01 Science Alive 6

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Living Thingsin Ecosystems

1Module A Living Things and Life Processes

Thinking

1. There are many largehabitats in the world.

Name some o them.2. There are many small

habitats in your schoolarea. Can you name someo them?

Habitats

In Grade 4, Unit 6, you were introduced to the idea o a habitat.

A habitat is the place where an organism lives.

The picture shows one habitat and two organisms in it.

Namethishabitat.

Namethetwoorganismsinthishabitat.

Whatotherorganismsliveinthishabitat?

A habitat provides organisms with everything they need to

survive.

Giveexamples ofwhat thetwoorganisms in thepicture

need to survive.

Listsomethingsthathabitatsprovideorganismswith.

In this unit, you will learn more about habitats and the organisms

thatliveinthem.Letsbegin!

Link it!HabitatsGrade 4,Unit 6

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A pond habitat.E.g. Frog (animal), waterlily (plant).

Forexamples, refertothe pond ecosystem onpage 5.

Animal: Food, air, water, warmth. Plant: Air, water, light. Reerback to Grade 3, Unit 1.

E.g. Food, shelter, protection rom enemies, a sae place to reproduce and look ateryoung.

1. E.g. Desert, (Arican) grassland,tropical orests, ocean, polarregions.

2. E.g. A tree trunk, a log, a bush,a lea, the soil, a pond, a wall,a fower bed.

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Populations and communities

An organism is a living thing. Many kinds o organisms can live

in the same habitat.

Forexample, ina pondhabitat,youmay nd the following

organisms:

PopulationOrganisms do not usually live alone. They usually live with other

organisms o the same kind.

Organisms o the same kind that live together in a habitat are

called a population.

Forexample,herearethreepopulationsinapondhabitat.

What is thesize of each population in thepictures?

Thesizeofapopulationisalwayschanging.Forexample,it

increases when organisms reproduce. It decreases when the

organisms are eaten by other organisms.

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Duckweed Cattail Water snail Frog

Pond population

Water snails Frogs

Duckweeds

Duckweeds = 4, snails = 3, rogs = 3.



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DOTHIS

Community =

Population 1 + Population 2 + Population 3 + .

Community

Plants and animals o dierent kinds share a habitat.

The dierent plant and animal populations living together in a

habitat orm a community. That is:

Forexample,apondcommunityismadeupofduckweeds,

water snails, rogs and other populations.

Howmanypopulationsof organismscanyouseeinthe

picture?

From habitats to ecosystems

A habitat is the place where organisms live.

The habitat together with the community orms an ecosystem.That is:WB Activity 1

Ecosystem = Habitat + Community

duckweed

dragony

cattail

snails

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Go to your school garden or pond.How many kinds of

plants and animals can you see? These make up the

community.

Four



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Eco meanshouse. Asystem hasparts thatwork together.

rog

ducks

elodea

terrapin

dragony

guppies

water lily

duckweed

cattail

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The picture shows a pond ecosystem. It is made up o the

habitat (the place) and the community (all the dierent kinds

o organisms in the habitat).

Look at the picture ofa pond ecosystem.Howmany

kindsoforganismsdoesithave?

Different ecosystems

There are many ecosystems in the world. Each ecosystem has

a habitat and a community o organisms.

Some ecosystems are large, such as deserts, grasslands,

tropical rainorests and oceans. Others are small, such as agarden, a tree trunk and a pond.

Smallerecosystemscanbepartoflargerones,forexample,

a pond or a river in a tropical rainorest.

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Herearethreeexamplesofecosystems.

A seashore ecosystem

Therearemanykindsof seashorehabitats.Anexampleis

a rocky seashore. Many living things are ound on a rocky

seashore.Thepicturesshowssomeexamples.

Hermit Crab

Barnacles

Starfsh Seaweed

Limpet

Worm

Seagull

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Lizard (Gecko)

Spider

Tree Frog

Flying lizard

Sun bear

Ground ochid

Monkey

Stick insect

Fungi Pitcher plant

Birds nest ern

Pit Viper

Tropical rain forest ecosystem

The tropical rain orest is home to a great variety o

organisms.

Inatropicalrainforest,youwillndtrees,grasses,fernsand

ungi. Ants and cicadas may built nests on tree trunks. Birds

and monkeys may perch and rest on trees.

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Thinking

1. The name tropicalrainorest consistso the words tropical,rain and orest.Explain why.

2. Name some smallerecosystems thatcan be part o a largeseashore ecosystem.

ScienceFun

An aquarium

Some ecosystems are made by

people. These are not natural

ecosystems. They are artificial

e c osys te ms. Exa mp le s a re

aquariums, zoos and gardens. Most

artifcialecosystems also provide all

the things needed for the organisms

to survive.

WB Activity 2

Garden ecosystem

Most garden are man-made ecosystems. People plant trees,

erns and fowering plants. Animals move into the garden rom

otherplaces.Inagarden,youwillndmanyinsectssuchas

ants, beetles, bees and butterfies.

Bee

Spider

Hibiscus

Snail

Buttery

Bird

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1. Tropical ound in the tropics (hot, humid regions near the equator);rain heavy rainall; orest a large area o trees.

2. E.g. Pool o sea water, sandy beach, rocky beach, clis, seashore stream,muddy shore.



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Conditions of ecosystems

There are many kinds o ecosystems on Earth.

Each ecosystem has dierent kinds o organisms. This isbecause the conditions o each ecosystem are dierent. For

example,tropicalrainforestsarehotandwetwhereasdeserts

are hot but dry.

Organisms are aected by the conditions o an ecosystem.

Only organisms that are adapted or the characteristics o an

ecosystem can survive there.

Whatconditions(orfactors)affectthesurvivalofanorganism

inanecosystem?

The actors include:light oodtemperature soilwater other organismsair

Whichofthesearelivingfactors?

Whichofthesearenon-livingfactors?

Link it!Adaptationsin organisms

Grade 5, Unit 4

Characteristicso environmentsGrade 4, Unit 6

In Grade 4, Unit 6, you learnt about light, temperature, water

and other organisms. And in Grade 5, Unit 4 you learnt aboutadaptations o organisms.

Light

In a tropical rain forest, trees block sunlight rom reaching

the ground. Plants, such as erns, that live on the ground have

large leaves to catch as much sunlight as possible.

Gardens have many fowering plants. These

plants need a lot o sunlight to make ood

during photosynthesis. The sunlight also

allows bees and other insects to indfowers.

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This ern has large leaves.

A bee on a mimosa plant.

Light,temperature,water,airandsoil.

Food, other organisms.



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Thinking

1. How are penguins, polarbears and whales adaptedto live in places wheretemperatures are cold?

2. List other ways you havelearnt o how animals andplants are adapted to livein hot and cold places.

Crocodiles keeping warm.

Seaweed in rocks.

The water lily lives in ponds. To get

enough sunlight to survive, the water

lily has large leaves that foat on the

water.

Temperature

Tropical rain forests are very warm. Many

plants are ound there as plants grow well in

warm conditions.

Reptiles,suchascrocodiles,lizardsandsnakesliveintropical

rain orests where it is warm. Reptiles need heat rom the Sun

to get the energy they need to be active. They cannot survive

in cold places.

Thinking

1. Why do sunowers not

grow on the ground o aorest?

2. What do bees get romowers?

3. Vines grow in orests.What do vines do to getsunlight?

4. Name one kind o animalthat does not need lightto survive.

In rocky seashore ecosystems,

the Sun can dry up organisms atlow tide. To prevent rom drying up,

organisms live under stones, in cracks

between rocks and on the shaded sides

o rocks.

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Thetide is the

rise and all othe sea.

1. All three animals have a layer oinsulating at. Penguins also haveeathers and polar bears have hairto keep them warm.

2. Reer to Grade 5, Uni t 4 orexamples.

1. Sunfowers need a lot o light to grow. It isdark on the orest foor.

2.Nectar(sweetliquid).3. To get enough sunlight, vines climb up

walls, ences or other plants.4. E.g. Earthworms.

For adaptations, reer toGrade 5, Unit 4.



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Water

Alllivingthingsneedwatertosurvive.Habitatsthatgeta

lot o rain usually, such as tropical rain forests, contain a

great diversity o lie. In dry places, such as deserts, there is

less lie. Only organisms that need little water to survive are

ound there.

In tropical rain orests, many living things live close to streams

and rivers.

Forexample,frogslayeggsinthewater.Thetadpolesthat

hatch, grow and eed in the water.

Other living things also live near in water habitats. Fish live

in water. To breathe in water, they have gills. To move, they

havensandatail.

On a rocky seashore, waves can wash away animals.

However,theyareadaptedtosurvivetheseconditions.Crabs

havestrongclawstoholdontorocks.Limpetshavesuckers

whichholdtightlytorocks.Starshhaveaatshapethatallows

water to fow over them easily.

Thinking

1. Camels live in hot, dryplaces. How are theyable to go or manydays without water?

2. Cactus plants also livin hot, dry places. Listthree adaptations thehave to conserve wate

3. Name other waysanimals are adapted breathing and moving water.

Seagulls have webbed feetto help

them move in water and walk on wet

sand without sinking into the sand.

Webbed eet

Fewer living things live in a dese

Frogs live closto water.

Limpet Crab Starfsh

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These questions revise work learnGrade 5, Unit 4. Reer back to this in Grade 5.



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Air

All living things, whether they live on land or in water, need air

to survive.

Animalsneedoxygentobreathe.Plantsneedcarbondioxideto make ood.

In a pond, rocky seashore or other water habitats, most plants

andanimalsgettheoxygenandcarbondioxidetheyneedfrom

air dissolved in water.

Food

All living things need ood. Most plants make ood by

photosynthesis. Animals get ood by eating plants or other

animals.

Forexample,ina tropical rain forest, chimpanzeesget

ood by eating ruits, leaves and seeds rom trees. In a rocky

seashore, crabs eat shrimps. And animals can only survive in

a garden i there is ood.

Thinking

In these pictures, nameanimals that are predatorsand animals that are prey.

Link it!Adaptation o

predators & preyGrade 4, Unit 5

Thinking

Guppies can survive in waterthat has little dissolved air.How?

A crab eating a shrimpA chimpanzeeeating ruit.

A garden spidereating a bee.

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Predators: crabs, gardenspider. Prey: limpets, bees.

The guppy comes to the suraceto take in air. In this situation, itsgills are able to serve as lungs.



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This Venus ytrap can

survive in poor soil.

Other organisms

As you have learnt earlier, organisms in an ecosystem depend

on each other to survive.

Forexample, ina tropical rain forest, a stick insect uses

camoufage to protect itsel rom other organisms that want

to eat it.

In a garden, trees provide a place or birds to reproduce and

lookaftertheiryoung.Withoutthetrees,thebirdscouldnot

live there.

Soil

Soil is important or plant growth. Plants get water and minerals

rom the soil.

The soil in gardens is usually loam.Loamcontainsalotof

humus and minerals and is good or growing plants.

Soil in tropical rain forests is oten poor with ew minerals or

plants. Pitcher plants and Venus fytraps get the substances

they need by catching and digesting small insects.

Humus is materialin the soil that has

decomposed. Humusgives soil its browncolour that you see!

A garden plant growing in loam.

WB Activity 3

The nest o a bird in a garden.

Thinking

1. Plants and animalsin water habitatsdepend on each otheror oxygen and carbondioxide. Explain howthis takes place.

2. From your earlier workgive some examples ohow organisms dependon other organisms.

This lea insect is difcult opredators to see it. Can yospot it?

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1. By photosynthesis,plants produceoxygenwhichanimalsuse or breathing.Thecarbondioxidethe animals produce

when breathing isused by plants orphotosynthesis.

2. Reer to Grade 4,Unit 6.



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WB Activity 4

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A pond ecosystem

Try not to disturbthe ecosystemwhen you study it.Do not harm theorganisms.

Studying an ecosystem

The best way to study an ecosystem is to visit and

observe it.

Herearethreequestionstoaskwhenyoustudyan

ecosystem.

Whatarethephysicalconditions?Forexample,is ithot,

cold,wet,dry,sunnyorshady? Whatplantsandanimalslivethereandinwhichpartofthe

ecosystemdotheylive?

Howaretheorganismsadaptedtoliveinthatecosystem?

You can now carry out the activity in your workbook to

observe a pond ecosystem.



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WB Activity 5

1. An organism is a living thing. Organisms live in habitats.

2. A population is a group o organisms o the same kind living together in a habitat.3. A community consists o dierent populations o living together in a habitat.

4. The habitat together with the community orms an ecosystem. Some ecosystems

are large, such as an ocean, a desert and a tropical rain orest. Others are small,

such as a garden and a pond.

5. Each ecosystem has conditions (or actors) that aect the survival o an organism

living in it.

6. The conditions (actors) include other organisms and non-living actors such as

light, temperature, water, air, ood and soil.

7. The best way to study an ecosystem is to visit and observe it.

MyConclusions

Stretch yourself

1. Investigating a rain forest reserve

(a) Organise a class visit to a rain orest reserve in your area.

(b) Observe plants and animals there. Identiy as many as you can.

2. The worlds ecosystems (a)UsetheInternettondoutaboutonelargeecosystemintheworld.

(b)Makenotesaboutwhatyoundout.

(c)Carryoutoneofthesetwoactivities:

(i) Prepare a poster on this ecosystem. Include pictures o the habitat

and some o the organisms.

(ii) Give a brie talk to your class on this ecosystem.

New words

population community ecosystem tropical tide to depend

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EncouragepupilstosearchforinformationontheInternet.Hereisonepossiblewebsite: http://www.worldbiomes.com/biomes_map.htm

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01 Science Alive 6