Interactions within Ecosystems — Science Test Study Guide

Science Test — Wednesday May 22g 2013

Part A- Identify Living and Non-Living Elements in an Ecosystem & TheOrganization of LifeReview the information sheet as well as the Matching Quiz for NewVocabulary(Multiple Choices & Short Answers)

Part B - Food Chains and Food WebsReview information sheets and questions(Short Answers)

Part C- Pesticides: Poisons in the Food ChainReview information and questions(Short Answers)

Part D- Technology and our Environment(Long Answer)

An ecozone is a geographic area whichshares common living and non-livingelements. The living elements are plants,animals and people. The non-livingelements are air, water, soil and rocks.Ontario has three ecozones: Hudson Plains,Boreal Shield, Mixedwood Plains.

What is an Ecosystem?An ecosystem is a geographic area whereplants, animals, people, air, water, soil androcks interact as a system. Interact meansthe way in which plants, animals and peopleuse living and non-living elements tosurvive.

The Living (Biotic) Elements

Plants include trees, shrubs, flowers,grasses and mosses. Living things like algae(e.g., seaweed) and fungi (e.g., mushrooms)do not belong to the plant family.Animals can be divided into two groups:vertebrates (animals with backbones) andinvertebrates (animals without a backbone).All animals eat things that have been alive.People are social animals that choose to livein family groups. People have changed theenvironment to suit their needs.

The Non-living (Abiotic) Elements

Air is a combination of different gases likenitrogen (78%) and oxygen (21%). Animalsand people breathe air to obtain oxygen tostay alive. Plants need carbon dioxide gas tostay alive.

Water is a combination of hydrogen andoxygen. Water can be found in threedifferent states: liquid, solid (ice) and gas(water vapour). The bodies of many livingthings are 50 to 90 percent water.

Soils are a combination of biotic and abioticmaterial. The biotic material is livingburrowing animals (e.g., earthworms) anddecaying plant and animal life. The abioticmaterial is sand, silt, clay and minerals.Rocks are a combination of minerals andother substances like cooling lava or theskeletons of dead marine animals.

A terrarium-aquarium

A terrarium-aquarium is an ecosystem in awatertight container that has two distinctsections; a terrarium that consists of a smallindoor garden, and an aquarium that consistsof a small body of water. Theterrarium-aquarium ecosystem is a placewhere plants, animals, air, water, soil androcks interact as a system.

A Few Human-made Features Within aTerrarium-aquarium

Use the biggest rectangular container thatwill fit in your classroom. A ten-gallon tankis the minimum size. Place about onecentimetre of crushed charcoal at the bottomof the container. Use a filter to keep thewater clear. Select a filter that will allow thecreation of a tiny waterfall. The water pathmust be made of rock with a waterprooflayer underneath. The water path will leaddirectly to the aquarium section.

Grade 7 Science and TechnologyStrand 1: Interactions in the Environment

What is an Ecozone?

Identity Living and Non-living Elementsin an Ecosystem (page 8)

Teacherleddiscussion

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Activity 2 Grade 7 Science and TechnologyStrand 1: Interactions in the Environment

Instructions: Read for understanding the facts onpage 8 then complete all sections on this page.

1. What is an ecozone?

An ecozone is a geographic area which shares

common living and non-living elements.

5. What are the four n-bving (éotic) elements?

a)Aw b) WaLer

c)Soil 4 locks

Identify Living and Non-living Elements in an EcosystemTeacher’s Answers (page 10)

6. Why is soil beth a living -léving element?

Almost all soil wks contain lii and

non-living elements - often the living examples

7. In the spaces below, label or draw appropriately.

a) What are the two major gases in air?

Nitrogen (73%). Oxygen (2196)b) Draw three diagrams that represent the three

states of water in the spaces below.

2. What is an ecosystem?

An ecosystem is a geographic area where plants,

animals, people, air, water, soil and rocks interact

as a system.

are too small to be seen

3. What does interact mean?

Interact means the way in which pIaats animals

andpeople use living and noa.&ving elements to

survive.

4. What are the living elements (bäic)? Law oneexample of the living elements that can be seenin a park with trees and a pond.

a) A few examples Dr3W a plant(s) toun4 li a parkof plants are:

Treet sbr’u)c

fiowert araccesand mocaec

c) Draw a diagram of biotic soil elements.

b) A few examples ofpark animals are:

$4L racoon.

Draw an animal(s) found in a park

wormcorrm

Grasshopper

Draw a socialc) An example of socialactivity in a park:

A nature hike

t)irouah a i,ark

What are the abiotic soil elements?

Ablotk so ekeflt(

(l)and (2)

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d) Rocks are a combination of:

Cealina lava. etc.

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The organization of fe

The Organization of LifeAs you have seen, polar bears can tolerate a wide range ofenvironmental conditions. They survive the bitter cold and fiercewinds of an Arctic winter, and the heat of the summer. They surviveon land, on ice, in fresh water, and in the cold salt water of HudsonBay. Bears see well enough to hunt in the dark of northern winter,and the almost perpetual day of northern summer. Few animals areadapted to so many different conditions or factors.

The changes in temperature, the changes in the amount ofsunlight, the strength and variation of the wind, the amount of rainor snowfall, and the presence of salt or fresh water are all abioticfactors of the polar bear’s environment. Abiotic factors are the non-living, physical factors of an environment.

There are other factors that affect the polar bear. If seals move toa new area, the bears must also move. If there are fewer fish in thebay, there will be fewer seals, and so the bears will go hungry. Effectssuch as these, caused by other living things, are the biotic factors ofthe environment.

Organizing RelationshipsNo organism lives alone, not even the solitary polar bear. All organisms haverelationships with other living things, as polar bears do with seals, fish, and people.They must also deal with the abiotic factors in their environment. Ecologists organizeall of these relationships among organisms and their environment to help study theinteractions. They do this by using terms to describe systems of living things, startingwith the individual living thing (an organism) and progressing to the largest system,which includes every living thing on Earth (the biosphere), as shown in Figure 1.

Ecologists use the term “ecosystem” to describe a wide range of systems. Some arelarge and some are very small. For example, the ice-floe ecosystem of Hudson Bay isvery large. The ecosystem is made up of a community that includes populations oflarge organisms such as polar bears and seals, and also many populations of smallorganisms such as algae and bacteria. However, we can also speak of a temporaryspring pond as an ecosystem, with a community made up of populations of tinyorganisms (see Table 1).

Small ecosystems can also exist withinTable 1: Three Ecosystems larger ecosystems. For example, the

Ecosystem Some populations in the ecosystem inside a rotting log is part of thecommunity larger ecosystem of the forest.

ce-floe system polar bears, bearded seals, Biomes are usually large and containof Hudson Bay ringed seals, herring, krill,

algae many ecosystems. The boreal forest biomestretches from the Atlantic coast through

raccoons, wood frogs,small pond mosquitoes, dragonflies, central Canada and north of the prairies to

fairy shrimp, algae the western mountains. This biome includesabandoned city cats, mice, ants, chickadees, many coniferous forests, and also thelot crab grass, dandelions ecosystems in their clearings, lakes, streams,

and rivers.

( OrganismAn organ sm is a singe liv ngthing Ecologists may studyfeed ng, da ly movements, orreproduction of the p0 ar beato help them understand theecological niche of theorganism in its ecosystem

258 Unit 5

Understanding Concepts j1. Explain the following terms in

your own words: population,community, ecosystem, biome,and biosphere.

2 Table I shows some of thepopulations in the community that jmake up a pond ecosystem.Create a list of abiotic factors thatwould affect the organisms in thatecosystem.

3. In Table 1, the community oforganisms that might be presentin the ecosystem of an abandonedcity lot is not complete.

(a) What other organisms might bepresent in the lot eitherpermanently or temporarily?

(b List the biotic and abiotic factorsthat mi9ht affect the organisms inthe abandoned lot ecosystem.

T,;__

cosystemAn ecosystem is a system of livingthings that interact with each other and

ith the physical world. An ecologistmight study how changes in snowfallaffect the community that lives in thece-floe ecosystem.

• BiosphereThe biosphere is all of the biomes,all of the ecosystems on Earth, fromThe poles to the equator, from the

. atmosphere to kilometres into thePock of the Earth’s crust. Whereveriing things are found, that is the

oosphere. An ecologist might studyhow the amount of light comingfrom the Sun affects the biosphere.

oA biome is a collection of relatedecosystems. An ecologist mightstudy how climate change affectsthe ecosystems of the Arctic biome.

0 PopulationA population is the number oforganisms of the same speciesliving in an ecosystem, Ecologistsmight study the effects of anincreasing population of polarbears on the ice-floe ecosystem.

1

o CommunityA community is all of thepopulatons of organismswithin an ecosystem.Ecologists might study theeffects on the communitywhen one of the speciesbecomes extinct.

sign ChallengeHow could you design yourlandfill site to discouragebears from visiting?

Interactions Within Ecos’tstems 259

Blackline Master 52.1

Matching Quiz for New Vocabulary

Name:_________________________________ Date:

________________

In front of each of the following definitions, place the letter for the term that best fits thedescription. Answers may be used once, more than once, or not at all.

1. The number of organisms of the same species living in a community.2.

____

All the non-living physical factors which influence living things.3. if The related ecosystems which share the same climate.4. C A single living thing.5. 1 The number of goldfish living in the pet store tank.6.

____

The entire surface of a planet where life is found.7. c A system of living things which interact with each other and with the physical

world.

8. ,4 All the effects caused by living things.. f All of the organisms that can interbreed under natural conditions to produce

fertile offspring.10.

____

An abandoned city lot which supports cats, mice, chickadees, ants, crabgrassand dandelions.

11.

____

All the living things found in the school grounds.12.

____

A non-living factor, such as the amount of oxygen, which influences the livingorganisms.

13.

____

All the ecosystems of the Prairies which share similar temperature andprecipitation ranges.

14. (rh, Polar bears live on ice floes in Hudson Bay with bearded seals, ringed seals,herring, krill and algae.

15. b The number of humans in your classroom right now.16. Life does not exist on Venus, therefore it cannot be called this.17. JZ All of the Earth’s biomes, when considered together.18. /E The number of dogs living in Sault Ste. Marie.19. C A cat sleeping in a chair.20.

_____

All the plants, animals, fungi, and single-celled organisms found in a fish tank.

A) Biotic D) Species G) EcosystemB) Abiotic E) Population H) BiomeC) Organism F) Community I) Biosphere

138 Interactions Wzthin Ecosyterns/B1ack1ine Masters © 2000 Nelson Thomson Learning

IA food chain is a feeding relationshipbetween organisms in an ecosystem. I

I Energy is transferred from producers Itjo consumers and predators. J

A food web is made up of severalfood chains in an ecosystem.

What is an ecosystem?

rAn ecosystem is a geographic areain which plants, animals, people, air;water; soil and rocks interact as a

system.

Food ChainTropical Grasslands Ecosystem:Small grass area in Kenya, Africa

Arrows show the feedingrelationship and flow of energyfrom producers to consumers

tPrimaryConsumerZebra eatsgrass togrow

The SunEvery food chain begins with the sun.Plants use sunshine to gather and storeenergy. Role: to provide plants withenergy (sunlight> to live and breathe.ProducersProducers are organisms (e.g., plants,algae) that use sunlight to make their ownfood. Role: to produce oxygen, to be foodfor organisms higher in the food chain.ConsumersConsumers are organisms that feed onothers below them in the food chain.Role: to eat organisms below them in thefood chain, to reduce the number ofrapidly multiplying organisms.

ScavengersScavengers eat dead or decaying plantsor animals. Rats, racoons, vultures,crows, flies, beetles, millipedes andcentipedes are a few examples ofscavengers. Role: to remove unwantedrefuse (dead or decaying plants andanimals) from the surface of the Earth.DecomposersDecomposers like centipedes andmicroorganisms break down theremains of dead plants and animals.Role: to turn organic matter (deadplants & animals) into inorganic soilmatter (soil minerals) which can beused by plants to grow.

Grade 7 Science and Technology fStrand 1: Interactions in the Environment

What is a food chain?

Introduction to Food Chains and Food Webs(page 20)

Teacherleddiscussion

What is a food web?

Vertical Food Web

Tertiary Consumer: Theseanimals eat animals

Tropical Grasslands Ecosystem (savannah):Very large grass area in Kenya, Africa

Tertiary

t ConsumerLion eatsZebra togrow

Vulture eats dead anddecaying animals

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Grade 7 Science and TechnologyStrand 1: Interactions in the Environment

Introduclion to Food Chains and Food WebsTeacher’s Answers (page 22)

Instructions: Use the facts on page 20 to complete the following.1) What is the role of producers

in a food chain?2) What is the role of consumers

in a food chain?3) What is the role of decomposers

in a food chain?

To produce oxggen and toprovide organisms abovethem with food.

To consume and reducethe numbers of rapidhjmultitluinL7 oruanicmc

To return organic matter(dead plants and animals)to the coil ac inoraanic

below them in food chain, matter (coil minerals).

tTertiaryConsumerTop predatorTurtle is anomnivore

SecondaryConsumer:Trout is acarnivore

Secondary

t Consumer;Frog is acarnivore

tPrimaryConsumer:Fry feed onplants

Producer:Aquatic plants andalgae use sunlightto gather energy

t

Instructions: Construct a food web in the ocean near Australia. Use the following organismsin your food chain: Blue Marlin Xa) People swimming (tertiary consumer);b) Great White Shark (tertiary consumer);c) Blue Marlin (secondary consumer);d) Tuna (secondary consumer);

—__....... Tunae) Big fish + small fish (secondary consumer);t) Fry [newborn fish] (primary consumer);

—___

Label each organism as a producer; primary consumer; secondary consumer.

Ocean Near Australia Food Web

isstrctius: Construct a food chain in asmaN interior Ontario lake, Use thetollc wing organisms in your food chain:a Painted Turlie (tertiary consumer);b) Trout (secondary consumer);C) Frog (secondary consumer);d) Fry [newborn fish] (primary consumer);d) Aquatic plants (producer);Label each organism as a producer;primary consumer; secondary consumer.

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Case Study

Pesticides: Poisons in the Food ChainAs much as 30% of the annual crop in Canada is lost to pests. The pestsinclude weeds, rusts and moulds, birds, small mammals, and insects. Foreach of these pests, we have created a pesticide. Pesticides are chemicalsdesigned to reduce the populations of unwanted organisms, both plantand animal.

Tires and MosquitoesWhat do we do with worn-out tires? Buryingtires in a landfill isn’t possible. After a fewyears they always push through to the surface.Just storing them separately has always been aproblem, because old tires can burn. As tiresburn they create a thick, choking smoke.

There is another problem with tire dumps:tires make excellent troughs for collectingrainwater. The still water, warmed by the sunhitting black rubber, makes an agreeableecosystem for hatching mosquitoes.

(a) Why is it a problem to create afavourable ecosystem for mosquitoes?

Mosquitoes and DiseaseSome mosquitoes carry microbes that causedisease. Malaria is one such disease, as shownin Figure 1. Thousands of people in tropicalareas of the world die of this disease everyyear.

(b) Used tires are often stored in one areaand then moved to another area fordisposal. What problem might thiscause?

Using PesticidesScientists developed a pesticide spray thatcould eliminate mosquitoes. When it was triedon an island, other effects were soon noted.Insects other than mosquitoes began todisappear, and then the number of lizardsbegan to fall.

(c) Why did scientists want to reduce thenumber of mosquitoes?

LIi’[fl1IThe malaria microbe is carried by one species of mosquito,The microbe cycles between animals such as humans andmosquitoes.

Q the parasite is transferred inthe next victim’s bloodstreaiwhen the mosquito bites.

(d)What do you think caused some otherinsects to begin to disappear?

(e) Provide at least two examples of insectsthat you would not want to destroy andexplain why they are important.

(f) Why might the lizards begin todisappear?

276 Unit 5

A

0 A mosquito draws bloodfrom an infected personand picks up the parasite.

Q Malaria microbes infectred blood cells, whichrupture and send sporesinto the bloodstream.

The parasite incubates in theliver and releases microbesinto the bloodstream.

The Problem SpreadsMost people on the island were not tooworried about the disappearance of a fewinsects and some lizards. However, they tooknotice once the local wildcats, which had fedon dead lizards, began to get sick and die.Without the cats the rat population soonincreased. Fearing an outbreak of diseaseslinked with rats, the local people importeddomestic cats.

(g) What problems could be caused bybringing in domestic cats?

nvasion of the CaterpillarsChanges to the food web became even moreobvious when caterpillar populations began toincrease. Apparently, the pesticide affectedwasps and other predators of the caterpillar,but it had little effect on the caterpillars.Once the predators were gone, the caterpillarpopulation increased greatly. Eventually;caterpillars searching for food moved intofields and devastated food crops.

(h) Use pictures of a beetle, cat, caterpillar,grasshopper, lizard, mosquito, rat. andwasp to draw a food web that shows theimpact of spraying with the insecticide.

iological AmplificationPesticides tend to stay in the bodies of animalsthat come in contact with them. (If pestscould easily get rid of the pesticide, it wouldnot he effective.) The result is that theconcentration of harmful pesticides increasesat each level in a food chain. Predators alwayshave more toxic chemicals in their bodiesthan their prey, as shown in Figure 2.

If the body of the prey contains harmfulpesticides, the pesticides will he taken in bythe predator. Predators eat many prey overtheir lifetimes. Each time prey is eaten, theamount of pesticide in the predator increases.This process of increase at each level of a foodchain is called biological amplification.

(i) Predict how scavengers, such as beetles,might he affected b’ biologicalamplification.

Understanding Concepts1. Explain in your own words what

pesticides are.2. Why do pesticides create the

greatest problems for carnivores?

Making Connections3. In Atlantic Canada pesticides

called pyrethoids were used tocontrol winter moths and leafminers in apple orchards.Unfortunately, the chemicals killedmore insects than intended,including predators of red mitesand apple mites. After orchardswere sprayed with pyrethoids, themite population rose quickly,damaging the trees and reducingthe yield of apples. Whatrecommendations would youmake to anyone who planned touse pyrethoids?

j2sign ChallengeMake a list of the problemscreated by disposing of tiresin a landfill site. What otherkinds of garbage might causesimilar problems? Think aboutsome solutions.

The concentration of a pesticide increases as it moves up thefood chain. (in ths case the pestcide is DDT.) The greater thenumber of links in the chain, the greater the amount ofbiologcal ampification. From water to osprey theconcentration of DDT increases 10 million times.

20 ppm DOT osprey

2 ppm DOT pike

0.4 ppm DOT minnow

0.000 002 ppmDOT water

ppm parts per million lone part per million is equivalentto one drop of the chemical in a full bathtubl

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0.03 ppm DOT planktonlsmall animals and plantsl

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SUGGESTED ANSWERS TO QUESTIONS

Case Study(a) Mosquitoes draw blood from people.

Mosquitoes are pests for humans and theiranimals, and may transmit diseases.

(b) Disease-causing mosquitoes can be transportedfrom one ecosystem to another. The newecosystem might not have natural predatorsthat regulate the numbers of the diseasecausing mosquitoes.

(c) By reducing the number of mosquitoes,scientists hoped to reduce disease.

(d) Other insects were also affected by thepesticide.

(e) Many different examples could be provided.They include: bees because they pollinateflowers and make honey, dragonflies becausethey are a natural control on mosquitoes, andscavenger beetles because they act asdecomposers within an ecosystem.

(f) The lizards ate the insects and the toxicpesticides were absorbed into their organs.

(g) Many different hypotheses may be accepted; afew samples are provided. The domestic catsmight introduce new diseases. The new catsmight multiply rapidly and alter the food web.The new cats might find another food sourceand leave the rats alone.

(h) After completing the food web, remove themosquito to view the effect of the pesticide.

(i) Beetles would take in high concentrations ofpesticides from higher-order consumers.

Understanding Concepts1. Pesticides are chemicals designed to reduce the

populations of unwanted organisms, both plantand animal.

2. Pesticides tend to stay in the bodies of animalsthat come in contact with them. The result isthat the concentration of harmful pesticidesincreases at each level in a food chain. Predatorsalways have more toxic chemicals in their bodiesthan their prey.

Making Connections3. Check to see what effect the pyrethoid had on

higher-level consumers. If the insecticide is moreharmful for predators than pests, expect thepopulation of pests to increase over time.