Let's Do Science 4 – Text Book A

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P mary 4 Prr i ma 2 Textbook

A

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. d disc

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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Anima

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.

r als are Animals es res ure or structur os malss to anim i id iv be divid n be an can ca c ess a tures tur ctur stt uc sstru

s u nall str n rnal terrn Exte Exte m warm birds wa bir birds bird ym fly o fly birdss to bird bi

Amazing Fact!

Great white sharks are the largest of all predatory fish in the world. They can reach lengths of up to seven meters and weigh up to 3,000 kilograms!

great white sh

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

Think Deeply

d In the Field

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

Energy Engineer ble En Renewable

wn ffossil dow osing down closing re cl are a e s ar ents ments overnm governm go round tthe world, govern aro trie around trie ntries un countries In many coun ss.. natives. g alterrnative ergy e energy able energ wable new en ene renew with rene th m with g them l ing d replac nd tionss and ations ation ower station fuel pow oduce od p oduce hatt pr ess tthat o ogies olo hnolo chnolo tech w ttechno nd new and farmss a a ms,, wind farm so s r ffarm nclu e sola These includ on tion oduction rod produ pro itty p city lectricity the elect e these se ecause ecau Becau energy. B ve energy. wave a wa da and dal tida g tidal ng sing y using icity ctricity ec electr . e en lean energy clean a clea t as red to ferred re refer y are ey hey miss ns, they missio du em produc o not produce hods do method

ns ns, is ons, mis missi u emissi r uce g to reduc elp ng helpin nd h and ya rgy an energ ean clean cl ed in cle rested intere ou are interest you If yo ewab energy ew rene e neer. A renewable gy engi energy energ ble ene e able b a renewable u may like to be ou o you yo es n no w technologi new ts ne nd tests and dev es, develops researches th t researche ngineer is a scientist that ng en e ergy. duce clean energy. tto produce

ng b burning y by elec of electricity r uction of produc p the pr ne , th n ine in ineer gineer engine g gy e rrg n rgy ne le ene ewable o a renewab To s ers see e ee eer gineer y engineers le energy en ene e em. Renewab em llem. problem. proble ed as a prob iffied entifi identifi fue iss id fuel ossill fuels ffoss fo as ve a ive na iv tern terna alternat energy al ble energy of a renewab o o io ttio tion ation at atio nt na en ent e entation ment men eme lement m leme iimp d im gn and e design he h th the lution.. olution h so th the

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off yo ty aiillabilility aila ailab vailab o the availab a on ngin rss collect data ng y enginee rgy rg energy able energy wa w ewa enewa ene Ren Re Renewa n, Sun e Su he th from the ne energ ook at how energy o e look hey h They T Th field The h field. tthe y in th rgy rgy energy le e ble ewab newa enew enewa enewable re renewa y tly. i tly. cien cie fiicien e ficien y ef ty e ectricity generate el ed to gener ssed use be use c n be nd ca d wind nd ater and at n water oving o moving m nd testt and rss to te ters computers u compu n use e and m dels models ey build mo hey ess, the ies, iie orries o tor to ator a orator n lab In d nd or and monitor o monit T y also The s.. Th d ei design thei ss off their t ctivene effec te the effe uate lu alua eval eva ucted. ucted ructe con tructe cons o ec ologiess onc technologi y technologi energy e energ ble re ewab int iin ren inta mainta renewable ou were a renew you work on if you uld y What would eer? engineer? gy engin energy

Engineer It!

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

In the Field

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

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A Closer Look Features of the Eart

h’s Surface

For Forces such ch ass mov movin oving gw water,, w wind in and the movem moveme Earth’s tect ent of the ent t ect ctonic onic o nic plates plates lat are contin continua ntin ti lly sh s aping ping the Earth’s Earth’s surfac and water sources. su f e

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1 10

lake

plateau

canyon

A Closer Look

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

island

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lagoon

peninsula ocean

Amazing Fact! eagle de bald bal

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Interesting facts to bui build interest and enthusiasm. nthusiasm.

l Structures

artss a par ntt pa n rent ren iffff re iffe diffe p off d ade up made p the stt ucturess help se str These s These s. ent and environm ir e th the n i in ve rvive u survi r ernal ded into two types – exte e es. urres. u tur tu ctur c r ctu ructur tru nd internall sstru n

b g ladybug la

p n orpio scorpio sco

Did You Kno Know?

o ger to nger ng stinge and a sti rs and incers have pince onss have ion orrpion o Sco Scor ea ave gs have ugs u ug ybugs adyb Ladyb y. Ladyb pray. eir pra heir killll tthei a dk ch an catc c ctt e ec te ote ot r pr c to p pss to elps hat hel ng that o ing over cover d outterr c rd ard har hard gs dy and wings. ody od its bod

e p ke kee h eatthers fea uc ass feat such re such ures tu tures ctu uctu t e p the lp ig t help eig eigh l htt we d their lig nd an . y y. sily s ea re easily ore mo mor

green palm snake

e and dolphins es snakes ks, snak ks s h as shar An als ssuch Anim boness to ac bone back ele ons and ba kelet l sk e erna inter have int have es odie nside the bodi inside gans Or Organs . es. ies dies eir bo hei h thei th ortt tthe upport supp gss ngs things thi g the th ge th m to get p the lso help also alss al ma aniima of anim duce. du duce duc ro pro ep repro grow and repro i , grow ive vive urvive ur su ed to sur ee y nee they they the Discuss some animals you know of and the structures they have that help them survive.

hark

Try This!

sea turtle

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

dolphin

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Science Words

13.

are blood vessels that at carry blood high h in oxyge heart to all parts of an ox n from the animal’s body. b

14.

Most mammals have specia alized li hairs, called their mouth and nose.

Use the words to comp lete the sentences. vertebrates invertebrates exoskeleton herbivore carnivore camouflage

endoskeleton lungs gills arteries capillaries

veins nocturnal whiskers antennae brain

1.

2.

3.

4.

The is an internal structure that processes and interpr information and instruc ets ts the body how to respon d to change.

Insects have a pair of sense receptors called . animals are active at night and rest during the day. are blood vessels that carry blood high in carbo from the cells back to n dioxide the lungs.

5.

Arteries branch out into a fine

6.

A

plants.

is an a anima i l that eats

other animals.

7.

A

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Animals without a backb ones

Use a chart to descri cribe how each h animal’s external structu to survive. res he help it External Structures

Animal

(a) a)

network of

is an animal that eats

are called

, surrounding

Review

1.

Body Cover overin ng g

Moveme ent

(b)

.

2.

. Some have a

Gettin etting gF Food

List and nd describe three interna l structures re of a dolphi do to survive n that help it surviv urvive i e.

mountain

A monkey eats a sweet rose ro apple. Draw aw and label a flow chart show how the sensory to input in is received by the monke process y and how it is ssed in the brain to help it surviv vive.

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glacier

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

Discussion

Activities 7.3 – 7.4

3.

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AB Activity

(c)

Describe the landforms and water sources shown in the diagram. Which of these can be found in your area?

AB

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

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

hill

river

Review

plain

delta

beach

sand bar

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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 2

Characteristics of Life Cells Organism Classification Review

4 6 14 27

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Unit 1 - Classification of Organisms

Unit 2 - Plant Structures and Functions Fun Plant Structures es External Structures re Internal Structures uctures ures w Review

Unit 3 - Animal mal Structures Str and Functions Structures Animal nimal Struc St External Structures xternal S Internal S Structures Animal Senses Anim Re ew Revie Review

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28 30 32 42 49

50 52 54 68 76 85

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Unit 4 - Human Body o Systems Your Amazing zing ng Body ensses Human Senses Review

Unit 5 - Ecosystems ms

What iss an Ecosystem? cosyst Energy gy in n Ecosystems Ec Eco cosystems y Review iew w

90 106 1 109

110 112 126 139

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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 used 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 teacher’s eacher’s instructions. in If you have or are ve any questions quest ques unsure ure of what to do, d raise your hand and nd ask your teacher. teac tea Do o not eat, d dr drink, play or run in the th laboratory. laborato

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

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

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Do not panic if an accident occurs.

Be aware of eyewash stations, fire 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. so

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

In the Field

Make sure you are re accompanied ccompanie by an adult when on field trips or doing other doin o activities outside schoolyard. ide of the schoolyar schoo On long trips, rips, make sure you take enough water and food. B Bring Bri insect repellent ent 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 n sunny sunn days, take ta Sun S protection long-sleeved shirt, hat such as a long long-sleev and sunscreen sunscreen.

Do not ot tou touch p plants, animals or other organisms unless instructed to do so by ms u your teacher.

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Classification of Organisms How can we distinguish living things from non-living things?

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In this chapter you will ...

n

1

• identify the needs and characteristics of living things.

e up of one • understand that all organisms are made or more cells.

• describe how scientists classify organisms into groups.

ovide examples exa • list the six kingdoms and provide of dom organisms within each kingdom.

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How can we classify the living things around us?

Go Online!

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

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fox with her cubs

squirrel eating

uc a

Some poison p is n dart dar a t frogs fr carry their eiir young e yo oun ung to water.

How w can we classify clas the living things gs around aroun us?

Characteristics of Life Characte The e plants plants and an nd animals on these two pages ages are all a living things. A living thing is called calle an an organism. We can tell if ssomething ometthin is an organism by looking at its n e ds and characteristics. needs Organisms need the same things to live and survive in their environment. Animals need water, food, nutrients and a place to live. They also need the gas oxygen.

Plants are organisms that produce their own food through the process of photosynthesis. To do this, plants need sunlight and a gas called carbon dioxide.

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All organisms grow as they get older. When organisms grow, they usually get taller and heavier. As organisms get older, they look more e like their parents.

All organisms can reproduce. This means eans they are able to produce young of the same ame kind. kin

AB

ga l

ngess around Organisms also respond to changes them. When an animal senses danger, ger, it may respond by running away. Some ome plants open and close their leaves or flowerss in response to the change from day to night. Many or any ny plants grow g bend in the direction off sunlight.

Responding to ssun Respo changes around them m helps all a organisms to meet their needss and a d survive s rvive e in their environment.t.

Activities ities 1.1 – 1.2 1.

Sunflower Sunflowe seedlings get bigger and taller as they grow.

Think Deeply

A plant’s response of growing or bending in the direction of sunlight is called phototropism. How does this response help plants to live and grow?

Sunflower plants turn and bend to follow the position of the Sun throughout the day.

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Cells

leaf cells

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stem cells

6

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All organisms are made of structures uctures called cells. Cells are the smallest llest unit within an organism thatt carries ries out life processes – including reproduction production and growth.

Some organisms one ms are made of o only o cell. Many of the us, he organisms ganisms around ar a such as most are st plants ants and animals, an made up of millions different cells. lions of diff dif

Most Mo plants and animals are made up of many cells. They are called multicellular organisms.

In a plant, cells in the roots take in water for the plant. Cells in the stem move water and food to different parts of the plant. In the leaves, many cells contain chloroplasts. Chloroplasts are the part of a cell that make food for the plant.

brain c cells

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Animal cells can be different in shape, size and their function. Cells in the brain of a kitten help it to send messages about its surroundings. Cells in the blood help to move oxygen to where it is needed.

ati o

Each type of cell plays a role in helping the organisms to function.

blood cells

Why do cel cells come in a variety of o different shapes and sizes? a

AB

Activities 1. 3 – 1.4 7

Try This!

ca

Draw a Venn diagram ram to show the similarities rities and differences ens between a hand lens and a microscope.

microscopic microsco mi microscopi sc ic chlorellas

Unicellular Organisms Unicellula

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Most M ost st cells cells are a very small and can only be seen using powerful c an o nly b microscopes.

Many organisms, from m iic crosc to giant blue whales, ttiny iny seedlings iny se a re made up of millions of cells. are Some organisms are made of only So o one cell. They are called unicellular organisms or one-celled organisms.

Chlorellas are unicellular green algae that are able to photosynthesize.

Parameciums are unicellular organisms that, when observed under a microscope, are shaped like a shoe.

microscopic pic p parameciums

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Amazing azing Fact!

Fac

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Bacteria are simple unicellular organisms found all over the world. Some bacteria can be harmful to plants and animals. Other bacteria can be helpful. Rhizobium is a bacterium found in soil that helps a plant to get the nutrients it needs.

People often use unicellular organisms in preparing food. Lactobacillus is a bacteria used to make yogurt. Yeast is a unicellular fungus used to make bread and other food oo od and drink products.

AB

A bacterium rium reprod reproduces by dividing cells. Each ng into two ce can then of the two cells c divide again to fform four reproducing in this cells. By repro way, billions of bacteria can be produced produc in just one day!

Go Online!

Activity 1.5

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Discover more about microorganisms in a video on the NGScience website.

QuickCode: T9L6 yeast y

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Multicellular Organisms

n

Most organisms are multicellular – they y are made up of many different cells.

ellular ar organisms organism The cells that make up multicellular come in a great variety of shapes hapes and a sizes. The shape, size and location of the cells within n an organism are suited d to their function.

Humans are multicellular ticellular ular organisms with h many any different types ess of cells. ells muscle cells

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The shape, size e, siz ze and ze location of muscle mu uscle cells uscle ell help you to move ove different ove diff mo parts ts of your yo body. body Bone cells bones strength ells give ive yourr bon bo and structure.

bone cells

10

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Your skin cells form a protective layer around your body. Blood cells help to transport gases to and from other types of cells.

sskin cells

Amazing Fact!

Activity Ac y 1.6 16

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AB

e

All of the cells within hin a multicellular multicellula organism work together ether to help the organism function system. ction as a system sys

The human body is an amazing and complex system. There are about 200 different types of cells and about 30 trillion cells in all!

red blood cells

Try This!

Observe some prepared slides of human cells under a light microscope. Draw and describe the cells you observe under low power and high power.

11

Cell Organization

ed uc ati on

Humans and many of the animals mals you are familiar famil with are complex, x, multicellular ulticellular organism at make u organisms. The variety of cells that up multicellu re organized in a multicellular organisms are way that helps the organisms anisms function functio as a system. whole sys Cells that are of the he same me kind and an have the same fun function are often groupe grouped together tissue. Intestinal your body, for as tissue stinal cells in you yo example, make kinds of ake up your different diff dif intestinal tissues. ssues. es.

intestinal tissue

12

Think Deeply Why do multicellular lticellular organismss have different differe types of organs? gans?

ga le du ca tio n

Two or more types of tissue that are grouped together make up an organ. Each organ has a primary function. Your small intestine is an organ that helps your body to absorb nutrients from food.

A group of organs that perform a central task is called an organ system. Your esophagus, sophagus, stomach and intestines are organss that work together as your digestive system. The primary function of the digestive system is to break down wn food to enable your body to get the he energy and an nutrients it needs to carry out life processess like l e moving about, growing and repairing itself. ring itself elf.

All of the organ systems work together ether er to make up an organism.

How are cells organized in a multicellular organism?

Activity 1.7

R

AB

intestines in intestine digestive system

13

ca tio n

Organism m Classification Cla There is a great variety of different organisms ms on Earth.

Earth From deep in the ocean to the mountains. More he top of the coldest co than one and a half h million different kinds of anisms have hav been named by scientists organisms and millions more are yet to be discovered.

Amazing Fact!

eg a

So far, about 1.6 million different kinds of organisms have been named, described and classified.

Scientists estimate there are more than 10 million n different kinds of organisms nism yet to be discovered.

14

du ca

bacteria

In order to better understand each kind of organism and their differences and similarities with other organisms, scientists stttss have classified them into groups called alled kingdoms. The six main kingdoms are ancient bacteria, bacteria, protists, fungi, un plants and animals.

fir sapling

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rganism To decide which kingdom an organism belongs to, scientists look at the organism’s characteristics tics ssuch as how it gets food, how it reproduces uces and an whether it is unicellular or multicellular. icellular

Volvox are unicellular algae.

Why is it important to classify organisms groups? ms into grou

AB

Activity 1.8

15

Did You Know?

Not all bacteria are harmful.

Blue cheese, Korean kimchi and soy sauce are just some of the many food made using different kinds of bacteria.

Bacteria Bacteria are the simplest organisms ms on on Earth.

Earth They are unicellular and their cells ellls are are simpler simple ler than that of other organisms. he remains remai s of o Most bacteria break down tthe plants and animals for food. bacteria ood. S Some ome b acte a ct get the food they need orr o on d by by living liv vin ng iin no her b acteria erria are ar able to other organisms. Other bacteria nd make make ttheir he own o photosynthesize and food.

Bacteria are able ble e to to rreproduce eproduc ce e rapidly uring tthis his process, proce a single by dividing. During bacterium divides divides iinto nto ttwo wo identical daughter bacteria. bac Bacteria cause diseases and infections Ba ac c ria can can c ause d in plants, and people. Salmonella is plan nts, animals animals a a bacteria can bacteria that ba that c a cause food poisoning in people animals. people and and some so

Re ga l

Bacteria Bacteria can also be helpful. Many organisms need bacteria to help them get org rg gan the nutrients they need. Bacteria in your help you to get nutrients from sstomach to tthe he food you eat.

salmonella salmone

16

In what ways can bacteria be harmful? In what ways can they be helpful?

amoeba

Protists Protists are a diverse group of organisms. nisms.

Some, like amoebas and parameciums, ums, n under are unicellular and can only be seen a microscope. Others, like giant kelp, are multicellular and can reach lengths gths of more m than 50 meters.

Think Deeply Why are kelp forests only found in shallow coastal waters and not in the deep ocean?

enas, make their Some protists, like euglenas, he food they th need d by own food. Others get the eating other organisms. ms.

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eproduce in different ways. wa ays.

Different protists reproduce o reproduce reprodu by dividing..

Some are able to Others have more ore complex life cycles.

AB

Activity 1.9

euglenas as

17

Fungi Go Online!

Discover more about fungi in a video on the NGScience website.

QuickCode: Y5S7

Think Deeply

Fungi are also different from om plants in tthe way they get their food. They do o not make their food as plants do, but instead stead break down the remains of plants and animals. An organism that gets its energy in n this way is called a decomposer. Decomposers om osers play pl an important role in an ecosystem helping to recycle dead m by help organisms into nutrients in the soil.

Unlike plants, ants, fungi do not produce seeds. Most fungi reproduce releasing microscopic spores roduce by re into the air. New fu fungi grow from the spores.

Common mmon types type of fungi include mushrooms, bracket cket fungi, fung puff balls and molds.

Re ga l

Many years ago scientists classified fungi as plants.

Upon closer observation, they noticed that fungi were different from plants in a number of ways. With a classmate, create a chart to show the similarities and differences between fungi and plants.

Fungi have many features in common with plants. They often grow in soil and do not move from place to place. Fungi lack the distinguishing stinguishin features of plants such as stems, leaves, flow flowers or fruits.

18

puff ball

ca

mold

Like bacteria, some fungi can be harmful ul to other organisms by causing infectionss and diseases. Fungi are also important to people. Mushrooms, for example, are an important source of food. Other typess of fungi, such as yeast, are used in the production of different food.

R

Penicillium is a type of mold that is used to make penicillin.

In w what ways are fungi similar to plants? In what ways are they different?

penicillium fungi

Amazing Fact!

Truffles are edible fungi found underground. They only grow in certain regions of the world and are hard to find. They range in size from the size of a strawberry to the size of an apple. Some truffles can sell for thousands of dollars.

AB Activity 1.10 19

A Closer Look

The Zombie Fungus Found mostly in tropical rainforests are a type of fungi that are truly fascinating.

Meet the mind-controlling cordyceps gus. fungus, sometimes called zombie fungus. ans Cordyceps are parasites, which means they infect and live inside other organisms. ganisms.

eg al

ects an an When a cordyceps fungus infects egins to to ttake ake animal, usually an insect, it begins over its mind. The fungus compels compel pels the tth he ne n esstt and and insect to leave the safety of itss nest grro gr ound nd that th move to a branch above the ground ure u re ffor o the cordyceps ordy p is the right temperature to reproduce.

20

uc Did You Know?

Cordyceps fungi are used in traditional Chinese medicine.

However, scientists have not found any evidence on their ability to treat human diseases.

After about bout a week, week, the the insect ins in dies and the cordyceps pushes ordyce eps pss p push ushess a spore-containing s growth head. Cordyceps wtth through w throu roug gh the th he insect’s ins fungi spores. The spores ungi un ngi reproduce ep duc ce through thro t are a re re elleas eased into in th released the air and land on other insects. nssec n ctts. The Th he insects insec become infected and the life cycle yc y cle repeats! re repeat

21

sequoia trees

Go Online!

Plants can be different in many ways. Learn about some of Earth’s more unusual plants in a video on the NGScience website.

QuickCode: L1K7

Plants are re organisms th that t can be found almostt everywhere on o Earth and they come in a diverse of shapes, sizes and erse range o colors. have named and classified lors. Sc Scientists ent sts h thousands of different kinds of hundreds reds of tho more plants are constantly plants ants and mo discovered. being ing discov disco Plants are able to make their own food P through the process of photosynthesis. During thro throug photosynthesis, plants use light energy from photo photosy the Sun to transform carbon dioxide, water minerals into food and oxygen. and m a

Re ga

Think Deeply

Plants

Hundreds of millions of years ago, plants only lived in the ocean and other er s. aquatic environments.

They eventually developed adaptations suitable table for living on land. more and. As mor plants adapted to life on land, nd, the amount amoun of oxygen gen in the Earth’s atmosphere sphere increased.

Why did this his occur? occ

22

Scientists classify plants into smaller groups S by looking closely at their external structures.

Plants that produce flowers and fruits are called flowering plants. Flowering plants reproduce from seeds. Plants that do not produce flowers and fruits are called nonflowering plants. Many non-flowering plants, such as mosses and ferns, reproduce from spores.

al e

Scientists can also classify plants by looking oking ng closely at their internal structures. Vascular ascular plants are plants with internal structures, ctures, called xylem and phloem, to transport nsport port food and water throughout the plant. nt. Plants ants without witho these internal structures are called non-vascular plants.

What characteristics ris of plants make m them different from fungi and animals? f

Amazing Fact!

The oldest living organism on Earth is a type of pine called the methuselah tree.

It is found in the California mountains in the United States and is estimated to be 4,853 years old!

moss

23

ed uc ati o

anemone fish hiding in a sea anemone

Sally ly Lightfoot cr crab cra

Animals

leopard

Th There is a greatt diversity ersity of anim animals on Earth.

They can be found in the coldest polar regions Th cold co to the driestt desert. sert. They fill our rainforests and coral reefss and all sorts of shapes and co nd come in a sizes. So have identified and named siz o far, scientists ha h over a million ov lion different differen kinds of animals and many m ny new ew animals are discovered every year.

Scientists Sc ientists estimat estimate there may be as many as eight ei ghtt to ten million millio different kinds of animals yet discovered, named and classified. to o be e discovere discove

king penguins

24

jellyfish

bee

eg al ed u

treefrog

Like plants, animals are organisms that need ne eed food, water and air. Unlike plants, animals mals are are not able to make food. To get the he energy nergy and an nd n nutrients they need, animals feed on other organisms.

Within the animal kingdom, om scientists entists divide d animals into two main groups. Animals n groups grou ma that have a backbone are re classified ssified as a vertebrates.

Animals without a backbone classified as ckbone are cla invertebrates. Aboutt 95 percen percent of the animals on Earth are invertebrates. vertebrates. tebrates

AB

Activity ctivity 1.11

dwarf crocodile

Amazing Fact!

Paedophryne amauensis is a type of frog discovered in New Guinea in 2009. At just 7.7 millimeters long, it is the smallest vertebrate on Earth!

See if you can find out the largest invertebrate on Earth.

Go Online!

Like plants, animals are a very diverse group of organisms. Discover some strange and outright weird animals in a video on the NGScience website.

QuickCode: M3H1

25

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. organism photosynthesis grow reproduce respond

cells multicellular organisms chloroplasts unicellular organisms

tissue e organ gan organ gan system syste kingdoms

1.

Organisms made of just one cell are called

2.

re called Organisms made of more than one cell are

3.

Organisms

4.

are the smallest unit nit within an org organism that carries out life processes.

5.

.

.

to changes around ound them.

are the part of a cell ell that make ma food for the plant.

6.

Cells that are of the same kind and have the same function . form a

7.

All organisms can young of the same me kind. kind

8.

Two or more types of tissue tiss that are grouped together make up an .

9.

Plants produce own food through the process of roduce their ow

10. When organism organisms

which means they are able to produce

, they usually get taller and heavier.

11.

ving thing is called an A living

12.

A group grou of organs that perform a central task is called an

13.

Organisms can be classified into six main groups called

26

.

.

.

.

Review List the characteristics of all organisms.

Re ga le du ca tio n

1.

2.

Provide an example of how an organism responds to changes anges in its environment.

3.

True or false. (a) All organisms are made up of at least one cell.l (b) All cells contain chloroplasts. (c) Different cells have different functions.

4.

How can bacteria be harmful to people?

5.

Draw a flow chart diagram to show how ow cells are organized in the human body.

6.

List the six kingdoms and provide de an example exampl of an organism in each.

7.

Copy and complete the chart below. belo Kingdom

Charac Characteristics

Examples

27

Plant Structures and Functions

n

2

Re ga

What are the external and internal structures of plants?

Go Online! ne!

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

28

In this chapter you will ...

• identify and list the external structures of plants.

• identify and list the internal structures of plants.

ti

• describe a plant system in terms of its components and their interactions.

ed uc a

al and • construct an argument that plants have internal rvival, external structures that function to support survival, growth and reproduction.

Re

How do a plant’s structures ure support its production? survival, growth and reproduction?

29

flower

Plant Structures es Plants are made up of different ere parts or structures. Many any plants, ants, for example, have roots, s, stems and leaves. There e are also parts ch h as the tubes that inside plants, such transport water er and nutrients nutrien around the plant.

fruit

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e structures uctures of a plant interact All of the and work ork together as a system to support port the survival, growth and reproduction the plant. production duction of th What hat are the functions of the tomato plant structures you tom can see here?

eg

leaf

stem m

roots

30

ga le du ca

Each plant structure has a function that helps the he plant to survive, grow and reproduce. The bright ght petals of flowers function to attract bees and nd other pollinators.

bee pollinating flower be

The thorns on a blackberry bush help p to protect otect its leaves and fruits from grazing by y wildlife. wildlife. dlife.

If one or more plant structures are removed ved or do not function as they are supposed the osed to, th survival of the whole plant system ystem em may be affected.

blackberry thorns

Discuss what would happen to a plant if all of its lea leaves d. were removed.

AB

Activity vity 2.1

31

Exte External Structuress

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Structu Structures that are observable on the he outside out of a plant pla are external structures. res. The These include roots, stems, leaves, flowers ers and fruits. structures that Roots are a usually the external xternal structur grow d down into the soil. il. The primary prima function of the rroots is to take ke in the water and nutrien nt needs eeds to survive surv nutrients the plant and grow.

are shallow and branch out to Some roots r are called cover a large ge area. rea. These roots r roots help the plant to fibrous roots. oots. Fibrous roo ro take up it rains. p lots of water when w Growing Grow owin win ng out from tthe roots are microscopic root roo oot hairs. ha airs. The root roo hairs help in absorbing water nutrients from the soil. w r and a nutr nutri

Root hairs take in water from the soil.

root hairs

32

ca tio

Tree roots branch out and hold the tree firmly in the soil.

Other plants have one main root, called a taproot, which grows deep into the soil. This helps to reach water deeper in the soil.

eg al ed

Roots also hold plants firmly in place. This helps to prevent them from being washed away by water or blown away by wind.

Amazing A m Fact!

The sshepherd tree grows in th the very dry grasslands of South Africa. It has the deepest roots of all plants – reaching depths of over 60 meters!

How are the shapes of roots oots suited to their function??

AB Activity 2.2 2

dandelion with w taproot

Go Online!

Observe how roots take in water and minerals in an animated video on the NGScience website.

QuickCode: Y3G5

33

Design and construct a device that mimics the external structures of a plant to produce electricity using solar cells.

Many plants have a stem. Stems can be different in many ways, but they usually perform two rm tw important functions for the plant.

ati on

Try This!

unlight ht in Plants need the energy from sunlight order to make food through the process of photosynthesis – a process that takes place plac in the leaves. One function off the stems in many m plants is to hold up the plant. nt. This allow allows the leaves to absorb more e sunlight. nlight. Stems Stem also hold up the plant’s reproductive ductive tive structures structure – flowers and fruits.

Some plants have stemss that are ave stem that a re soft and can can bend easily. They herbaceous y are called h erbaceous plants.

Herbaceous grow us stems ms g row quickly. q quic ckly.

34

For protection against animals, als, s, some plants have coverings ve erin on their their stems. Trees have an n outer outte er layer lay of bark. Some plants and nts like like roses ro oses a os n bougainvilleas have with ave stems stem ems w ith thorns for protection against animals. ection a gainsst a n im

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Other plants, such as trees, have stiff, strong stems. They are called woody plants. The strong stems of woody plants grow thicker and taller each year. This allows the plants to reach ch high into the sky where the leaves ves can trap the sunlight they need ed to to photosynthesize.

Try This!

With your classmates, visit a place in your area that has lots of plants. Classify the plants you spot into groups.

Draw a diagram or create a chart to show how you classified the plants.

AB Activity 2.3

35

eucalyptus ucalyptus leav leaves

ca

maple leaves

Amazing Fact!

The bryophyllum plant can reproduce from its leaves.

Small plantlets with roots develop along the edges of the leaves. The plantlets can grow into new plants when they fall to the ground.

How is the shape e of leaves leave suited to their eir primary function? f Plants are organisms nisms that a absorb the energy in o make ake food through th thr sunlight to the process of photosynthesis. ynthesis. nthesis. In most plants, photosynthesis takes place leaves. To take in lots of place in the leav sunlight, ig ght, leavess are external structures that are often out to cover a large area. ften n fflat lat and and branch bra bra

a

The key food is what lies inside the ek ey tto o making ma leaf. W We’ll e’l’ll take tak a look at that in more detail later.

36

c

Victoria ctoria lily pad pads

Leaves have a large surface area for absorbing sunlight, but this can also lead ead to water loss. To reduce water loss, many any leave leaves have a waxy outer covering called d a cuticle. cutic cle. e Some plants in hot and dry environments nvironments ments like e deserts store water in their leaves. eaves. ves. They have hav ha a thick cuticle to prevent water ater loss.

Think Deeply The leaves of a cactus are modified into sharp spines and do not contain chloroplasts. How is a cactus able to photosynthesize?

ga l

What is the function on of the cuticle on a plant’s ant’s leaves? leaves

AB Activity vity 2.4

37

ga le du ca tio n

longhorn beetle covered in pollen

hummingbird feeding ding on nectar

Flowers are external structures tures found on flowering plants. Their primary rimary mary function functio is to help the plants reproduce.

Go Online!

Watch the process of pollination in an animated video on the NGScience website.

QuickCode: E1V7

en at the base of o a flower.

The sepals are often Their function is to protect the flower as it fl flo develops.

owering ng plants to t reproduce, For most flowering pollination n needs to occur. occu Pollination is the occ transferr of pollen from the male part of the flower, er, the he stamen, stame , to stamen t the female part of the flower, wer, the he pistil pistil..

The petals are a often the brightly-colored part off a flower that surround the reproductive parts. th t The petals pollinators, such as help to attract at etalss h iinsects ins inse sects and birds, which transfer pollen between flowers flowe ers rss and other plants.

38

ca

dandelion fruit

Flowers develop into fruits which help to protect the seeds from which flowering plants reproduce. Fruits can also help plants to es. reproduce by spreading seeds to new places.

Think Deeply T

Many plants produce seeds that are dispersed to new places by wind. What characteristic would you expect these seeds to share?

Re

o new By spreading seeds to places, the seeds are able to grow in areas away way from the th parent plant where ere there is less ompetition for water, w chance of competition d nutrien sunlight and nutrients.

AB B Activ Activity 2.5

39

A Closer Look

Seed Dispersal

ca

Most flowering plants reproduce from seeds. For seeds to germinate and grow, they often need to be scattered in areas away from the parent plant where there is less competition for the water, er,, nutrients and sunlight the new cess of of plants need to survive. This process scattering seeds to new placess iiss called called seed dispersal.

milkweed m seeds

Re g

daptatitions Flowering plants have different adaptations en nt ways. ways. wa to disperse their seeds in different Some plants have fruits that burst bu urst open open and d throw the seeds into the air. Seeds can also ter. be dispersed by wind and water.

Go Online! line!

Learn all about out seed dispersal ersal in a video on the e NGScience website. webs QuickCode: E7X1

40

coconut floating on water

Engineer eer It! I

ed uc ati on

Many flowering plants develop fruits and seeds that are moved to new places by the animals they attract. Seeds can be dispersed when animals that feed on the fruits move or drop the seeds.

Seeds may stick to the fur or feathers of he en animals and are moved to new places w when d they fall off. Seeds can also be dispersed when they are eaten. They are moved to to new new places in the animal’s waste.

Design and d build a seed that can be dispersed ispersed by b wind.

Test and your design nd evaluate yo with your classm classmates.

How does seed dispersal help plants survive?

young wombat with seeds stuck to its fur

AB Activities 2.6 – 2.7 squirrel holding an acorn fruit from an oak tree

41

Internal Structures The roots, stem, leaves and flowers are external structures that each play a role in helping the plant function as a whole system.

There are structures inside a plant too. They are called internal structures. Like external structures, each internal structure has an important role in helping the plant function as a whole system.

One important internal structure is called vascular cular tissue. Vascular tissue is a series of tubes that hat transports water, nutrients and food throughout ghout ut n the th the plant. There are two main structuress within vascular system – xylem and phloem.

Amazing Fact!

xyle xylem ye

phloem

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Mosses are non-vascular plants. They don’t have xylem to transport water. In fact, they don’t have roots at all. They absorb water and nutrients directly into their bodies. They have root-like rhizoids which help to hold them in place.

42

root section

root hair

Xylem are tubes that transport water and he stem to nutrients from the roots, through the the leaves. Phloem are tubes thatt transport ansport food in the form of sugar from the leaves eaves to all al a parts of the plant.

The vascular tissue in the roots, stem an and leaves is arranged in different the fferent ferent ways to help h plant function and meet eet its needs.

ca

xylem phloem

Go Online!

Observe how water, food and nutrients are transported through the stem in an animated video on the NGScience website.

QuickCode: P6Z5

AB Activity 2.8

eg a

stem section s

What are e the primary primar functions of the xylem and nd phloem in vascular plants?

43

Internal Leaf Structures

tio n

A Closer Look The leaves of the plant are where the food-making process ss of photosynthesis takes place. In order to photosynthesize, e, the he external and internal structures in the leaves work together ether as a system. Let’s take a closer look!

Re ga le du

Water and nutrients travel in the xylem from the roots through the stem to the cells in the leaves. Tiny holes, mostly on the underside of the leaves, called stomata, open and close to take in the air the plant needs.

phloem p hloe hloem

xylem

stoma

vascular tissue in leaf

cells on underside of leaf

44

leaf section

Re ga le du ca tio chloroplas hloroplasst st chloroplast

stoma

Inside the cells of a leaf are special spec sp structures called Chloroplasts lled chloroplasts. chloroplast Ch are the partt of the cell where photosynthesis wh p takes place. chloroplasts, the ce. In n chloroplas th energy from sunlightt is used dioxide ed to convert conve carbon c and waterr into food for the th t plant. The food is transported ansported ported from the leaves to the rest of the e plant in phloem phloe tubes. tu

AB A Activities 2.9 – 2.10

Think Deeply

Would you expect to find chloroplasts in animals cells?

Explain your answer.

Go Online!

Observe how water and food are transported within leaves in an animated video on the NGScience website.

QuickCode: X9Y7

45

We have learned that flowers are the external reproductive structures uctures of al structures uctures flowering plants. Internal within the flower also play an n reproduction. productio important function in

du ca tio n

anther

n occurs, pollen When pollination re male sex cells, ce grains, which are e stamen to the th pistil. move from the The pollen grains ins move down do a pollen he ovary. The ovary ov tube to the holds the emale sex cells. eggs – the female

stamen stam stame

46

pistil

ed uc ati o

Fertilization occurs when the male sex cell joins with the female sex cell. The fertilized egg cell then develops into a seed. The petals and reproductive parts of the flower fall away and the ovary develops into a fruit.

Once developed and under the right conditions, ditions, ns, the seeds will be dispersed and grow to o become come new plants.

Once fertilized, tthe ovary in a tomato flower develops into a protective fru fruit.

Think Deeply T

Wh is the difference What between pollination and fertilization?

A Closer Look

Parts of a Flower

petal

stigma

style anther

pollen tube

stamen

pistil

ame en ntt filament

Re

ovule ovary

sepal sep

AB A Activities 2.11 – 2.14 47

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. fibrous roots taproot herbaceous plants woody plants cuticle sepals

pollination stamen pistil petals seed dispersal

vascular tissue issue xylem phloem hloem stomata fertilization

1.

is the scattering of seeds to new ew places.

2.

are roots that are shallow and branch out.

3.

The series of tubes that transport and food through a ort water, nutrients nutrie plant is called .

4.

transports water and nd nutrien nutrients from the roots to the upper parts of the plant.

5.

transports food d from the th leaves to all parts of the plant.

6.

are openings enings in the leaf that take in air.

7.

is the e transfer of o pollen from the male part of the flower, , to the female fem part of the flower, the .

the

8.

Many leavess have a w waxy outer covering called a

.

9.

When a male sex cell jjoins with a female sex cell,

occurs.

are often brightly-colored and surround the 10. The reproductive parts of a flower.

11.

48

are often at the base of a flower and help to protect the flower wer as it develops.

12.

Some plants have one main root called a into the soil.

that grows ows deep dee

Re ga le du ca tio n

13.

have stems that are soft and bend easily.

14.

have stiff strong stems often covered in bark. rk.

Review

1.

Copy and complete the chart below.

External Structure

Functions ctions

roots

stem

leaves

2.

What is the primary function off root hairs? hairs

3.

How can you distinguish between plants and woody plants? etween herbaceous her

4.

On leaves, what is the primary of the cuticle? ary function fun

5.

Draw a diagram to show the th process of pollination.

6.

List two ways plants ants disperse disper their seeds.

7

Copy and complete omplete the chart below.

Internal nal Structure

Functions

xylem

phloem phlo

chloroplasts

8.

Describe the process of fertilization.

49

Animal Structures and Functions What are the external and internal structures of animals?

50

n

3

In this chapter you will ...

ca tio n

• identify and list some of the external structures of animals. als.

• identify and list some of the internal structures of animals.

onents and the • describe an animal system in terms of its components their interactions.

ernal and ex • construct an argument that animals have internal external structures avior and reproduction. that function to support survival, growth, behavior

Go Online!

R

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

How do an animal’s structures support its survival, growth, behavior and reproduction?

51

bald eagle

Animal Structures es Animals are made up of different ffe t p parts truct res help elp p the or structures. These structures n their the eir environment environm animals to survive in and wo ttypes ypes – external can be divided into two structures and internal rnal structures. ru uctu

Amazing Fact!

es such uc a External structures as feathers keep nd ttheir h irr light ligh weight help the birds warm and mo or easily. sil birds to fly more

Great white sharks are the largest of all predatory fish in the world. They can reach lengths of up to seven meters and weigh up to 3,000 kilograms!

al

great white shark g grea

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scorpion

ladybug

uc at

Scorpions have pincers and a stinger to catch and kill their prey. Ladybugs have a hard outer covering that helps to protect their body and wings.

ga le

Animals such as sharks, snakes and dolphins dolp phins have internal skeletons and backbones ne to o die support their bodies. Organs inside the bodies of animals also help them to get et tthe he tthings hings they need to survive, grow and d rreproduce. prod du

green palm snake

Discuss some animals anim you know of and the structures they struct have that help p them survive. surv sea turtle

dolphin dolp do

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Watch how elephants use their different external structures in a video on the NGScience website.

QuickCode: H7S6

External Structures Animals have parts on the outside of their bodies that help them to survive vive and get the things they need to g grow and reproduce. Let’s look at the he e external externa ernal features of eleph hants. elephants.

n

Go Online!

Re ga l

d

Wrinkly skin helps to trap moisture between the cracks. This helps to reduce water loss and keep the elephant cool in its often hot and dry environment.

Elephantss have a tail ta with a hairy tip. p. They use their tails to swish and wish away insects ins bitin animals. otherr small biting

Like e most land mammals, ma elephants use ttheir legs and from place to feet to move fr place ce in ssearch of food or when evad evading predators.

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uc at

Elephants have big ears with a large surface area. Blood vessels are close to the surface. Flapping their ears helps them to stay cool.

Tusks are modified teeth.

They The are used to dig, gather food fo and for protection against predators.

Elephants are well known for their impressive trunks. The trunk is actually a nose. It’s used to smell, breathe and shovel food and water into the elephant’s mouth.

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Movement Try This!

With a classmate, compare an aquatic mammal with a land mammal. Create a chart to show the differences in their external structures for movement.

Legs are external structuress tthat hat help e lp many land animals to walk, alk, rrun u and crawl. Cheetahs, the e fastest asstest land animals, can run att na speeds as fast as a c car. p a

eg al ed

springbok

orrgan Animals are organisms that eat other organisms for food. To get the food they need, most os animals niima need to move from place to place. Moving ov vin g from place to place is also helpful ffor escaping or e scapin danger. Different animals have external v different ffe e x structures to help them move. ve

tiger shark

56

ca tio n spider piid monkey onk k

Animals like spider monkeys, have long ng legs and arms and a tail to help p them em ests. swing effortlessly through forests.

ma have ve fins Sharks and other aquatic animals and a tail which help them to to move move and an change direction underwater. at r.

AB bullfrog

al

yin insects tss have hav wings Birds, bats and flying and move about b by y fflying. ly

Amazing Fact!

Wandering albatrosses have the largest wingspans of all birds, measuring almost 12 feet from end to end.

They can fly thousands of kilometers without needing to flap their wings!

Activity ivity 3.1

wandering wande an a nde derriing deri ng albatross alb lba attrro osss

57

Spiky fur is not the only unique feature of echidnas.

They are also one of just two mammals that reproduce by laying eggs.

The other is the platypus.

Both of these egglaying mammals, called monotremes, can only be found in the wild in Australia.

Body Coverings Animal body coverings are externall structure structures ucture that help them to survive in their environment. ronment. rs. Reptiles Rep Mammals have fur. Birds have feathers. and fish have scales.

ati on

Amazing Fact!

A tiger’s fur helps to keep it warm. It also helps h it to blend into its environment nment ment when sneaking sne s dnas are mammals m up on prey. Like tigers, echidnas han keeping it warm, w with fur too. Rather than an echidna’s fur is in the spikes. This he form f rm off sharp shar h om predators. predator helps to protect itt from

king penguin

tiger

58

ga le du ca tio freshwater carp

Feathers keep many birds warm and help them em to o fly. Penguins are flightless birds. Their waterproof rproof oof feathers help them to stay warm and swim. im.

Scales provide fish and many reptiless with an n outer layer of protection. Turtles are e reptiles with modified scales called plates. When en a turtle senses sense danger it retreats into its plate-covered covered red d shell. ell.

Smooth and hard scales provide fish with an outer layer of protection.

In what ways do animal al body co coverings env support their survival in their environment?

AB Activity 3.2

cobra

echidna ch hidn

59

A Closer Look

Animal Body Armour – Exoskeleton Many of the animals we are familiar with are vertebrates. Vertebrates are animals with a backbone and an internal skeleton of bones. Mammals, birds, reptiles, amphibians and fish are all vertebrates. The skeleton provides vertebrates with structure and support. It also protects vital organs like the heart, lungss and brain.

ed

bon or or Most of the animals on Earth don’t have a backbone internal skeleton. They’re called invertebrates.. While W ile some invertebrates like worms, jellyfish and octopus oc ctopus have soft bodies, many have a hard outer cove covering ing o the e called an exoskeleton. It’s like a skeleton on outside of their bodies.

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ca ti

Insects, like ants, bees and beetles, have exoskeletons made of a substance called chitin.

Like the internal skeleton of vertebrates, the m exoskeleton gives the insects shape, helps them move and provides protection. It also helps to prevent water loss. Lobsters, crabs, scorpions and n an nd spiders are other animals with an exoskeleton to on made of chitin.

Think Deeply Thin

As animals an grow, they break out ut of their exoskeletons and build a new one in a an process called molting.

Explain why a molting animal may be more vulnerable to predators.

61

ati on chameleon meleo

Catching atching hing Pr Prey re rey

When predators predato catch up with for a meal isn’t their eir prey, the fight f over.r. They n ne need to hold on to it too.

Predators have h external structures to do just that. has a tongue that A chameleon cha twice the length of its body. It is tw extends its tongue to reach its prey. ex Sticky saliva on the tip of the tongue holds the prey in place as the tongue is pulled back to the mouth.

Eagles and other birds of prey have sharp beaks and large claws, called talons, to catch and kill prey. bald eagle

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ti

le du ca

Grizzly bears have large and sharp teeth for catching and killing their prey.

Teeth are external structures that help animals alss get the food they need. The shape and size e of od an n teeth are always suited to the types of food animal eats.

Animals that eat plants, called herbivores, vores,, often vores have strong and flat teeth for grinding ding ing grasses and leaves. Animals that feed on n other her animals are called carnivores. They often ften have ave large canine teeth for catching and d holding olding prey.

Amazing Fact!

Crocodiles are fierce predators. They have powerful jaws lined with sharp teeth. When a crocodile catches its prey, it dives underwater and rolls rapidly in a behavior known as the `death roll’.

Westt African Afric ender-snouted er-snouted crocodile cr slender-snouted

63

monarch caterpillar

monarch butterfly

Defense A Against Predato Predators Many animals have external ernal struc structures for defense against again other animals. The Th monarch has bright yellow, black, butterfly caterpillar cate y and white that i stripes i hat scare away predators.

Adult butterflies are also brightly colored to let bri predators know they are poisonous. hey a frilled-necked lizard

When lizard senses hen a frilled-necked frilleddanger, it expands its neck making it appear larger and scarier to potential predators. pred When threatened, a millipede responds by curling into a tight ball for protection. millipede

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A common mmon gray treefrog on a leaf.

ca

A common gray treefrog on bark.

Many animals are camouflaged which meanss they are able to blend into their surroundings, g making them hard to spot. The color of a gray ray treefrog changes in response to its environment. rk and a It takes on a gray color when on bark green color when on leaves.

es, have Stick insects, as their name implies, external structures that make them look a lot like hem loo sticks. This makes them almostt impossib impossible for predators to spot.

In a small group, design and build an object that will be camouflaged in your school garden. Test the effectiveness of your design by getting other groups to act as predators and try to spot your object.

Activities 3.3 – 3.4

R

AB

Engineer It!

H How does being camouflaged help prey survive in their environment?

How could it help predators?

65

A Closer Look Peregrine falcons have many external structures that allow them to live in a range of different environments and climates. From icy tundras to hot and dry deserts.

With a light and sleek body and large wings, peregrine falcons are the fastest animals on Earth. They can dive through the sky at speeds of up to 320 kilometers an hour.

They have excellent excelllent vision too, to oo, u sing using their thei ir large large eyes to spot spot prey prey from high hi hig igh gh iin n the sky. sky.

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a ti

The World’s Fastest Animal

Re ga l

Specialized external nall structure structures ress h help ellp el p tthe he peregrine falcon to catch, hold h ho old on on to o ve e sharp harp p claws cla aws and kill its prey. They have d beak beak for called talons and a hooked y tearing the flesh of their prey.

Did You Know?

Peregrine falcons have excellent vision. Scientists believe they are able to see eight times better than humans. They are able to spot prey from more than three kilometers away.

Go Online!

Watch the amazing peregrine falcon in action in a video on the NGScience website.

QuickCode: S5H7

AB Activity 3.5 67

Internal Structures

Try This!

With a partner, take turns in naming some of your internal structures.

Discuss the function of each structure.

Most animals are complex organisms. Along Alo ong with external structures to help them survive, surr ve, ucttures tthat animals also have many internal structures et the thin work together to help the animal g get things it nd reproduce. needs to stay alive, grow and ones that w A cow has muscles and bones work together to help it move. Lungs ngs help it to get oxygen from the air and d pass it to the th blood. Its heart pumps the oxygenated nated blood bloo throughout its body. It has four stomachs tomachs that tha work together with its intestines to get energy from the grass it og ne eats. All of the internal work together te nal structures uc to help the cow function n as as a whole system.

How do the internal structures of a cow help it to survive, grow and reproduce?

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leopard opa opard

Support and Movementt

le d

Vertebrate animals – mammals,, birds, ds, reptiles, amphibians and fish – have an structure n internal rnal struct structu ms an internal nternal of connected bones that forms eleton leton on. on The bones bon b skeleton, called an endoskeleton. ide the animals anima anim are hard and rigid and provide with support. The endoskeleton ton also gives their th bodies shape and protects vital ital al organs org o organ like the th brain, heart and lungs.

leopard skeleton

69

ed uc ati on

Muscles are internal structures u found throughout the bodies odiess of vertebrate animals. Many ny muscles are attached d to bones. bone When these muscles es contract, they pull on the bones. s. This allows allo allow the animal to move. ove. lp invertebrates vertebrates move Muscles help too. An earthworm arthworm worm moves move by contracting cting its muscles muscle in waves.

cts have muscle Insects muscles attached to the inner nner surfac surface surf of the Insects move their exoskeleton. skeleton. Ins Inse wings by contracting legs gs and win wing and nd relaxing these muscles.

muscles

orangutan ang angutan ng ngutan grasshopper

70

Gas Exchange Animals have internal structures to help them get the oxygen they need from their surroundings. The same structures also get rid of the carbon dioxide which animals produce.

Mammals, birds and reptiles have lungs to take in oxygen from the air when they breathe in. In the lungs, the oxygen passes into the blood. Carbon dioxide passes from the blood and is removed from the body when the animal breathes out.

Along with having lungs, some amphibians are able to take in oxygen gen through their moist skin.

Aquatic mammals and reptiles have es also also h ave lungs. To take in oxygen and d remove remove carbon dioxide, they must come come to to the the surface to breathe in air.

seagull ullll lung

ai a ir sa ac air sac

Amazing Fact!

Dolphins are marine mammals that must come to the surface about every eight to ten minutes to breathe. Another marine mammal, Cuvier’s beaked whale, can stay underwater for more than two hours before needing to breathe at the surface.

Re

blowhole

dolphin dolp

lung

71

Fish and many aquatic invertebrates like lik crabs, squid and clams do not have e lungs. lungs. on dioxide oxide Taking in oxygen and removing carbon illss. takes place in an organ called g gills.

Re ga

ed

When water washes over the he gills, llss oxygen ge moves into the blood and carbon carb bon dioxide dioxide e moves from the blood to o the the water. wat wate err.

Go Online! line!

Watch how fish use gillss to take in oxygen and give out carbon dioxide de in an animated video on the NGScience nce website.

QuickCode: Cod A1Z2

72

What is the primary function of gills and lungs?

Did You Know?

Blood Circulation

The hearts of different differe eat at differe animals beat different eart of o a turtle rates. The heart time per beats about 10 times minute. te. The heart hea of the world’s smallest mammal, the beats he Etruscan shrew, s about 1,500 times a minute!

al ed uc ati on

All vertebrates and some invertebrates have internal structures to move blood throughout their bodies. Central to these structures is the heart. The heart is an organ made mostly of muscle. When the muscle in the walls of the heart contract, blood is pumped through the heart and around the body.

Branching out from the heart is a network of fine tubes called blood vessels. Arteries are blood vessels that carry blood high in oxygen en y. from the heart to all parts of the animal’s body. ork of The arteries branch out into a fine network blood vessels called capillaries. In the capillaries, laries, oxygen and nutrients move from the e blood ood to om m the cells the cells. Carbon dioxide moves from sselss that carry y to the blood. Veins are blood vessels blood high in carbon dioxide from om the he cells back bac back to the lungs.

turtle heart

What is the primary function nction of an animal’s heart and blood vessels?

AB Activity 3.6

internal anatomy of the painted wood turtle

73

An Internal System

ion

A Closer Look The various internal structures of an animal have specific functions. These internal structures work together to allow w the he animal to function as a whole system.

Re ga le

When a tiger breathes in, air moves to the lungs where the oxygen needed passes e to the blood. When the tiger breathes out, carbon rbon dioxide is removed.

The heart pumps umps blood rteries to through arteries laries where oxygen o capillaries nd nutrients are exchanged and for carbon diox dioxide. Veins carry the carbon dioxide ck to th back the lungs.

74

ca tio n

Food broken down into small pieces in the mouth is sent to the stomach. The stomach further breaks down food and sends it to the intestines where nutrients are absorbed.

An internal nal network of bones helps to o protect vital organs such as the brain, h heart and lungs. s. Joints allow the tiger to move its limbs lim and other body when bones are ody parts w muscles. pulled by m

Muscles pull on bones to help the tiger move. Muscles also provide protection for other internal organs. The heart is an organ made mostly of muscle.

AB Activity 3.7 75

The Australian platypus has a very poor sense of sight and often closes its eyes when hunting. To find food, it uses its bill which is filled with electro-receptors that pick up electrical signals given off by its prey.

ca tio n

Amazing Fact!

platypus llatypu t

Animal Senses S ns

Humans have ave five senses s to take in information ormation about the world around them.

Ourr five senses are sight, smell, hearing, taste te and touch. to also have senses. They use their Animals al senses enses to gather information about their environment. Processing and responding environ this information help them to survive, to thi grow and reproduce.

Sense Organs Animals have a variety of different sense organs. Like humans, many animals have eyes, ears and a nose. Other animals have specialized structures and systems for gathering specific information about their surroundings. long-eared owl

76

grey long-eared bat

Owls are nocturnal. This means they are re e T active at night and rest during the day. To e sense their prey at night, owls have large ow light. ight. ght. eyes that allow them to see well in low They also have a keen sense of hearing ring g which they use to sense small prey as they hey ey ound. d rustle in leaves in trees or on the ground. nal. Most bats Like owls, bats are also nocturnal. have a very poor sense of sight.t. To ‘see’ ‘see in ecia technique called the dark, bats use a special ver echolocation. Bats let out a very hrough their mouth high-pitched sound through which is too high for humans to hear. The y from the bat, but is sound travels away o reflected back when it hits other objects. ensitive ears to receive these Bats use their sensitive echoes which h allow them to determine how far away and nd how big the object is.

Go Online! ine!

Bats are great reat listeners!

They can use se their sense of hearing to ‘see’ in the dark. Find out more about echolocation on the NGScience website.

QuickCode: P1T3

phins and shrew Dolphins shrews also use echolocation to o sense their surroundings. su

77

ed uc ati on

Many animals rely on a strong sense of smell to help them find food or esca escape nearby predators. The African near an elephant elephan takes tak ke in smells through nostrils ostrilss located at the e tip t of its trunk. Its keen en sense ense of smell sme sm can ca an detect sources of water ter up to 20 kilometers away. kilo om You may have Yo e noticed oticed that sn ssnakes regularly flick re ck their heir tongues out. It llooks like e they ey are using their tongue to taste e the air. In fact, their tongue functions tionss more like a nose to smell the tongue collects particles e air. Their tongu ton in brings them to a n the e air and bri br part inside their mouth special ial body p pa examination. fforr examinatio examinat

African elephants

pit viper

78

African lion

ed uc at

Imagine trying to make your way from your desk to the classroom door in complete darkness. What would you use to sense the objects around you?

Similar to humans using their fingers and skin to feel the things around them, m, most mammals have whiskers to help elp in n sensing their surroundings. A whisker ker is a specialized hair attached to the animal’s mal’s skin and is surrounded by many ny nerve rve cells at the base of the hair. Whiskerss are often located around the mouth h and nose. nose Sea lions use whiskers to o detectt vibrations vibrat vibrati vibratio in the water er caused by y fish. h. Nocturnal No na hunters, like ke lions and nd cheetahs, etahs, s, use u whiskers to o sense and a d catch prey. prey

Australian sea lion

Did You Know?

Cockroaches have two antennae which are used mostly for smell. They also g covered in many have legs that are hair-like structures stru touch organs. highly sensitive sensit even the They can detect de slightest movement mo in the air.

Re

Insects have ve a pair p r of sense receptors rrecep eptors called antennae enn nnae e attached to t their th heir heads.

Many insects ct use cts e their antennae ante antenn nnae to smell.

Others use se e their heir antennae for fo f touch, to detect sou sounds unds nd or to taste. ste e.

American Ameri ic cockroach

79

The e Brain

Re ga le du ca tio n

An A n animal’s sense organs are constantly nstantly antly gathering information about the world ga wo around them. This information a ation travels avels along alon a network of nerves to the brain he brain. The br b is an internal structure e that processes process and interprets the information mation ation and instructs instr the body how to respond Such spond to change. chan ch changes may include nclude e sound, light, lig odor or temperature.

IInformation sentt to the brain brai bra can be processed immediately pr mediately as perception of the also be stored as th he environment. nment.t. It can als a memories to engage in me em s to enable nable animals anim appropriate app ro ate behaviors in the future.

Go Online!

Chimpanzees are one of just a few animals that are able to use tools. Find out what other animals use tools on the NGScience website.

QuickCode: K9N5

Using organs, a chimpanzee detects U i its sense organ termites mound. It uses a stick to catch and mites in a mound moun feed After a successful meal, it ed on the termites. term termi in its brain and will return to stores es the memories m mem the next time it is hungry. he mound ne n

chimpanzee

80

Imagine an animal that sees a brown, rotten fruit and also smells bad odor. This sensory information is processed in the brain and stored as memories. The animal uses this stored information to identify other fruits that appear to be rotting and makes decisions about whether or not to eat them.

In a rainforest, toucans use their eyes to spot fruit. A toucan may spot a green papaya and an orange papaya and eat them both. In doing so, the toucan learns that the unripe green fruit tastes bitter and the ripe orange fruit tastes sweet. It can use this sensory information, perceived and stored as memories, to guide its fruit choice next time it is hungry.

Sensory input, the brain, and behavioral output are all parts of a system that allow animals to engage ge in i appropriate behaviors. rs.

a

AB Activity 3.8

toucan

81

A Closer Look

Senses and Behaviorr Let’s use the example of a barn n owl vide an explanation spotting its prey to provide erent types t that animals receive different of heir senses, process information through their the information in their eir brain and an respond to the information in different ways.

1

Using sing its eyes, which whi are its sense ense organ orga for sight, the s barn owl spots a mouse.

2 The image of the mouse is sent to the barn owl’s brain where the information is processed.

82

The brain recognizes the mouse as a source of food and instructs the barn owl to attack.

4

The barn owl attacks, catches and eats the mouse.

a

3

5

The Th experience is stored in the barn owl’s brain as memories. The memories will guide its actions in the future.

83

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. vertebrates invertebrates exoskeleton herbivore carnivore camouflage

veinss nocturnal octurnal whiskers hiskers antennae brain rain

endoskeleton lungs gills arteries capillaries

1.

The is an internal structure that processes and interprets information and instructs the body how to o respond to change.

2.

Insects have a pair of sense receptors called

3.

.

animals are active at night and re rest during the day.

4.

are blood vessels that hat carry b blood high in carbon dioxide from the cells back to the lungs. g

5.

Arteries branch out into a fine network of netw

6.

A

is an n animal anim that eats plants.

7.

A

is an animal th that eats other animals.

8.

out a backb Animals without backbones are called hard outer covering called an ca .

9.

Animalss with a backbo backbone are called structure an ure of bones called ca

.

. Some have a

. They have an internal

.

10. An animal’s ab ability to blend into its surroundings is called

.

11.

are internal structures used to take in oxygen from the air.

12.

are internal structures used to take in oxygen from water.

84

are blood vessels that carry blood high in oxygen from the heart to all parts of an animal’s body.

14.

Most mammals have specialized hairs, called their mouth and nose.

Review 1.

al ed uc ati on

13.

, surrounding

Use a chart to describe how each animal’s external nal structures structure help it to survive.

External Structures tructures

Animal

(a)

(b)

Movement ovement

Getting Food

(c)

List and describe three intern internal structures of a dolphin that help it to survive.

Re

2.

Body Covering

3.

A monkey eats a sweet rose apple. Draw and label a flow chart to mo show the sensory input is received by the monkey and how it is w how h processed in the brain to help it survive.

85

In the Field

Sniffer Dogs All animals have senses that collect information about the world around them. Some animals have more heightened tened en senses than others. Compared to people and most other mell. ell. They animals, dogs have a very heightened sense of smell. not. This are able to detect and interpret smells that we cannot. makes them great companions for doing all sortss of jobs. tain smells. By Dogs are trained by people to identify certain n smell, ell, the dogs dog rewarding dogs when they find a certain form memories and are then able to search in earch ch for the smell sm s the future.

86

du ca tio n

orts and and stations, station dogs are used by law At airports enforcement officers me ent o fficer to search for and locate drugs, weapons This helps to keep people safe. apo or explosives. exxplos Dogs can also D ogs c an a an lso be used in search and rescue operations. o pera pera ations. In In the the case of a natural disaster such as an earthquake orr hurricane, dogs can assist in locating e arthquake o by ssurvivors urvivors vivorrs b y iidentifying the smell of human breath amongst a mong ongst the th rubble.

By a piece of clothing belonging to a missing B y smelling sme person, p erso dogs are able to use their sense of smell tto o ffind i the smell again. This can lead people to the missing person. m Imagine you had the sense of smell of a dog. What things do you think you could smell?

87

Human Body Systems

n

4

What are the primary functions of the human body systems?

88

ati on

How do the human body systems work together?

Go Online!

e

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

Re ga l

What are the human hum sense organs?

What sensory do they provide?

Wha ory information info

In this chapter you y will ...

• list and describe escribe the organs and systems that make up the n body. human cribe the ways w • de describe in which body systems work together to help he human body function as a whole system.. the

lis the human sense organs and describe their function.

• list

89

Your Amazing Body What body parts and internal body systems do sprinters use when they run a race?

The human body is an amazing machine achine ne that tha can do all sorts of things. It is made de up p of many ork together gethe to internal body systems that all work gs itt needs to stay st help your body to get the things healthy and grow.

n

Think Deeply

Re ga l

muscle

Each body system consists of a group of organs that work together to perform a specific function. Your nose, mouth, windpipe and lungs form a system that helps you to get the oxygen you need from the air.

90

n

In order for your body to function properly, all of the body systems must interact and work together. When oxygen enters your lungs, it passes into your blood. Your blood, heart and blood vessels are another body system. It delivers the oxygen to all of your cells.

brain

If an organ that makes akes up a body system is not ot functioning ctioning properly, the body dy as a whole can be affected. ed.

bone

heart

AB

Activity 4.1

lung

What are some body systems in the human body? How do they work with other body systems?

91

Amazing Fact!

Take your hand and squeeze your forearm, orearm, arm, w wrist and fingers. What do you feel? The e hard ard parts you feel are bones. Just like the internal nal skeleton in vertebrate animals, humanss also bones so have bon bone that make up our skeletal system. ystem.. ystem

Re ga le du ca tio n

When you were born, your skeleton was made up of 300 different bones. As you grow, some bones fuse together. By the time you are an adult, you’ll have just 206 bones.

The Skeletal System

One main function of the e skeletal system is to provide the body with it th support pport and give g structure. structure If it were not ot for or bones, we would not be able to t stand or move ve about.

Another system to is Anoth function nction n of the skeletal ske protect our internal organs. The rib cage pro ternal org orga is a series eriess of bones tthat protects the heart, organs. The skull heart,, lungs and other o surrounds and protects the brain. s Bones are hard, strong and not flexible.

How are you able to do things like bend your elbow, stand up or clench your elb e fingers finge to form a fist? ffinger

The Th h he place where two or more bones meet are called joints. Our bones, joints mee m all work together to help us and muscles m Your elbow joint allows you to move your move. Yo mov forearms. for forearm arms Your hip and knee joints allow you to move your legs. mov Look at the skeletal system on the next page. Which bones protect our internal organs? Which bones and joints help us to move?

AB Activity 4.2

92

skull

humeruss

Re ga le du c

ribss

elbow w spine pine

pelvis

femur

knee

tibia

fibula

skeletal system

93

The Muscular System

ca tio n

For you to move different parts of your body, your skeletal system needs to work rk together ogether with wit another body system – the muscular scular system. system The muscular system consistss of all the mus muscles musc in your body.

There Th re are thre three ee main types of muscle muscle, cardiac muscle and – smooth mu us skeletal muscle. mus usc muscles Smooth hm musc are layers of muscles musc muscle cles in your yo internal organs.

Smooth Smo Smoo ooth muscles musc in your stomach and intestines, inte testines, for example, help you to digest food. d are the muscles Cardiac muscles mus that make up u your heart. They work together to pump blood all around your body. bod Smooth muscle and cardiac muscle are involuntary muscles. muscle This means they cannot canno be controlled. They work on their th own.

muscular system

94

Heart

Skeletal Muscle

le du ca tio n

Intestines

smooth muscle cells

cardiac muscle cells

skeletal skeleta al muscle cells

Skeletal muscles are the muscles that connect nnectt to t your bones. They are voluntary muscles. s. These hese are the muscles you use when you throw row a ball, go for a run and chew your food.

Try This!

Bend different parts of your body. Identify which muscles contract and which muscles relax.

Muscles can only pull on bones, not push. When Wh you bend your arm, the muscles les on top contract contra contr and get shorter. At the same e time, me, the muscles musc on the bottom relax and get et longer. nger. The opposite o happens when you straighten your arm. arm

R

ps contract ontract biceps

triceps riceps relax

biceps relax

triceps contract

AB Activity 4.3 95

The Circulatory System Try This!

The number of times your heart beats per minute while you are relaxed is called your resting heart rate. The best time to record your resting heart rate is the moment you wake up.

Measure your resting heart rate. How does it compare to your classmates’ resting heart rates?

Think Deeply

Your heart is a organ gan made mostly most of muscle that pumps blood the body. Blood od throughout hroughout th travels to and from the heart hea through a network of tubes called ed blood vessels. vesse The heart, blood vessels and in a system nd blood d work together to called the e circulatory system. ssy The primary mary function functio functi of the circulatory system is to deliver oxygen, food and nutrients to all ver the oxy ox partss of the bod body. It also helps to remove wastes.

Re

a

Your heart beats about 80 times in one minute. With a classmate, work out how many times your heart beats in one hour, one day and one week.

Place your hand over the left side off your ourr chest. che c Can you feel your heart beating?

96

heart

ca

Blood vessels that carry blood away from the heart are called arteries. Blood in arteries carries the oxygen needed by all of the cells in your body.

els blood vessels

Amazing Fact!

If all of your blood vessels were laid out in one straight line, they would stretch for about 100,000 kilometers (about 62,000 mi).

circulatory system m

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Blood vessels that hat carry blood bac back to your heart are called veins. eins. Blood in veins vein is low in oxygen, but high in the waste gas carbon dioxide. The carb ca ioxide de moves from fr m the heart to the carbon dioxide lungs where e it is removed from f the body.

What are the parts and primary function functions of the circulatory system?

AB Activities 4.4 – 4.5 97

The Respiratory System When you exercise, your heart rate and breathing rate increase. Why does this occur?

Air is a mixture of different gases. It contains nitrogen, oxygen, carbon n dioxide oxid and water vapor.

ati on

Think Deeply

The respiratory system is the he body system that delivers and removes different emoves moves differen gases from your body. The he e respiratory system is made up of your nose and mouth, windpipe, lungs ngs and diaphragm. diaphra

When you u breathe eathe in, or inhale, i air enters through h yourr nose and mouth. It moves down a tube, the windpipe, and into ube, called tth gs yourr lungs.

windpipe

lung

diaphragm

respiratory system

98

Re ga le du ca tio n

In the lungs, the oxygen is passed to your blood and moves through blood vessels to all parts of your body. Your body uses the oxygen to get the energy from food. When energy is produced, the waste gas carbon dioxide is also produced.

The unwanted carbon dioxide passes into the blood and is transported back to the lungs. The carbon dioxide is removed from the body when you breathe out, or exhale.

What are the parts and primary functions of the respiratory system?

Try This!

With a classmat classmate, calculate how w many times time you inhale and exhale in one full day.

Share your calculation with your class. others in y

AB Activity 4.6

A Closer Look

Inhalation and Exhalation ion on

Inhalation and exhalation occurr when en a muscle musc below the lungs, called the diaphragm, contacts and d relaxes. es. When you inhale, your diaphragm contracts and pulls downward. ard. The space in the lungs increases, drawing air in. When you exhale, the diaphragm relaxes and pushes upwards. The space aphragm ragm rela relax in the lungs decreases and air iss forced out.

Inhalation

rib cage gets g ts b bigger gg

diap diaphragm contracts

Exhalation

rib cage gets smaller

diaphragm relaxes

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The Th he Digestive System

Re ga le du ca tio n

Y Your Yo body gets all of the energy y it needs eeds tto grow and carry out life processes g essess from the food you eat. In order to get et energy ergy from fr food, it first needs to be broken ken down into pieces that are small mall enough to be b absorbed into the blood. lood. ood.

The process by which h food is broken bro down and absorbed is called d orbed ed into the blood bl digestion.

It is the primary function of your d fun digestive system. dig d tem.

Digestion begins Dige est gins in the mouth mou where teeth begin to t cut, cut grind d and d tear food. A digestive juice, called saliva, iva, also helps to break down food.

Go Online!

Take a journey through the digestive system in an animated video on the NGScience website.

QuickCode: X8W4

Try This!

Take a piece of fruit and put it in your mouth. Describe escribe what happens to the he fruit as you chew itt and swallow. swallow

AB Activity 4.7

1 00

The tongue the food down a tube ongue ue helps to push p called ed the e esophagus. esophag Muscles in the wall of the esophagus sophagus hagus push the t food into the stomach.

The stomach works like a concrete mixer. Food is churned urned and a mixed with acids and other digestive d dig e jjuices to form a soupy liquid.

Food moves mov from the stomach into the small m intestine.

Here, food is further broken down intestine ntes by digestive juices into substances that are dige absorbed into the blood. abso

Any A undigested food then moves to the large intestine where water is removed. The unused food is then stored in the rectum before leaving the body as waste through the anus.

What are the parts and primary functions of the digestive system?

n mouth

esophagus

liver

stomach

pancreas

small intestine

large intestine

rectum

R

anus

digestive system

1 01

The Excretory System yst

ga le du ca tio n

Your body is an amazing ng system ystem that can do all sorts of things. hing In carrying out life processes, sses, your body also produces roduces uces wastes. wastes Wastes are substances body bstances the b bod produces thatt itt does not nee need. To stay healthy, y, wastes need to be removed from m the body regularly. r The removal moval al of wastes from the body iss the of e primary function fu f the excretory retory system. syste Parts of the excretory cretory ory system include the liver, bladder. kidneys ys and blad bla

liver

kidney

an organ that filters The liver is a waste from the blood. The waste, urea, is sent to two beancalled ur shaped ape organs called kidneys.

Kidneys further filter the urea to Kidn Kidne produce urine. pro

ureter

bladder er

Urine moves through two tubes, called ureters to the bladder. The bladder stores urine until it leaves the body through another tube called the urethra.

Why can your lungs be considered part of your excretory system? What waste do they remove from your body?

AB Activity 4.8

excretory system

1 02

The Nervous System Your body’s sense organs are constantly gathering information about the world around you. This information travels through your spinal cord in a network of cells called nerves to your brain. Your brain interprets the messages and instructs the body on how to respond. All of your nerves, spinal cord and brain function together as your nervous system. Its primary function is to control and communicate information throughout the body.

brain

spinal cord d

Re ga le du

There are two main types of nerves – sensory nerves and motor nerves. es. s Sensory nerves send messages from m your sense organs to your spinal al cord and brain. Motor nerves send messages from your spinall cord rd and brain to all parts of your body. dy

nerves

When you smell a rotten ten en apple, ap appl information about the he smell ell is sent sen s from your nose to o your ur brain. Your You brain interprets the information formation and instructs you not to o eat the rotten ro food.

Some nerves inside erves es control the organs org or the body. dy. They hey regulate breathing, br heartbeat, the tbeat, body temperature, temper tem digestive other activities. gestive system a and o

AB Activity 4.9

nervous system

1 03

The Immune System m

ed uc ati on

Our amazing bodies do a great at job of keeping us healthy, butt sometimes metimes germs can cause us to get sick. ck. If too to many germs get into yourr body, they can cause infectionss or diseases. Luckily, Lu L our bodies have a number of ways way of stopping germs into mss from getting gett our bodies. If germss do get inside, our ins bodies are able to find and kill k the germs before we get too oo sick. All Al of the cells, tissues and protect you from nd organs that p getting you get well make g sick k and help y up your system. our immune mmune sys sy

thymus

spleen

lymph mph nodes odes

of the immune system.

Your skin is part o layer of protection around It provides a la lay internal parts of the body. Your all of the inte nostril hairs, eyes lashes and tears saliva, nost nostr are parts of the immune system too. All of th these parts of your body stop or kill germs germ before they get inside the body.

R

Sometimes germs can get into your So body through your mouth, nose, eyes or o a cut in your skin. White blood cells, which are found in blood and lymph nodes, are special germ-fighting cells.

They are able to locate and kill germs.

They are also able to ‘remember’ the types of germs they fight and kill, so that they can fight them more effectively the next time these germs enter the body.

104

Why is it important to maintain a healthy immune system? immune system im

A Closer Look

Viruses

ed uc ati o

Viruses are tiny germs that can only be seen using very powerful microscopes. Viruses can cause us to get sick if they get inside our bodies. The common cold and influenza (flu) are illnesses caused by viruses. s.

Viruses are not living organisms as they are only able to o replicate inside a host organism. Once inside your our body, the virus enters a cell and takes over its function. The cell is forced force to replicate the virus which then damages or kills the cell.

This causes infections within the body. The in he buildup of mucus m the throat and nose, skin rashes and fever ever occur as your yo immune system fights the virus.

Medicine can help you feel better or the flu, but er if you have a cold c to get rid of the virus for good, it’s up system. That’s p to your immune im why it is important to keep your so it can fight the our body in top shape s viruses on its own.

1 05

Human Senses

ed u

Eyes are the sense organs for the sense of sight. Light passes into the eyes and travels as electrical signals in nerves to the brain. The brain interprets the signals as images.

Re ga l

Ears are the sense organs for the sense ense of hearing. Sound waves enter the ears ea causing parts in the ear to vibrate. ate. The vibrations travel as electrical signals ignals along nerves to the brain. The brain interprets the signals as soundss of different volumes and d pitch. pitch

Skin is the sense e organ for the t sense of touch. When n skin comes come in contact with an object, ect, signals travel trav along nerves to the brain. The brain interprets b the information nformation and an responds.

106

ion

People have five senses that take in information about the world around them. The information is sent along nerves to the brain where it is interpreted and processed. The brain uses the nd. The processed information to instruct the body how to respond. five senses are sight, smell, hearing, taste and touch.

le du ca

tio n

The brain is the control center of the he body. It constantly receives, processes esses and interprets information from m the sense dy’s response. respons organs and controls the body’s ent and the th The brain controls movement regulation of body systems. stems.

The nose is the sense ense organ orga for the sense of smell. Receptors eptors in the nose detect odors and send along nd the information in nerves to the brain. The Th brain interprets the information tion as a smells.

The tong tongue and mouth are the sense organs for the sense of taste. Special cells on the tongue, called taste buds, respond to different types of taste. Information about taste travels along nerves to the brain where they are interpreted as sweet, salty, bitter, sour and umami tastes.

1 07

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. skeletal system joints muscular system blood vessels circulatory system

respiratory system inhale exhale diaphragm digestion

digestive ve system excretory tory system nervous system syste immune mmune system syste

1.

The

2.

The internal network of bones make up the he

3.

ect you from getting sick and The cells, tissues and organs that protect . help you get well make up your

4.

The removal of wastes from the e body is the primary function of the .

5.

d is broke The process by which food broken down and absorbed into the blood . It is the he primary prima function of your . is called

6.

e in, you yo When you breathe you .

7.

Inhalation and exhalation occurs when a muscle below the lungs, called xhalation o the , contracts contract and relaxes.

8.

The

9.

Bones meet at points called of our bodies. different parts o

10.

0.

are a network of tubes through which blood flows. These, along with blood and the heart make up the alon .

11.

Your nerves, spinal cord and brain make up your

1 08

delivers and removes different nt gases fro from the body. .

. When you breathe out,

consists onsis of all the muscles in your body.

which allow us to bend

.

Review What characteristics of bones make them suited to their function? ction?

2.

Use the chart to describe the function of each body system em when you compete in a bicycle race.

Re ga le du ca tio n

1.

Body System

Function o

skeletal

muscular

respiratory digestive

3.

What is the primary function off the heart? hea

4.

Describe two functions of the respiratory espiratory system.

5.

Name and describe the function each organ. List the body system nction of eac it belongs g to.

(a) a)

(b) b))

(c)

(d)

(e)

(f)

1 09

Ecosystems

n

5

How do organisms nisms in an ecosystem interact with each nteract wi other and their surroundings? surro

R

ed

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

ca ti

Go Online!

110

uc a

How does energy flow through ecosystems?

Re ga l

In this chapter pter you will ...

• describe and d provide examples ex of different types of ecosystems.

ecosys • describe how ecosystems are organized and the interactions ke place within them. that take

de ribe how energy flows through different ecosystems.

• describe se mode • use models to describe how energy in animals’ food (used for bo body repair, growth, motion and to maintain body warmth) was once energy from the Sun.

111

What Is an Ecosystem? em?

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In a rainforest, there is a great diversity ersity of of organisms. There are many different erent kinds kinds of of ant trees. trees. Hiding tr Hiding plants, from tiny mosses to giant nd d many many different differe amongst the plants you’ll find lso ffungi ungi g rowin on kinds of animals. There’s al also growing the forest floor or attached ed to to logs logs and and tree trunks.

Did You Know?

All of the living things in led an ecosystem are called biotic factors. All of the non-living thingss are calle called abiotic factors.

There T here are also many non-living things in a such as air, water, rocks and soil. rrainforest, ainf Allll of the organisms and non-living things in a A rrainforest along with the interactions between them, make up a rainforest ecosystem.

An ecosystem is group of organisms that live and interact with each other and with the non-living things in a specific environment.

112

ati on

Think Deeply Dee

What organism organisms can you spot in the rainf rainforest? How do the organisms interact with each other and their environment?

R

The organisms in n a given given ecosystem ecosystem live in different places. ess. In n a rainforest, rainforest, there the are leeches and insects crawling inse ec cts c rawling on on the moist rainforest floor. flloor. Fish Fish and and frogs an frogs can be found in and around ound streams. strre st eams. Monkeys Mon and birds move from from tree tree to to tree tree high hig up in the canopy.

The place lives within an place where where an an organism org ecosystem An organism’s osystem iiss called calllle led a habitat. h abitat p ab rovides itit w i all of the things it needs habitat provides with to to survive. survive.

AB

Activities 5.1 – 5.2 1 13

Ecosystem E tem m Interac Interactions All ecosystems ysstems have hav ve living ve liivin v and non-living components with each other so on ne ne ent nts ts that th ha att interact inte inte er that the as a whole. th he system sy system em functions func fu c Fro ogs are are e organisms orga org gani Frogs found in a pond ecosystem. e cosystem. osystem. The T Th h frogs interact with the insects and and other other small ot sm animals they eat for food.

They y iinteract in ntera with plants when they use them for fo shelter te from predators. Birds and snakes preying pre reyi on frogs are interactions too.

114

Think nk Deeply

ca tio n

Frogs also interact with the non-living parts of the pond ecosystem. They take in oxygen from the air through their lungs and skin. The water in the pond provides the frogs with a place to live and reproduce.

The interactions between the components in an ecosystem keep the whole system in balance. When a component of an ecosystem changes, the ecosystem as a whole can be affected. If the water in a pond was to dry up,, there th here would would be e no no place place e for frogs to live and an nd reproduce. rep produce. With Witth no no ffrogs, rog gss, there would be fewer fe ewer birds. ssnakes nakes and d bir rds.

Discusss how the co components in a pond ond ecosystem ecosyste would the water be affected if th polluted. becomes ecomes comes pollu poll pol u d

1 15

A Closer Look

Ecosystem Organization

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To study different parts of an ecosystem and to better understand the interactions between organisms e and the environment, scientists organize ecosystems into different levels.

eg a

The simplest level is a single organism, called an individual. In an African grassland, land nd, a single antelope is an example of an individual. All of the organisms of the same kind within an ecosystem are called ca alle ed a population. All of the same kind of of antelope in the African grassland up d make make u ma p a population. Organisms within a population populat lation interact and reproduce together. her.

116

In the African grassland, there he ere are are populations populat popula of many other pullattion pulations ns of of acacia aca aca organisms. There are populations trees, termites, y others. othe hers. All Alll of of the th h populations in an zebras, lions and many communi nity. ecosystem make up a community.

The community and with the non-living and the the interactions th inter int eract cti components of their make up the ecosystem. heir ssurroundings urr rroundi The interactions on n between een the the gazelles, zebras, lions and other organisms with with the tth he e air, soil, il water and other non-living things make up the ecosystem. th he African African frican grassland g

1 17

Wetland Ecosystems Did You Know?

Wetlands are often located between a source of water and dry land. They help to maintain the level of water while also protecting the land from flooding.

nd that A wetland ecosystem is an area of land is covered in water for part or alll of the he year.

Wetlands can contain fresh water ater or salt water wate wa and are often found in low-lying ying areas near lakes and rivers.

The water-covered soill in n a wetland is i often rich in minerals which grow. h helps elps plants plantts g Wetlands have a rich ch diversity off plants p growing in and around round the edges edg ge of the water.

R

Wetlands are important for many important habitats habi kinds of vertebrates. great tebrates. A g rea variety of birds re can be found und in in wetlands wetland nds which provide them with food, od d, a safe safe place pla ace to reproduce and a place during p lace tto o rrest est du d urring rin ing migration. m gr

spoonbill spoonb

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Fish, amphibians and snakes are also common wetland animals.

ca t

moose

As the amount of water in a wetland and changes changes from season to season, the type e and and diversity diversi sity of organisms can change. When hen the the wetland wetland is at its driest, plants may die e and and there there are are fewer animals. During the w wet plants et sseason, eason, p la grow back and animal diversity also ersity a lso iincreases. nc

Re ga l

Why does the diversity o of organisms g ms in a wetland throughout wetlan nd often ften change chan chang c ange th the year? r?

freshwater carp

Go Online!

Head to the NGScience website to watch a video about wetlands.

QuickCode: Y6Y6

red-eared turtle

AB Activity 5.3

1 19

macaw

Tropical Rainforest orest est Ecosystems Forests are ecosystems ysstem ms with with h tall ta tallll trees and an undergrowth. Tropical Trop pical ic cal rrainforests ainfore are dense forests close to They are to the the Earth’s Earth’s equator. eq warm and moist and receive moist all all year year round ro nlligh ht – although although much of the lots of sunlight sunlightt is is blocked b lo ock ck ked by by a thick canopy.

In tropical opical cal rrainforests, ain nffores there are usually only wo sseasons eas aso onss – a wet season and a drier two green leaves all sseason. easo so on. Plants Plantts have Pla h year y ear round. rou und.

Tropical rainforests are off al allll T ropica cal ra rain nforessts a re the the most most diverse diverse o lland la and ecosystems. ecosy ystem ms. The single singlle largest largest rrainforest ainforest in in the th he e world, world, the the Amazon, Amazon, is home ho ome to to about about 10 10 percent off a allll known pe p ercent o know wn organisms. organisms.

red-eyed -eyed d treefrogs

Why are rainforest ecosystems home to such a variety of organisms?

120

Tropical rainforests have a great diversity of plants. Tall trees form a dense canopy that blocks much of the light from reaching the forest floor. Under the canopy is a layer of shorter trees and shrubs. Mosses, ferns and orchids can often be found attached to trees.

uc a

A warm, moist environment with a great variety of plants makes rainforests the perfect ecosystem for many different kinds of animals.

There are spiders, leeches and all kinds of of insects. There’s a great variety of mammals, mmals, birds, reptiles, amphibians and fish too. oo.

spider monkey

Go Online!

Head to the NGScience website to watch a video about rainforests.

QuickCode: Q4E3

Amazing Fact!

Leopards are the only big cats that can be found in dry deserts and moist tropical rainforests. They spend most of the day resting, camouflaged in trees and are active predators at night.

AB Activity 5.4 leopard

121

great horned owl

Temperate T emperate fforests or are ecosystems with enough nough rainfall rainf and sunlight for tall trees to grow. They They also have a diverse layer of grass, sshrubs, h fferns and mosses on the forest floor.

T empe Temperate forests are generally cooler than ttropical ropical rrainforests.

eg a

Go Online!

Tem Temperate mperate p perate erate e Fores Forest Ecosystems

Head to the NGScience website to watch a video eo about temperate forests. ests QuickCode: Y4Y8

T emp Temperate forests usually have four distinct sseasons ea – summer, fall, winter and spring. The changes in weather from season to season c affects the organisms in the ecosystem.

In fall, the weather begins to cool. To conserve energy, the leaves of some trees change color and fall to the ground. They grow back when the weather warms as spring approaches.

During winter, some animals leave the ecosystem and return in the spring.

122

ca t

Temperate forests are home to a wide variety of mammals, including bears, squirrels, deer and rodents. The high branches and hollows in trees provide a safe place for many birds to live and raise young. There’s also a variety of invertebrates including snails, spiders, cicadas and beetles.

Re g

squirrel

In what ways are a temperate forest a tropical rainforest? different from fr ways are they similar?

In what w

AB A Activity 5.5

grizzly bear

123

ati o

hawksbill sea turtle

Amazing Fact!

The ocean is a large e body o of salt water that covers more than percent of the Earth’s an 70 perce surface and gives the Ea Earth its deep blue color.

Within the e ocean are a range of different ecosystems. depth of the ocean ms. The average a is over 3.5 Most organisms can be 5 kilometers. kilome nd at depths of less than 100 meters. At this found th, sunlig depth, sunlight can reach plants like seagrasses so they hey can photosynthesize.

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Some animals in coral reef ecosystems have venom to kill prey. The blue-ringed octopus is less than 20 centimeters in length, but contains enough venom to kill 25 adults. The blue rings on its body glow brightly before it bites and injects venom into its prey. p y

Coral Reef Ecosystems cosysstem stem ms

moray eel

1 24

du ca t

grey reef shark ark

seagrass

anemone fish a

Th most diverse ecosystems in the The ocean are coral reefs. Corals are small animals that stay in one place throughoutt ether their adult lives. They usually live together in groups called colonies. The colonies ies form large reefs.

Coral reefs provide many placess for d food. animals to seek shelter and find They are home to a great variety ety of fish, fish h to giant reef from tiny anemone fish sharks and rays.

Re g

There are lobsters, clams jellyfish. ams and jel There are marine reptiles ptiles like sea s turtles and sea snakes.

Why are coral reef ecosystems e home to such uch a variety of animals?

AB B Activ Activity 5.6

Go Online!

Go to the NGScience website and take a virtual field trip to the world’s largest coral reef – the Great Barrier Reef in Queensland, Australia.

QuickCode: U6A9

125

Energy in Ecosys Ecosy Ecosystems All of the organisms orrganis nisms in in an an ecosystem ergy. Some Some e make mak food through need energy. sy ynthes hesis. Some S Som om me eat other photosynthesis. nismss. Others Others b Oth organisms. break down the mains of of dead plants p remains and animals. How an gets its energy determines n organism org rganism anissm get tthe he role it plays play ays in the ecosystem.

Re g

Producers, Consumers and Produce Deco Decom Decomposers

Think k Deeply

In most ecosystems, all of tthe energy can be traced back ba to the Sun. Why is this so?

1 26

n organism or An that makes food through photosynthesis is called a producer. In mo ecosystems, plants are the main most producers.

They use light energy from pro od th Sun, carbon dioxide from the air and the water to produce food in the form of sugar.

An organism that gets energy by eating other organisms is called a consumer.

All animals are consumers. They get the energy they need by feeding on other organisms in the ecosystem.

Check out the he ‘All About Fungi’ video on the NGScience website. ience web QuickCode: R7D R7D5

R

AB Activity 5.7

Go Online! e!

tio n

Some organisms meet their energy requirements by breaking down, or decomposing, the remains of dead plants and animals. They feed on the broken down material. These organisms are called decomposers. Bacteria and fungi are decomposers. Decomposing releases nutrients back into the ecosystem.

Wha role do decomposers What play ay in an ecosystem?

127

Types of Consumerss T

ca tio n

C Consumers can be classified d into to three thr main groups based on the m e organisms ganisms they eat. t Animals that eat only plants or the products of plants lants are called herbivores. Grasshoppers, rasshoppers, sshoppers, sq ssquirrels, horses, antelope, and ope, giraffes an elephants are herbivores. B Butterflies feed on the by flowers, he nectar ctar produced produc produ too. sso butterflies flies are herbivores herbivo herbiv Animals other animals are A mals that at eat oth called c ed carnivores. carnivores arnivores Big cats like lions, are carnivores. ttigers gerss and cheetahs cheeta chee sharks, snakes and eagles are Spiders, shark S sharks too. carnivores arnivores to

1 28

Some animals eat both plants and o other therr animals. They are called omnivores. re es. es Omnivores can eat algae and fungi un ngi gi too.

Many birds are omnivores. Ostriches ches eat eat at plants and grasses. They also eat small insects and lizards. Bears are omnivores omnivore omnivo ores too. In some months they hey huntt for salmon ssalm alm and deer. At other times mes they th eat leaves, ea berries and mushrooms. ooms.

R

Some reptiles are omnivores. mnivores. Box tturtles eat fish, frogss and animals. d other other small sma all a n They also eat berries flowers. berries and flow

AB

Think Deeply Mosquitoes feed on different things at different stages of their life cycle.

Mosquito larva feed on microorganisms in water.

Many adult mosquitoes feed on flower nectar. Adult female mosquitoes feed on the blood of animals to help them produce eggs. As a class, discuss how you would classify mosquitoes as consumers.

Activities 5.8 – 5.9 129

Food Chains

R

a

ati on

All of the organisms in an ecosystem m need eed energy from food. This energy can n be e traced back to the Sun when producerss use its ts light ligh energy to photosynthesize. The e energy nergy is passed pass pas to herbivores and omnivoress when they e eat the producers. Energy passes to when o carnivores w they feed on other animals.

Decomposers get als. s. Decompose Decompo energy when they break of ak down own the remains rem other organisms.

The Th acacia tree is a produc producer.

130

The giraffe is a herbivore.

al ed uc at

This energy pathway from the Sun to producers ers to consumers and decomposers is called a food chain. There are usually many food chains ns in an ecosystem.

In a food chain diagram, arrows are used d to show the direction of the flow of energy. In n an African savanna food chain, acacia treess use e the energy from the Sun to make food. Energy ergy is passed to giraffes when they use their long ong necks to feed fee fe on the leaves of the acacia trees. to ees. Energy is passed pa lions when they prey on the giraffes. affes.

AB Activity 5.10 0

Go Online!

Learn about the food chains in other ecosystems on the NGScience website.

QuickCode: R4W4

What are some other food chains in an African savanna ecosystem?

R

The lion is a carnivore.

1 31

Food Webs

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A food chain shows one energy pathway in an ecosystem from the Sun, to a producer and to a consumer. In all ecosystems, there are many overlapping food chains. A food web shows how all of the food chains in an ecosystem are connected.

As in a food chain, the arrows in a food web show the direction of the flow of energy.

gazelle

al

giraffe raffe

acacia

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uc ati o cheeta heetah cheetah

lion

wildebeest

eg al

zebra

grass g rass

Think Deeply What other animals can be found in an African savanna?

Where would they fit in the food chain?

AB Activity 5.11 1 33

A Closer Look

An Arctic Food Web

tio

Not many plants are able to grow in the cold, and often dark, Arctic ocean water. Producers in this ecosystem are tiny single-celled, photosynthesizing organisms called phytoplankton.

ed u

leopard seal

Arctic c Arct cod

baleen whale

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seagull

silverfish

These organisms provide food for a great diversity of animals. From tiny zooplankton to giant whales. Energy is passed on to other Arctic ocean predators when they feed on other animals.

ed uc ai

polar po pola p olar la ar bear bear a

Re ga

walrus

orca

krill

phytoplankton phy phytopla

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In the Field

Ecologists eb eing If you love plants, animals and the great outdoors, you’ll love being an ecologist. An ecologist is a scientist that studies the e relationships relatio onships between all of the organisms in an ecosystem and their heir eir interactions in nteractions with the non-living things around them. Ecologists measure man many m an ny aspects of an ecosystem such as the number off organisms anisms in n each e population. They measure the non-living thingss ttoo, oo, such as air and water temperature and the condition of the soil. so oil.

An important role of an ecologist is to observe serve ve the impacts imp pac of changes to the ecosystem on the organisms thatt llive Such ive there.. Su S uch changes may include climate, natural disasterss or or the the addition addition or removal of a population within the ecosystem’s community. ommunity.

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d eg a

1 37

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. ecosystem habitat individual population community

producer consumer decomposer herbivore

carnivore re omnivore ore food ood chain chai food web

1.

A

2.

All of the populations in an ecosystem make ake up a

3.

n an ecosy All of the organisms of the same kind in ecosystem form . a

4.

A model that shows one energy the Sun to producers to y pathway from fr consumers and decomposers iss called a .

5.

is a model that hat shows show how all of the food chains in an A ecosystem are connected.

6.

A

is an n animal anim thats eats other animals.

7.

An

eats ats both plants pla and other animals.

8.

breaks dow down the remains of organisms and feeds on the A broken down n material. materia

9.

A is an org organism that makes its own food through photosynthesis. ynthesis.

is an animal that eats only plantss or the pr products of plants.

is an organism that gets energy by eating 10. A other organisms. organ

138

.

The place where an organism lives within an ecosystem is called its .

Re ga le du ca tio n

11.

.

12.

A single organism in an ecosystem is an

13.

is a group of organisms that live and interact with each e other and with the non-living things in a specific environment.

Review

1.

Provide an example of an individual, population on and com community in a forest ecosystem.

2.

What is the difference between a community mmunity and an ecosystem?

3.

Copy and complete the chart. In n the last row, add a an ecosystem in your local area.

Ecosystem

Characteristics aracterist

Organisms

Wetland

Tropical Rainforest Temperate Forest est Coral Reeff

4.

Provide an example of a producer, consumer and decomposer in a temperate ecosystem. ate forest ecosy

5.

make a food chain diagram.

Use U e the e Sun a and organisms below elow to ma

lio lion

6.

grass

zebra

Sun

What is the difference between a food chain and a food web?

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Re ga le du ca tio n © Blue Ring Media Pty Ltd ACN 161 590 496 49 2013 - 2021.

This publication possible without the tireless effort of our production team. cation would not have been pos Speciall thanks to: Matthew hew Cole, Daniel Cole, Wang Hui Guan Joseph Taylor-Pritchard, Sophie Taylor-Pritchard, Tejal Thakur seph Anderson, Halle T Taylor-P Varasinun Mathanattapat, Kanungnit Pookwanmuang, Saijit Lueangsrisuk Natchanuch Nakapat, Va Varasinu

Original Illustrations: Natchanuch Nakapat, GraphicsRF, Blue Ring Media and Interact Images Illustra Na Royalty-free images: Shutterstock, Adobe Stock imag S