need using lungs to breathe in air. Many any y amphibians are also able to take ke in oxygen through their moist skin.

spotted salamander

Re

Some me poison poison dart fro frogs carry ca their to a ir young ng g on their backs ba source ource off water. wat

What are the characteristics o of amphibians?

AB Activity 3.12 85

al ed uc ati o Nile crocodile codile odile

Reptiles

A Nile crocodile hatching from its egg.

Reptiles are cold-blooded d-blooded animals a with bodies covered or plates. Most vered d in scales o reptiles live ve on land, but ssome live in the ocean and fresh water o wate habitats. All reptiles get the g he oxygen they need from air using ng g lungs. classified into three main groups: Reptiles les are cla

Did You Know?

Most reptiles are oviparous – they reproduce by laying eggs. Some snakes, including many vipers are viviparous – they give birth to live young.

• crocodiles crocodi and alligators. and lizards.

• snakes a • turtles. urtles

blue viper snake

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al ed uc ati

Reptiles ha have bodies covered or plates. overed in scales sc

chameleon

Reptiless reproduce sexually sexu and have internal ernal fertilization. means the eggs are fertilized ion. This m ized inside the body of the female. Most reptiles eptiles lay ay eggs from which young hatch.

Many reptiles, such as crocodiles es and d snakes, are fierce predators. Crocodiles es and alligators ful jaws aws to catch have large teeth and powerful e large fangs fa fang and kill prey. Many snakes have which can inject powerful venom om m into their th prey.

What are the characteristics acter of reptiles?

Amazing Fact!

Reptiles have some of the longest life-spans in the animal kingdom. Some large tortoises can live for over 200 years. Accurately verifying the age of a giant tortoise can be difficult as they often outlive the scientists studying them.

AB Activity 3.13

green sea turtle

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du ca ti

great grey owl

Birds

osprey feeding its young

With light muscles, ght bodies and powerful p many ny birds use their th wings to fly. There are e flightless birds, birds like emus and cassowaries, sowaries,, that tha move about by walking are also flightless and d running. Penguins P birds ds that use us their wings as fins and rudders to swim. ru

e

great tit

Birds are animals mals with bod bodies covered in feathers. All birds ds also have ha hav two wings, two feet and nd a beak or bill. bil

turkey chicken n hatchling

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Re ga le du ca t macaw

adelie penguins

Try This!

All birds are warm-blooded, d, which hich means they regulate their own body temperature. Birds reproduce od by y internal interna fertilization whereby the he e egg eg cells are re fertilized inside the female bird. Hardemale e bird H shelled eggs then develop velop and are ar laid la in a nest. The eggs and gs are re kept warm wa a are cared for by the the he parents until u t young hatch from m each egg. egg

Take a set of binoculars and go bird-watching with your classmates. Describe and try to name the birds you spot.

Once hatched, tched, ed, most birds care c ca for their young. They y provide them with warmth, food and protection from predators.

What are the characteristics of birds? o

AB Activity 3.14

common magpie

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Mammals

ga le du ca tio n

Bats, sea lions, koalas and many of the anima animals we keep as pets are mammals. Mammals ma are warm-blooded animals with a body covered in hair or fur.

Lyle’s flying fox

Another characteristic of mammals ammals is the way in which they reproduce. Mammals reproduce by mmals reprod repro internal fertilization. Rather ther than laying eggs, the in itss mother. Once On mature, young develops within the mother gives birth to young. The mother o live young youn nurses the newborn orn with milk until un it is able to feed on its own..

Some mammals, kangaroos and koalas, are mmals, s, like kang marsupials. are mammals that give als. Marsupials a birth to partially develo developed young. The newborn develop is then pouch attached to the n cared ared for in a p female male par parent.

Platypuses ypuses and spiny anteaters are unique types of egg-laying gg-laying mammals called monotremes.

These can only be found in Australia e mammals mam and New Guinea. a an wG

platypus l t A female e ka kangaro kangaroo cares for its joe in its pouch. young, called a joey, koalas

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eg al ed uc at Californian sea lion

Mammals have lungs and take in oxygen when they breathe in air. Aquatic mammals, mals, such as dolphins, sea lions and whales,, must st come to the surface to breathe.

Mo Most mammals reproduce by giving birth to live young. g

Adult mammals often care for their heir young until they are old enough to survive rvive on their own. They may teach their young oung how to find fin food or hunt. They may also how o teach ach them ho to stay safe from other animals. mals. s.

What are the characteristics harac of mammals?

AB

Activities ties 3.15 – 3.16

kitten

young deer brown rat

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Science Words

Re ga le du ca tio n

Use the words to complete the sentences. asymmetrical radial symmetry bilateral symmetry endoskeleton

exoskeleton cold-blooded metamorphosis

external fertilization tilizat internal fertilization fertilizatio warm-blooded arm-blooded

1.

An

is a hard internal body structure. e.

2.

An

is a hard outer body covering.

3.

Fertilization that takes place inside the female called male is ca

4.

Fertilization that takes place outside the fema female is called

5.

Animals with have bodies that are a arranged around a central point with more than one ne line of symmetry. s

6.

have a body with a single plane of symmetry Animals with which divides it into two mirror images. irror ima

7.

animals als ha have bodies with no lines of symmetry.

8.

The temperature of their environment. nt.

9.

Animals thatt are able to regulate their own body temperature . are

10.

is the proc process by which the body of a larva changes in form into an adult. orm as it develops devel

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animals is regulated by

.

.

Review How do sponges get the food they need?

Re ga le du ca tio n

1.

2.

What are cnidocytes? Into what group do animals with cnidocytes belong?

3.

Of the three main types of worms, which are the e most advanced? advance

4.

Which group of invertebrates can only be found in the ocean? ocea

5.

Ethan spotted an invertebrate under a log and d noticed it has pairs of jointed legs. To which invertebrate group does animal belong? oes the anim

6.

While snorkeling, Halle spotted an animal radial symmetry and mal with rad rough, spiny body. What animal did Halle Into which invertebrate lle spot? In group can she classify the animal? ma

7.

List the three main types of fish..

8.

List two invertebrates that undergo metamorphosis during their met life cycle.

9.

Copy and complete te the t table. e

Vertebrate Classification Verte

ma Type of Animal

Description

Examples

Fish

ibia Amphibians Reptiles i d Birds

Mammals

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Energy in Ecosystems

ga le du ca tio n

4

In this chapter you will ...

• describe an ecosystem in terms of its biotic and abiotic biotic factors. fac rganized.

• describe the way organisms in ecosystems are organized.

• describe and provide examples of food chains, food webs and energy pyramids for a given ecosystem. mals’ food was once • use models to describe that energy in animals’ energy from the Sun.

mate • support an argument that plantss get the materials they need for er. growth chiefly from air and water. movem • develop a model to describe the movement of matter among ers and the t environment. plants, animals, decomposers

How does energy flow through ecosystems? Where does the energy come from?

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ed uc ati o

What are the different roles of organisms in an ecosystem??

Go Online!

Access interactive content relating to this topic on the NGScience website. ngscience.com

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What Is an Ecosystem? em?

A system is something that is made de u up p ether to to of different parts that work together Ecos osystem ems perform a common function. Ecosystems nature. All All off the th are examples of systems in nature. organisms in an ecosystem m are called biotic bi bio clude lude all of the plants, p factors. Biotic factors include animals, fungi and microorganisms. croorganisms. organisms.

e

The biotic factors interact other in nteract act with each eac e many ways. They with non-living y also interact w things. The non-living n-living ing things in an ecosystem are called abiotic factors biotic factors. factors. Abiotic A include sunlight, water, nutrients, nlight, t, heat, air, w rocks and d soil. soil.

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Go Online!

Scientists organize ganize the th ecosystems ms on Earth into in regions called A ed biomes. bio e is defined by its biome climate te and the types of organisms that live there.

Discover scover more in a video on NGScience website. the NGScie QuickCode: S9T3 QuickCode

ca tio n

An ecosystem consists of all of the biotic and abiotic factors and the interactions between them. The factors in an ecosystem are dependent on each other. When a change occurs to a biotic or abiotic factor, the other factors within the system can be affected.

In a pond ecosystem, the water in the pond is an abiotic factor. If the water dries up or becomes polluted, the plants and animals dependent on the water may die or move out ut of the ecosystem.

ed

The algae in the pond are a biotic factor. orr. IIff tthe he population of algae increases, the amount mount of of oxygen in the water can change which hiich can can affect other organisms in the ecosystem. osystem. syst m.

What are the biotic and abiotic otic factors factor in a coral reef ecosystem? m?

Think Deeply T

T main diet of the green The sea turtle is sea grass. During floods, sediment in the water can prevent sunlight from reaching the sea floor. How could this affect the green sea turtle population?

AB

Activity 4.1

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Ecosystem Organization ation on To T o sstudy tudy different biotic factors tors in in an an ecosystem and to better u understand e cosy ysst nderstand tthe he between biotic and abiotic iinteractions ntera ac ct otic ic a nd a biotic ecosystems ffactors, actto o scientists organize rg ganize e cosyste iinto ntto o different levels. ve els. called A single organism rganiism is is c alllle an al iindividual. ual. IIn n a rrainforest ainfore inffore ecosystem, a tree an example of an e ffern ern iiss a n exa e xam individual. div vidual. A rred-eyed ed-ey green tree frog in a fro og iiss another anot other individual in ecosystem. rrainforest ainfor inforest e co c os

ed

off tthe organisms of the same kind Alllll o A he o r tthat hat at intera iinteract nterac and reproduce within ecosystem make up a population. an a ne cosystt co Allll of ferns in a rainforest form A of the the tree t population. a po p op op pu ullatio All of the red-eyed green u ttree ree ffrogs rog ogs form another population. The within the same population iindividuals nd div ividu iinteract nteract when they compete for food, water, mates, m ates space and other resources. How interacts and uses the biotic tthe he population p and a nd abiotic factors in the ecosystem can determine its size. d

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In most ecosystems there are many different populations that interact and depend on each other for survival. The interacting populations within an ecosystem form a community. In a rainforest, there are thousands of different populations of plants, animals, fungi and other decomposers that interact and form the rainforest community.

The final level of ecosystem organization iiss tthe he ecosystem itself. An ecosystem includes es tthe he interacting community along with the abiotic ea biotic factors that affect it.

Re ga

Collecting data on individuals, populations and opulat ulation tio ons a nd community interactions help scientists scientists predict predic the effects o off c changes the han nges to to th he ecosystem eco cosystem as as a whole system. em.

How is it useful seful to organize orga the organisms ms in ecosystems? ecosy

AB

Activity 4.2

99

Energy in Ecosystems ms sers Producers to Decomposers posers The organisms in an ecosystem em get get tthe he energy they need in different nt ways. ways. Some Some make food through photosynthesis. osynthe hesi sis. Some Som thers b rea eak d ow eat other organisms. Others break down the remains of dead plants plants and and animals. anim Organisms within an ecosystem can ne cosys ystem c a be classified by how tthey obtain hey o btain the the energy they need to carry out ut life life processes. proc ocesses An organism m tthat hat at makes makes ffood o through photosynthesis hesis is is called called d a producer. In most land ecosystems, nd de cosy osystem ms, plants are the main producers. aquatic ecosystems, producers. IIn na q microscopic algae phytoplankton are oscopic a lgae called c the e main main producers. produce Plants and phytoplankton use energy u se llight ight e nergy from the Sun, carbon dioxide and water produce food in the form of a nd w ater tto op and oxygen.

They obtain the energy ssugar ugar a nd o x need tthey hey n eed from the sugar that is produced.

ga l

What producers can be found in a pond ecosystem? How do the producers obtain the energy they need?

1 00

An organism that gets energy by eating g other organisms is called a consumer. e All animals are consumers. They get the energy they need by feeding on other organisms in the ecosystem.

ca

Animals that eat plants are herbivores. They are primary consumers. They obtain their energy from the plant matter they eat.

What are some examples of consumers in a grassland?

How do g o they obtain the energy they need? need ed d?

1 01

Animals that eat other animals are carnivores. arnivores.

They are also called secondary consumers. nsumers They obtain their energy from the e tissues in tthe animals they feed on.

A bee-eater is a secondary consumer.

Organisms that feed on secondary consumers eed o are called consumers. They are often d tertiary cons referred to and are not usually o as top predators pred prey to other animals in the ecosystem. ther anim

A short-toed ssnake eagle is a tertiary ertiary consumer. con

1 02

eg a

uc a

Some organisms meet their energy gy requirements by decomposing organic matter – the remains of dead plants and animals.

They feed on the broken down material. These organisms are called decomposers. The processs of decomposing organic matter releases nutrients back into the ecosystem. Bacteria and fungi are e decomposers, as are some small invertebrates such as earthworms, s, termites and millipedes.

What role do decomposers decomp play in an n ecosystem? ecosystem

AB

Activity 4.3

1 03

The energy in a food chain enters an ecosystem as light energy from the Sun.

Food Chains Foo Animals A nim m get the energy they need by eating other er organism organisms. energy from food is used for body repair, growth, The e movement and to maintain body warmth. h. The energy released from food was once energy from om the Sun that tha was captured by plants during photosynthesis. sis.

Re ga le d

A food chain is a simple and often graphical model that raphical mo shows how energy and nutrients flow w tthrough hrro gh an a ecosystem.

Arrows are used to show the direction flow. ction off energy ene

Marsh Mar arsh sh grass gra rass ss gets get etss th the e en energy it n needs in need eeds by by using usin using g the the energy ene sunlight photosynthesize. unlig unl nlig ight ht to to p ph otos ot osyn os ynthe

Energy flows from producers to primary consumers when a vole feeds on marsh grass.

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Producers are at the bottom of the food chain, followed by primary, secondary and tertiary consumers. Decomposers play a continual role in recycling nutrients in the ecosystem.

By following the energy path in a food chain, from producers to primary and secondary consumers and decomposers, we can see that hat most of the energy in an ecosystem can be traced back to the lightt energy from the Sun.

AB

Activity 4.4

a

Explain why most of the energy in an ecosystem can be traced back to the Sun.

R

Energy flows from secondary dary consumers consume ons ers to to tertiary consumers when a marsh snake. h harrier har arri rierr eats eat atss a garter ga

Energy flows from primary consumers to secondary consumers when a garter snake eats a vole.

1 05

Food Webs

Re ga le du ca tio n

A food chain shows how energy moves from one organism to another. However, in an ecosystem, consumers get the energy they need by eating more than one type of organism. Consumers are also eaten by more than one type of consumer. So, in an ecosystem, there are many interconnected food chains.

elff ow owl

A food web is a model used to show these interconnected food chains. It shows the many paths energy can take as it flows from one level to the next.

AB

Activity 4.5

mantid

antelope squirrel

fluff grass fl

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wood rat

h t ant harvester ha harvest

prickly pear cactus Sonoran Desert food web

How is a food web different from a food chain?

Re ga le du ca t

red-tailed hawk

iamondback rattlesnake rattlesnak diamondback

collard lizard

gra gras grassho grasshopper mouse

pallid-winged grasshopper opper er

brittlebrush

gila g ila woodpecker

saguaro cactus

1 07

Energy Pyramids

In a rainforest ecosystem, would the number of organisms in a frog population be fewer or greater than the number of organisms in a leopard population?

Explain your answer.

Activity 4.6

An energy pyramid id is a model that tha th shows how much energy gy is available at a each level in an ecosystem and the number of organisms each level can less energy is n support. port. Because Beca available att each you go up a food chain, h level as y the number ber of organisms organism that can survive at each level vel el decreases ttoo. to

e

AB

uc ati on

Think Deeply

Organisms use the energy they obtain ain to survive. sur Approximately 90 percent of the energy rgy at each level in an ecosystem is used to carry out life lif processes like body repair, respiration, spiration, ation, digestion, digest digestio motion, and in warm-blooded ed animals, to maintain body warmth. Only nly y about 10 percent per is stored in the tissues off the he organisms organism and is available to the organisms sms in the next level.

Re ga l

tertiary yc consumers

energy pyramid for a grassland ecosystem

sec secondary consumers

primary consumers

energy in

1 08

producers energy passed to next level

energy used or lost

Re ga le du ca tio n

In any healthy and balanced ecosystem, the number of producers is greater than the number of primary consumers. The number of primary consumers is greater than the number of secondary consumers. Only a small amount of the energy remains to support the top predators.

Scientists use energy pyramids to determine if an ecosystem is balanced. If the model does not resemble a pyramid shape, it may indicate the ecosystem is unstable, unhealthy or is undergoing change.

What do energy pyramids show?

How are they useful?

Think Deeply Dee

Imagine an eco ecosystem with four levels in a food chain. If producers capture 10,000 the produce energy from the Sun, units of en work out how much energy will be available to tertiary consumers. cons

AB

Activity 4.7

energy pyramid for an Arctic Ocean ecosystem

energy in

energy passed to next level

energy used or lost

1 09

Think Deeply Wyatt placed a tomato seed in a pot containing 500 grams of soil. He added 50 ml of water to the pot every other day for one month. He then removed the plant from the soil and measured the mass of the plant and the mass of the soil. The mass of the plant was 20 g. The mass of the soil was 495 g. What can Wyatt infer about where the plant acquired the materials it needed for growth?

Matter in Ecosystems ms Just as energy flows through an ecosystem, ec cosystem, sso too does matter.

While the available energy at at each each level level of of an ecosystem changes, the he available available matter ma in the ecosystem does not change no ot ch c hange – itit cycles c through.

Consider a growing plant an gp lant in na n ecosystem. eco Each day, week and m month ont nth that that passes, the plant grows and increases mass. Plants nd incre ncrea eases iin nm acquire the material need matterial tthey hey n e to grow primarily from om air airr and and water. wat Through the process o off p photosynthesis, hotos osynthes plants convert the air, w water and nutrients from the soil into ater a nd n utri matter er tthat hat iiss food food iin n the form of sugar.

Try This!

R

a

In small groups, plan and conduct an investigation to demonstrate that plants acquire the materials they need for growth chiefly from air and water.

T The he m h matter atte at te er that that a makes mak up young p tthe h y he oung ou o ng g oak oa ak k tree tre came primarily pri rima rim mari ma m rily ri ly y from fro om the matter in water wa ate er and a the air.

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ca ti

Matter moves es through th th an ecosystem m when whe hen en animals consume ons n um um me e plants pllant ants an ts and other animals, er an nim ima allss,, drink dri rink nk k water a and air. an nd breathe brea brea br atth he in na irr

Did Y You Know?

Matter moves through the ecosystem em as as primary consumers eat plants, drink water and riink nk w ater a nd excrete wastes.

As ma matter cycles within an ecosy ecosystem, the weight of soil doe does not change significantly.

S Soil only provides a small amount of material for plant growth. Scientists are able to grow some plants without the need for soil. This method of growing plants is called hydroponics. y p

sumers ttake ake iin n Secondary and tertiary consumers matter as they eat other animals and animals a nd also als take tes. in air, water and excrete wastes.

Re g

ms die, die, they th are consumed When these organisms by decomposers. The decomposers The d ecompose transform the organic matter nutrients that ter iinto nto iinorganic norganic n u d back back iinto nto the the ecosystem. eco can be recycled How doess matter move m through ecosystems? systems? Where does the matter come me from?

Engineer It! Design and build a hydroponics system to grow a tomato plant as tall as possible. Compare your system to those of your classmates. How could your system be improved?

111

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. biotic factors abiotic factors individual population community

producer consumer primary consumer secondary consumer tertiary consumer

decomposers sers food chain hain food ood web energy pyrami pyramid

1.

break down organic material and absorb the th broken down remains.

2.

is an organism that gets energy nergy by eating e A other organisms.

3.

A

4.

An animal that feeds on secondary is a dary consumers consu

5.

A single organism in an ecosystem called an osystem is c

6.

All of the organisms in an ecosyste ecosystem are called

7.

All of the non-living things in an ecosystem are called

8.

sms of the same kind that interact and reproduce All of the organisms system mak . within an ecosystem make up a

9.

is a model mod used to show the interconnected food chains A in an ecosystem. osystem.

is an organism that hat makes food through photosynthesis. .

.

.

.

10. A is a simple and often graphical model that shows how energy and nu nutrients flow through an ecosystem.

11.

112

consists of all of the interacting populations within A an ecosystem. eco

An animal that feeds on a producer is a

13.

An animal that feeds on primary consumers is a

. .

Re ga le du ca tio n

12.

14.

An is a model that shows how much energy iss available at each level in an ecosystem.

Review

1.

List three biotic factors you would expect to find in a tropical tropica rainforest ecosystem.

2.

List three abiotic factors you would expect to find in a tropical t rainforest ecosystem.

3.

Draw and label a simple diagram to show a population ow an individual, ind and a community in a grassland nd ecosystem.

4.

What role does each organism play in a desert ecosystem?

(a) hawk

(b) b) rattlesnake ratt rattlesn

(c) brittlebrush

(d) wood rat

5.

What does a food web show?

6.

How is an energy pyramid different from a food web? pyra

7.

Explain how all a of the food within an Arctic Ocean ecosystem can be traced ced back to the energy in sunlight.

8.

Riley thinks most of the material for plant growth comes from the soil. iley th Do you ou think Riley is correct? Explain your answer.

1 13

Earth’s Land and Water

ed uc ati on

5

In this chapter you will ...

• describe the structure of the Earth and the movement ment of the Earth’s Ea tectonic plates. nd water so • list and describe the Earth’s main landforms and sources.

ater and describe des • explain the importance of clean, fresh water the ways in which it is used by people.

What processes pro shape the surface of the Earth?

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What makes up the Earth’s hydrosphere?

Go Online!

Access interactive content relating to this topic on the NGScience website. ngscience.com

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Structure of the Earth Amazing Fact!

The temperature of the Earth generally increases with depth. Where the crust meets the mantle, the temperature is about 1,000oC. Where the mantle meets the outer core, the temperature is about 3,500oC. The temperature of the inner core is about 5,200oC.

Evidence from earthquakes, volcanoes and other natural hazards has enabled ed he Earth scientists to support the claim that the is composed of four layers, with each layer he interactions having unique properties. The between the Earth’s layers affect the surfa processes that shape the Earth’s surface. e Earth’s rocky roc The outermost layer, the surface, is called the crust. crust is the us The cr o between 6 thinnest layer with a thickness of to 70 kilometers.

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The Earth is composed mposed of four fou distinct layers, each with unique properties. que pro

crustt

mantle

outer core

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Try This!

Use modeling g clay of o different colors olors to make a model of the he Earth. Carefully Ca cut the model in half hal to reveal its layers.

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Beneath the crust lies the mantle, which extends from the crust to a depth of 2,890 kilometers. The mantle is made up of hot solid and molten rock.

The central part of the Earth is the core. At a depth of 2,890 to 5,150 kilometers is the outer core, which is made mostly of molten rock. Below the outer core lies the inner core stretching from 5,150 to 6,370 kilometers. The inner core is solid.

Discuss and describe the characteristicss and properties of the different layers off the Earth.

Go Onli Online!

Head tto the NGScience eb website to learn more abo about the Earth’s layers and their properties.

QuickCode: V2T2

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inner core

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Plate Tectonics Go Online!

There are three kinds of tectonic plate boundaries – divergent, convergent and transform plate boundaries.

Discover how each type of boundary shapes the surface of the Earth in different ways in a video on the NGScience website.

QuickCode: Z9P6

The Himalayas were wer ere e formed f movement by y tthe he m he ov o vem emen entt of tectonic en t es tow eac ach h other. plates towards each

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By observing patterns in the movement ement ent of of continents and fossil evidence, scientists cientis tissts developed a model of the structure off the ucture re o Earth’s crust, called plate tectonics. ctonics nics. s The model mo mo explains that tectonic plates es lie lie on n top top p of of a flowing region of molten rock rock k in in the th he upper upp part of the Earth’s mantle.

The tectonic platess float floa at and and move mov slowly on the molten rock. As they they do, they bump, slide and grind against nstt each ea ea ach ch other.

The Thingvallavatn llav vat atn n valley valley v in Iceland was as formed med d by b tectonic plates ates moving g away from m each ach other.

Forces from these tectonic plate e interactions inte eracti actio ons ns can cause the Earth’s crust to buckle buck kle and d bend ben be over many years. These interactions eractiions can rresult es in the release of large amounts ounts of energy in the form of earthquakess and an nd d volcanic volcan eruptions.

The slow movement of the Earth’s continents on tectonic plates, along with extensive fossil evidence, has led scientists to believe that long ago the Earth consisted of a giant supercontinent called Pangaea. It began assembling about 335 million years ago and began to break up about 175 million years ago.

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Along with weathering the ering and d erosion, ero movement and interactions nteractions actionss between betwee tectonic plates are the m main ain processes processse processe es tthat hat continually change the surface Earth urface ace e of the Ea Earth h – on land and in the ocean. n.

Amazing Fact!

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Activity 5.1

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n

What are some landforms on the Earth’s surface? How did they form?

Earth’s Landforms ms

Shaping the Earth’s h’s Surface

Grand Canyon

Go Online!

Take a virtual field trip to the Grand Canyon and discover its many fascinating landforms.

QuickCode: B3G4

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Over millions of years, forces orces es a and nd processes nd p proce roce have been continually shaping of ping the the surface su su the Earth and they continue inue to do so today.

Some processes occurr too slowly for us to notice from day tto The Grand o day. day. y. T he Gr G ra Canyon in the United States over ta ates has has been been forming be f millions of years by weathering, erosion ea ars b y tthe he w eat and deposition by tion caused caused b y the Colorado River running through hrough it. it.

Denali, highest mountain peak in the USA, lii, tthe he h ighes est m has also been over millions of years. also b een fforming orm It rrises ises above above the the ground around it due to the pressure caused p ressure c ause by the movement of tectonic au plates beneath p la ates b ene neat it.

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Denali is the highest mountain in North America.

Other forces and processes, like a volcanic eruption or earthquake, change the Earth’ss surface almost instantly.

Try This!

w The combination of these rapid and slow changes have shaped the Earth’s surface urface into physical features called landforms. ms. Mountains, teauss are some som plains, valleys, canyons and plateaus examples of landforms.

In small groups, discuss the different landforms in your area. Create a chart to classify the landforms by how they formed.

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Denali was formed by the movement ement ent of tecto tect tectonic plates towards each other.

North th American Plat Plate

Pacific Plate

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A mo mountain ou is a landform that rises above the sur rro surrounding land. A mountain is taller than a hill h and usually has steep slopes and a sharp or rounded peak. There are three sh main types of mountains that m at differ in how they formed.

Volcanic mountains n are formed when magma pushes up beneath the p from bene Earth’s surface. When magma hen the ma reaches the surface, creates a volcanic ace, it create mountain. The mountains can get larger m ountains c and taller when an a n larva cools during volcanic eruptions.

Mount Japan is an example er ru nt Fuji in J volcanic mountain. of a v

A photograph of Olympus Mons taken by the unmanned Viking 1 spacecraft.

Amazing Fact!

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Other planets in our solar system have mountains too. The tallest mountain, Olympus Mons, can be found on Mars. It is a volcanic mountain with a height of about 21 kilometers met (13.6 miles). That’s about two and a half times taller ler than Earth’s tallest mountain, untain, Mount Everest.

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Mount Fuji

Fold mountains are created when two or more of Earth’s tectonic plates are pressed together.

The force pushes sedimentary rock upwards into n a series of bends and folds. The tallest mountain range on the Earth, the Himalayas, are an example of fold mountains.

Block mountains are formed by the e movement of the Earth’s crust along cracks called lled faults. The movement causes the Earth to pull apart and break into large chunks of rock. Some me rocks are a pushed upwards, forming mountains. tains. The Sierra Sierra Nevada mountain range in the Western United nite ed States are block mountains.

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Sierra Nevada Ne mountains

Mount Everest in the Himalayan mountain range is the tallest mountain on Earth.

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What are the different fferent ways w in which ch mountains are e formed?

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ga le du ca tio n

At the base of many mountains are plains and valleys. Plains are wide, flat expanses anses of land with little change in elevation. Plains ns are generally in low-lying areas, but can also form on plateaus. Plains that extend from m land to the t ocean are called coastal plains. plains ns. The he size of p can vary between a few hectares ectares ctares to hundreds hund hundre of thousands of square kilometers. lometers. ometers. Being wide and flat also make plains agriculture ns suitable for ag a and livestock farming.. Many ny plains were we formed over time by the erosion osion n of the land from nearby hills or mountains. Otherr plains were we formed by deposition of sediment diment ent by water wate or wind.

Did You Know?

A plain adjacent to a source of water such as a lake or river can be flooded when the water level is high. Called floodplains, these landforms are rich in diversity. Many organisms are attracted to floodplains when water releases nutrients into the soil.

Like plains, valleys areas, often alleys ys are low-lying low-ly lowbetween mountains ains or hills. hills hill Water may flow through a valley as streams or rivers. Some strea valleys are re caused by tthe weathering and erosion on of glaciers and an have a u-shape. Others are water such as a river or e formed ed by running runn run stream tream am and have a sharper v-shape. y between two hills valley

The Great Plains are re a broad expanse expans off flat fllat land in the United States. tates. They cover an a area area on square kilomete kilo of more than 2.5 million kilometers.

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Canyons, also called gorges, are deep, narrow channels that run between steep mountains or cliffs. Canyons are created by weathering and erosion of uplifted sedimentary rock caused by a river running through it. The formation of canyons usually takes millions of years. Scientistss believe the Grand Canyon in the United States took between five to six million years to form.

A plateau, also called a high plain or tableland, is flat terrain that elevates sharply from the surrounding land on at least one edge. e Plateaus are often formed by the erosion of the surrounding area, leaving part of the terrain above ground surrounded by steep ledges. tiv vitty.

Plateaus can also be formed by volcanic activity.

The Tibetan Plateau in the Himalayas as is Earth’s highest and largest plateau. It coverss an area na rea of 2.5 million kilometers (970,000 sq mi)i) and has an average elevation of about 4,500 0 meters mete ers (14,800 ft).

The view from the Tibetan an np plateau l to the Himalayan mountains.

Colca Canyo Canyon on

Amazing Fact!

The Colca Canyon in southern Peru is formed by the erosion of volcanic rock caused by the Colca River. With a depth of over 3,270 meters (10,730 ft), it is one of the deepest canyons on Earth.

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Activity 5.2

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The Hydrosphere Scientists and engineers have discovered several ways to turn salt water in the ocean into fresh water suitable for human use – a process called desalination.

Desalination is used extensively in the Middle East, particularly in Saudi Arabia.

Engineer It! As a class, design and build a device that uses heat to desalinate salt water. Test the effectiveness of the design.

Suggest and test how it could be improved.

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The hydrosphere is the combined mass ss of all a of the water on Earth. It includes water er in the rs. It also atmosphere, oceans, lakes and rivers. ater in the form of o includes groundwater and water ers ers. ice at the poles and in glaciers.

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Amazing Fact!

The water sources in the e hydrosphere can c be divided into two main groups on the ps based o amount of dissolved d salts ts they contain. conta

Water that contains salts is ains a lot of dissolved disso diss called salt water. high level of salts, er. Due to the h people cannot ot drink rink salt water. wat wa

Water that at contains ontains little dissolved salts is called fresh water. water ater.. Clean, fresh fre water is suitable for people le to o drink and use u for various purposes.

The he vast majority of water on Earth, about water held in the ocean. About 2.5% 97.5%, %, is salt wa off the he water in i the hydrosphere is fresh water.

Much h of the Earth’s fresh water is frozen at the poles or in glaciers. Only a small amount, about po pol 0.5%, is available for people to use.

The Ocean

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The ocean covers more than three-quarters of the Earth’s surface. The ocean gives the Earth its blue appearance when viewed from space. The ocean is a diverse environment stretching from warm shallow coral reefs to the cold and dark deep ocean where no sunlight reaches the ocean floor.

The high amount of dissolved salts in the ocean means the water cannot be used for drinking or the many other ways people use usse fresh water.

The process p of desalinizing salt water often requires large amounts of electricity. How could a hot, dry and sunny country like Saudi Arabia produce large amounts of fresh water using renewable energy sources?

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The ocean is home to a great diversity off sitty o organisms that are adapted to living ng n g in in salt water.

Think T hi Deeply

Why is the salt water in the ocean not no suitable for most human n uses?

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low tide

high tide

high tide Earth

moon m

low tide Tides are caused by the gravitational interactions between twee tw een the he Earth Ear and its moon. The gravitational pull of the Sun also influences tides. ue tiid

Wav form as wind blows The water in the ocean is constantly moving. Waves across the surface of the ocean. This to move in a iss causes use the e water w circular motion. Waves can slow down wn n and and stop stop as a they lose energy or break when they reach shallow water or tthe er o he shoreline.

The gravitational pull of the Earth’s moon tides. Tides are the th h’s m oon causes ca rise and fall in the level of waterr in and other bodies of water i the th ocean o connected to the ocean.

Another way water in the e ocean oce moves is in currents. An ocean current is the continual movement water entt of w ate usually in one direction. Currents close to the surface of the ocean, surface currents, are caused by wind. oc an n, called cal

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Currents move in large circular patterns.

Usually currents move in clockwise spirals in the Northern Hemisphere and in counter-clockwise spirals in the Southern Hemisphere.

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Water deep in the ocean moves too.

Deep ocean currents are caused by differences in water temperature and salinity.

Salinity is the amount of salts dissolved in water.

Ocean currents play a critical role in regulating the Earth’s climate. Currents continually move e warm water from the equator towards the poles and cold water from the poles back k to the tropics.

Currents are of vital importance to many organisms. Currents help to move nutrients utrients from the deep ocean to the surface. face. e. Many marine organisms are also dependent ependent ent on ocean currents for reproduction. ction. n.

Ocean c cu currents play an important role in the migration patterns of whales and many other marine organisms. m

Think Deeply

In what job and professions would it be useful to know about the movement of water in ocean currents?

Discuss with your classmates.

surface current deep ocean current

map of surface and deep ocean currents

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The Ocean Floor

Use modeling clay and a clear plastic container to build an ocean basin. Fill the container with water to show the different depths at which different features are found.

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Try This!

The ocean basin is a depression of the e Earth Earth’s surface in which the ocean lies. It fills the areas between continents. Just as plate te movements vemen e Earth’s arth’s land, th tthey and other processes shape the basin. also shape the floor of the ocean b The continental shelf is where continen continents meet conti the ocean. This is the shallowest underwater part west unde under of the ocean basin that down. hat gradually slopes slo At the end of the continental ontinental ental shelf at a depth of about 200 meters drop-off called the rs is a sharp dro continental slope. ope.

The continental ental slope leads to the abyssal plain.

Similar to plains ins on land land, tthe abyssal plain is a large open pen en flat area of the ocean floor. At depths of between tween ween en n three to six s kilometers, sunlight does not reach h the ocea ocean floor of abyssal plains. The few ew organisms rganisms that th live at these depths ths have special spe adaptations for or surviving survivin in the dark and island cold ecosystem. ecosyst

continent

abyssal plain

seamount

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du ca tio n

Scattering the vast abyssal plain are underwater landforms caused by the movement of tectonic plates and volcanic activity. There are hills, valleys and underwater mountains called seamounts. A seamount that reaches the surface of the ocean forms an island.

Where tectonic plates meet underwater lies the mid-ocean ridge – an underwater mountain range that stretches for over 65,000 kilometers (40,000 mi).

cean n At the deepest part of the ocean floor lie ocean trenches – long and narrow depressions in the e ocean floor. Ocean trenches occur at places laces es where one tectonic plate slides underr another. her.

How are the formations on the e ocean floor similar to Earth’s landforms? rm

Go Online! nline!

Through a comb combination of boundary tectonic plate bo interactions and volcanic nteractions an activity, new oceanic crust is continually continua forming along mid-ocean ridges. The mid-oce oceanic crust slowly moves ocean away from the ridge, creating awa new areas of ocean floor.

Discover more in a video on the NGScience website.

QuickCode: G4P1

AB

Activity 5.3

g

continental shelf

mid-ocean ridge

ocean trench continental slope

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Try This!

Distribute 1,000 milliliters of water between different containers to show the different amounts of salt and fresh water in the hydrosphere. Create a pie chart to present the data.

Go Online!

Head to the NGScience website to discover how glaciers have been shaping the Earth’s surface for millions of years.

QuickCode: L7W9

Glaciers and Ice Caps The majority of water in the hydrosphere osphere ere iss salt s water held in the ocean. This saltt water watter ter is not not on and d cannot can can nnot suitable for human consumption d animals. anim mals. be used by many land plantss and ut three percent, percent of Only a small amount, about the water in the hydrosphere herre is is fresh fresh fr esh water. wa ter in in the th he hydrosphere, hydr hydros Most of the fresh water ce ent, is in in the the form for of solid about 68 to 70 percent, ice sheets at or near Earth’s and ear the the E arth’s North N me fresh fresh water fr water ice is held in South Poles. Some cebergs. glaciers and icebergs. larg rge, usually usual elevated, body of A glacier iss a large, frozen w water ater that that slowly slow lowly moves downwards ds tthe he ocean ocean o oc towards orr lake. Icebergs are chunks e tthat hat break bre reak o ff of ice shelves or glaciers of ice off nd float float freely freely into in the ocean. and T he ffrozen rozen w a at the poles, in glaciers and The water eb bergs cannot ca icebergs be accessed by people for ng and ng a other purposes. drinking

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Groundwater

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Most of the fresh water in the hydrosphere that is in liquid form is underground. This water, called groundwater, seeps into cracks and spaces in soil, sand and rock. The water is stored in large bodies of rock called aquifers.

Groundwater that is close to the surface of the Earth can be extracted by drilling or digging wells. The extracted fresh water can then be used by people.

Think nk Deeply

What human activit activities groundwater to can cause groun polluted and no become pollute longer onger suitable for use?

aquifer

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Lake Superior or is the largest lake lak in the United States. tates. es.

Rivers, Lakes kes and Streams S A very small mall amount mount of tthe water on ut 0.3 percent, percen is held in lakes Earth, about w in rivers ivers and streams. s or flow These urcess of water are a essential parts of sources errestrial strial ecosystems ecosys ecos terrestrial and can be used by people people.

The meandering river provides a source of fresh water for the residents of the town.

AB

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Activity 5.4

People often ofte build cities and towns near oft lakes akes and rivers. The fresh water is often cleaned and filtered in treatment plants befo being distributed to homes, before farms and businesses where it is used in farm variety of different ways. av

Storing Water

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The amount of precipitation in a region changes throughout the year. This results in changes to the amount of fresh water available for people to use. To help make water available year-round, people often store water in reservoirs. A reservoir, also called a dam, is an artificial lake used to store water.

Reservoirs allow people to control the amount of water that is sent to homes, farms and businesses. They help to ensure that fresh water is available all year round.

Many reservoirs can also be used to generate enerate ate electricity using hydroelectric power stations. tio

Go Online! ne!

Learn how hydro hydroelectric use flowing power stations u water to gener generate electricity on the NGS NGScience website.

QuickCode: W5V5 QuickCode

Think Deeply

In what ways can storing water in reservoirs harm the environment and the organisms that live there?

What are some reasons people ople store water? How is the water used? d?

People use se e reservoirs rese reserv to store sto and control the water. e flow flow of wa wate

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ga le du ca tio Using Water

Did You Know?

Many devices and appliances in our homes are designed to reduce the amount of water they use.

Examples include watersaving shower heads, halfflush toilets and washing machines with reduced wash times. What are some other examples?

Fresh water is used sed by people in a variety of different ways. s. Drinking king clean, clean fresh water is essential for or our ur bodies to carry out life processes.. We need wate water to digest food, stes and transport tran tra remove wastes food and oxygen bodies. All of the cells in n around und our bo our bodies es need fresh fre fres water to function.

Fresh h water is us used in our homes in many water is distributed from a ways. s. Often, wa w our homes by a water company. reservoir eservoir to o amount of water used by each house The amo amoun is me easu asu measured and people pay the water company com om mpa for the amount they use. our homes, fresh water is used for In ou o activities such as cooking, cleaning and ac c ct washing. Fresh water is used to maintain w llawns and gardens.

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Fresh water is essential to farming. It is used to grow crops and raise animals.

Clean, fresh water is used to process food and beverages and to produce medicines, cosmetics and cleaning products.

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Businesses and factories use fresh water in manufacturing, cleaning, cooling and electricity production. As the water is not consumed by people or other organisms, it is often not as clean as drinking water. Salt water can also be used in manufacturing and cooling.

In some regions, the amount of fresh water hr gho available for human use changes throughout the year. Fresh water can also become me e. ItIt iss polluted, making it unsuitable for use. of water w err important to conserve the amount of h water water we use and ensure that our fresh sources are kept clean.

Activity 5.5 .5

Try This!

Create a chart to show the ways you use water from day to day. Estimate the liters of water used. In small groups, discuss some ways you can reduce the amount of water you use.

R

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AB

Water is often used for cooling during manufacturing and electricity production.

Why is it important to conserve fresh water and keep it free of pollutants?

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In the Field

Seismologist

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A seismologist is an Earth scientist that specializes in the study of seismic waves.

Seismic waves are waves of energy that travel through the Earth’s crust, usually as the result of tectonic plate interactions or volcanic activity.

Events that produce seismic waves are called seismic activities.

To measure the size of seismic waves, seismologists use an instrument called a seismograph. They are usually secured to rock ock in permanent positions on the ground.. They y record even the slightest vibrations in n the Earth’s crust and allow seismologists to determine etermine termine the size of an earthquake or volcanic c eruption. ruption.

The R Richter scale was Ric developed in 1935 by develo Charles F. Richter.

Ch Char

Seismologists often work in the he field. They may m use portable seismographs to obtain accurate information about seismic activity. curate ate inform informat Special computer software iss used analyze and interpret the data they sed to an collect. A scale, called the Richterr scale scale, is used to determine the size of he R gher the th number b on the Richter scale, the more a seismic event. The higher powerful and destructive seismic uctive ve the seis seism event.

Mod Moderat Moderate

Ligh Light Minorr

Strong

6.0 5.0

7.0

Major

4.0 8.0 Great

3.0

9.0 2.0 Micro o 1 1.0

10 the Richter scale

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Science Words

plate tectonics tectonic plates mountain plain valley canyon

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Use the words to complete the sentences. plateau hydrosphere salt water fresh water tides surface currents

deep ocean an currents curren ocean basin glacier ac groundwater reservoir eservoir

1.

Currents close to the surface of the ocean are e called calle

2.

A

3.

.

is an artificial lake used to store wat water.

are the rise and fall in the level vel of water in the ocean.

4.

are deep, underwater er currents caused c by differences in water temperature and salinity.

5.

Fresh water stored in underground is called rground aquifers aqu

6.

The combined mass of all of the w water on Earth makes up the .

7.

A is a landform that t rises above the surrounding land and usually has steep p slopes and an a peak.

8.

is a large, usually elevated, body of frozen water that A slowly moves towards the ocean or lake. es downwards downwa

9.

Water that contains a lot of dissolved salts is called

g

.

10. Water that con contains little dissolved salts is called

. .

11.

The Earth’s crust is made up of large, moving pieces called

12.

is a low-lying area, often between mountains or hills. It A may have a u-shape or v-shape.

.

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A in elevation.

is a wide, flat expanse of land with little change

Re ga le du ca tio n

13.

14.

is a model based on the idea that the Earth’s crust ust is made up of large, moving pieces.

15.

is a deep, narrow channel that runs between steep A mountains or cliffs.

16.

The ocean lies.

17.

is flat terrain that elevates sharply harply from the surrounding A land on at least one edge.

is a depression of the Earth’s surface rface in which whi the

Review

1.

Copy and complete the table.

Feature of Earth’s Surface

Description

Canyon Plateau

Abyssal Plain lain

Mid-ocean Ridge Ocean Trench

2.

List the three of mountains and describe how they form. e main types ty

3.

Draw a labeled diagram that shows the features of the ocean floor.

4.

Describe the wa ways in which water moves in the ocean.

5..

What of fresh water on Earth is available for people to use? hat percentage perce Where Whe is the remaining fresh water?

6.

Why is it important to conserve fresh water and keep available fresh water sources clean?

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