Let's Do Science 3 – Text Book A by Regal_Education

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P mary 3 Prr i ma 2 Textbook

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.

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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gre

Charact

Fish are anim live in the oc can also be such as stre

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.

Most fish re some give b

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.

Ecologistt

n and ms an isms rrts of organisms orts or alll so al n all d iin ed ted erested eres ter te nterested nteres e iinteres ou are you If yo he hen ent,, tthe environment envir heir environment he th the n their hin hin th ithin within ct with c act ract erac eract nteract in y int ow they how h o ologist. ologist. ecol e be an eco o be ke tto ke you’d like yb yo aybe maybe

on ons eractions eracti nteracti nt int their in nd their and ngss a ng ings things g th ing l ing lilivi off liv ty o munity mmunity A comm tem. tem tem. ystem ys sys o osys cosys c co ec ca ed an e call ent is called ment nm onm rron iron nviro nviron environ ir e h their th with with wi ese hes th ess these ies die tud who stud st w ientist cient scie sci scientist is a sscient st is ec gist eco n ecologist An s.. ms. ems. em e tems. c cosystems ecosys eco ec e ecos and ons a ractions erac e interacti of interacti ange o range ra e ran dy a wide ud ttudy stss stu iists gist log olog colog Ec Ecolog ma m ey may em. The o stem co cosyst ven ec v given n a given hin with sh s wit nship nshi nsh onshi tionship atition rela re relati all small a sm such as m such tem y tem osys cosy eco an ec arts of an mall parts small smal sma y sm study e ge ag d lar udy a so stu y al ey may The Th oil. The so e soil. tthe g in th iving iv lliving ugss liv ugs bu bugs n an ocea the ocean ns in the ation a lation p la popu hp a fisssh ch as uc u uch su ctionss such e actions teractions ntera intera her here. atmosphere. th atmosp ct the ffec efffec eff rests ef ores or o orests nffforests nforests rainf ho rainf or how or

Engineer It!

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

A Closer Look Graphing Weather

Scientists are e con onstant onstan antly ntltly co collec e ng data about the ecting ectin weat w Th They he ather ather. ey o ofte ften create create tables tables and grap aphs to em un underrsstand sea onal sseaso nal chang ta cha es in weather. Tables help them ables an and charts are also a way to t comm useful us ommu unicate we weather inf i forma matio tion n to pe people. 133 Let’s t’ take ake a look at the yearl ye y chang ges es in weath weat er for Franci ancisc San sco, o, U United nited States.

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Average Daylight Hours – San Francisco Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 10 11 12 13 14 14.5 14.5 13.5 12.5 11.5 10 9.5

120 mm

Average Precipitation

– San Francisco

100 mm 80 mm

In the Field

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

A Closer Look

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

60 mm

40 mm

20 mm 0 mm

Jan

Feb Mar Apr May Jun

Jul

Aug Sep

Oct Nov Dec

Amazing Fact! Interesting facts to bui build interest and enthusiasm. nthusiasm.

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fish gills

stingray

eat white shark

Fish have body parts well-adapted to life in water. They have gills to take in oxygen from the water. They have fins and tails to help them swim.

teristics of Fish

mals that live in water. Most fish cean, which is salt water. Fish found in freshwater habitats, eams, rivers and lakes.

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

‘fish’ in its name. Do you think a starfish is a fish? Explain your answer.

Like reptiles and amphibians, fish are cold-blooded.

eproduce by laying eggs, but birth to live young.

Did You Kno Know?

Think Deeply

Try This!

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

Science Words

Use the words to comp lete the sentences. mammals metamorphosis fish insects pupa 1.

Review

oxygen invertebrates amphibians larva chrysalis

Animals need a specia l part

vertebrates birds reptiles caterpillar

of air called

Animals with a backb one are Animals without a backb one

are animals with a body covered in fur. They give birth to live young.

5. 6. 7. 8. 9.

are called

are the only animals with

are cold-blooded with

A change in body form

a body covered in feathe rs.

a body covered in scales

Frogs and salamander s are

or plates.

. They have smooth, moist

during g an animal’s l s life cycle

live in water and have

List three vertebrate anima als. l

List three invertebrate

How are mammals differe d nt from m most other animals reproduction? in terms of o

2. 3.

called

List the needs of anima ls.

is called ll d

gills to help them take

an animals.

List the characteristics so of birds.

List four kinds of reptile s.

How is the life cycle of

List the he characteristics h

Descri escrib be e insect insec s in term terms of their

birds similar to that hat of

10. Classify the he animals as either

skin.

(a)

reptiles?

of fish.

number of legs and body parts. .

(b)

in oxygen.

Discussion

(d)

15oC 10oC 5oC 0oC

How does the weather change throughoutt tthe year in San Franci cisco? s

Avera ve ge M Maximum Temperatt ure – San Franc Fr isco o

25oC 20oC

Jan

Feb Mar Apr p May Ma Jun

J Jul

Aug Sep p

Review

Oct Nov Dec

Activities 9.7 – 9.8

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

verteb v rates or invertebrates

(c)

AB Activity

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

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

Science Words

Lists the essential science vocabulary covered in each chapter.

Contents

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Unit 1 - Living Things Around d Us What Are Living Things? Needs of Living Things Classifying Living Things Review

Unit 2 - All About Plants

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Plant Needs Plant Parts Classifying Plants ants Review

Unit 3 - Alll About Animals Needs Animals eeds of A An Classifying Classifyin Animals Vertebrates Verte Vertebra Invertebrates The The Circle of Life Th Review Re

4 9 13 14

16 18 20 26 35

36 38 42 44 66 75 77

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Unit 4 - Inheritance and Traits Heredity and Traits Behavioral Traits Environmental Traits Natural Selection Review

Surviv Unit 5 - Adaptations for Survival What Are Adaptations? ptations? tations? Living in Groups ps Chang ng ge ge Surviving Change Review

Unit 6 - Organisms rganism of the Past Life on Ear Earth Long Ago Eart Fossils Foss R i Revie Review

80 84 86 88 91

96 114 122 130

136 138 142 154

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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.

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

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.

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

Why does warm rm water waater ate ter cool fasterr in a m met metal e l cup than inn a foam foam cup? ccuup? p?

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 It re than just a guess. gu g is a statement based sed on knowledge knowled you 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 cedure ure and repeat 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.

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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Living Things Around Us

In this chapter you will ...

• list the characteristics of living things. • list the needs of plants and animals.

• understand that all living things are made up of one or more cells.

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isms. • list the four main groups of organisms.

How w can you tell th that something is a living thing?

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What do plants and animals need to live and grow?

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

How can we organize living things? and classify cla

What Are Living Things? ngs There is a great diversity of things around und us. Some are living things. A living thing ng iss called an n-living. g organism. Other things are non-living.

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Try This! Predict how much you think you will grow in one year. Measure and mark your height on a wall once a month. How accurate was your prediction? In what other ways do you change as you grow?

How can we tell which ch things are living and which are non-living?

Activity 1.1

Growth

Look at a photograph ograph aph of when you were one or two years old. d. How ow have you yo changed since you were a baby? by? e a living thing and a like all living things, you You are grow as you get older. olde A newborn wborn kitten grows as it gets older. It gets taller. As an adult cat, it will produce bigger ger and ta talle new ew w kittens of o its own.

A young kitten n gets ts larger and heavier avier as iti grows into an n adultt cat. ca

Activity 1.2

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Sunflower seedlings get bigger and taller as they ey y grow. As adult sunflower plants, they will develop elop p seeds and produce new sunflower plants.

Response to Change

sunflower seedlings

Living things respond to changes around ound d them. Some plants bend their leaves to face ace ce the sunlight. Other plants, like the mimosa mosa a plant and Venus flytrap, close their leavess in response respo esponse nse to touch. The leaves of an oak tree ree change ange e color colo and fall to the ground in response ponse nse to changes cha ang in ang seasons and the weather.

Animals respond to changes too. hanges ange around nd them t Kangaroos may seek hot days in the ek shade ade on h Australian bushland. senses d. When a meerkat meerk mee danger, it will respond to its burrow. spond d by retreating retrea

Activities vities 1.3 – 1.4

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Living things move. ove. Animals mo move from place to place in search from danger. ch of food or to flee f nts move ve their the parts p Some plants in response to T Venus flytrap closes changess around them. The its leaves ves to catch small sma insects.

her plants ants move their stems, leaves or flowers Other o follow llow the mov mo to movement of the Sun.

Think k Deeply

A car can n move from place e. Explain why a car ca to place. is not a living thing.

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Reproduction

All living things reproduce. To reproduce means to produce new young of the same kind.

An adult lion will give birth to lion cubs. ubs. bs. An adult chicken will lay eggs from which h baby y chicks will hatch.

An adult tomato plant has flowers lowers ers and fruits. fruits. Under the right conditions, the seeds inside the insid ins th he fruits will fall to the ground and into g d grow g int new ew w tomato plants. Why is it important rtant that all a living things are able le to reproduce? reprod

Some living things, such as bacteria, are made up of only one cell. They are called unicellular, or one-celled organisms.

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Did You Know?

Cells

All living things are made de up of tiny tin building blocks called cells. s. Most ost cells are too small to see using only yourr eyes. observe cells, scientists es. To observ use a microscope. is a scientific cope. e. A microscope micros microsc instrument that is used to closely c observe very small objects. ects. Most organisms made up of many different anisms are m types cells help the es of cells. The different d organisms ways. rganisms nisms in different diffe

onion skin cells

AB 8

Activity 1.5

Needs of Living Things Another way you can tell if something is a living thing is by looking at the things it needs. All living things need food, air and water. Different living things get what they need in different ways.

Food Food gives living things the energy they need to grow and carry out life processes. Plants use air, water and the energy in sunlight to make their own food. This food-making process is called photosynthesis.

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Plants store the energy they make in different parts. This energy is passed sed to animals when they eat those plant parts. par Other animals get the energy they ey need by eating other animals.

Water All living things need water. ater. Many animals drink water. Others get water from the th food they eat. The water helps animals imals to break down and transport food inside nside their bodies. b Plants take roots. The water is ke in water through thro used in photosynthesis. hotosynthesi It also helps to transport food, nutrients rients and minerals within the plant.

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Oxygen and Carbon Dioxide

Air is a mixture of different gases. To make food, plants need a gas in air called carbon n dioxide. They take in carbon dioxide through ough small openings found mostly on the he underside und d sid ders de off de their leaves.

When plants make food, they also o produce roduce a gas called oxygen. The oxygen leaves plant lea aves es the plan pla ant through the openings in the leaves. eavess. Oxygen is the part of air needed ee eded eded d by b people and animals. Many an land and animals get the oxygen en n they they need by breathing in n air using using lungs. Many aquatic tic animals, animals nimalss, such as fish, have ve gillss that help them take e in oxygen from water.

Gases enter er and exit a plant through h tiny openings found f mostly tly on the underside undersid of leaves.

What will happen to an organism if it does not get org enough food or water?

Amazing Fact! Every year, about 25,000 humpback whales swim thousands of miles from the icy waters of Antarctica to the much warmer waters of Queensland, Australia. In the warmer waters, they give birth to young before making the return trip to Antarctica.

A Place to Live ve All organisms need d a place to live. Animals need a place that provides vides them with all the food, water and oxygen n they need. The place an animal lives ves also keeps them safe from danger and provides with a safe space to raise des them wi their young. ng. Some animals, like a frog or fish in a pond, only need a small place to live. Others, such h as humpback humpba whales and grizzly bears, d much larger l need places to live.

Plants need a place to live too. They need space for ttheir roots to spread out and take in minerals water. The need a place with enough and w sunlight to photosynthesize. sunli

Activities 1.6 – 1.7

Classifying Living Things Go Online! e!

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There is a great variety of living things around us. Plants fill our parks, gardens and forests. Animals, big and small, can be found all over the Earth, underground and underwater too. There are also many living things that are too small for us to see!

Watch a video eo about ab cientists classify class how scientists organisms into groups on the NGScience web website. QuickCode: G8S6 G

To organize and learn more about different types of organisms, scientists classify them into four main groups – microorganisms, fungi, gi, plants and animals.

AB A

Microorganisms

Fungi

Plants

Animals

Activity 1.8

Mak a list of some organisms found in your local Make area. How can you classify them into groups?

Science Words

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Use the words to complete the sentences. organism respond reproduce

cells photosynthesis

carbon dioxide ide oxygen

To help them survive, organisms

All organisms are made up of one or more

rocess of Plants make their own food through the process

All organisms produce new young of their they heir own, th

A living thing is also called an

Plants take in of their leaves.

em to take tak in Fish have gills that help them

to changes hanges around aro them. .

through gh holes found f mostly on the underside

from water.

Review

True or false. (a) Plants take in and give out oxygen. n carbon dioxide d (b) All organisms as they get older. isms grow a (c) Only organisms that can move from place to place are living things. rganisms th

List the things plants ne need in order to carry out photosynthesis.

use to observe the cells that make up all organisms? What can you u

4..

What hat must the place an organism lives have?

List st the four main groups of organisms.

A Closer Look

Fungi

ca t

Mushrooms are similar to plants in some ways. They often grow in soil or are attached to trees, and they don’t move about like animals. In fact, up until about 150 years ago, scientists classified mushrooms as a type of plant.

Mushrooms however, are not able to photosynthesize. They get the energy they need by breaking down dead or living plants t and animals. As such, scientists now classify y ms mushrooms into a special group of organisms called fungi. Other types of fungi include brackett fungi, puffballs and molds.

Go Online! Discover more about fungi on the NGScience website. QuickCode: E6G3

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All About Plants

In this chapter you will ... • list the needs of plants.

• list and describe plant parts and functions. ons.

• describe the life cycle of a flowering pla plant.

What ar are the needs of plants? How do tthe parts of a plant help it to get the things it needs to survive? thin

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

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

Plant Needs

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Plants come in all shapes, sizes and d colors. ors. They Th live in all areas of the Earth – from m lush, sh, tropical o live on rainforests to icy tundras. Plants also e a plant lives is its and in water. The place where ent provides a plant p environment. An environment with the sunlight, water, airr and nutrients iti needs to live, grow and reproduce. uce. e.

Think Deeply

Deep inside a cave is one place you will not find any plants. Why is this so?

Carbon Dioxide de

Air is a mixture off different ferent gases. gases gase To make food, plants need a gas in n air called carbon dioxide. They take in carbon small n dioxide through t openings found ound mostly on the t underside of their leaves. es. When they also produce a n plants ants make food, fo gas called The oxygen leaves the plant d oxygen. T through in the leaves. thro rough ough h the th he openings openi open How is gas exchange different in plants and animals?

Water and Nutrients Try This! his!

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All plants need water to survive. They take in water through their roots. The water travels from the roots, through the stem to the leaves. In the leaves, plants use water to make food. When plants take in water, they also take in nutrients from the soil. Nutrients are substances dissolved in water. They help the plant to grow and stay healthy.

You know that hat all plants need water. What do d you think happens if a plant water? gets too much w investigation to Conduct an inv find out.

Light

You have learned that plants need carbon on dioxide from the air and water to make e food. od. This process of making food is called photosynthesis. tosynthesis hesis. The word ‘photo’ means light and the he word ‘synthesis’ means to put together.. That’s at’s exactly what plants do! They use the energy nergy y in light to combine carbon dioxide and water to make food. Without light, plants would ould d not be able to make food and would not live ive and grow. grow

Think Deeply

A vegetable garden is an environment for plants made by people. What things do people have to do to make sure the plants grow and stay healthy?

Space to Grow w

All plants need a space pace e to grow. Some So plants are e together. gether. Other Othe plants p able to grow close need row too close cl more space. If they grow together, nts may not get eno individual plants enough sunlight. eno There also may not be enough water and nts to grow. nutrients for plants

Activity 2.1

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Plant Parts Try This! Make a list of the plant-based foods you eat in a week. Group the foods by the part of the plant they come from.

Plants can be found in almost most all areas of the Earth. They come in all shapes sizes. So far, apes and size siz scientists have identified ed about bout 390,000 390,00 types of e the same b plants. Most plants have basic parts. tems and leaves. leave They have roots, stems Many plants also so have ave flowers and fruits. Each plant part plays ays an important importan role in helping the he things ngs it needs need to survive plant get the and reproduce. oduce oduce. e

How do the parts of a plant help it to get the things it needs to survive?

Roots Roots are the plant part that usually grows down into the soil. They often branch out in all directions or grow deep underground.

Re ga le du ca t

The roots hold the plant firmly in the ground. Tiny structures on the surface of the roots, called root hairs, take in water and minerals from the soil.

Stems

The stem is usually the part that holds up p the plant. The water and minerals taken in n through through ugh h the roots travel through the stem to the upper up parts of the plant. By holding up the e plant, the ore sunlight. stem also helps leaves to take in more

Leaves

re the food-making food- aking The leaves of a plant is where om ma od, plants od pla s need process takes place. To make food, the energy from sunlight. ight. ht. Many Ma plants have leaves that are wide e and nd flat. This gives g ves them a a which hich enables enable them th hem to take large surface area food leaves le lea aves take in in more sunlight.t. To make food, carbon dioxide de from om the air. The The e food-making f process produces oduces es oxygen. The The oxygen leaves the plant through ugh the e leaves. leaves

Think T h Deeply

Som plants, such as vines, Some are called climbers. They ar have stems that wrap around and cling to the trunk and branches of trees. How does this help the plant get the things it needs?

Go Online! Observe how water and food are transported through a plant on the NGScience website. QuickCode: K8T5

Activities 2.2 – 2.4 Activiti

Photosynthesis Plants do not eat food as animals mals do. To get the energy they need ed to survive, plants make their own food through an amazing process called photosynthesis. Photosynthesis usually takes place in the leaves of plants. The large surface area of leaves allows them to absorb lots of sunlight. They also take in carbon dioxide from the air. Water taken in by the roots is transported through the stem to the leaves.

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A Closer Look

Sunlightt is absorbed by the leaves. ves

The leaf now has all the things it needs to make food. Using the energy gy ater from sunlight, it converts the water and carbon dioxide into glucose. e. The he glucose is the food the plant needs. eeds. It gives the plant the energy rg gy it needs to live, grow and reproduce.

Water and minerals are taken in through the roots.

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Small openings in the leaves take in carbon dioxide from the air.

Go Online! nline!

Get a better und understanding photosynthesis by of photosynthe watching an animation on NGScience website. the NGScie QuickCode: G6S8 QuickCod

Oxygen p produced during photosynthesis is given off ph hotosyn through through the leaves.

During photosynthesis, plants produce ven off throu oxygen. The oxygen is given through a that the leaves. Oxygen is the part of air survi animals and people need to survive.

AB Activity ty 2.5

Think Deeply

Plants are able to photosynthesize in moonlight, but they cannot produce as much food as they do during the day. Why is this so?

Flowers and Fruits its ts Try This! Go into your schoolyard and observe flowering plants. Make some notes about the similarities and differences between the flowers.

Most of the plants on Earth Earrth th produce prod duce e flowers. f Flowers are often brightly ightlly ly colored d or o produce odors to attract insects sectss and and d other oth othe her animals for pollination. Once a flower e pollination pollin nation tion occurs, occ ntto a fruit. fru ruit. A fruit frru u holds and may develop into often protects which new ts the seeds ssee eed ds from fr plants will grow. gro ow.

ga le du ca tio n

The flowers, fruits and seeds of different plants can look very different. If you look k otice very closely at a sunflower, you will notice er ers. it is made up of many smaller flowers. Each small flower develops into a hard ard fruit containing the seed. evelops ops into a A white strawberry flower develops bright red fruit. The seeds are attached to the outside of the fruit. ak trees tre produce Some plants, such ass oak h as papaya papay trees, hard fruits. Others, such produce fleshy fruits. uits.

sunflower seeds

AB Activity ity 2.6 2.

Papayas yas are e fleshy fruits.

Strawberries have seeds on the outside of the fruit.

Acorns are hard fruits produced by oak trees.

Classifying Plants nts ersity o There is a great diversity off plants around us. To To organize organize and better understand rstand plants, rs plants, we can classify y them them into into groups. They may classified ym ay be be c lassif by their appearance, ppearance, habitat habit or how they y reproduce. reproduce. Scientists S ci classify plants yp lants in iinto nto two two main groups non-flowering plants ps – n on-flower and d flowering flowering plants. plan

on-flowe Non-flowe Non-flowering Plants As As tthe he name name suggests, nonflowering flo lowerin ing plants do not produce flowers. Common types of nonflowers. C flowering flow oweri plants include mosses, ferns ferns and conifers.

cones on a conifer

fern fe

moss

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fern spores

Non-flowering plants reproduce uc ce in in different ways. Mosses and ferns ferns Co onifers have have reproduce from spores. Conifers ds from from which whic ich cones that hold the seeds w new conifers can grow.

Re ga l

AB Activity y 2.7

Amazing Fact!

The tallest plant in the world is a type of giant conifer, the sequoia tree, found in California, USA. They can reach heights of almost 100 meters!

sequoia trees seq

Flowering Plants More than 80 percent of the he plants on Earth are flowering plants. nts. Flowering plants produce duce e flowers flow lowers ers and an a fruits. They reproduce ce e from om m sseeds. eed eeds.

Amazing Fact! So far, scientists have named and classified more than 300,000 different kinds of flowering plants. Many more flowering plants have yet to be discovered.

Flowers contain a sticky stick ky powder called pollen. To make pollen ke seeds, seed ds, polle en needs to move from m one one part part of of a flower to another. Th This his process process ess is called pollination. Pollination on. Po ollinat nattion iiss often done by animalss ca called pollinators. alllled p ollinato To attr attract pollinators, ract p ollin llinato many flowering plants produce that are brightly ants p roduce flowers ro fl colored, have col olored, ed d, h ave a strong smell or contain a sweet sweet liquid liqu uid d called nectar.

uc a

white daisies

Brightly colored flowers attract pollinators like bees and other insects.

Try This! In small groups, observe the flowering plants in your schoolyard. Identify and record the pollinators you observe.

Seed Germination Flowering plants reproduce from seeds. Inside a seed are all the things needed for the seed to grow into a new plant. The outer covering of a seed is called a seed coat. The seed coat protects the seed and keeps it from drying out. Inside the seed coat is a tiny plant, called an embryo. A tiny root, called a radicle, is attached to the embryo. Surrounding the embryo are seed leaves.

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A Closer Look

Parts of a Seed ed

embryo (tiny plant)

radicle (tiny root)

seed leaves

seed coat

Try This! Do you think k seeds n need sunlight to germinate? onduc an Plan and conduct igation to find out! investigation

ca tio n

What does a seed need to start to grow? Under the right conditions, a seed will start to grow or germinate. To germinate, most seeds need air, water and warmth. The root is normally the first part to grow from the seed. It grows down to hold the seed in the soil.

Next, a shoot grows upwards. It uses the food od in the seed leaves for energy. As leaves begin n to develop, the seed leaves fall away and the he young ung plant, called a seedling, begins to make ke food od of its own.

Go Online Online!

Watch a seed germinate on NGScience website. the NGS QuickCode: uick G3Q9

AB Activity 2.8

Flowering Plant Life fe Cycle

ion

tomato seeds

All plants have a life cycle thatt ensures ens their kind continues to survive urvive e and reproduce. All of the stages tagess of a plant’s plant life make up its life cycle. cycle e. The life cycles of flowering in g plants nts are similar simi sim many ways.

al ed

The life of a flowering ering plant starts s as a seed. Under der the right conditions, con the seed will germinate. minate. Roots Roo Root grow under the soil.. A stem em emerges emerg emerge from the soil and the he seedling begins beg to develop leaves. ves. The he seedling seedli usually gets taller and nd develops evelops mo more leaves as it grows.

Go Online!

ion

Observe how w flowering flower plants grow w and change chang throughout their life l cycle on the e NGScience website. w QuickCode: kC N2D6 N2

The seedling grows into an adult plant and develops flowers. The flowers hold the seeds from which new plants will grow. After pollination, many flowers will develop fruits. The fruits protect the seeds and also help to spread the seeds to new places. Under the right conditions, the seeds will grow into new plants and the life cycle repeats.

Activities A t 2.9 – 2.10

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. nutrients leaves roots life cycle flowering plants

germinate carbon dioxide non-flowering plants environment flowers

seeds photosynthesis otosynthesis fruits ts stem pollination pollinat

To make food, plants need a gas in air called

are substances dissolved in water. ater. They he help the plant to grow and stay healthy.

provides it with the e sunlight, sunlight water, air and A plant’s nutrients it needs to live, grow and reproduce.

Water moves from the of a plant.

nts make food is called The process by which plants

Many plants have bri brightly colored olored

nto which hold and protect the Flowers develop into from m which new plants will grow.

is the process proces whereby pollen moves from one part of a flower to another. nother.

When a seed gets air, water and warmth it will w

, thro through the

to the

to attract insects.

10. All of the stage stages of a plant’s life make up its

11.

Plants that produce flowers are called

12.

nts that t Plants do not produce flowers are called

13.

Use the words to label the diagram. embryo

seed leaves

radicle

Re ga le du ca tio n

seed coat (a)

(b)

(c)

(d)

Review

List the needs of plants.

Describe two functions of the roots of a plant.

Describe the main funct function of leaves.

Where does a plant ant get the energy it needs to make food during photosynthesis?

Describe the e function of flowers and fruits.

List two non-flowering plants. o types of non-fl

of pollination. Describe the process pr

8..

How ow does a flowering plant change during its life cycle?

All About Animals

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In this chapter you will ... In this chapter you will ... • list the needs of plants. • list the needs of animals.

• list and describe plant parts and functions. • identify the characteristics of different animal groups. mal group

• describe the life cycle of a flowering plant. • develop models to describe that animals unique ls have u and diverse life cycles. NGSS: 3-LS1-1

What are the needs of plants? How do the parts of plant help it to get the things it needs to survive?

What are the stages in the life cycles of different animals?

What are the needs of animals? How do the different animals get the things they need to survive?

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

How are the needs of animals similar to the needs of plants? How are they different?

Amazing Fact! A panda’s diet consists almost entirely of bamboo. Because the bamboo is low in nutrients and energy, a panda eats for about 14 hours every day and eats about 12 to 15 kilograms of bamboo!

Needs of Animals Animals live in a great variety of places acess on Earth. They live on land in forests, deserts erts and grasslands. They live in the ocean, an, rivers vers and streams. Some animals live underground too. nderground rground too

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Think Deeply

The place where an animal al lives is called its environment. An environment onment ment provides provid the animal with the food, water, it r, air and shelter sh needs to survive.

Getting Food ood d

Unlike plants, animals not able to make their mals are no own food. They get the energy they need by ene eating other her living things. things Many y animals mals move from place to place to get the food they need. need They move in different ways using sing legs, wings or fins.

Different body parts help animals get the food they need in different ways. An eagle uses its large wings, sharp claws and powerful beak to catch and kill its prey.

bald eagle

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A giraffe’s long neck and tongue are adaptations to help it get food.

A giraffe has long legs and a long neck eck to reach leaves in treetops. Its long tongue tears ears the leaves from the trees.

Getting Water

o help elp their bo b Animals need fresh water to bodies nim to o process proces the function. Water helps animals elps the th food they eat. It also helps them to re remove wastes and stay healthy. althy.

Amazing Fact!

The kangaroo rat can go its entire life without drinking any water. It gets any water it needs from the seeds and grasses it eats.

rink fresh resh water fou Many animals drink found in puddles, nd streams. reams. Some Som animals a lakes, rivers and get the d from the food fo they t water they need eat.

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Fish have gills to get the oxygen they need from water.

fish gills fi

Did You Know? Plants take in carbon dioxide from the air and give off oxygen. Animals take in oxygen from the air and breathe out carbon dioxide. This movement of carbon dioxide and oxygen in the air is called the oxygen cycle.

Adult frogs have lu lungs to o take in oxygen from the air. They can also take in oxygen through their n oxyge moist st skin. skin

Getting ing ng Air

Animals mals need a sp spec special part of air called oxygen. Mammals, ammals, ls, reptiles and birds have lungs to take in n oxygen ygen from the t air. h do not have h Fish lungs and cannot breathe air. They have T ave gills to take in oxygen from water.

Some animals, such as worms and some an amphibians, are able to take in oxygen through amp amphibia their he skin. sk

Seeking Shelter

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An animal’s environment provides it with shelter. err. Shelters may provide shade for animals when n itt is too hot. They keep the animals warm when it is cold or wet. Shelters can also protect animals from other animals or provide them with a safe place to raise their young. Many animals use plants for shelter. Squirrels and raccoons seek shelter in the hollows of trees. Many birds build nests in trees. Rabbits build their homes among blackberry bushes. The sharp thorns of the blackberry bush protect them from other animals.

Non-living things provide shelter too. Logs gs and rocks can provide shelter for insectss and otherr small animals. Caves and burrows provide rovide shelter for many mammals and reptiles. ptil

Anemone fish seek shelter in sea anemones.

Activity 3.1

A blackbird feeding her chicks.

Classifying Animals Run your hand down the center of your back. What do you feel? Would you classify people as vertebrates or invertebrates?

Animals come in all shapes and sizes. es. To make them easier to study, understand and d name, scientists classify animals into groups ps based on ways they are the same.

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Try This!

One way animals can be classified is by the presence or absence A e of a backbone. backbone backbo backbone is a series of small mall bones, called c vertebrae, that run down n the center of an animal’s back.

Animals with a backbone ckbone kbone a are classified together as vertebrates. without a backbone are tes. Animals with wit classified together invertebrates. ogether her as inve

Re g

backbone ckbon

A domestic cat has an internal skeleton of bones.

What is a main difference between vertebrate animals and invertebrate animals?

eg al ed uc ati squid

horned starfish horne

Most of the animals on Earth are invertebrates. s. Invertebrates include small animals such as insects, spiders, worms and snails. Sea creatures such as giant clams, squid, uid, lobsters and starfish are invertebrates es too. o

tarantula

earthworms th

snail

honeybee

akeet et parakeet

al ed uc

corn snake

eagle

Vertebrates V ttebrates

M ny of of the large animals Many a you are familiar with w ith are e vertebrates. vertebrat By looking closely at the vertebra structures, sstructur cturres, body coverings and ways in which vertebrates reproduce, we can further classify vertebr v rtebrrates re smaller groups – mammals, tthem hem em into in nto o five fiv f birds, amphibians and fish. b ds, reptiles, rept re ept

tree t frog f

salamander

terrapin

stingray

du c

trevally fish sh

Compare the vertebrate animals on these pages. How can you tell which h animal group they belong to?

Re g

AB Activity 3.2

hamster hamst hamstter ter

chimpanzee

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dolphins

Characteristics eristics stics of Mammals M Tigers, monkeys, onkeys, s, dolphins, dolphins dolphin squirrels and polar bears Mammals ears are mammals. mamm are animals nimals with a body bo covered in ma hair or fur. Most mammals reproduce by giving ing birth to lilive young. Female produce milk which they mammals mmals produ prod young. feed their youn

hedgehog

tiger cub

young bonobo

Re ga le du ca t humpback whale

Mammals are warm-blooded animals. They have lungs and take in oxygen when they breathe in air. Some mammals, such as dolphins, sealss and d whales, live in the ocean. They must ust come to the surface to breathe. What are the characteristicss of mammals?

squirrels sq

polar bear cub

The time it takes for a mammal to grow and develop inside its mother is called the gestation period. Generally, smaller mammals have shorter gestation periods than larger mammals. The gestation period for a mouse is about 20 days. The gestation period for an elephant is 22 months.

Mammal Life Cycles All of the stages of an animal’s life - from m first entering the world, to growing and d changing, hanging, and reproducing young of its own, wn, make ake up its life cycle.

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Did You Know?

Most vertebrates reproduce eggs. ce e by laying egg Mammals’ life cycles are e different in that tha th the unborn young, called an embryo, inside mbryo, develops deve her then gives birth b the mother. The mother to live young. The young look similar to their parents. th t

male lion

female lion

lion cub

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Adult hippopotamuses with their young.

Adult mammals often stay and care for their young until they are old enough to survive on ow to their own. They may teach their young how find food or hunt. They may also teach them how to stay safe from other animals.

Amazing Fact!

The echidna and platypus are two kinds of animals found only in Australia. These strange-looking mammals reproduce by laying eggs.

Re g

AB Activity 3.3

Galapagos Galapago Galapag sea lions

8-month old lion

hornbill

Characteristics acteristics eristics o of Birds

ed u

Birds are re the he only animals anim that have bodies covered red in n feathers. Birds also have two wings, ngs, two feet and an a beak or bill. Most ost birds use their wings to fly. There are flightless birds such as ostriches and some me flightle kiwis. These birds walk and run using their are also flightless birds. They legs. Penguins Peng P their wings as fins and rudders to help use the swim. t them

kingfisher

kiwi

emperor penguins

du ca t

hummingbird

Like mammals, birds are warm-blooded. ooded. They Th have lungs and get the oxygen they ey need by breathing in air. Birds reproduce by laying eggs. ggs.

mallard duck

mallard duckling

cockatoo

Re ga le du ca sunbird feeding its young

fieldfare eldfare hatchlings hatch

Bird Life Cycles ycles

Go Online!

Watch a video on the life cycle of a chicken on the NGScience website. QuickCode: W2P1

All birds reproduce eproduce ce by laying llayi eggs. The eggs are often laid helps to protect the d in a nest. The nest n eggs. The parents sit o on the eggs to keep them m. warm. As a young bird develops, it gets all the things it inside the egg. needs ds from ins i O deve Once developed, a young bird will break out of egg, or hatch. the eg

egg

hatchling

Re ga le du ca

robin bin bird feeding fee fe its chicks

goose with eggs

Many birds feed and care for their young until they are able to fly about and find food on their own. When a young bird grows into an adult, it will reproduce ce e young of its own.

AB Activity 3.4

chick

adult chicken

du ca t

marine iguana

banded band sea snake

Characteristics eristics ics of Reptiles R Alligators, snakes, nakes, es, turtles and an lizards are reptiles. Reptiles have ave lungs and get g the oxygen they y breathing in air. air Most reptiles live on need by a sea turtles, sea snakes, land, but some such as odiles es and alligators alliga allig g crocodiles live in water.

crocodile

terrapin

ga le du ca tio n leopard gecko

Reptiles have bodies covered in scales or hard plates. The scales and plates hem protect the reptiles and also keep them eptiles les from drying out in hot weather. Reptiles are cold-blooded. This means their body temperature changes with the e temperature perature of their surroundings. In what ways are re reptiless similar simila to birds?

Galapagos tortoise

Think Deeply

Few reptiles can survive in cold environments. Why is this so?

viper snake

drragon Chinese water dragon

tio

adult corn snake

Reptile Life e Cycles i similar to that of The life cycle of reptiles is birds. Let’s ’s look at the life l cycle of reptiles by looking of a corn snake. ng at the life cycle cyc c

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snake lays eggs. The young A female male corn sn snakes kes grow and a develop inside the eggs. Once developed, a young snake will hatch ce e develo ffrom each ach egg. The young snakes look similar their parents. to th

eggs eg

corn snake hatching from egg

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crocodile hatchlings

turtle turtle hatchling

Unlike mammals and birds, snakes and other reptiles do not often care for their young after they hatch.

hey get bigger As the young snakes grow, they in size and look more like their heir ir parents. Once mature, they will reproduce produce duce corn snakes of their own.

AB Activity 3.5

Think Deeply

Some snakes, such as the pit viper, live in cold climates and therefore do not lay eggs. Instead the eggs are kept inside the mother’s body until they hatch. How does this help the snake reproduce?

young corn snake

caecilian

Amazing Fact!

Characteristics aracteris of Amphibians Amphibians phibians are animals that usually spend the first rst part par of their lives in water before moving onto land. The most common type of m amphibians are frogs. Other amphibians include amph amphib salamanders and caecilians. salam salamand

Wallace’s flying frog, also known as a parachute frog, has wide webbed feet that help it to fly through the air. It can glide distances more than 15 meters!

red-eyed green tree frogs

salamander

Like reptiles, amphibians are cold-blooded. Their body temperature is dependent on the temperature e of the environment. A young amphibian has gills and takes in n oxygen from fro water. The gills develop into lungs as it gets older. ets older

Most amphibians moist skin. ians have smooth, sm They often live ve in moist places or near bodies of water such uch as ponds pon and puddles. Why do most m amphibians live in moist places or near water?

cane toad

Watch a video on the fascinating life cycle of amphibians on the NGScience website. QuickCode: U4E6

Go Online!

Amphibian n Life Cycle Cy ycle of a frog is different from other The life cycle vertebrate cycles in that the young ate animal life c do not look ok like their parents. As they grow and develop, their bodies bodie change form. This change in body metamorphosis. dy form is called ca

Re g

Frog eggs are usually laid in water with many eggs usually laid at one time. A frog larva, called tadpole, hatches from each egg. A tadpole a tadp does not look like a frog. It has a tail to help it swim and uses gills to take in oxygen. sw frog eggs

frog larva (tadpole)

young frog undergoing metamorphosis

du ca tio

A northern leopard frog in the process of metamorphosing from a tadpole to an adult.

As a tadpole grows and develops, it starts to look more like a frog. Its tail gets smaller and it begins to develop legs and feet. Its gills develop into lungs as it prepares to move onto land. As a frog grows, it moves from life in water to life mostly on land.

AB Activity 3.6

reticulated eticulated glass frog

adult a frog

As a frog grows, rows, it develops legs, feet and lungs.

How are the life cycles of amphibians similar to that of am reptiles? How are they different?

great white shark har

Characteristics cs of Fish Fis Fish are animals that hat live in water. Most fish live in the ocean, which is ssalt water. Fish can also be found freshwater habitats, ound in fresh ams, river such as streams, rivers and lakes. Most fish reproduce eprodu by laying eggs, but some me give birth to live young.

ca tio

fish gills

stingray

Fish have body parts well-adapted to life in water. They have gills to take in oxygen from the water. They have fins and tails to help them swim. Like reptiles and amphibians, fish are cold-blooded.

Think Deeply T

A sstarfish has the word ‘fish’ in its name. Do you think a starfish is a fish? Explain your answer.

Fish Life Cycles Let’s take a look at the life cycle off fish h by looking at the life cycle of a salmon. mon. Female salmon lay eggs in water. fish er. Young fis hatch from the eggs. The y young oung salmon salmon have h an attached yolk that they ey use use for for food. food

eggs

adult salmon

alevin

As the salmon get older, they get larger and look more like their parents. The young salmon grow into adults and will produce young of their own.

AB Activity 3.7

fry ry

parr

smolt

ed uc at

jellyfish

earthworms eart earth

Invertebrates brates ates

caterpillar

Many of the he animals nimals around arou us are invertebrates. invertebrate is an animal rates. An n invert inv that does oes not have an internal skeleton of bones backbone. Without bones or a es orr a backbon backbone support, invertebrates are ckbone one for sup supp smaller in size than vertebrates. generally lly smalle

centipede

scorpion

pill millipede

du ca t

fiddler crab

brates es For support and protection, many invertebrates ebrates such as insects, spiders and crabs, have e a hard outer body covering. Some insects have ave one e or two sets of wings and are able to fly. y.

octopus

Did You Know?

The bones inside vertebrates is called an endoskeleton. The hard outer body covering of invertebrates is called an exoskeleton.

honeybee hon

praying mantis garden snail a

Re ga le du ca t ladybug

dragonfly dr d

Characteristics istics cs of Ins Insects

Insects are the e most st diverse animals on Earth. So far, scientists more than one ntists have classified class million different and many more fferent ent kinds of insects, i are yet to o be discovered. discovered discovere Insects with a hard outer body ects are invertebrates inverteb inverte covering. have six legs, two antennae and a overing. ng. They ha into three parts. body y divided int in head

thorax

antenna na

Go Online! lin

Observe the great diversity of insects nsects on the NGScience website. websit QuickCode: uickCode A4J3 J3

leg

ant

abdomen

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stag beetle

All insects reproduce by laying eggs. Some insects have one or two pairs of wings and can fly.

honeybee honeybe

How are insects similar to spiders? piders? How are they different?

grasshopper

Butterfly Life Cycle Like many insects, butterflies have e a four-s four-stage sta life cycle that involves metamorphosis. butterfly starts orpho osis. A butte osis. orm m-llike larva, larv va, called c its life inside an egg. A worm-like a om each each egg. egg. Caterpillars Ca caterpillar, hatches from grow very quickly. They spend nd d most of of their thei time eating the leaves around them. m.

chrysalis (pupa) caterpillar (larva) rva) rv a)

When the th larva larv reaches a certain size, it attaches itselff to to a leaf le or branch and spins a covering, called a chrysalis, chrysal over its body. It enters an inactive state chrysali called a pupa.

adult butterfly

Inside sid side de the th h chrysalis, the caterpillar’s body changes form completely. from the chrysalis as an It will will emerge e adult ad dult butterfly. The butterfly will have the same body parts as its parents. It will go sa on to reproduce young of its own. o

ad adult butterfly emerging from chrysalis em

Go Online! Watch butterfly metamorphosis in action in a video on the NGScience website. QuickCode: V9P5

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ladybug dybug ug eg eggs

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Ladybug Life e Cy Cycle Cyc e

Like a butterfly, the e life cycle of a ladybug has four stages with the offspring ring undergoing undergoin metamorphosis. Adult ladybugs bugs gs lay eggs. The T larvae that hatch from the eggs look k very ry different differe from their parents. Eggss are o often laid on plants with small insects like aphids aid do or mites the larvae to feed on. The larvae shed their es for fo th skin, several times as they grow. kin, kin or molt, seve se

adult ladybug

ed uc a ladybug larva

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After a certain time, the larva attaches ches itself to a leaf and enters the inactive ctive pupa stage. After a few days, it will emerge as an adult ladybug. g.

ladybug pupa

Grasshopper Life Cycle

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The life cycle of a grasshopper is a threeeestage life cycle. The adult lays eggs gs - often ofte underground. The young that hatch atch from rom the th eggs are called nymphs. Although ough h they look similar to adult grasshoppers, s, nymphs do not no have wings, cannot fly and d cannot reproduce. reprod

nymph

As the nymph grows, itt develops elops wings. wing As an adult, adu it will reproduce adul e and nd lay eggs of o its own. eggs e

adult dult g grasshopper

AB Activity 3.8

The Circle of Life

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The life cycles of living things can be different in many ways.

A small root will emerge from the germinating seed of a flowering plant. A shoot and leaves will develop. As an adult plant, it will produce flowers and fruits containing seeds. Under the right conditions, each seed will grow into a new plant. A newborn deer looks a lot like its parents. It will grow bigger and stronger as it gets older. Ass an adult deer, it will produce young of its own. n.

Frogs and ladybugs look nothing like their the heir i parents when they hatch from eggs. bodies s. Their T change completely as they grow an and nd develop. As adults, they will go on to produc produce uce young of their own. Although there is great diversity ersity y in the life lif c cycles of living things, they are all similar milar lar in one way – living things enter the world, they wo worl y grow, grow develop, reproduce and die. The he e life cycles cy cyc of living things ensure their kind continues survive. ontinues ues to su surv

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. mammals metamorphosis fish insects pupa

oxygen invertebrates amphibians larva chrysalis

vertebrates ates birds ds reptiles reptile caterpillar

Animals need a special part of air called

Animals with a backbone are called

Animals without a backbone are called

are animals with a body covered iin fur. They give birth to live young.

are the only animals ls with a body b covered in feathers.

are cold-blooded ded with a body covered in scales or plates.

nd Frogs and salamanders are

. They have smooth, moist skin.

A change in body form during durin an animal’s life cycle is called

live in n water an and have gills to help them take in oxygen.

10.

have six legs le and a body divided into three parts.

11.

m-like A worm-like butterfly egg. fly egg

12.

A caterpillar aterpillar spins a covering over its body, called a enters state called a ters an inactive in .

, called a

hatches from a

, and

Review List the needs of animals.

List three vertebrate animals.

List three invertebrate animals.

How are mammals different from most other animals terms of nimals in term reproduction?

List the characteristics of birds.

List four kinds of reptiles.

How is the life cycle of birds similar to that hat of reptiles? rep

List the characteristics of fish.

Describe insects in terms of their ir number of legs and body parts.

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10. Classify the animals as either or invertebrates. her vertebrates verte

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(a)

(c)

(b)

(d)

Inheritance and Traits

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Why do offspring often look similar to their parents?

In this chapter te you u will ... .

• understand thatt plants and a animals have traits inherited from parents. • understand d that there are variations in traits within a group of similar organisms. organisms • provide de examples of o traits that can be influenced by the environment. nvironment. • explain plain how ho variations in traits of the same species may provide advantages for survival. prov

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How can the environment affect an animal’s appearance or behavior? havio

Go Onlin Online!

Access interactive in content relating to this topic on the relatin NGScience website. GS ngscience.com ngs

Heredity and Traits

Go Online! Learn more about inherited traits in plants and animals on the NGScience website. QuickCode: T4X6

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Look at the photograph of the e cheetah family. What similarities do ties d you see between the parents ents and their offspring? Why are they similar? sim

Like their parents, the young ung ng cheetah cubs cub have the same eye color. They ey all have four legs ered in spots. spot spots These and a tail. Their fur is covered eristics ics of the cheetahs ch features or characteristics are called traits. Plants have traits shape of a plant’s aits too. oo. The sh sha leaves and flowers ers or the type ty of fruit it produces are examples ampl mple of o traits.

The young cheetah cubs have inherited traits from their parents.

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fir saplings

When living things reproduce, traits are passed from parents to offspring. This process rocesss is called heredity. lar ar to their The young cheetah cubs look similar parents because of their inherited d traits. aits.

A young fir plant will grow into o a tall fir tree with thin, spiky leaves due to itss inherited traits. tr People inherit h traitss too. What W are some e traits trait you have inherited from your you parents?

Think Deeply

firsome trees seeds Chelsea found on the ground. How can she find out which plant the seeds came from?

Activities 4.1 – 4.2

Variation in Offspring

Think Deeply

Look at a family photograph. What variation can you see between you and your siblings?

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Why don’t the kittens look exactly ctly like their parents or their siblings?

When most living things reproduce, oduce, ce, inherited traits are passed from both parents to the g may look more like offspring. Some offspring y look ook more like lik their their mother. Some may father. They may look similar milar to both parents, but the offspring willll nott look identical identic to their al to each ach other. parents or identical

characterist characte The differencess in characteristics between individuals off the e same kind d is called variation.

Re ga le du ca t

color v variation in tulips

We can see variation in the same kind of plants ants too. The plants above are all the same kind d of tulip. They are similar in many ways. We can also lso see variation in the heights of the plants ts and d the colors of the flowers. Sometimes, variation within living g things ngs of the same kind can result in some offspring ring surviving survivin surviv g and some not surviving. Certain may ain offspring spring ma m be stronger or be able to survive withoutt urvive ve longer wit food or water. Variation may ay mean some som offspring have a body covering at co g that is better b hiding from other animals. mals.

Think Deeply

How could knowledge of inherited traits be important to crop farmers and the plants they grow?

How could color olor variation in the ghost mantises he chances of increase the survival of an indivi individual?

Activities 4.3 – 4.5

g ghost mantises

Behavioral ral Traits Instinct Characteristics cs such as b body coverings, body parts and eye color a are physical inherited traits. Offspring can also a inherit behaviors from their An inherited behavior is heir parents. A nstinc An instinct is the way an called an instinct. animall acts tha that it has not learned from its parents arents or environment. env When you young ducks hatch from eggs, they start to follow their mother. t This instinct helps the young to stay T ssafe afe and learn from their mother.

Other instincts include a spider spinning a web, animals fighting and nest building.

Learned Traits

lioness with her cubs

squir squirrel monkey

As young animals grow and develop, they learn earn new skills from their parents or from other experiences around them. Animals can als also learn new skills and behaviors by playing aying with other animals. These newly-acquired d skills and behaviors are called learned traits. Learning to hide from animals and hunt for food are examples of learned traits. These The learned traits are not passed on from parent as p to offspring. Learned traits be learned by raits must m the offspring each time e an animal anim reproduces.

AB Activity 4.6

Environmental Traits

Think Deeply Is the shape of the tree an inherited or environmental trait? Explain your answer.

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How can changes in an environment affect the traits of the th plants and animals that live ve there?

There is a great variety of environments nvironments on o Earth and they are always yss changing. The traits of plants and animals can be influence influenced by the influenc ironment. ment. These Thes traits are conditions in their environment. tal traits. traits raits.. called environmental The availability of water and the amount of sunlight in an environment can affect the plants onment ca c e. In an environm environ that live there. environment where there is plenty off waterr and sun sunlight, the plants may su grow taller more leaves than the same ler and have mo plants in a drier or dar darker environment. The e flowers ers of the hydrangea plant are either pink or blue. The color of the flowers depends on the type of soil s in its environment.

Re ga l

Hydrangea plants produce blue flowers in acidic soil and pink flowers in alkaline soil.

Changes in seasons and temperature can also affect the traits of animals. Some animals have thicker fur when the weather is cold and shed the fur when the weather gets warmer. The mountain hare has a thin layer of brown fur in the summer months and a thick layer of white fur during winter. How do environmental traits help organisms to survive?

Think Deeply Poison dart frogs produce pro a deadly poison. The mes from fro their poison comes ter diet off ants and termites. Why is this an example of e an environmental environment trait?

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Animal traits can be affected by their environment too. At times when there is plenty of food available, animals may become overweight. When less food is available, they may become thinner again.

The mountain hare has thick white fur in winter and thinner brown fur in summer.

AB Activity 4.7

Natural Selection

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A living thing of the same kind is called a species. Although the traits of individuals uals within a species are very similar, there are always slight lways slig differences. Sometimes, these slight ght differences differenc between individuals provide advantages in surviving, finding mates and d reproducing.

Survival of the Fittest test

Imagine a group of giraffes affes living in i an African savanna. One trait is rait of all giraffes g a long neck. This helps to reach elps the giraffes giraf leaves high in trees.. A variat variation within the giraffes may be that some have longer necks than others. rs. If shorter shor trees begin to produce ce less leaves, tthose giraffes with ecks will have a greater chance of longer necks survival. The They will a also have a better chance of reproducing. ducin . This Th process by which the best suited orga organisms survive and pass on theirr traits is called natural selection.

peppered moths

Another variation in traits that may give individualss within a species a greater chance of survival is being better camouflaged. etter camou Camouflage is an animal’s ability to blend into surroundings. o iits t surro The peppered moth is a day-flying moth that at is camouflaged c on the bark of trees. In habitats where ere the trees are ar light in color, lighter-colored peppered moths have of survival ve a greater chance c than darker moths. In these habitats, s, most off the peppered moths are light. In habitats where the trees are dark k in color, most of the peppered moths are dark.

Finding a mate and reproducing for the survival of g is important impo a species. Often males tha that are stronger, or have other desirable traits, attract more mates. s. This helps to ensure that the stronger traits are passed on to offspring. o offsprin ng.

Activities ties 4.8 – 4.9 Two male gemsbok fighting to compete for a mate.

Science Words

Re ga le du ca tio n

Use the words to complete the sentences. heredity instinct species traits

environmental traits learned traits natural selection variation

Features or characteristics passed from parentss to their offspring off are called .

is the passing of traits from parents arents to offs offspring.

Differences in characteristics between individuals o of the same kind is . called

An is the way an animal nimal acts tha that it has not learned from its parents or environment.

Skills and behaviors taught by parents tto their offspring are

Traits that change as a result changes in a living thing’s surroundings ult of cha are called .

is the process by which the best suited organisms survive and pass on their traits.

is a living thing of the same kind.

Review List two traits the young monkeys inherited from their parents. s.

List two inherited traits of the pine saplings.

Why do offspring look similar ilar but not n identical to their parents?

Provide an example instinct. le of animal a

List two learned traits of the young bear cubs.

How can the environment affect a living thing’s traits?

How does do natural selection help a species survive?

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A Closer Look

Attracting Mates Attracting mates is important to ensure the survival of a species. Different kinds of animals have different and very ery interesting ways of attracting mates. Bird courtship displays are a fascinating example of attracting mates. During a courtship display, a bird, usually y the e male, behaves in a manner to ‘impress’ the female. This may includ include a display of colorful feathers, an elaborate dance or a song. song By choosing the male with the best courtship display, offspring play, the offs will likely inherit these desirable traits and d therefore refore have ha a greater chance of survival.

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male frigate bird

male peacock

Male frigate birds inflate large red pouches hanging below w their throat. They extend their large wings and make sounds undss much like the beating of a drum. Birds with bigger and d brighter bright pouches and louder sounds are more likely to attract ct a mate. Perhaps one of the most impressive courtship displays splays ys is that of the peacock. To attract a mate, male peacocks cks spread out their large and brightly colored feathers. The peacocks cocks with the t larger and more impressive feathers attract ct more ore mates.

Go Online! female peacock

Watch some fascinating bird courtship displays in a video on the NGScience website. QuickCode: Y5S8

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Adaptations for Survival

Re ga le d

What is an adaptation? How do adaptations help organismss survive?

In this chapter you will ...

• understand that some animals form groups to oup survive. su help members of the group ovide examples exa • describe and provide of how organisms have adaptations ons to help them survive in their environment. • describe and nd provide provid examples of how environments ments can change. ch scribe and provide examples of how organisms • describe are affected by changes in their environment.

ca tio Go Online!

Access interactive inte content relating elating to this topic on the NGScience website. NGScien ngscience.com ngscie

How are organisms affected by changes to their environment?

What hat at Are Ad A Adaptations? Go Online!

Surviving in the freezing Antarctic is a tough job. Find out what adaptations animals have to survive in this harsh environment on the NGScience website. QuickCode: S9W6

The e Antarctic Antar arrctic c is is a region of the Earth that is so year o cold cold ld all alll ye y ea arr rround that few animals can survive vive the tthere. herre. T The animals that live in the Ant tarct tarc ctic ic have h ha av adaptations that help them Antarctic survive viive iin n tthe extreme cold. An adaptation is is a trait or o behavior that helps an organism surv rviv survive. Ad A delie penguins have adaptations that help Adelie them them m survive in the Antarctic. They have wat waterproof feathers and a thick layer of fat, ca called blubber, that help to keep them warm. Their small, yet strong, wings help them to swim in search of food. Camouflage is an adaptation that helps animals blend into their surroundings. This can help them to hide from predators or sneak up on prey.

Plants may have spikes on their stems to stop them being eaten by animals.

Many plants and animals have adaptations to survive in places that are very hot or very cold.

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Many animals have specialized body parts that help them move about, or get food and water.

Think Deeply What adaptations do polar bears have that help them to survive in an icy Arctic environment?

Adaptations to the Environment Visit a natural environment in your area. List the animals you spot and the adaptations they have that help them survive in the environment.

Go Online! Discover some amazing animal adaptations to their environments on the NGScience website. QuickCode: S1X5

There is a great variety of different living ving things on Earth. There is also a great variety iety of habitats. habi anisms can survive su In a given habitat some organisms can well, some survive less well, and some cannot survive at all Often, a living thing can only be foun found in one type of habitat. This is because living things have ecause liv adaptations that allow w them to ssurvive in certain environmental conditions. dition A red-eyed tree frog has adaptations to survive ad in a tropical rainforest. You will not find a redainforest. Y eyed tree e frog in an icy tundra or dry desert. Similarly, you will not find tundra or desert f animals living rainforests either. ivin in ra

Try This!

Why can’t can an animal like a tree frog survive in a hot and dry desert? surviv

Surviving in a Desert A desert is a very dry habitat. It may only rain a few times a year. Deserts are also often hot during the day and much cooler at night.

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What are some adaptations of desert organisms? How do the adaptations help them to survive? Not many plants can live in deserts. Those plants that do have adaptations to survive with little water. Some plants have deep roots that can take in water from deep in n the th he soil. Others have shallow roots that spread ea ad out out to take in water over a large area. Desert plants also have small leaves help ves tto oh e lp reduce water loss. In some desert plants, errt p lants, tthe he leaves are in the shape of spines nes to to keep keep animals away.

joshua tree

prickly pear cactus

Desert horned lizard izard camoufl camouflaged on sand.

Desert viper camouflaged in sand.

Think Deeply

Some animals, such as snakes, are camouflaged nimals, suc or bury themselves hemselve under the sand. This helps m to hide from other animals. them

al e

Why do many nocturnal animals, such as owls and geckos, have large eyes?

Desert animals anim have e adaptation adaptations to survive in hot weather with little water. Som Some desert animals are nocturnal. This means tthey sleep during the day and are active night. Some animals also ve at nig elter in burrows to help them stay cool. seek shelter

Why are many desert animals active at night?

The giant ground gecko hunts for insects other ects and othe mals at night. small animals

1 00

Amazing Fact! Camels can survive for witho up to six months without n they do find water. When drin up water,, they can drink to 40 gallons at once!

ca tio n

What adaptations does a camel have for surviving in deserts? Camels are well-adapted to surviving in deserts. They have a hump on their backs which stores fat for energy. They can also survive for many months without drinking water. Camels have large, flat feet that spread their weight on the sand. They have thin, narrow nostrils and two rows of eyelashes to help keep out sand.

Activity 5.1

1 01

The Saguaro Cactus

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A Closer Look

The saguaro cactus is a tree-like cactus found in the Sonoran Desert in Arizona, United States. The Sonoran Desert is very hot all year round and it may y not rain for many months. The saguaro cactus hass many adaptations which allow it to survive in thiss harsh environment. Saguaro cacti are able to store large amounts unts of water in their thick stems. The stems are also also covered in a waxy substance which helps elp ps to to prevent water loss. Its leaves are in the he shape sha ape of of sharp spines that stop animals from getting mg ettin tting tto o tthe he precious water inside the stem.

1 02

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The saguaro has modified leaves in the shape of sharp spines.

The strong aroma of saguaro flowers attract insects. The Gila woodpecker helps pollinate the flowers when it feeds on the insects.

Saguaro cactii also also h have ave sshallow hallow rroots that branch out over a large area. When it does Sonoran es rrain ain iin n tthe he S onora Desert, the roots are able to take in a lot of water er and and store store itit in in the the stem.

ros produce produce bright bri right flowers that have a strong smell to attract Saguaros pollinators. night attract bats. During the day they attract nators. At At n ight tthe he flowers f bees, butterflies and birds. The flowers develop into fruits which can es, b utterflies a nd b contain c ontain up up to to 2,000 2,000 seeds. The seeds are dispersed to new places when a nimals ssuch uch a animals ass b birds and small mammals feed on the fruits.

AB A Activity 5.2 1 03

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Surviving ng in n a Rainforest Rain

Go Online! Rainforests can be divided into four different layers with each layer providing a habitat for different organisms. Learn more on the NGScience website. QuickCode: H9W9

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Tropical rainforests are d dense forests with warm weather er and lots of rain ra all year round. They are e to millions of o different d home kinds of organisms d are the most diverse d and land habitat on Earth. diversity comes lots of competition With h high diver div forr the he things thing organisms need to survive. Trees in rainforests fores have tall trunks. The trunks lift the leaves lea leave eaves high in the sky to take in sunlight. The leaves eavess branch b out in all directions.

ed uc ati on bird’s-nest fern

With so many tall trees, very little sunlight light reaches the rainforest floor. The plants ants n low ow there have adaptations for living in ve large rge light. Many rainforest plants have ht. Other er leaves to take in more sunlight. plants, like bird’s-nest ferns and orchids, ng on the get more sunlight by growing trunks of trees.

orchid

1 05

leaf-tailed gecko

leaf insect

Rainforest forest orest animals h have adaptations that ha help elp them hem get the things they need and afe in a warm w and moist forest. stay safe wa With such a great diversity of animals, important to stay safe. A leaf hiding is im insect into its habitat by looking sect blends ble k a leaf. An adaptation where a lot like o an organism looks or acts like another organism is called mimicry. org organ pit viper

Gre viper snakes and tree frogs us Green use c er animals. anima camouflage to hide from other

Javan tree frogs f

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Toucans use their specialized bills to tear fruits from branches.

ca t

ey ey spider monkey

Many rainforest animals have adaptations that help get d i h h l them h food that other animals cannott igh reach. Spider monkeys live high in the rainforest canopy. They ey swing effortlessly from tree to tree feeding on fruits. ve beaks eaks or bills bill b Rainforest birds have of all shapes and sizes. es. A toucan has a large bill that hat helps elps it to cut c es. Parrots arrots have a fruits from trees. k to break open seed strong beak seeds and nuts.

octurnal rainforest rainfo Owls are nocturnal rainfor animals. mals. They have large larg eyes to see their powerful e at night and u use th claws to catch wings and sharp cla and their prey. d kill th

AB Activity 5.3

buffy fish owl

1 07

Surviving in a Savanna ann A savanna is a tropical grassland rassland and ainforest, ores it habitat. Like a tropical rainforest, d. S avannas nn nass is warm all year round. Savannas season asonal nal rains, are mostly dry, with seasonal mm mer. usually during summer. ossttly wid wid de op o Savannas are m mostly wide open gra asses, sshrub hrubs bs and places with grasses, shrubs ees. s. scattered tre trees. lants tss in in savannas sava ann nn have long Many p plants p rroots, oots, ts, calle a ed taproots, tta a deep called that reach ep underg u nderground un nd Some plants, deep underground. such store water in uch as as the th he baobab, bao ob b their th heiirr sstems. stems tems. Baobabs store water in their stems.

Living wide open savanna means Li L iviing iv ng in in a w hiding h idin ng from fro fro animals and escaping danger d anger is important. Animals like meerkats hide in burrows A nim to avoid predators. Others, such to as gazelles run, jump and change direction quickly to avoid getting caught by animals like cheetahs.

1 08

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al ed

Escaping a cheetah is a tough job! A cheetah’s dark spots camouflages it in the dry vegetation allowing it to sneak up p on its prey. Cheetahs are also the fastest stt land animals on earth. They can reach ch speeds of more than 60 kilometerss per hour when chasing prey.

What are some other animal nimal adaptations to living in a savann savanna?

AB Activity 5.4

Meerkats dig d burrows to stay cool and avo avoid predators.

Did You Know?

The Serengeti is a vast grassland habitat in Africa. It is home to many big predators including lions, cheetahs and leopards. Lions in the Serengeti are often seen climbing trees. Scientists believe this may be an adaptation to avoid getting bitten by insects on the ground.

1 09

Surviving in a Tundra A tundra is a habitat that is very ery cold co all year round. It is often windy and there is little water available. The organisms in a tundra have special adaptation adaptations to survive in the cold.

Leaves with a hair-like coating protect tundra plants from cold winds.

Plants are often small and live close to the ground. Many close any plants live l together and have a hair-l hair-like coating on their leaves. s. This helps help to protect them from the leaves e wind. Small S also stop the plants ffrom losing water. Many tundra ndra plants plan are deciduous. Deciduous uous means mean they lose their leaves part of the year. ves for par

Blubber and thick fur keep polar bears warm.

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Tundras have frozen soil with only the top layer suitable for plants. To survive in the soil, tundra plants have very shallow roots.

Reindeer eindeer migrate migr to warmer areas reas during the th tundra winter.

Animals adapt to the cold in different ways.. Many animals, such as polar bears, foxess and hares, have a thick fur coat and a layer ayer of blubber to keep them warm.

Polar bears hibernate during the tundra winter.

During the coldest months of the year, ar, some tundra animals go into burrowss o orr caves to hibernate. Hibernation is like a deep deep sleep sle that allows the animals to save energy.

AB Activity 5.5

move in large groups to Other animals m warmer rmer places for part of the year. This movement men nt is called migration.

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A Closer Look

Surviving the Deep Ocean The deep ocean is a habitat very different from any other on Earth. At more than 1,000 meters deep, there is no light, no plants and the hat live there th water temperature is very cold. The strange animals that ake a look at a have unique adaptations to help them survive. Let’s take few deep sea creatures.

The viperfish can live at depths of m more than 2,000 meters. s. It has ha large needle-like ne teeth and a wide e mouth. outh. In the th darkness cean, n, the viperfish viperf viperfi has a of the deep ocean, ing organ rgan to attract att light-producing its prey.

Giant isopods use their seven pairs of legs and four sets of jaws to scavenge for food on the deep ocean floor. They can curl their segmented bodies into a ball shape for protection against predators.

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The ferocious-looking anglerfish lerfish has a fleshy, light-emitting growth on its head h to attract prey. It has teeth as long, sharp te de it can eat ea prey and a mouth so wide n size! bigger than its own

To see in almost complete darkness, the colossal squid has the largest eyes of all known animals. The animal is believed to g reach lengths of up to 15 meters and weigh over 700 kilograms.

1 13

Living in Groups Discover the many advantages of animals living in groups in a video on the NGScience website. QuickCode: Y8S7

Animals can be found in all regions of the Earth – from the icy Antarctic to the he p them open plains of the Serengeti. To help ny animals survive in their environment, many form groups.

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Go Online!

What are some animals nimals that form groups? How does oes forming a m survive? group help them

Keeping Warm rm Think Deeply What other adaptations do emperor penguins have that help them survive in the Antarctic?

Some animals cold habitats form als that hat live in co groups to stay penguins live y warm. Emperor Em in one off the coldest habitats on Earth – the ha Antarctic. ctic. Temperatures Temperatur get as low as –50°C (–58°F) are 8°F) F) and nd d there th a ar very strong winds.

huddle together in large groups The penguins h hu warm. The penguins rotate between to keep eep warm being ng g on the inside of the group, where it is the warmest wa st tto the outside of the group, where it is coldest. the co

Emperor penguins huddle in groups to keep warm.

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ga le du ca

Leaf cutter ants gather food in groups. The food is taken back to the colony and shared among the group. oup.

Finding and Sharing Food

When animals form groups, they can increase ase their chances of finding food. It may also o allow them to gather more food than they ey y would as individuals.

Groups of insects such as ants nts and nd bees are able to search for food overr a large arge area. are When W members of the group find a rich ich source sourc of er m bers of the group, food, they signal to other members directing them to the food ood source. sou so

When a lion pack catches ches and kills kil its it prey, the food is shared with alll the members of the group. mem

Amazing Fact!

Honeybees live in large groups. When a honeybee finds flowers with a lot of nectar, it performs a special dance, called a waggle. The waggle dance tells other bees the exact location of the flowers.

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Defense fense A Against Predators

Amazing Fact!

A group of lions living together is called a pride. es Within a pride the lionesses er raise their cubs together e can c and any cub in the pride suckle milk from any y female.

H How does forming groups help animals stay safe from predators?

In the Afr African savanna, lions often prey on elephants. In the photograph above, two lions elep elephan on as a group of elephants walk by. While w watch the lions may be able to catch an elephant on its own, they cannot take on the whole group. There o ow is a greater risk of getting injured or killed by other elephants in the group. Staying in a group keeps the elephants safe. Forming groups also gives animals a greater chance of survival during fights with other animals of the same kind.

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Different kinds of African animals often form large groups. As a large group, the animals have a better chance of spotting predators.

Another way that forming groups helps animals stay safe is by keeping a lookout utt ffor or predators. As a group, the animals are e able le e to o spot predators faster and warn other err group p members of danger. This gives the animals ea nimals mals in the group more time to flee orr defend defe efen end themselves as a group.

Think Deeply

Generally, living in groups gives animals an advantage to survive. What could be some disadvantages to animals living in groups?

Deer stay safe by keeping a lookout for predators as a group.

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Strength in Numbers bers Imagine a young zebra being chased cha by a lion. The lion is much stronger than the nger and faster fa young zebra and it would not take ta much time before it’s caught. Most zebr zebras however, move in large groups. Evading pre predators as a group increases each individual dividu animal’s chance of survival. Large groups also a confuse the predator and make e it harder to focus on just one animal.

Many types of fish move about in large schools. They swim and change direction in coordinated movements. This makes it difficult for predators like sharks and dolphins to catch them.

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Reproducing and Raising Young g Living in large groups often makes it easier forr animals to find a mate and reproduce. Older er members of the group can also help raise e each ch other’s young. This allows time for different ent members of the group to go off in search arch of food, knowing their young are safe. Living in groups also helps the young oung g animals learn from other members of the group. roup. They may learn to hide from predators ators rs or hunt for fo food. Young animals in groups ups often pla play with w each other. In doing so, they develop evelop the skills they will need to survive e as adults. ts

Living in la lar large colonies makes it easier for ea animals tto find a mate.

Think Deeply

What skills and behaviors can young animals learn by playing with other members g of their group?

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Different groups of animals have different names. Here are just a few: Monkeys – troop Elephants – parade Lions – pride Kangaroos – mob Giraffes – tower See what other names you can find for groups of animals.

Engineer It! Use art and craft supplies to design and build a model of a bird beak. Describe how your beak is suited to the food the bird eats.

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Catching Prey Many animals hunt for prey in groups. ps. When hunting in groups, different members bers of the group can take on different roles. The animals in the group may also o communicate mmunicate with each other to increase the he chances hances of o catching their prey.

tio n

Did You Know?

Hunting in groups also allows ws animals tto use the combined strength gth of the group to prey on animals that are much bigger or stronger. sst A cheetah riskss being ng injured if it tries to take down a wildebeest in a group beest alone. Hunting Hu H increases the and killing he chance hance of catching ca the wildebeest. beest. st. The catch cat is then shared among the members of o the group.

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Killer whales hunt in groups. They communicate with each other to find and catch prey.

Usually, an individual ant would not be able to prey upon a large beetle. As a group, ants are able to overpower the beetle and share the he meal with the rest of the colony.

Activities 5.6 – 5.7

By working as a group, the cheetahs heetahs ahs are able to catch larger prey. Ants work in groups to attack much larger animals as a source of food or for defense.

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Scientists have observed that human activities, such as the burning of fuels, are causing the Earth to warm up faster than usual. This process is called climate change.

What are some ways an environment can change?? How do such changes affect the e organisms in the environment? t?

he e Earth Ea Earth rth are e constantly con o Environments around the changing. They may change cha ange nge e from from season fr se to season. They may y change cha ange nge due tto a flood, drought or fire. Human uma an activities activities tivities can c change environments too. oo. When an environment the types of nvironment ment changes, chan cha organismss thatt live there m may change. Some organisms ms may adapt to the change and continue Some may move to new ue to survive. So places. that place places es. es s. Organisms O s th th are unable to adapt to change move the ec cha an nge or mo n o to a new place, may die.

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Along with higher temperatures, climate change is also causing changes in rainfall patterns, rising sea levels and the melting of sea ice and glaciers. How could these changes affect organisms?

Surviving Change

ion

Think Deeply

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Did You Know?

ca tio n

Rapid, Natural Changes

A wildfire causes auses rapid rap changes to o the environment. environ Plants are not able ab to flee fires like can and ke animals ca many Some y do not survive. su plants in wildfire areas are able re-sprout rapidly after a fire. Others have seeds that germinate in response to the heat and smoke from the fire.

Floods and droughts are extreme weather events that can change an environment rapidly. During a flood, rivers may overflow, blocking the sunlight and air which plants need to survive. During a drought there may not be ood. Some enough water for plants to make food. se changed plants may be able to survive in these d regrow if i conditions. Other plants may die and the environment returns to normal.

During g floods and droughts d animals need to adapt to the cha changes in water and food. Some ome may survive survi and continue to reproduce. Others may flee fle to new areas. Some animals su may not survive.

AB Activity 5.8 123

Seasonal Changes An environment can change a lot from from season to season. There are changes ng in yp pes of temperature, rainfall and in the types here. plants and animals that live there. Some organisms are able ble to t survive survive and und d. O ther may not reproduce all year round. Others ery y dr ry summer um m be able to survive a very dry or very cold winter. monarch butterflies

Many organisms in i seasonal se ea on n environments have adaptations on to t help help them survive. Some animalss m migrate te to new places when conditions unsuitable. Some ditions become bec co animals g go underg underground and hibernate in winter save energy when there is little te er tto sa ave en food available. availab ble

About 500,000 monarch butterflies migrate from the Eastern United States to Mexico in the fall and return in the spring. Female butterflies lay eggs part way through their return to the United States. Due to their short life cycles, no individual butterfly ever completes the full migration pattern.

Amazing Fact!

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Emperor penguins have young during the Antarctic Anta tar tic winter. Although they have adaptations to su urv r ve e in the cold, many young do not survive. survive

winter

spring

summer

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fall

How do the trees and plantss change with the change of seasons? s? How H rvive? does this help them survive?

Unlike animals, plants cannot migrate to new places as the environment changes during ment c men es d seasons. Some plants ts die e whe when there is not enough water during ng summer, or it gets too cold during winter. er.

Think Deeply Some plants produce seeds that are inactive, or dormant, when it is too cold or too dry. How does this adaptation help the plants? The needle-like leaves of a spruce tree. p

Many plants have e adaptations adaptation to survive seasonal changes. trees lose their hanges. es Deciduous cidu leaves through energy when there is rough h fall to save en e less sunlight leaves grow back in nlightt in winter. The le spring. – they keep g. Other er plants are evergreens e theirr leaves all year rou round. Pine trees have thin, needle-like eedle-like leaves leave with wit a waxy surface. This water loss and stops the his helps reduce reduc w leaves freezing. es from freez

AB Activity 5.9

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Human Changes

Go Online! The large-scale clearing of forests by humans is called deforestation. More than half of the world’s tropical rainforests have been destroyed by deforestation. This has caused many organisms to become extinct. Find out more about deforestation on the NGScience website. QuickCode: T7B4

Throughout history, humans have been been en changing the environment in many any ways. ways. We change the environment when when we we cut down trees for wood, or dig dig mines mines to to the ground. ground. We We take resources from under the change the environment when when we we clear clear land to make way for roads,, houses houses and and cities. c it Pollution can also change ange tthe he environment. environ armful substances substan Pollution is when harmful are added to the air, water water or or land. land. Human changes ges to to the the environment enviro can affect the there in he organisms organisms living liv many ways. ys. There There may may be b changes in the availability itty of of food, food, water wate or shelter. The types of in the environment of organisms organisms living liv can also change. also c hange.

Think Deeply

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Cities often have higher temperatures than the natural environments they replaced. Why is this so?

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Human activities can also change the natural flow of streams and rivers. This affects the plants and animals that were dependent on the water for survival.

Human n changes to the environment nvironment have ha caused many o organisms to be endanger endangered. Endangered means the Endanger organism is in danger of disappearing forever. disappea

Discuss the different ways humans can change the environment and the effect it has on the organisms that live there.

Did You Know? Know

ati on

When humans make big changes to the environment, the organisms living there are unable to adapt and do not survive. When forests are cleared to make way for human activities, the plants die, as do many of the animals that cannot move to new areas.

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The Gold Coast, Australia was built on a coastal wetland environment.

Adapting to Human Human Changes Ch All over the world,, people people have cleared c natural environments to o make mak ke k e way for cities and homes. Sometimes, animals are nimals as a re able to adapt to living in these urban n or or city city ty environments. en env viron

Australian white ibis

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The natural natu habitat of the Australian white nat ibis is a coastal wetland. When its habitat wass cleared to make way for cities, the c ibises survived by feeding on food scraps in trash tra cans.

ent monkeys living in an urban environment

Many monkeys and other small mammals such as rodents and squirrels have become well-adapted to urban and city environments.

Parks and gardens are often constructed in and around urban and city environments. m ts. The T plants that live there are adapted to o living in the environment.

Activity 5.10

Often, changes to an environment made by people cause the animals that live there to die or move to new places. What are some things people can do so that more animals are attracted to cities and neighborhoods?

Think Deeply

Discuss some other examples of organisms adapting to human changes ada to the environment.

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Science Words

Re ga le du ca tio n

Use the words to complete the sentences. adaptation nocturnal mimicry

hibernate dormant

deciduous evergreen

animals are active during the night and nd sleep or rest during

the day.

trees lose their leaves through the he fall to save sa energy when there is less sunlight in the winter.

trees keep green leaves throughout hroughout the th year.

A seed that is inactive and will not germinate iis

Some animals go underground and da

rganism looks loo or acts like another organism An adaptation where an organism . is called

during winter months.

is a trait trai or behavior that helps an organism survive.

Review

List two adaptations ptations that help each organism survive in its environment.

(a)

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(b)

(d)

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(c)

List the environment each plant can be found and d one adaptation adap that helps them to survive.

(a)

(b)

How can mimicry help an organism nism to survive? s

Describe two ways that living help individual animals survive. ng in groups gro

List two natural changes ange to an environment.

List two ways people change an environment. ople can cha

What happenss if organisms are not able to adapt to changes in organis their environment? nment?

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In the Field

Ecologist If you are interested in all sorts of organisms and how they interact within their environment, then maybe you’d like to be an ecologist. A community of living things and their interactions with their environment is called an n ecosystem. An ecologist is a scientist who studies sttudies es these ecosystems.

Ecologists study a wide range of interactions action ons and and relationships within a given ecosystem. em. They They may may study small parts of an ecosystem m such such su ch as as small smallll bugs living in the soil. They may also also sstudy tudy llarge arge arg interactions such as fish populations ations in in the the ocean oc or how rainforests effect the atmosphere. atmosphere. phere.

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ca t Ecologists E co c ol usually choose a specific environment orr living thing to study. For example, an ecologist o may only study desert or ocean environments. m They may also choose to study one type of interaction such as weather events or how human activities impact environments. If you were an ecologist, which environment or organism would you choose to study?

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A Closer Look

The Great Migration

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One of the largest movement of animals in groups is the Great Wildebeest Migration. During this spectacular event, more than two million wildebeests, zebras and gazelles migrate in a circular pattern as they follow green pastures from the Serengeti in Tanzania to the open grasslands in Kenya. In one year, the animals move more than 800 kilometers.

Go Online! line!

Watch the massive movement of animals mals during the Great est Migration on Wildebeest the NGScience Science website. QuickCode: kCo X5Z7

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ca t

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During the migration, the animals pass through the habitats of predators such ch as as lions and cross crocodile infested rivers. vers. Moving in such a large group increases rease ea ases the the th nima als. ls. chance of survival of individual a animals.

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Organisms of the Past

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In this chapter you will ...

• describe how fossils provide evidence of organisms rganisms ong ago. and the environments in which they lived long sil data and an • identify and describe relationships in fossil organisms that are alive today. ived long lon ago • provide evidence of organisms that lived but have become extinct.

What organisms lived on Earth rth long ago? How do we know they existed?

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ca tio Go Online!

Access interactive int content relating tto this topic on the NGScience website. NGSci ngscience.com gs

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Life on Earth Long Ago Go Online! Take a virtual field trip to the Ice Age and discover more about fascinating woolly mammoths on the NGScience website. QuickCode: T6V3

Woolly mammoths were large elephant-like ntt-liike mammals that roamed the Earth about ou ut 20,000 000 eA g years ago during a period called the Ice Age. ery cold. old d. Mostt o During the Ice Age, it was very of the Earth’s land was covered d in ice. Woolly Woo o ll y mammoths were well-adapted apted to living livi y covered in in the cold. They had a body blubber fur and a thick layer of blubber.

woolly mammoth mot

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Over many years, the climate on Earth changed. The temperature increased and much of the ice melted. The food that woolly mammoths ate was no longer available. They were also hunted by people. Eventually they become extinct about 10,000 years ago. An organism becomes extinct when all of its kind are no longer alive.

uc a

How do scientists know about woolly mammoths if they became extinct so long ago?

An ancient cave painting of cavemen hunting a mammoth.

al e

We know a lot of things about woolly mammoths. We know about their size, body dy dy covering, what they ate and where they y lived. lived. We know these things because scientists have entisst h ave found evidence of their existence. They hey have have found frozen mammoths deep under er the t ice. ce They have found skeletons, tuskss and and teeth. teeth. Paintings in caves are also evidence off ttheir en e o existence long ago.

Activity 6.1 Activit

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Causes of Extinction Go Online! Scientists have discovered that human activities, such as the burning of fuels, are causing the Earth to get warmer. It is feared that this could cause many more extinctions. Find out more on the NGScience website. QuickCode: C9D3

Did You Know? About 66 million years ago, three-quarters of all plants and animals on Earth became extinct. Scientists believe this mass extinction occurred when a large asteroid hit the surface of the Earth.

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Using evidence, scientists have discovered red th that life first appeared on Earth over three billion years ago. Throughout this time, different rent kinds of living things became extinct and nd new kinds of living things evolved. The process of a new n kind of living thing gradually from an y developing fr existing living thing is called d evolution. evolutio Living things can become me extinct for different reasons. In the case of the woolly mammoth, the slow changing off the climate, climat called climate change, caused the e environment environme to become unsuitable for the woolly mammoths. ma Living things can also become extinct due be to more rapid changes change to their environment. Rapid changes include things like volcanic anges can in eruptionss and wildfires. Rapidly-spreading wild diseases can also cause extinctions.

Human activities can also lead to the extinction of living things. The thylacine was a mammal that was only found in Australia. Due to hunting by people, the thylacine became extinct about 100 years ago.

ed u

thylacine acine

Changes to a living thing’s habitat itat by y people can c ca also cause extinction. Habitats ts can an be changed chang ads, houses and a cities. when we make way for roads,

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Go Online! Watch a fossil slideshow on the NGScience website. See if you can guess the organisms that formed the fossils. QuickCode: B7B8

Fossils How Do Fossils Form? Scientists can learn about the characteristics haracteristics of organisms that lived millionss o off y years ears ago ago by looking at fossils. A fossil iss the the preserved preser erved remains or trace of an organism. ga anism sm. Most of the time when an an organism organism dies, di its remains are eaten orr b broken roken down down by b other organisms, leaving no For an no ttrace. race. F or a n organism to form a fossil, it m must be buried ust b eb uried in mud, sand or other substance nce soon soon after aft fte er iits death.

Amazing Fact!

To be called a fossil, a specimen must be more than 10,000 years old. The oldest fossils ever discovered are over three billion years old. That is almost as old as the Earth itself!

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The process of an organism becoming a fossil is called fossilization.

Organisms from long ago can also be preserved in n amber. amb Amberr is fossilized tree sap. By studying the the amber, organisms in th able to scientists are a about the plants learn abou and animals anima that made habitats long ago. up habita Some amber fossils are more or than 100 million years old. yea

AB Activity 6.2

Did You Know?

ca tio n

Over many years, the layers of mud or sand turn to rock. Groundwater washes away the organism, leaving an imprint in the rock. The imprint is the same shape as the skeleton of the organism. Sometimes the imprint is also filled with rock.

Wh organism may have formed What this fossil? How do you know?

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A Closer Look

How Fossils Are Formed Most of the time when an organism dies, its body quickly decomposes, omposes, leaving no trace it ever existed. Under certain conditions, parts rtts off an an organism such as bones, shells and teeth, can become e buried b ried in layers laye of s is i called foss sediment before being fully-decomposed. This process fossilization. Let’s take a closer look at one way fossilization occurs. s

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AB Activity y 6.3

An organism dies. es. The soft, fleshy parts par of its body begin egin to decompose. e.

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2 The skeleton of the organism gets covered in sediment, such as mud and sand. Layers of sediment form on top.

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yers of form on 3 As more layers top, the sediment around iment arou the organism’s anism’s skeleton compacts acts and turns to rock. through the Water seeps thr rock, dissolving the skeleton. Minerals nerals fill the t spaces in the rock where the skeleton was, leaving eaving a fossilized replica of the skeleton. ke

4 The fossil is discovered by scientists during excavations or when layers of rock become exposed due to weathering and erosion. Fossils are carefully removed and taken to laboratories to be studied.

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fern-like fossil

dragonfly fossil

Learning from m Fossils Think Deeply What can scientists infer if they discover a plant and an animal fossil in the same piece of rock?

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By studying fossils, ls, scientists are able to learn about life on Earth rth long ago. ag They can learn about which plants grew in different hich types of pl environments. ments. They can ca learn about animals sil of a skeleton skel too. A fossil can let scientists know an animal’s al’s size and an body parts. They can also work out how the animals moved and what food ate. d they ate

Archaeopteryx pteryx fossil

The Archaeopteryx was a bird-like dinosaur that lived on Earth about 150 million years ago. Scientists are able to use Archaeopteryx fossils ssils as evidence to make predictions about how the animal looked, moved and what it ate. Wings and feathers are evidence that Archaeopteryx haeopteryx could fly. Sharp claws and teeth means an it probably ate other animals. Archaeopteryx optery

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Scientists tists can c use fossil evidence to learn about how the Earth has changed over time. A a b ttrilobite rilobit was an animal that lived in the ocean more m ore than tha 500 million years ago. When a ttrilobite rilobite fossil is discovered on land, scientists can c an iinfer that the area was once underwater. When the fossils of tropical plants are W discovered in the Antarctic or Arctic regions, we can infer that those areas were once much warmer. How deep underground a fossil is discovered can also help scientists learn about the Earth in the past. Older fossils are found deeper underground than newer fossils.

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Fossilized dinosaur footprints are evidence that dinosaurs once walked on the land. Fossilized woolly mammoth footprints may indicate that the environment was once much colder than it is now.

AB Activity 6.4

ca t

Another way scientists can learn about living things and the Earth long ago is by studying trace fossils. A trace fossil is evidence such as a footprint, burrow, nest or eggshell that indicates the presence of life.

A fossilized dinosaur footprint is trace evidence that dinosaurs lived long ago.

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A Closer Look

Dinosaurs hm ore tthan h Dinosaurs were a diverse group of animals that ruled the Earth more 200 millions years ago. The word dinosaur comes from Greek ek words ords which wh mean ‘terrible lizard’. Like lizards, dinosaurs were reptiles. es. They ey were e cold-blooded and reproduced by laying eggs. Scientists have been able to learn a lot about dinosaurs from urr fro om tthe h large number of fossils and trace evidence that have been all over the en discovered disco world. Dinosaurs varied greatly in size, body shape,, where whe e they th lived and what they ate.

Go Online! Go back to the time when dinosaurs ruled the Earth in a video on the NGScience website. QuickCode: A8M8

Tyrannosaurus aur urus u

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Argentinosaurus Arg gen ntitnosa

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Stegosaurus

Based on fossil evidence, scientists have discovered and named more than 700 different kinds of dinosaurs. One of the most well-known dinosaurs, Tyrannosaurus, was up to 14 meters long and weighed up to 10,000 kilograms. It had a large rge head with sharp teeth. Tyrannosaurus was a a meat-eater, feeding on other dinosaurs. aur

Think Deeply

For how many years did dinosaurs roam the Earth?

The largest of all dinosaurs discovered ed wass tthe h Argentinosaurus. Fossil evidence shows ow ws tthat hatt this gigantic, plant-eating dinosaur aur could could reach re lengths of more than 40 meters. rs. Fossils and other data collected by scientists colle show that the dinosaurs became becam extinct about 66 million years ago.

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crocodile

Learning From om Organisms Orga Most of the fossils ils and trace fossils discovered by scientists are from that are now rom organisms o extinct. Usually, organisms organism become extinct when they are not able to adapt to changes in their ad men environment. Sometimes, scientists discover fossils of metimes, scie organisms anisms that th are still around today. These anisms have h organisms been able to adapt, survive and reproduce as the environment changed. crocodile fossil

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horseshoe crab fossil

Fossils that are similar to organisms alive today oday can tell us things about the environment in the he past.

ve survived rvive Crocodiles and horseshoe crabs have on Earth for millions of years. By looking king at where wh these animals live, what they eat, and how at, a nd h ow they move and reproduce, we can infer nf r things th ng about the environment in the past.

Activities 6.5 – 6.6 6

horseshoe crab

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Science Words

Re ga le du ca tio n

Use the words to complete the sentences. extinct evolution

climate change fossil

fossilization trace fossil

The process of an organism becoming a fossil is called

ally developing develop The process of a new kind of living thing gradually from an . existing living thing is called

The slow change of the Earth’s climate is called

is evidence such as a footprint, otprint, burrow, burr nest or eggshell A that indicates the presence of life in the past.

An organism becomes

is the preserved remains emains or trace tra of an organism.

when all of its kind are no longer alive. whe

Review

True or false. (a) Dinosaurs are e an example examp of extinct animals. (b) Some extinct ct animals live on Earth today. (c) Changes to the Earth Earth’s climate can cause plants and animals to become e extinct.

How have ve scientists been bee able to learn so much about animals that lived on n Earth so long ago?

In point form, d describe how fossils form.

What is the difference between a fossil and a trace fossil? Wha

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What things can scientists learn from trace fossils?

Paleontologists discover trace fossil footprints and leaf fossils in the same layer of sedimentary rock. What can they infer about the environment when these organisms were alive?

Re ga le du ca tio n

d its environment. environme Describe the organism that formed each fossil and (a)

(b)

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In the Field

Paleontologists If you are fascinated by the great diversity of organisms that lived on Earth millions of years ea ars ago, then maybe you’d like to be a paleontologist. ntolo ogist st. A paleontologist is a scientist who searches ches ffor orr rgani nisms sms all alll a and studies the fossils of all kinds of organisms over the world! Paleontologists are trained to use se e special spec pecial ttools ools ols tto carefully remove fossils from the th he rocks roc ocks and and nd soil so in which they are found. They ey y study study udy the the fossils foss fo ss to work out how old they are the e and and to to learn learn lea rn about ab interactions of organisms long ago. on ng a go.

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Fossils discovered by paleontologists are used d tto o build models of all kinds of organisms. These se are are often donated to museums so that people allll over le a over er the world can learn about the history off life our life on on o ur amazing planet!

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

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