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66 BiomesC H A P T E R 6

1 What Is a Biome?

2 Forest Biomes

3 Grassland, Desert, andTundra Biomes

PRE-READING ACTIVITY

Four-CornerFoldBefore youread this chap-

ter, create the FoldNoteentitled “Four-Corner Fold”described in the Reading andStudy Skills section of theAppendix. Label each flap ofthe four-corner fold with“Forest Biomes,” “GrasslandBiomes,” “Desert Biomes,”and “Tundra Biomes.” As youread the chapter, define eachbiome, and write characteristics ofeach biome on theappropriate fold.

This thorny devil lives in the desertof Australia. The grooves in its roughskin help it collect waater to drink.Water from rain or condensationlands on its back and runs along thetiny grooves to iits mouth.

OverviewTell students that the purpose ofthis chapter is to help them under-stand the different terrestrial bio-mes found throughout the world.Biomes are described by their vegetation, temperature, and pre-cipitation. The terrestrial biomesof the world include tropical rainforest, temperate forest, taiga, tem-perate grassland, desert, tundra,chaparral, and savanna. Threats to habitats in each biome are alsodescribed.

Using the Figure Animals such as this thorny devilhave adapted to the desert’s hightemperatures and low precipita-tion. Ask students to identify adap-tations of the thorny devil in thephotograph. (Sample answers: thecolors of the thorny devil’s skin helpit blend in with the desert environ-ment, it has pointy spikes on itsrough skin to help it ward off preda-tors. And its thick skin helps retainwater in the hot, dry climate.) Askstudents to think of other desertanimals and explain how each hasadapted to living in a hot, dryplace. (Sample answer: Armadilloshave thick skin and are nocturnal.)

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152 Chapter 6 • Biomes

GENERAL

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PRE-READING ACTIVITY

LS 3a Species evolve over time. Evolution is the consequence of the inter-actions of (1) the potential for a species to increase its numbers, (2) the geneticvariability of offspring due to mutation and recombination of genes, (3) a finitesupply of the resources required for life, and (4) the ensuing selection by theenvironment of those offspring better able to survive and leave offspring.(Section 2 and Section 3)

LS 4c Organisms both cooperate and compete in ecosystems. The interrela-tionships and interdependencies of these organisms may generate ecosystemsthat are stable for hundreds or thousands of years. (Section 2 and Section 3)

LS 4d Living organisms have the capacity to produce populations of infinitesize, but environments and resources are finite. This fundamental tension hasprofound effects on the interactions between organisms. (Section 2 andSection 3)

LS 6b Organisms have behavioral responses to internal changes and to

external stimuli. Responses to external stimuli can result from interactions withthe organism’s own species and others, as well as environmental changes;these responses either can be innate or learned. The broad patterns of behav-ior exhibited by animals have evolved to ensure reproductive success. Animalsoften live in unpredictable environments, and so their behavior must be flexibleenough to deal with uncertainty and change. Plants also respond to stimuli.(Section 2 and Section 3)

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Earth is covered by many types of ecosystems. Ecologists groupthese ecosystems into larger areas known as biomes. A is alarge region characterized by a specific type of climate and certaintypes of plants and animal communities. The map in Figure 1shows the locations of the world’s major land, or terrestrial, bio-mes. In this chapter, you will take a tour through these terrestrialbiomes—from lush rain forests to scorching deserts and the frozentundra. When you read about each biome, notice the adaptationsof the organisms to their very different environments.

Biomes and VegetationBiomes are described by their vegetation because the plants thatgrow in a certain region are the most noticeable characteristics of that region. The plants, in turn, determine the other organismsthat can live there. For example, mahogany trees grow in tropicalrain forests because they cannot survive cold, dry weather.Organisms that depend on mahogany trees live where trees grow.

Plants in a particular biome have these adaptations thatenable them to survive there. These adaptations include size,shape, and color. For example, plants that grow in the tundratend to be short because they cannot obtain enough water togrow larger. They also have a short summer growing season.Desert plants, such as cactuses, do not have leaves. Instead, cac-tuses have specialized structures to conserve and retain water.

How are ecosystems related to biomes? (See theAppendix for answers to Reading Checks.)��Reading Check

biomeObjectives

� Describe why vegetation is used toname a biome.

� Explain how temperature andprecipitation determine whichplants grow in an area.

� Explain how latitude and altitudeaffect which plants grow in an area.

Key Termsbiomeclimatelatitudealtitude

S E C T I O N 1

What Is a Biome?

Figure 1 � The ecosystems of theworld can be grouped into regionscalled biomes. These biomes, shownbelow, are named for the vegetationthat grows there.

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TT BellringerTT Biomes of the WorldTT Temperature Vs. Precipitation

OverviewBefore beginning this section,review with your students theObjectives in the Student Edition.In this section, students are intro-duced to biomes. This section alsoexplains how climate and biomesvary with latitude and altitude.

Have small groups of students lookat a world map. Ask students tofind the latitudes of their city ortown, and then find a large city in Finland, Argentina, Vermont,and Cameroon. Have them com-pare these latitudes to the map inFigure 1 in order to find the bio-mes associated with these cities.Ask students to think about whythe biomes might be different ineach of these locations. (Finland has taiga, Argentina has grasslands,Vermont has temperate deciduousforest, and Cameroon has tropicalrain forests. Different biomes havedeveloped at different latitudesbecause of the different climatic conditions.)

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IdentifyingPreconceptionsBiome Mix-up Perform this exer-cise before students begin to readthis section. Write the names of thebiomes of the world on the board.Mix the names up, so they are notin order by latitude. Now ask stu-dents to tell you whether the tem-perature of each biome is hot,moderate, or cold. Then ask stu-dents to tell you whether eachbiome is wet, moderate, or dry.Write their guesses next to eachbiome. Then have students look atFigure 3, to find out how accuratethey were. Logical

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkBiomes are composed of many different ecosystems.

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MISCONCEPTION ALERT

Biome Vs. Ecosystem Students may havedifficulty distinguishing between the termsbiome and ecosystem. This is not an easydistinction—in fact, the terms are not usedconsistently by scientists. A biome and anecosystem are defined by abiotic and bioticfactors, and by the types of interactionsamong the organisms that live in each. Tohelp students understand the difference,discuss the following hierarchy: the bios-phere is divided into biomes, which aredivided into smaller ecosystems.

• Lesson Plan• Active Reading• Section Quiz GENERAL

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Biomes and ClimateBiomes are defined by their plant life, but what factors determinewhich plants can grow in a certain area? The main factor is cli-mate. refers to the weather conditions, such as tempera-ture, precipitation, humidity, and winds, in an area over a longperiod of time. Temperature and precipitation are the two mostimportant factors that determine a region’s climate.

Temperature and Precipitation Most organisms are adapted tolive within a certain range of temperatures and will not survive attemperatures too far outside of their range. Plants are also affectedby the length of the growing season, as shown in Figure 2.

Precipitation also limits the organisms that are found in abiome. All organisms need water. The larger an organism is, themore water it needs. For example, biomes that do not receiveenough rainfall to support large trees support communities domi-nated by small trees, shrubs, and grasses. In biomes where rain-fall is not frequent, the vegetation is mostly made up of cactusesand desert shrubs. In extreme cases, lack of rainfall results in noplants, no matter what the temperature is. As shown in Figure 3,the higher the temperature and precipitation are, the taller anddenser the vegetation is. Notice how much more vegetation existsin a hot, wet tropical rain forest than in a dry desert.

Why does temperature limit which plants can grow

in a certain biome?��Reading Check

Climate

Savanna

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Tropical rain forest Desert

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Figure 3 � Temperature and precipi-tation help determine the type ofvegetation in an ecosystem. As tem-perature and precipitation decrease,the climate of an area becomes drierand vegetation becomes sparser.

Figure 2 � The soil of the tundrabiome is frozen most of the year.Plants such as these have about twomonths in summer to grow andreproduce before temperaturesbecome too cold again.

Using the FigureClimatograms Ask students totrace or draw Figure 3 in theirEEccooLLoogg.. Students do not need todraw all of the vegetation accu-rately; they should just sketch afew key plants. Have studentsleave space near the name of eachbiome. Then have students find theclimatograms (the graphs that givemonthly averages of the tempera-ture and precipitation for eachbiome) throughout the rest of thechapter. On their sketch, ask themto record the range of temperatureand the approximate annual pre-cipitation for each biome from theclimatograms. (You might want toreview how to read a climatogramwith students before they do this.)Have them discuss whether or notthe climatograms match the gen-eral trends indicated in Figure 3.(they should match approximately)Ask students to figure out wherechaparral fits into the figure. (Itshould fit between temperate grass-land and desert.) Visual

Plants and Animals Ask studentsto research two of their favoriteplants or animals to find out whichbiome each organism lives in. Havestudents write a short paragraphabout each organism that details its maximum and minimum tem-perature and precipitation needs,its typical biome, and some of theadaptations that allow it to survivein that biome. Have them include a picture of the organism above thedescriptive paragraph. Encouragestudents to add these paragraphs to their Portfolio. Intrapersonal

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkPlants can live within only a certainrange of temperatures, and they areaffected by the length of the growingseason.

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Paired Summarizing Have students formpairs. Then ask students to quiz each other onthe temperature and precipitation traits of eachbiome by using Figure 3. Have each studentwithin the pair switch off and work togetheruntil both of them can name all the traits with-out looking at the figure. AuditoryLS

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GENERAL

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CareerCareerMeteorologist A meteorologist is a scientistwho studies atmospheric phenomena, such aspressure fronts and humidity, often in order topredict weather. Meteorologists use sophisti-cated machinery, such as Doppler radar, to readcloud patterns and pressure systems within thelayers of the atmosphere. They also predictsevere weather, such as tornadoes and hurri-canes, in order to save lives and minimize prop-erty damage. Contact a local news station tosee if you can set up a tour of the weather pre-diction facility, or have the meteorologist visitthe class to give a presentation on weather andclimate in your area.

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AAnnsswweerrss ttoo SSeeccttiioonn RReevviieeww 1. Scientists name biomes after their vegetation

because the plants that grow in an area deter-mine what other organisms can live there.

2. Plants are adapted to a particular range oftemperature and can usually survive only in a climate with that particular range.

3. Plants are adapted to a particular level of precipitation. In general, the larger a plant is,the more water it needs.

4. Latitude is the distance north or south of theequator. Altitude is the height of an objectabove sea level. Both latitude and altitudedetermine the temperature and precipitation

of a biome. Therefore, if an organism lives in abiome that is close to the equator and at a lowaltitude, the organism must be able to survivein a very warm, moist environment.

5. Sample answer: Part of the Andes Mountainsis located in Ecuador. The resulting wide rangeof altitudes in Ecuador creates the wide rangeof climates.

6. Desert, chaparral, tropical savanna, temperategrassland, temperate forest, and tropical rainforest are the biomes that are located betweenthe equator and 30° north latitude.


1. Describe how plants determine the name of abiome.

2. Explain how temperature affects which plants growin an area.

3. Explain how precipitation affects which plants growin an area.

4. Define latitude and altitude. How is latitude differentfrom altitude? How do these factors affect the organ-isms that live in a biome?

CRITICAL THINKING5. Making Inferences The equator passes through

the country of Ecuador. But the climate in Ecuadorcan range from hot and humid to cool and dry. Writea short paragraph that explains what might cause thisrange in climate.

6. Analyzing Relationships Look at Figure 1, andlocate the equator and 30° north latitude. Whichbiomes are located between these two lines?

WRITING SKILLS

S E C T I O N 1 Review

Figure 4 � Latitude and altitude affect climate and vegetation in similar ways.

Latitude and Altitude Biomes and vegetation vary with latitudeand altitude. is the distance north or south of the equa-tor and is measured in degrees. is the height of an objectabove sea level. Climate varies with latitude and altitude. Forexample, climate gets colder as latitude and altitude increase. So,climate also gets colder as you move farther up a mountain.

Figure 4 shows that as latitude and altitude increase, biomesand vegetation change. For example, the trees of tropical rainforests usually grow closer to the equator, while the mosses andlichens of the tundra usually grow closer to the poles. The landlocated in the temperate region, between about 30° and 60° northlatitudes and 30° and 60° south latitudes, is where most of thefood in the world is grown. This region includes biomes such astemperate forests and grasslands, which usually have the moderatetemperatures and fertile soil that are ideal for agriculture.

AltitudeLatitude

www.scilinks.orgTopic: BiomesCode: HE80158

ReteachingMountains Have students discusshow altitude is related to precipita-tion and temperature. (The higherthe altitude, the colder the tempera-ture. Colder temperatures limit theamount of available moisture in anarea.) Ask students, “Are all moun-tains like Figure 4?” (No, moun-tains located in hotter regions aremore like deserts at the top.)

Logical

Quiz1. Why is it hard for trees to sur-

vive at the tops of very highmountains? (The conditions athigh altitudes are too cold, dry,and windy for trees.)

2. Which biome would you expect to find in warm to hot condi-tions with a large amount ofmoisture? (Tropical rain forest)

3. Coniferous trees can be found inboth the subarctic taiga and inwarm chaparral regions. Whatkind of conditions have thesetrees in these areas adapted to?(A lack of moisture.)

Alternative AssessmentWorld Biomes Have students lookat Figure 1 and write down at leastthree biomes that do not seem tofit the latitude and altitude modelpresented in Figure 4. Ask them todecide why the biomes do not fitand to write their reasons in ashort essay. (The biomes may beinfluenced by oceans, which wouldprovide cooler temperatures andmore moisture. Mountains may alsoblock moisture from the deserts.)

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TT Latitude Vs. Altitude

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Nutrients in Tropical Rain Forests

The air is hot and heavy with humidity. You walk through theshade of the tropical rain forest, step carefully over tangles ofroots and vines, and brush past enormous leaves. Life is allaround you, but you see little vegetation on the forest floor. Birdscall, and monkeys chatter from above.

Tropical Rain ForestsOf all the biomes in the world, forest biomes are the most wide-spread and are home to the greatest diversity of plants, animals,and other organisms. Trees need a lot of water, so forests existwhere precipitation is plentiful. Tropical forests, temperate forests,and taiga are the main forest biomes.

are located in a belt around the Earthnear the equator, as shown in Figure 5. They help regulate worldclimate and play vital roles in the nitrogen, oxygen, and carboncycles. Tropical rain forests are always humid and warm and getabout 200 to 450 cm of rain a year. Because they are near theequator, tropical rain forests get strong sunlight year-round andmaintain a relatively constant temperature year-round. This climateis ideal for a wide variety of plants and animals, as shown inFigure 6. The warm, wet conditions also nourish more species ofplants than any other biome does. While one hectare (10,000 m2)of temperate forest usually contains a few species of trees, the samearea of tropical rain forest may contain more than 100 species.

Tropical rain forests

Objectives

� List three characteristics of tropicalrain forests.

� Name and describe the main layers of a tropical rain forest.

� Describe one plant in a temperatedeciduous forest and an adapta-tion that helps the plant survive.

� Describe one adaptation that mayhelp an animal survive in the taiga.

� Name two threats to the world’sforest biomes.

Key Termstropical rain forestemergent layercanopyepiphyteunderstorytemperate rain foresttemperate deciduous foresttaiga

S E C T I O N 2

Forest Biomes

� Glasswing butterflies live in therain forests of Costa Rica.

� The Rafflessia keithii flowergrows in the rain forests of Borneo.


OverviewBefore beginning this section,review with your students theObjectives in the Student Edition.This section describes the tropicalrain forest, temperate rain forest,temperate deciduous forest, andtaiga.

Light a wooden match in front ofstudents, and allow it to burn.Then explain that in the time ittook the match to burn (45 sec-onds), approximately 97 acres ofrain forest were destroyed by slash-and-burn techniques. This amountis roughly the size of one footballfield every second.

Demonstration Exotic Fruit Many rain forestfruits, such as carambola (“starfruit”), are considered to be exoticthroughout much of the UnitedStates. However, most of theseproducts are quite common inmore tropical areas of the world.Bring in some samples of rain for-est fruits and nuts (which are usu-ally available at specialty grocerystores) to the classroom. Find outin advance where each productcomes from (the plant and itscountry), and share this informa-tion with students. Allow studentsto feast on the food as you discussits origins. Be sure that studentswith allergies to nuts do not eatthem. VisualLS

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MISCONCEPTION ALERT

A Dark and Tangled Jungle Ever noticehow Hollywood creates tropical rain foreststo appear as an impenetrable tangle ofplants? Check out some old Tarzan movies,or current movies with a jungle theme, fromyour local library. Watch some scenes thattake place in the “jungle.” Then, comparewhat a rain forest really looks like by rent-ing a video about the ecology of the rainforest. Rain forests are not covered in densejungle undergrowth. Tall trees dominatethe rain forest and the rain forest floor istypically not covered with plants.

Lesson PlanActive ReadingSection Quiz GENERAL


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Nutrients in Tropical Rain Forests You might think that thediverse plant life grows on rich soil, but it does not. Most nutri-ents are within plants, not within soil. Organic matter decaysquickly in hot, wet conditions. Decomposers on the rain-forestfloor break down organic matter and return the nutrients to thesoil, but plants quickly absorb the nutrients. Some trees in atropical rain forest support fungi that feed on dead organic mat-ter on the rain-forest floor. In this relationship, the fungi transferthe nutrients from the dead organic matter directly to the tree.

The nutrients are removed so efficiently from the soil in atropical rain forest that water running out of the soil may be asclear as distilled water. Most tropical soils that are cleared ofplants for agriculture lack nutrients and cannot support crops formore than a few years. Many of the trees form above-groundroots, called buttresses or braces, that grow sideways from thetrees and provide the trees with extra support in the thin soil.

Tropical Rain Forest(Limon, Costa Rica)

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Figure 5 � The world’s tropical rain forests have heavy rainfall during much of the year and fairlyconstant, high temperatures.

Figure 6 � Species of TropicalRain Forests

� These mountain gorillas live in therain forests of Rwanda.

� The tropical rain forests in the Andes mountains inEcuador are among the wettest places on Earth.

� Scarlet macaws live in the trees of rain forests of Peru.

Using the Figure Climatograms Figure 5 is the firstof many climatograms that studentswill encounter in this chapter. Thisgraph has two y-axes: one for pre-cipitation and one for temperature.The blue bars correspond with theprecipitation axis, and the red linecorresponds with the temperature.Make sure students are readingthe values correctly by askingthem questions about the figure.

Logical

Group Activity Rain Forest Collage Bring in ma-gazines with good photos of tropi-cal animals and plants (such asNational Geographic). Organizethe class into six groups and assigneach group the task of finding pho-tos of rain forest mammals, birds,reptiles, amphibians, insects, trees,and epiphytes. Have the groups cutthese photos out and assemble themas an ecosystem on one piece ofposter board. Have the groups labeleach organism with its common andscientific name. If there is space, alsohave them describe each species’role in the ecosystem. Display the poster in your classroom.

Interpersonal

Demonstration Visual Precipitation Have stu-dents add up the total annual pre-cipitation represented in Figure 5for the Costa Rican rain forest.(approx. 338 cm, or 3.38 m per year)Provide them with some string, andhave them measure out a piece thatis as long as the yearly precipita-tion. Have them do the same forthe total annual precipitation rep-resented in Figure 25 for the desertin Egypt (and for the precipitationfrom other biomes, if they areinterested). Hang the strings on awall in the class-room. VisualLS

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Tropical Rain Forests

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Key Terms

S E C T I O N 2

Forest Biomes

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GENERAL


Limiting Factors Every organism in anecosystem needs certain resources, bothbiotic and abiotic. When a resource is in such short supply that it limits thegrowth of a population, it is called a limiting factor. Abiotic factors such astemperature, water, light, and nutrientsin soil are usually the most limiting. Asyou proceed through the chapter, havestudents identify the limiting factors foreach biome.

BRAIN FOOD

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Layers of the Rain Forest In tropical rain forests, different typesof plants grow in different layers, as shown in Figure 7. The fourmain layers above the forest floor are the emergent layer, theupper canopy, the lower canopy, and the understory. The top layeris called the This layer consists of the tallest trees,which reach heights of 60 to 70 m. Trees in the emergent layergrow and emerge into direct sunlight.

The next layer, considered the primary layer of the rain forest,is called the Trees in the canopy can grow more than 30 m tall. The tall trees form a dense layer that absorbs up to 95 percent of the sunlight. The canopy can be split into an uppercanopy and a lower canopy. The lower canopy receives less lightthan the upper canopy does. Plants called such as theorchid in Figure 8, use the entire surface of a tree as a place tolive. Epiphytes grow on tall trees for support. Some grow high inthe canopy, where their leaves can reach the sunlight needed forphotosynthesis. Growing on tall trees also allows them to absorbthe water and nutrients that run down the tree after it rains. Mostanimals that live in the rain forest live in the canopy because theydepend on the abundant flowers and fruits that grow there.

Below the canopy, very little light reaches the next layer,called the Trees and shrubs that are adapted to shadegrow here. Most plants in the understory do not grow more than3.5 m tall. Herbs with large, flat leaves grow on the forest floor.These plants capture the small amount of sunlight that penetratesthe understory. Most of our house plants are native to tropicalrain-forest floors. Because they are adapted to low levels of light,they are able to grow indoors.

In which layer of the rain forest is most of the animal life found?��Reading Check

understory.

epiphytes,

canopy.

emergent layer.

Emergent layer

Upper canopy

Lower canopy

Understory

Bright light

Filtered light

Dense shade

Figure 7 � The plants in tropical rainforests form distinct layers. Theplants in each layer are adapted to aparticular level of light. The tallertrees absorb the most light, while theplants near the forest floor areadapted to growing in the shade.

ChemistryConnection to

Medicines from Plants Manyof the medicines we use comefrom plants native to tropical rainforests. Chemists extract and testchemicals found in plants to deter-mine if the chemicals can cure orfight diseases. Rosy periwinkle, aplant that grows in the tropicalrain forests of Madagascar, is thesource of two medicines, vinblas-tine and vincristine. Vinblastine isused to treat Hodgkin’s disease, atype of cancer, and vincristine isused to treat childhood leukemia.

Group Activity Light in the Forest Have stu-dents simulate the way light is fil-tered through the forest by havingthem put together tubes of layeredpaper. Divide students into fourgroups, and give each group a 12-inch piece of cardboard tube. Haveeach group cut their tube into adifferent number of pieces (2, 3, 4 and 5 pieces). Then, have themtape a thin piece of writing paperto 1, 2, 3 or 4 of their pieces oftube. Ask students to tape thetubes back together. Then, shine a flashlight over the top of each of the tubes. Compare the amountof light that gets through 1, 2, 3 or 4 sheets of paper. With hun-dreds of leaves for light to travelthrough, it is easy to see why therain forest floor is dark. Visual/Kinesthetic

Familiar Epiphytes Bromeliadsand orchids are two families ofmostly-epiphytic plants common in rain forest canopies. They arealso popular plants in homes andgreenhouses. Bromeliad speciesthat students may have seeninclude pineapples, Spanish moss,and ball moss. Bring in examplesof these types of plants. Have stu-dents observe the adaptations these plants have for “living onair,” such as water-catching mecha-nisms and dangling roots. Tell stu-dents that some bromeliads arecarnivorous—they trap and digestinsects to get nutrients.

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Tropical Medicinals Many rain forest plantsand animals have yielded chemicals used tocreate powerful new drugs. Have each studentresearch one of these medicinal plants or ani-mals (besides the rosy periwinkle). Ask themto identify the active ingredient in each ofthese organisms, the drug that it helped to cre-ate, and what the drug helps to cure. Have stu-dents find the chemical structure of the activeingredient, if possible. Encourage students to write up their findings to include in theirPortfolio. IntrapersonalLS

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CONNECTIONCONNECTIONCHEMISTRYCHEMISTRY Notable Quotes

“There is more information of a higherorder and complexity stored in a fewsquare kilometers of forest than there isin all the libraries of mankind.”

— Eugene Odum, Ecologist.Have students discuss the types of infor-mation one could gather from a forest.(relationships among species, genetic infor-mation, evolutionary history, chemical for-mulas, artistic forms, perfumes, differenttastes)

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AAnnsswweerr ttoo RReeaaddiinngg CChheecckkMost of the animals that live in therain forest live in the canopy.

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Species Diversity in Rain Forests The tropical rain forest is thebiome with the greatest amount of species diversity. The diversityof rain-forest vegetation has led to the evolution of a diverse com-munity of animals. Most rain-forest animals are specialists that usespecific resources in particular ways. Some rain-forest animals haveamazing adaptations for capturing prey, and other animals haveadaptations that they use to escape predators. For example, thecollared anteater in Figure 8 uses its long tongue to reach insects insmall cracks and holes where other animals cannot reach. Thewreathed hornbill (shown below) uses its strong, curved beak tocrack open nutshells. Insects, such as the Costa Rican mantis inFigure 8, use camouflage to avoid predators. These insects may beshaped like leaves or twigs.

EcofactA Little Land, A Lot of SpeciesTropical rain forests cover less than7 percent of Earth’s land surfacebut contain at least 50 percent ofall the plant and animal species inthe world.

Figure 8 � Examples of plantand animal adaptations in thetropical rain forest include thelong tongue of a collared anteater,

the strong, curved beak of awreathed hornbill, the shape of aCosta Rican mantis, and an orchidattached to a tall tree.

Discussion Coevolution Ask students toresearch some of the animal-plantrelationships that have coevolvedin the rain forest. Many of themost interesting relationshipsinvolve plants and their bird or batpollinators, so make sure some stu-dents research these relationships.Then have them discuss how therelationships may have evolved.Ask them to discuss the adapta-tions some of the species have thathelp them interact with each other.

Verbal/Logical

Activity We’re All Thumbs! To help stu-dents understand how animals arespecially adapted to their environ-ment, share the following exam-ple. Many primate species, suchas monkeys, have a special adap-tation for climbing trees, peelingfruit, and holding objects—theirhands are equipped with oppos-able thumbs. Since humans arealso primates, we share the char-acteristic of opposable thumbs.Conduct the following activity toshow students what it is like notto have this adaptation. Tape thethumb of each student to the restof his or her hand (making thethumbs immobile). You will, ineffect, be creating “paws.” Next,challenge students to crack opena peanut, peel a banana, or opena door. Have students discusshow possessing opposablethumbs gives primates so manyabilities.

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Biodiversity Scientists have long debatedthe reason for the great biodiversity in trop-ical rain forests. One theory suggests that itis a combination of energy (in the form ofsunlight), available area, and stability of theclimate. Ask students, “Why would the sta-bility of the climate promote the evolutionof biodiversity?” (In temperate and polarregions, organisms have to be adapted to a

wide range of seasonal variations in tempera-ture and nutrient availability, so they need tohave more flexible adaptations. The environ-ment is less predictable, so specialization ismore difficult. In contrast, in the relatively sta-ble climate in the tropics, organisms can counton specific foods being available all or most ofthe time.)

BRAIN FOOD

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Deforestation,Climate, and Floods

A plant absorbs water from the soil

through its roots and transports the

water to its stems and leaves. Water

then evaporates from pores in plant

leaves into the atmosphere through

a process called transpiration. A

large tree may transpire as much as

5 tons of water on a hot day. Water

absorbs heat when it evaporates.

Therefore, the temperature is much

cooler under a tree on a hot day

than under a wood or brick shelter.

Trees that provide shade around

homes keep homes much cooler in

the summer.

When rain falls on a forest, much

of the rain is absorbed by plant roots

and transpired into the air as water

vapor. Water vapor forms rain clouds.

Much of this water will fall as rain

somewhere downwind from the for-

est. Because of the role trees play in

flow freely down the river and

spread across fields and into towns

during the seasonal monsoon rains.

Deforestation has also caused

terrible floods in places such as

Bangladesh. The Ganges River starts

high in the Himalaya Mountains

and flows through Bangladesh.

Deforestation of the Himalaya

transpiration, deforestation, the clear-

ing of trees, can change the climate.

If a forest is cut down or replaced by

smaller plants, much of the rainfall is

not absorbed by plants. Instead, the

rain runs off the soil and causes

flooding as well as soil erosion. The

climate downwind from the forest

becomes drier.

Deforestation led to the disas-

trous flooding of the Yangtze River

in China in 1998. More than 2,000

people died in the floods, and at

least 13 million people had to leave

their homes. When the Yangtze

River flooded, the water poured

into a flood plain where over 400

million people lived. It is estimated

that 85 percent of the forest in the

Yangtze River basin has been cut

down. The millions of tons of water

that these trees once absorbed now

� A man makes his way past floodedbuildings in his street on a makeshiftraft after the Yangtze River floodedin July 1998. Water of the YangtzeRiver reached record-high levels.

Threats to Rain Forests Tropical rain forests once covered about20 percent of Earth’s surface. Today, they cover only about 7 per-cent. Every minute of every day, 100 acres of tropical rain forestare cleared for logging operations, agriculture, or oil exploration.Habitat destruction occurs when land inhabited by an organismis destroyed or altered. Habitat destruction is the usual reason fora species becoming extinct.

An estimated 50 million people live in tropical rain forests.These people are also threatened by habitat destruction. Theirfood, building materials, culture, and traditions come from andare uniquely connected to the rain forest. The loss of this habitatdestroys their way of life.

Plants and animals that live in rain forests are also threatenedby trading. Many plant species found only in tropical rain forestsare valuable and marketable to industries. Animals are threatenedby exotic-pet trading. Some exotic-pet traders illegally trap ani-mals, such as parrots, and sell them in pet stores at high prices.

What are two main threats to the organisms thatlive in tropical rain forests?��Reading Check

www.scilinks.orgTopic: Threats to

Rain ForestsCode: HE81521Activity

Ecotourism Before you cover thischapter with students, order somebrochures from various rain forestecotourism companies, or find bro-chures and advertisements on theInternet. Be sure to get brochuresfrom multiple countries. Pass thesebrochures out to students, and havethem outline the kinds of activitiesincluded in each trip, and the kindsof organisms they would see in eachforest. Have students compare theiroutlines, and discuss the diversity ofspecies presented in the brochures.Discuss why certain kinds of organ-isms are valued by humans andothers are not. This exercise shouldalso help students to see the effortsby some countries to gain economi-cally from their ecological treasures.

InterpersonalLS


Costa Rica Some countries with tropical rainforests, such as Costa Rica, have created largepreserves to protect their unique ecologicalareas. To generate income for the country,Costa Rica has developed ecotourism in thesepreserves. While the Costa Rican program hasbeen a success and a model for other countries,it is also a special case. Costa Rica is a fairlyprosperous and educated country, largely freeof the poverty and civil unrest that plague someCentral and South American countries. Forother countries, setting aside large amounts of

land as ecological reserves may not be politi-cally or economically realistic. Ask students,“Why would a poverty-stricken country be lesslikely to follow the Costa Rican example?” (An increase in population and poverty wouldforce people to use whatever resources were avail-able.) Ask students, “What can we as residentsin a developed nation, do to help less devel-oped nations follow the Costa Rican exam-ple?” (Answers may vary. Suggestions includeoffering grants, increasing ecotourism, or buyingthe land from the country.) LogicalLS

Temperate Forests


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GENERAL

CONNECTIONCONNECTIONREAL-LIFEREAL-LIFE

GENERAL

CulturalAwarenessCulturalAwareness GENERAL

Threatened Cultures Pointout to students that the destruc-tion of many ecosystems threat-ens the livelihood of groups ofindigenous people. Have stu-dents research some of thesegroups, such as the Yanomamiof Brazil and Venezuela. Theorganization Cultural Survivaloffers current information aboutthese groups. Ask students tofind out how these groups haveadapted to the ecosystem wherethey live, and what are the cur-rent threats to their culture and way of life. Have studentswrite a short report and sharetheir findings with the class.Encourage students to includetheir report in their Portfolio.

InterpersonalLS

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkSample answer: Two main threats tothe organisms that live in tropicalrain forests are habitat destructionand trading.

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Deforestation,Climate, and Floods

Threats to Rain Forests


Temperate Forestsoccurs in North America, Australia, and

New Zealand. Temperate rain forests have large amounts of pre-cipitation, high humidity, and moderate temperatures. The PacificNorthwest shown, in Figure 9, houses North America’s only tem-perate rain forest, where tree branches are draped with mossesand tree trunks are covered in lichens. The forest floor is blan-keted with lush ferns. Evergreen trees that are 90 m tall, such asthe Sitka spruce and the Douglas fir, dominate the forest. Otherlarge trees, such as western hemlock, Pacific silver fir, and red-wood, can also be found in temperate rain forests.

Even though the temperate rain forest of the PacificNorthwest is located north of most other rain forests, it stillmaintains a moderate temperature year-round. The temperaterain forest also rarely freezes because the nearby Pacific Oceanwaters keep temperatures mild by blowing cool ocean wind overthe forest. As this ocean wind meets the coastal mountains, alarge amount of rainfall is produced. The rainfall keeps the tem-perate rain forest cool and moist.

Temperate rain forest

Mountains left few trees to stop the

water flowing down the mountain.

So, most of the water flows into the

river when it rains. Heavy rains have

eroded and carried away so much

soil from the slopes of the moun-

tains that the soil has formed a new

never been flooded before. The

townspeople claimed that authorities

had permitted developers to cover

the hills with homes. These develop-

ers cut down most of the trees and

covered much of the land with

asphalt. After heavy rains, the water

was no longer absorbed by trees and

soil, so the water flowed down the

hills and flooded the town.

CRITICAL THINKING

1. Identifying RelationshipsHow might deforestation in Chinaand other countries affect the over-all climate of the Earth?

2. Analyzing a ViewpointImagine that you are a city councilmember and must vote on whetherto clear a forest so that a mall canbe built. List the pros and cons ofeach viewpoint. After reviewingyour list, how would you vote?Explain your answer.

island in the Bay of Bengal, which is

off the coast of Bangladesh.

People are beginning to under-

stand the connection between defor-

estation and floods. People held

protests in northern Italy in 2000

after floods covered a town that had

� Deforestation reduces the amount of water that is absorbed by plantsafter it rains. The more trees that are cleared from a forest, the more likelya flood will occur in that area.

Figure 9 � The only temperate rainforest in North America is located inthe Pacific Northwest, as shownabove in Olympic National Park inWashington State.


Group Activity Pacific Northwest Food Web Inthe past, the northern spotted owlhas received a great deal of atten-tion in a battle between loggersand environmentalists over the fateof old-growth forests in the PacificNorthwest. Students may not real-ize that the spotted owl is part of a complicated food web that alsocontains martens, flying squirrels,red-backed voles, Douglas firs,pseudoscorpions, termites, andblack and yellow mycorrhizalfungi. Have students form teams,and have each team investigate the ecological role of one of theseorganisms. Then have students worktogether to make a bulletin boarddisplay. At the center of the display,place an illustration or photographof a tree from an old-growth forest.Groups should add a picture oftheir organism to the display alongwith a written description of itsniche and interaction with the tree.

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Deforestation, Climate, and Floods Havestudents research the major floods in history.Have students research how and why thesefloods occurred and the amount of damagethat each flood caused. Have them sharetheir research. Discuss with students theimportance of preserving areas to preventflooding.

AAnnsswweerrss ttoo CCrriittiiccaall TThhiinnkkiinngg1. Deforestation may affect the overall climate

of the Earth because deforestation releases

carbon into the atmosphere and removes thetrees that would normally take up carbon.Carbon dioxide can contribute to globalwarming.

2. Answers may vary. Students should deter-mine whether forests are plentiful locallyand whether the removal of the forest wouldcause other problems, such as flooding, erosion, or species loss.

StrategiesStrategiesINCLUSIONINCLUSION

To help students understand the concept of habitat destruc-tion, ask them to write a storyfrom the perspective of an ani-mal living on land that has beendestroyed or altered. The storyshould include how the animalwill adapt or move as a result of the habitat destruction. Thestory can be word processed or dictated into a tape recorder.Drawings of the land before and after the destruction can be added.

••AAtttteennttiioonn DDeeffiicciitt DDiissoorrddeerr••LLeeaarrnniinngg DDiissaabblleedd••DDeevveellooppmmeennttaallllyy DDeellaayyeedd

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Animals of Temperate Deciduous Forests

Taiga

Temperate Deciduous ForestsIf you walk through a North American deciduous forest in thefall, you will immerse yourself in color. Leaves in every shade oforange, red, and yellow crackle beneath your feet. Most birdshave flown south. The forest is quieter than it was in the summer.You see mostly chipmunks and squirrels gathering and storing thefood they will need during the long, cold winter.

In trees drop their broad, flatleaves each fall. These forests once dominated vast regions of theEarth, including parts of North America, Europe, and Asia.Today, temperate deciduous forests are generally located between30° and 50° north latitudes, as shown in Figure 10. The range oftemperatures in a temperate deciduous forest can be extreme, andthe growing season lasts for only four to six months. Summertemperatures can soar to 35°C. Winter temperatures often fallbelow freezing, so little water is available for plants. Just as temper-atures change with the seasons, so does the vegetation, as shown inFigure 11. Although there is enough moisture for decomposition,temperatures are low during the winter. As a result, organic matterdecomposes fairly slowly. This means that the soil contains moreorganic matter and nutrients than the soil in a tropical rain forest.

Plants of Temperate Deciduous Forests Like the plants of tropi-cal rain forests, the plants in deciduous forests grow in layers.Tall trees, such as maple, oak, and birch, dominate the forestcanopy. Small trees and shrubs cover the understory. Because thefloor of a deciduous forest gets more light than the floor of a rainforest does, more plants such as ferns, herbs, and mosses grow ina deciduous forest.

temperate deciduous forests,

Temperate Deciduous Forest(Stuttgart, Germany)

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Figure 10 � The difference betweensummer and winter temperatures in temperate deciduous forests is extreme.

Figure 11 � The change of seasonsin a temperate deciduous forest inMichigan is shown below.

www.scilinks.orgTopic: Temperate

Deciduous Forests

Code: HE81503

Activity Forest Soil Field Trip Foreststhroughout the world can havestrikingly different soils. Each typeof forest tends to have its owncharacteristic soil type. For exam-ple, the soil in tropical rain forestsis acidic, with few nutrients. If possible, have students investigatethe soil in two forested areasaround your town or city. Eachforest should feature a differentdominant tree species. In each areahave students dig a hole and meas-ure a cross section of the soil. Theyshould also draw a picture thatillustrates the layers they see, anduse their drawings to compare thetwo different areas. Encourage stu-dents to note any small organismsthat they uncover (without disturb-ing the organisms). While studentsare out in the woods, also havethem measure the thickness of theleaf litter layer at each site. Thislayer serves as a protection for ani-mals that use the forest floor, andit is an important nutrient sourcefor forest plants. After students are finished taking soil and litter meas-urements, have them use a soil testkit to analyze the soil for mineralsand pH levels. Suggest that studentsinclude their field notes, drawings,and soil-test results in their Portfolio.

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162

The Father of Forests John Muir (1838–1914)was an American naturalist, explorer, andwriter. His conservation efforts included helping persuade Congress to establish bothYosemite and Sequoia National Parks in 1890and establishing the Sierra Club in 1892. Hetraveled to many parts of the world and isknown for his work explaining Yosemite’s gla-cial origins, as well as for his discovery of a

glacier in Muir Woods, a redwood forest nearSan Francisco which was named after him in1908. His books include The Mountains ofCalifornia (1894), Our National Parks (1901),and The Yosemite (1912). Have studentsresearch and report on John Muir, or anotherAmerican naturalist, such as Aldo Leopold orJohn James Audobon.

CONNECTIONCONNECTIONHISTORYHISTORY

GENERAL

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Concept Mapping Have students create aconcept map using the animals of the temper-ate deciduous forest mentioned on this page.Ask them to map the animals by what theyeat, where they might live, and whether or notthey leave in winter. After they are finishedwith their maps, ask students to pair up to dis-cuss how they created the connections on theirmaps. Also have students include their map in their Portfolio. LogicalLS

SKILLBUILDER

READINGREADING


Temperate-forest plants are adapted to survive seasonalchanges. In the fall, most deciduous trees begin to shed theirleaves. In the winter, moisture in the soil changes to ice, whichcauses the remaining leaves to fall to the ground. Herb seeds,bulbs, and rhizomes (underground stems) become dormant in the ground and are insulated by the soil, leaf litter, and snow.In the spring, when the sunlight increases and the tempera-ture rises, trees grow new leaves, seeds germinate, and rhizomes and roots grow new shoots and stems.

Animals of Temperate Deciduous Forests The animals oftemperate deciduous forests are adapted to use the forestplants for food and shelter. Squirrels eat the nuts, seeds,and fruits in the treetops. Bears feast on the leaves andberries of the forest plants. Grasshoppers, such as the oneshown in Figure 12, eat almost all types of vegetationfound throughout the forest. Deer and other herbivoresnibble leaves from trees and shrubs.

Many birds nest in the relative safety of the canopy.Most of these birds are migratory. Because many birdscannot survive harsh winters, each fall they fly south forwarmer weather and more available food. Each spring,they return north to nest and feed. Animals that do notmigrate use various strategies for surviving the winter. Forexample, some mammals reduce their activity so that theydo not need as much food for energy.

TaigaThe is the northern coniferous forest that stretches in a broadband across the Northern Hemisphere just below the Arctic Circle.As shown in Figure 13, winters are long (6 to 10 months) and haveaverage temperatures that are below freezing and often fall to–20°C. Many trees seem like straight, dead shafts of bark andwood—until you look up and see their green tops. Plant growth ismost abundant during the summer months because of nearly con-stant daylight and larger amounts of precipitation.

taiga

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Figure 13 � The taiga has long, coldwinters and small amounts of precipi-tation, as shown in the climatogrambelow.

Figure 12 � Grasshoppers, wood-peckers, and deer are among themany animals that live in the temper-ate deciduous forest.

Activity Touring the Forest Have stu-dents develop a travel brochurethat advertises camping vacationsin one of the four forest ecosystemspresented in this section. In additionto making a list of the supplies thatcampers will need, students shouldprovide information about the climate (including any importantseasonal variations, such as a rainyseason or temperature variations),a description of the plants and ani-mals that campers might encounter(including any that might be dan-gerous or endangered), and recom-mendations on how campers canlessen the environmental impact of their activities. The brochuresshould include photos or illustra-tions of the forest and its inhabit-ants, as well as a map showing the location of the forest described.Have students also map any areasthat are off-limits to camping, dueto sensitive species or dangeroustrails. Encourage students to includetheir brochure in their Portfolio.

Visual

Group Activity Biome Components Organizestudents into four groups, and pro-vide each group with a large sheetof poster board or butcher paper.Each sheet should be labeled witha type of forest biome discussed in this section. Ask students toillustrate in light colors the vegeta-tion that grows in the listed forestbiome. Then have the groupsswitch posters and use darker colors to add the appropriate ani-mals for the biome. Encourage stu-dents to also include decomposers,such as insects, fungi, and bacteria.Have students switch illustrationsonce again, this time describing the interrelationships between the organisms shown. Finally, students can switch posters againto label and describe some of theorganisms’ adaptations. Displaythese posters in your room.

Visual Co-op LearningLS

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163

Temperate Deciduous Forests

Plants of Temperate Deciduous Forests

GENERAL

Notable Quotes

“Humanity is cutting down its forests,apparently oblivious to the fact that wemay not be able to live without them.”

—Isaac Asimov, Science Fiction Writer. Have students discuss the great variety of services and products provided byforests. Ask them to identify some of the most important services or products.(oxygen production, temperature media-tion, flood and erosion prevention, carbonstorage, habitat, and wood products.)

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Plants of the Taiga A conifer is a tree with needle-like leaves andseeds that develop in cones. The shape of the leaves and their waxycoating prevent the tree from losing too much water. This is espe-cially important when the ground is frozen and the roots cannotreplace lost water by absorbing more from the soil. As Figure 14shows, many conifers are shaped like a large cone. The cone-likeshape helps to prevent snow from building up on the branches andcausing the branches to break under the weight.

Conifer needles contain substances that make the soil acidicwhen the needles fall to the ground. Most plants

cannot grow in acidic soil, which is one reasonthe forest floor of the taiga has few plants. Inaddition, soil forms slowly in the taigabecause the climate and acidity of the fallenleaves slow decomposition.

Animals of the Taiga The taiga has many lakesand swamps that in summer attract birds that feed

on aquatic organisms. Many birds migrate south toavoid winter in the taiga. Because food is scarce during the

winter, some year-round residents, such as jumping mice, burrowunderground to hibernate. As shown in Figure 15, some animals,such as snowshoe hares, have adapted to avoid predation by lynxes,wolves, and foxes by shedding their brown summer fur and grow-ing white fur that camouflages them in the winter snow.

1. List three characteristics of tropical rain forests.

2. Name the main layers of a tropical rain forest. Whatkinds of plants grow in each layer?

3. Describe two ways in which tropical rain forests ofthe world are being threatened.

4. Describe how a plant survives the change of sea-sons in a temperate deciduous forest. Write a shortparagraph to explain your answer.

CRITICAL THINKING

5. Evaluating Information Which would be bettersuited for agricultural development: the soil of a tropi-cal rain forest or the soil of a temperate deciduousforest? Explain your answer.

6. Identifying Relationships How does a snowshoehare avoid predation by other animals during thewinter in a taiga biome? How might this affect theanimal that depends on the snowshoe hare for food?WRITING SKILLS


Figure 14 � The taiga has cold win-ter temperatures, a small amount ofannual precipitation, and coniferoustrees. The seeds of conifers are pro-tected inside tough cones like theone above. Also, the narrow shapeand waxy coating of conifer needleshelp the tree retain water.

Figure 15 � In the taiga, a snowshoehare’s fur changes color according tothe seasons to help camouflage theanimal from predators.

Reteaching News Flashes Some students mayhave trouble distinguishing betweenthe different forest biomes. Askvolunteers to prepare a three tofive minute news report featuringthe characteristics of, the locationof, and the threats facing the differ-ent forest biomes. Then have stu-dents present their news flashes tothe class. Ask all students to takenotes and include them in theirPortfolio. Verbal/Interpersonal

Quiz 1. Do animals of the tropical rain

forest generally migrate? Explainyour answer. (No. The climate isstable year-round, so a reliable foodsource is available year-round.)

2. How do small mammals survivewinter in the taiga? (They mayburrow to stay warm.)

3. Most rain forest animals arefood generalists, true or false?(False. Because the plants providea stable, consistently availablefood source, animals in the tropicsare mainly specialists.)

Alternative Assessment Detailing a Biome Organize theclass into groups of five or six stu-dents. Give each group a detailedpicture of a forest biome, and askthem to describe the characteristicsof the biome. (Answers shouldinclude a description of where thebiome is located, what types of ani-mal and plant species live there, andwhat special adaptations help thoseorganisms to survive in the biome.)

Visual/InterpersonalLS

LS

CloseClose

AAnnsswweerrss ttoo SSeeccttiioonn RReevviieeww1. Tropical rain forests are typically humid and

warm, receive 200 to 450 cm of rain per year,and have nutrient-poor soil.

2. The main layers of a tropical rain forest are theemergent layer, the upper and lower canopies,and the understory. The emergent layer consistsof the tallest trees. The upper and lowercanopies consist of tall trees and epiphytes.Trees and shrubs that are adapted to shade,grow in the understory.

3. Answers may vary, but should include two ofthe following: logging, farming, ranching, oilexploration, and trading.

4. Sample answer: In order to survive the changeof seasons in the temperate deciduous forest, aplant loses its leaves during the fall and winterand remains dormant until spring.

5. Temperate deciduous forest: Organic matterdecays slowly in the temperate forest, andforms a deep, rich soil that would be bettersuited for agriculture.

6. A snowshoe hare avoids predation by sheddingits brown summer fur and growing white furthat camouflages it in the winter snow.Predators will have a difficult time finding asnowshoe hare during the winter.


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GENERAL

GENERAL

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In areas with too little precipitation for large trees to survive, thebiomes are dominated by smaller plants. Where there is almostno rainfall at all, few plants can grow and we find desert. Thus,warm areas with little precipitation are characterized by savannaand desert biomes. Temperate areas have grassland, chaparral,and desert biomes, and cold areas have tundra and desert biomes.

SavannasParts of Africa, western India, northern Australia, and some partsof South America are covered by grassland called savanna.A

is a tropical biome dominated by grasses, shrubs, andsmall trees. As Figure 16 shows, rain falls mainly during the wetseason, which lasts for only a few months of the year. This is theonly time that plants can grow. The plants support an amazingvariety of herbivores, such as antelopes, giraffes, and elephants,as well as the predators that hunt them—cheetahs, lions, and hye-nas, for example.

Plants of the Savanna Because most of the rain falls duringthe wet season, plants must be able to survive prolonged pe-riods of time without water. During the dry season, plants losetheir leaves or die down to the ground. When the rain returns,they start to grow again. Many plants have large, horizontalroot systems so they can draw water from as large an area aspossible. The coarse savanna grasses have vertical leaves thatexpose less of their surface area to the hot sun to further helpthe grasses conserve water. Some trees of the savanna also losetheir leaves during the dry season to conserve water. Trees andshrubs often have thorns or sharp leaves that keep hungry herbivores away.

Name two herbivores and two predators that

savanna plants support.��Reading Check

savanna

Objectives

� Describe the difference betweentropical and temperate grasslands.

� Describe the climate in a chaparralbiome.

� Describe two desert animals andthe adaptations that help themsurvive.

� Describe one threat to the tundrabiome.

Key Termssavanna

temperate grassland

chaparral

desert

tundra

permafrost

S E C T I O N 3

Grassland, Desert, and Tundra Biomes

Tropical Savanna(Nairobi, Kenya)

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Figure 16 � Savannas have periodsof heavy rainfall followed by periodsof drought.


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OverviewBefore beginning this section,review with your students theObjectives in the Student Edition.This section introduces students tothe characteristics of the savanna,grassland, desert, chaparral, andtundra biomes. Students will alsolearn how the adaptations of plantsand animals in each biome helpthem to survive.

Before students begin to read thissection, ask them to list five char-acteristics of grasslands. You canguide students by asking themabout types of grasslands, tempera-ture, precipitation, seasons, soil,plants, and animals.

IdentifyingPreconceptions Ask students to write down as manyexamples of African animals asthey can think of in their EEccooLLoogg..Ask one student to write down allof the names the class could thinkof on the board. Circle the animalsthat are found on the Africansavanna—the vast grasslands ofAfrica. Most of the animals willprobably be from the savanna.Have students discuss how theseanimals are adapted to survive inthe savanna biome. Also remindstudents that the savanna is not the same as the “jungle” (rain forest). LogicalLS

MotivateMotivate

Bellringer

FocusFocus33SS EE CC TT II OO NN

The Serengeti in Texas Studies have shownthat antelopes need much less water and donot degrade the environment as much as cattledo. Many farmers in areas such as CentralTexas are farming large African game animalsfor sport hunting or food. Students can findthe Web sites of these ranches on the Internet.Ask students to identify the similaritiesbetween the African savanna and CentralTexas.

GENERAL

• Lesson Plan• Active Reading• Section Quiz GENERAL


Transparencies

TT BellringerTT Biome Climatograms: B


GENERAL

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkSample answer: Savanna plants support herbi-vores such as antelopes and giraffes, as well aspredators such as cheetahs and lions, which huntthe herbivores.

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Figure 17 � Herbivores of thesavanna, such as the elephants shownhere, range widely in search of food.

Temperate Grassland(Wichita, Kansas)

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)Figure 18 � Temperate grasslandsare characterized by small amountsof rainfall, periodic droughts, andhigh temperatures in the summer.

GeofactDeep Soil Gravel or sand becomesfertile soil when decomposersslowly break down organic mattersuch as dead leaves. Decomposerswork most effectively in hot, wetweather. As a result, the world’sdeepest soil is in grasslands. In tem-perate grassland biomes, wintersare cold and summers are dry,which causes leaves to break downslowly. So, organic matter builds upover time. Some North Americanprairies had more than 2 m of top-soil when the first farmers arrived.

Animals of the Savanna Grazing herbivores, such as the elephantsshown in Figure 17, have adopted a migratory way of life. Theyfollow the rains to areas of newly sprouted grass and wateringholes. Some predators follow and stalk migratory animals for food.Many savanna animals give birth only during the rainy season,when food is most abundant and the young are more likely to sur-vive. Also, some species of herbivores eat vegetation at differentheights than other species do. For example, small gazelles graze ongrasses, black rhinos browse on shrubs, and giraffes feed on treeleaves.

Temperate GrasslandsTemperate grassland covers large areas of the interior of conti-nents, where there is moderate rainfall, but still too little for treesto grow. The prairies in North America, the steppes in Asia, theveldt in South Africa, and the pampas in South America are tem-perate grasslands. Their locations are shown in Figure 18. Twoexamples of temperate grasslands are shown in Figure 19.

Mountains often play a crucial role in maintaining grasslands.For example, in North America, rain clouds moving from thewest release most of their moisture as they pass over the RockyMountains. As a result, the shortgrass prairie just east of theRockies receives so little rain that it looks almost like a desert.

Discussion Introducing Grazers When cattleor other nonnative species are intro-duced to grasslands, the result isoften degradation of the environ-ment. Ask students to discuss thefollowing question: “Why wouldgrazers native to a grassland biomehave less of an impact on the areathan newly-introduced grazers?”(When a community has remainedstable for a long period of time, theanimals and plants that comprise itare generally well adapted to eachother’s presence. For example, anative grass will be adapted to sur-vive the amount of grazing that isnormal for the region’s native herbi-vores. When a new species is intro-duced, different consumption patternsmight be too severe for a native grassto withstand, and it may die out. Theloss of the grass species could thenaffect the entire ecosystem.) VerbalLS

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Giraffes The giraffe is a resident of thesavanna, and occupies a special niche.Because of its long neck, it can reach treeleaves 2 to 5.5 m from the ground. Itstongue can stretch up to 17 inches, so it can reach even taller leaves. Males andfemales forage differently; males stretch upto reach vegetation, and females eat lowervegetation. This probably eliminates foodcompetition between the sexes. Giraffes live

in groups, whose sizes are dictated by theamount of food in the area. A male estab-lishes dominance in a group by pushing at another male’s neck, or by hitting theother male’s neck and head with his horns.Giraffe reproduction is slow; gestation takesabout a year and a half, and produces oneoffspring. Offspring are very vulnerable topredation.

BRAIN FOOD

CulturalAwarenessCulturalAwareness GENERAL

Prairie Fires Students maybe interested to know that theNative Americans who inhab-ited the plains of NorthAmerica discovered a methodfor avoiding prairie fires. First,they would start another smallfire near their community. Then,the small fire would burn out asafety zone in a short time.Finally, when a large fire boredown upon the community, itwould pass by the alreadyburned area. This method ofavoidance was later used byEuropean settlers on the plains.

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Animals of the Savanna

Temperate Grasslands

Bison Today Have students research andwrite a report on the status of bison in NorthAmerica today. Ask them to find out where thebison are, how and if they are being managed,where the largest herds are, if they are conflict-ing with cattle and other animals on the grass-lands, and how bison products are used byhumans. If you are in an area where bison areranched, ask to interview a rancher. VerbalLS

PrairyErth Students who are interested inthe American prairie may enjoy the bookPrairyErth (A Deep Map): An Epic History ofthe Tallgrass Prairie Country by William LeastHeat-Moon. In this unique work, the authorexplores the plants, animals, and people thatmolded the history and ecology of a tallgrassprairie remnant in central Kansas. Encouragestudents who read this book to write a bookreport for their Portfolio, linking informationfrom this chapter to details in the book.

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The amount of rain increases as you move east, which permitsthe growth of taller grasses and some shrubs. Grassland plantsdry out in the summer, so lightning strikes often start fires.

Plants of Temperate Grasslands Temperate grassland vegetationconsists of grasses and wildflowers. Although there is only a sin-gle layer of vegetation, many species may be present. Shrubs andtrees grow only where the soil contains extra water, usually onthe banks of streams.

The root systems of grassland plants form dense layers thatsurvive drought and fire. Figure 20 shows how the heights ofgrasses and the depths of their roots vary.

Grasslands are highly productive because of their fertile soil.The summer is hot and the winter is cold, so the plants die backto their roots in the winter. Low temperatures in the winter slowdecomposition. As a result, the rate at which dead plants decay isslower than the rate at which new vegetation is added each year.Over time, organic matter accumulates in the soil. This meansthat grasslands have the most fertile soil in the world. Mostgrasslands have been converted to farmland for growing cropssuch as wheat and corn.

Figure 19 � The steppes in Asia (left)and the pampas in South America(right) are dominated by grasses andother plants that are adapted to tem-perate grasslands.

HistoryConnection to

The State of Bison More than60 million bison once roamed thetemperate grasslands of NorthAmerica. But these large grass-eating mammals were almostbrought to extinction by the late1800s because of hunting bywestern settlers. By 1889, fewerthan 1,100 bison remained inNorth America! The first bill tosave the bison was introduced byCongress in 1874. In 1903,President Theodore Rooseveltstarted the National WildlifeRefuge System to provide pro-tected areas for bison and otheranimals. Today, North Americahas more than 200,000 bison.

Shortgrass prairie(about 25 cm rain per year)

Mixed or middlegrass prairie

(about 50 cm rain per year)

Tallgrass prairie(up to 88 cm rain per year)

Figure 20 � The height of grasslandplants and the depth of their rootsdepend on the amount of rainfallthat the grasslands receive.

Activity Grass Roots Gather some trowelsand plastic bags, and take studentsout to a weedy grassland on ornear the school grounds. Havestudents dig out clumps of grass,being careful to try to dig out all ofthe root system as well. Since grassroots spread horizontally and verti-cally quite extensively, students willfind that it is difficult to get thewhole system out without breakingsome of the roots. Ask students totry to shake as much soil off of theroots as possible. Then have themput the grass and root systems intoplastic bags, and bring them backto the classroom for further study.Carefully rinse each specimen, andask students to measure bothabove ground and below groundcomponents of the grass. Studentswill find that the below groundcomponent, with all its branching,is much longer. Ask them why theroot system is so large. (Large rootsystems help grasses to survivedrought, fire, and grazing in a grass-land ecosystem, by allowing them to store water and nutrients belowground. Shoots also form alongspreading roots, which helps thegrass to cover more area and repro-duce asexually.) Kinesthetic

Group Activity Plant a Prairie! If your climateis appropriate, get permission toplant a prairie garden on yourschool grounds. Many sources ofnative prairie seeds exist, and seedsuppliers can help your studentslearn how to prepare the groundand tend the garden properly. Withproper maintenance, which includesperiodic burning, this garden willthrive with a wide variety of grassand flower species. Your pocketprairie will also attract butterfliesand other interesting insects, andcan be a great educational resource.

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Animals of Temperate Grasslands Grazing animals, such aspronghorn antelope and bison, have large, flat back teeth forchewing the coarse prairie grasses. Other grassland animals, suchas badgers, prairie dogs, and burrowing owls, live protected inunderground burrows as shown in Figure 21. The burrows shieldthe animals from fire and weather and protect them from preda-tors on the open grasslands.

Threats to Temperate Grasslands Farming and overgrazing havechanged the grasslands. Grain crops cannot hold the soil in placeas well as native grasses can because the roots of crops are shal-low and the soil is ploughed regularly, so soil erosion eventuallyoccurs. Erosion is also caused by overgrazing. When grasses areconstantly eaten and trampled, the grasses cannot regenerate orhold the soil. This constant use can change fruitful grasslandsinto less productive, desertlike biomes.

ChaparralTemperate woodland biomes have fairly dry climates but receiveenough rainfall to support more plants than a desert does. Onetype of temperate woodlands consists of scattered tree communi-ties made up of coniferous trees such as piñon pines and junipers,as shown in Figure 22.

is a temperate shrubland biome that is foundin all fives parts of the world with a Mediterranean climate.These areas have moderately dry, coastal climates, with little or

The chaparral

168 Chapter 6 Biomes

Figure 21 � Prairie dogs, such asthose shown here, live in temperategrasslands. Prairie dogs live incolonies and burrow in the groundto build mounds, holes, and tunnels.

Figure 22 � Temperate woodlandsare usually too dry to support a for-est, but they receive sufficient pre-cipitation to support vegetation thatgrows in bunches, such as the piñonand juniper trees shown here.

QuickLABSponging It Up

Procedure1. Completely saturate two small

sponges with water and allowthe excess water to drain off.

2. Measure each sponge’s mass byusing an electric balance.Record the mass.

3. Using plastic wrap, completelycover one of the sponges.

4. Place the sponges outside in a sunny place for 10 to 15 minutes.

5. Measure each sponge’s massafter removing it from outside.Record the mass.

Analysis1. Which sponge lost the most

mass? Why?

2. How was the covering you cre-ated for the sponge similar tothe adaptations of the plants inthe chaparral biome?

Activity Native Grasses Have studentscollect a variety of samples ofgrasses native to their area and dis-play pressed specimens on a posterboard. Students could also write ashort report to accompany theirdisplay. The report should indicatethe major characteristics of eachtype of grass represented, such asheight, abundance, and habitat.Suggest that students include theirdisplay in their Portfolio. VisualLS


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QuickLABSkills Acquired:• Experimenting• Identifying and Recognizing

PatternsTeacher’s Notes: If you cannotfind a sunny place outside, placethe sponges under a heat lampin the classroom.

AAnnsswweerrss 1. The sponge that was not

covered in plastic wrap lost themost mass because the waterevaporated more quickly fromthat sponge.

2. The plastic wrap is similar tothe adaptations of chaparralplants because they have thick,leathery leaves that help theplant retain water.

CONNECTIONCONNECTIONHISTORYHISTORY

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The American Dust Bowl In the 1930s,extreme weather conditions and poor farmingpractices created a “Dust Bowl” in the for-merly rich agricultural areas of the GreatPlains. Beginning in 1930, a drought early inthe year prevented planting seeds and contin-ued for four years. Wind blowing acrossabandoned fields kicked up incredible duststorms across the region. Heat followed thedrought of the first four years, killing peopleas well as causing more dust storms. On aSunday in 1935, an epic dust storm roaredacross the land at 60 mph. This day was

called “Black Sunday” by those who wit-nessed the storm. Drought and dirt stormscontinued through the decade, blowing awaythe precious, nutrient-rich topsoil that hadbeen formed over centuries by the decay ofthe prairie grasses. Fortunately, the UnitedStates learned from the Dust Bowl years, andbegan a soil conservation service to spreadinformation about soil management practices.Have students search the Internet for informa-tion about the Dust Bowl and soil conserva-tion methods.

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Animals of Temperate Grasslands

Threats to Temperate Grasslands

Chaparral

Sponging It Up

Reading Organizer Have students look atthe climatograms in the chapter to determine if each biome’s seasonal temperature and rain-fall are stable or fluctuating. Then have stu-dents match the biomes that have similarseasonal temperature or precipitation. Forexample, the chaparral and the tropical rainforest would be similar because their tempera-tures remain relatively stable throughout theyear. However, chaparral has a rainy season in the winter months, so chaparral would bemore similar to savanna and desert biomeswith respect to precipitation. LogicalLS

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READINGREADING


no rain in the summer. Look at the famous white letters that spellHollywood across the California hills in Figure 23. Now imaginethe scrub-covered settings common in old westerns. Both of theselandscapes are part of the chaparral biome. As shown in Figure 24,chaparral is located in the middle latitudes, about 30° north andsouth of the equator.

Plants of the Chaparral Most chaparral plants are low-lying, ever-green shrubs and small trees that tend to grow in dense patches.Common chaparral plants include chamise, manzanita, scrub oak,olive trees, and herbs, such as sage and bay. These plants havesmall, leathery leaves that retain water. The leaves also contain oilsthat promote burning, which is an advantage because natural firesdestroy trees that might compete with chaparral plants for light andspace. Chaparral plants are so well adapted to fire that they canresprout from small bits of surviving plant tissue.

Animals of the Chaparral A common adaptation of chaparral ani-mals is camouflage, which is shape or coloring that allows an ani-mal to blend into its environment. Animals such as quail, lizards,chipmunks, and mule deer have a brownish-gray coloring that letsthem move through the brush without being noticed.

Threats to the Chaparral Worldwide, the greatest threat to chapar-ral is human development. Because chaparral biomes get a lot ofsun, are near the oceans, and have a mild climate year-round,humans tend to develop the land for commercial and residential use.

How does camouflage help chaparral animals?��Reading Check

Chaparral(Santa Barbara, California)

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Figure 24 � Chaparral biomes arelocated in areas that haveMediterranean climates.

Figure 23 � The chaparral biome inthe Hollywood hills is home to plantssuch as the manzanita, which isshown above.

Demonstration Plants of the Chaparral Bring insome fresh leaves from plants thatcan be found in the Mediterraneanchaparral region, such as rosemary,sage, lavender, or bay laurel. Passthe leaves around, and invite stu-dents to crush them and smell theessential oils in the leaves. Ask stu-dents, “Why do these plants haveoils in their leaves?” (The oils allowfires to start easily in the chaparral,and fire keeps trees and other com-petitors out of chaparral areas.)Have students describe the leaveson these plants. (They are small orthin and leathery.) Ask students,“Why are the leaves small withtough skin?” (To prevent water lossin the dry conditions of the chaparralbiome.) If you live near chaparral,bring in samples of leaves fromnative plants in your area andcompare them to leaves of theplants of the Mediterranean region.

Kinesthetic

Chaparral Fire Control Fire is anatural and necessary force in thechaparral. However, large humanpopulations live near areas ofchaparral, and work to eliminatefires to protect their homes andbusinesses. Suggest that studentsresearch some of the consequencesof human attempts to control chap-arral wildfires. Also, ask them tofind out whether government landmanagers in areas of chaparralpractice prescribed burning. Havethem record their findings in theirEEccooLLoogg.. Interpersonal

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkCamouflage helps chaparral animalsmove through the brush withoutbeing noticed.

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StrategiesStrategiesINCLUSIONINCLUSION

Ask students to write the name of one ofthe major forest, grassland, desert, and tun-dra biomes on a note card. On the back ofeach note card, students can write descrip-tive phrases, pictures, or words about thebiome. The note cards can be used for indi-vidual or small group review sessions.

••AAtttteennttiioonn DDeeffiicciitt DDiissoorrddeerr••LLeeaarrnniinngg DDiissaabblleedd

••DDeevveellooppmmeennttaallllyy DDeellaayyeedd


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DesertsWhen some people think of a desert, they think of the hot sandthat surrounds the Egyptian pyramids. Other people picture theSonoran Desert and its mighty saguaro cactuses, or the magnificentrock formations of Monument Valley in Arizona and Utah. Manykinds of deserts are located throughout the world, but one charac-teristic that they share is that they are the driest places on Earth.

are areas that have widely scattered vegetation and re-ceive very little rain. In extreme cases, it never rains and there is novegetation. The distribution of Earth’s deserts is shown in Figure 25.Even in hot deserts near the equator, there is so little insulatingmoisture in the air that the temperature changes rapidly during a24-hour period. The temperature may go from 40°C (104°F) duringthe day to near-freezing at night. Deserts are often located nearmountain ranges, which block the passage of rain clouds.

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Figure 25 � Deserts are the driestplaces on Earth. They typicallyreceive less than 25 cm of precipita-tion a year.

� The flapnecked chameleon livesin the deserts of Botswana.

� The Sonoran Desert in Arizonaappears lush with plant life justafter the winter rains.

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Oregon’s Rain Shadow Manystudents may think that Oregonis a state that is completelydominated by lush forests. Infact, some of the state has ashrub-steppe ecosystem that can receive as little as 25 cm ofrainfall per year. This situationis due to an effect called rainshadow. In western Oregon, theCascade Range of the RockyMountains (which runs fromthe northern to the southernedges of the state) creates a bar-rier that blocks ocean moisturefrom moving to the eastern sideof the mountains. Because ofthis effect, ecosystems on thewestern side of the mountainsare dominated by old-growthforest, while ecosystems on theeastern side are dominated by sagebrush. Have studentsresearch the types of plants and animals found in Oregon’sshrub-steppe ecosystem. Alsohave them look at a world mapto identify other areas that mayhave arid ecosystems caused bythe rain shadow effect. Havestudents research those areas todetermine if they were correct.

CulturalAwarenessCulturalAwareness

People of the Desert Just as plants andanimals are adapted to desert life, peoplehave also found a way to survive there.Have students research groups of peoplewho live in the world’s deserts, such as theSan of the Kalahari, the Tuareg of theSahara, or the Native Americans of theSouthwest. Have students report their find-ings to the class and include their report intheir Portfolio. InterpersonalLS

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Home, Home on the Biome Ask students tofind a song or poem that was inspired by oneof the biomes in this chapter. Have studentstry to find at least one selection for each typeof biome. Have students list, highlight, or pantomime the unique aspects of the biomesthat are mentioned within the selections.

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Deserts

Xeriscaping As urban and suburban desertareas become more populous and water inthose areas becomes more scarce, some peoplehave begun to landscape their yards using native plants instead of typical grass. Thismethod of landscaping, called xeriscaping,can be an interesting way to learn about nativeecosystems while conserving water resources.Have students use the Internet to research thespecies of plants used to xeriscape areas in a desert region. Ask groups to create a land-scape plan for a home in an urban desert area.

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Waxy Resistance To help students under-stand how wax helps a plant retain water,bring in some hand lotion that containsbeeswax, and have students put some on their hands. Explain that the waxy barrierkeeps the skin on their hands from absorbingor excreting water. Then, have them dunk their hands in water, to observe how waterbeads on their skin.


Plants of the Desert All desert plants have adaptations forobtaining and conserving water, which allow the plants to live indry, desert conditions. Plants called succulents, such as cactuses,have thick, fleshy stems and leaves that store water. Their leavesalso have a waxy coating that prevents water loss. Sharp spineson cactuses keep thirsty animals from devouring the plant’s juicyflesh. Rainfall rarely penetrates deeply into the soil, so manyplants’ roots spread out just under the surface of the soil toabsorb as much rain as possible.

Many desert shrubs drop their leaves during dry periods andgrow new leaves when it rains again. When conditions are too dry,some plants die and drop seeds that stay dormant in the soil untilthe next rainfall. Then, new plants quickly germinate, grow, andbloom before the soil becomes dry again. Some desert plants haveadapted so that they can survive even if their water content dropsto as low as 30 percent of their mass. Water levels below 50 to 75 percent are fatal for most plants.

Animals of the Desert Reptiles, such as Gila monsters and rattlesnakes, have thick, scaly skin that prevents water loss.Amphibians, such as the spadefoot toad, survive scorching desertsummers by estivating—burying themselves in the ground andsleeping through the dry season. Some animals, such as the elfowl shown in Figure 26, nest in cactuses to avoid predators.Desert insects and spiders are covered with body armor that helpsthem retain water. In addition, most desert animals are nocturnal,which means they are active mainly at night or at dusk, when theair is cooler.

Figure 26 � Desert plants surviveharsh conditions by growing deeproots to reach groundwater and byhaving specialized structures thatlimit the loss of water. Desert animalsbury themselves underground or bur-row in cactuses to avoid extremetemperatures and predators.

FIELD ACTIVITYFIELD ACTIVITY Miniature Desert Create aminiature desert by growing asmall cactus garden. Purchasetwo or three small cactus plants,or take several cuttings from alarge cactus. To take cuttings,carefully break off the shootsgrowing at the base of the parentcactus. Place the plants in rockyor sandy soil similar to the soil ina desert. Keep the cactuses inbright sunlight, and do not waterthem frequently. Record yourobservations of your cactus gar-den in your Ecolog.

� Elf owls burrow in cactuses to avoidhot temperatures during the day.

� This sidewinder has a unique wayof moving so that only small portionsof its body are in contact with thehot sands at any one time.

Debate ATVs in the Desert Encouragestudents to debate the use of all-terrain vehicles in a desertecosystem. First, have studentsbrainstorm or research the possiblenegative effects of driving all-terrainvehicles in desert ecosystems.(Effects could include crushed vegeta-tion, the destruction of bird eggs laidon the ground, pollution from leak-ing motor oil, and discarded trash.)Then have them find or think ofreasons why these vehicles shouldbe restricted to designated trails inthe desert. (If some areas were desig-nated as trails, this would keep all-terrain vehicles out of the moresensitive areas of deserts.) Finally,ask students to debate whether all-terrain vehicles should be used atall in the desert. Verbal

Activity Animal Adaptations to HeatAnimals that live in extremely hotand dry conditions have developedmany adaptations that allow themto retain water and stay cool. Someof these adaptations are listed inthe Student Edition, but manymore exist. Have students researchthe cavernous sinus system, whichkeeps mammal brains cool even inintense heat. In this system of heatexchange, blood from the veins iscooled in the nose by the evapora-tion of water in the nasal passages.This cooler blood then movesthrough the veins up into the cav-ernous sinus in the head. In thecavernous sinus, veins and arteriescome into contact with each other,and the warmer arterial blood iscooled before it reaches the ani-mal’s brain. Have students sketcha diagram of the cavernous sinussystem to include in their Portfolio.

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TundraThe biome is located in northern arctic regions, as shownin Figure 27. The winter is too cold and dry to permit the growthof trees in this biome. In many areas of the tundra, the deeperlayers of soil, called are permanently frozen through-out the year. As a result, the topsoil is very thin. In the summer,when the thin topsoil layer thaws, the tundra landscape becomesquite moist and spongy and is dotted with bogs. These wet areasare ideal breeding grounds for enormous numbers of swarminginsects, such as mosquitoes and black flies, and for the manybirds that feed on the insects.

Vegetation of the Tundra Figure 28 shows the Alaskan tundra inthe summer. Mosses and lichens, which can grow without soil, covervast areas of rocks in the tundra. The soil is thin, so plants havewide, shallow roots to help anchor them against the icy winds. Mostflowering plants of the tundra, such as campion and gentian, areshort. Growing close to the ground keeps the plants out of the windand helps them absorb heat from the sunlit soil during the brief sum-mer. Woody plants and perennials such as willow and birch haveevolved dwarf forms and grow flat or grow along the ground.

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Figure 27 � The precipitation thatthe tundra biome receives remainsfrozen much of the year.

Figure 28 � During its brief summer,the Alaskan tundra is covered byflowering plants and lichens.

Venn Diagram

Create theGraphic Organizer entitled“Venn Diagram” described in theAppendix. Label the circles with“Tundra” and “Desert.” Then, fillin the diagram withcharacteristics thateach biome shareswith the other.

Activity Tundra Creatures Review withstudents the characteristics of thetundra. (extreme cold, low precipita-tion, limited winter sunlight, per-mafrost, large numbers of insects inthe summer, small plants with shal-low roots) Based on these condi-tions, have students invent ahypothetical organism that couldthrive in the Arctic tundra. Havethem write an essay about theircreature and its adaptations.(Students should describe the crea-ture’s appearance, size, color, skincovering, defense mechanisms, diet,and reproductive strategy.) Encour-age students to draw a sketch toaccompany their essay and sharethe new creatures with other classmembers. Have students add theirwork to their Portfolio. Visual

Group Activity Arctic Science Experiments todetermine how global warmingwill affect arctic areas are beingcoordinated by the Arctic SystemScience (ARCSS) Data CoordinationCenter, through the InternationalTundra Experiment (ITEX) project.Have students locate informationfrom ARCSS about predictedtundra thaw depths, vegetationchanges, snow melt, methaneflux from warming tundra, andother possible effects of globalwarming. Have them create ashort news announcement thatexplains this information, andencourage them to share this with the rest of the school.

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Toolik Field Station One of the designatedlong-term ecological research (LTER) sites inNorth America is located above the treelinein arctic Alaska. The Toolik Field Station ismanaged by the Institute of Arctic Biology atthe University of Alaska, Fairbanks. At thestation, researchers focus on ecological proj-ects related to the tundra environment.Sample projects have examined freeze avoid-ance in hibernating ground squirrels, changesin tundra plants and soil due to artificial

warming (as a model for global warming),fish community structure and vertical migra-tion of zooplankton in arctic lakes, changesin rivers due to artificial fertilization, and thehydrology of tundra wetlands. Students whoare interested in studying biology as under-graduates may want to explore researchopportunities at the Toolik Station. Encouragethose who are interested to find the ToolikWeb site on the Internet, and to contact theUniversity of Alaska for more information.

GENERAL

Venn DiagramYYoouu mmaayy wwaanntt ttoo hhaavvee ssttuu--ddeennttss wwoorrkk iinn ggrroouuppss ttoo ccrreeaatteetthhiiss VVeennnn DDiiaaggrraamm.. HHaavvee oonneessttuuddeenntt ddrraaww tthhee mmaapp aanndd ffiilllliinn iinnffoorrmmaattiioonn pprroovviiddeedd bbyyootthheerr ssttuuddeennttss ffrroomm tthheeggrroouupp..

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Tundra

Vegetation of the Tundra

AAnnsswweerrss ttoo SSeeccttiioonn RReevviieeww1. Sample answer: Elf owls burrow in cactuses to

avoid hot daytime temperatures. Sidewindersmove so that only small areas of their bodiescontact the hot sand at a given time.

2. Tropical grasslands are located in tropical andsubtropical areas near the equator, and theyare full of grasses, scattered trees, and shrubs.Temperate grasslands are located farther fromthe equator and are dominated by grasses.They have extremely fertile soil.

3. Plants that grow in deserts and plants native to tundra are adapted to low moisture andextreme temperatures. Both desert and tundra

plants grow and flower quickly in the shortgrowing season. Desert plants have specialstructures that allow them to trap and storewater. Tundra plants grow low to the groundto stay out of the cold and dry wind.

4. Oil exploration is a threat to the tundra.5. Moderate to warm temperatures, consistent

rain during the growing season, and fertilesoils make for productive farming regions.

6. Large herbivores migrate due to the cycles of rain and drought in temperate grasslands.Migratory herbivores follow the rains to findnewly sprouted grass and water.


Animals of the Tundra Millions of migratorybirds fly to the tundra to breed in the summer.Food is abundant in the form of plants, mollusks,worms, and especially insects. Caribou, shown inFigure 29, migrate throughout the tundra insearch of food and water. Wolves roam the tun-dra and prey on caribou, moose, and smaller ani-mals, such as lemmings, mice, and hares. Theseanimals burrow underground during the winterbut they are still active. Many animals that live inthe tundra year-round, such as arctic foxes, lose their brown fur andgrow white fur that camouflages them with the winter snow. Theseanimals are also extremely well insulated.

Threats to the Tundra The tundra is one of the most fragilebiomes on the planet. Its food chains are relatively simple, so theyare easily disrupted. Because conditions are so extreme, the land iseasily damaged and slow to recover. Until recently, the tundra wasundisturbed by humans. But oil has been located in some tundraregions, such as in northern Alaska. Oil exploration, extraction,and transport has disrupted the habitats of the plants and animalsin many parts of the tundra. Pollution caused by spills or leaks ofoil and other toxic materials may also poison the food and watersources of the organisms that live in the tundra.

1. Describe two desert animals and the adaptationsthat help them survive.

2. Describe how tropical grasslands differ from temper-ate grasslands.

3. Compare the plants that live in deserts with theplants that live in the tundra biome.

4. Describe one threat to the tundra biome.

CRITICAL THINKING

5. Making Inferences Former grasslands are amongthe most productive farming regions. Read thedescription of temperate grasslands in this sectionand explain why this statement is true.

6. Analyzing Relationships Explain why elephantsand caribou, which live in very different biomes, bothmigrate.

READING SKILLS


079_P FPO

Figure 29 � Many migratory ani-mals, such as geese (left) and caribou(below), return to the tundra eachyear to breed.

MATHPRACTICEU.S. Oil Production On average, the United States produces an estimated 8.1 million barrels of oil per day. Howmany millions of barrels of oil doesthe United States produce in 1 year?If all of the oil-producing countriesof the world produce an estimated74.13 million barrels of oil per day,what percentage of worldwide oildoes the United States produce?

Reteaching Biome Collage Ask students tocut out pictures from science ornature magazines and use themto create a colorful collage of asavanna, temperate grassland,chaparral, desert, or tundra ecosys-tem. Hang the collages in the class-room, and suggest that studentsinclude their collage in theirPortfolio. Visual

Quiz1. Name two adaptations that ani-

mals might have to desert condi-tions. (Sample answers: Animalsmay have thick skin or bodyarmor to prevent water loss, theymay estivate during the summer,or they may be nocturnal.)

2. How is the tundra similar to thedesert? (Water is relatively scarcein both biomes.)

3. In which biome do plants tendto have deep root systems?(Tallgrass prairie, which is a typeof temperate grassland.)

AlternativeAssessment Similar Adaptations Ask stu-dents to list similar plant and ani-mal adaptations for desert andtundra biomes. (Some adaptationsinclude: avoiding extreme heat orcold by burrowing and sleeping; athick outer covering of skin or fur tokeep heat in or out; shallow rootsthat take advantage of a smallamount of rain; a thick cuticle thatminimizes water loss) Have studentsdescribe why animals would evolvesimilar strategies to different situa-tions. Logical/VerbalLS

LS

CloseClose

173

GENERAL

AAnnsswweerrss 8.1 million � 365 � 2.96 billionbarrels of oil per year; (8.1 million � 74.13 million) �100 � 10.9% of oil worldwide

MATHPRACTICE

GENERAL

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HighlightsCCHHAAPPTTEERR

66 HighlightsC H A P T E R 6

1 What Is a Biome?

2 Forest Biomes

3 Grassland, Desert, andTundra Biomes

KKey Termsbiome, 153climate, 154latitude, 155altitude, 155

Main Ideas� Scientists classify the ecosystems of the worldinto large areas called biomes.

� Biomes are described by their plant lifebecause specific climate conditions support thegrowth of specific types of vegetation.

� Climate determines which plants can grow inan area. Latitude and altitude affect climate insimilar ways.

tropical rain forest,156

emergent layer, 158canopy, 158epiphyte, 158understory, 158temperate rain

forest, 161temperate deciduous

forest, 162taiga, 163

� Major forest biomes include tropical rainforest, temperate rain forest, temperate decidu-ous forest, temperate evergreen forest, andtaiga.

� Tropical rain forests have high rainfall andhigh temperatures throughout the year. Theyare the most diverse of all biomes.

� Temperate forests experience seasonal varia-tions in precipitation and temperature. Theirvegetation is adapted to surviving thesechanges.

� Forest biomes are threatened by deforesta-tion through logging, ranching, and farming.

savanna, 165temperate grassland,

166chaparral, 168desert, 170tundra, 172permafrost, 172

� Savannas are located north and south oftropical rain forests and have distinct wet seasons.

� Temperate grasslands get too little rainfall tosupport trees. Grasslands are dominated mostlyby different types of grasses and floweringplants.

� Deserts are the driest biomes on Earth.

� Plants and animals found in each biomeadapt to the environment in which they live.

AlternativeAssessmentBiome Expert Chat Organize theclass into four groups, and assigntwo different biomes to eachgroup. Tell students that they havebeen asked to appear on a majortalk show, and they must prepareanswers to the questions below.Then, have students in each grouptailor the questions to their biomes.Give students 2–3 days, and thenstage mock interviews in front ofthe rest of the class where one per-son in each group is the TV hostand the others are the “authori-ties.” Some students may want tovideotape their interview. Interview Questions

1. What can you tell our viewersabout the climate conditions of the ________ (first biome)?(Answers may vary, but studentsshould include information abouttemperature and precipitation.)

2. After visiting the ________ (firstbiome), spending time in the________ (second biome) musthave been quite a shock. Is thistrue? Why or why not? (Answersmay vary depending on the pair ofbiomes. Students should point outdifferences in plant and animal lifeas well as differences in climate.)

3. What do the biomes have incommon? (Answers may vary.)

4. What was the most unusualplant or animal that youencountered in either of the twobiomes, and how was it adaptedto survive in its environment?(Answers may vary.) VerbalLS


174

Writing Have each student research and writean essay about the daily activities of a rain for-est insect. What does it eat, when does it for-age, what are its predators, and how does itavoid them? Encourage students to add thisessay to their Portfolio. VerbalLS

BUILDERSKILL• Chapter Test• Chapter Test• Concept Review• Critical Thinking• Test Item Listing• Design Your Own Lab• Math/Graphing Lab• CBL™ Probeware Lab• Consumer Lab• Long-Term Project GENERAL

GENERAL

GENERAL

GENERAL


GENERAL

GENERAL

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ReviewUsing Key TermsUse each of the following terms in a separatesentence.

1. biome2. climate3. epiphyte4. tundra5. permafrost

For each pair of terms, explain how the meaningsof the terms differ.

6. understory and canopy7. latitude and altitude8. chaparral and desert9. tropical rain forest and temperate deciduous

forest

Understanding Key Ideas10. Approximately what percentage of the Earth’s

species do tropical rain forests contain?a. 7 percentb. 20 percentc. 40 percentd. 50 percent

11. Animal species of the tropical rain foresta. compete more for available resources than

species native to other biomes do.b. have adaptations that minimize

competition.c. have adaptations to cope with extreme

variations in climate.d. are never camouflaged.

12. Migration of animals in the savanna ismostly a response toa. predation.b. altitude.c. rainfall.d. temperature.

13. Spadefoot toads survive the dry conditionsof the desert bya. migrating to seasonal watering holes.b. finding underground springs.c. burying themselves in the ground.d. drinking cactus juice.

14. The tundra is most suitable to a vertebratethata. requires nesting sites in tall trees.b. is coldblooded.c. has a green outer skin for camouflage.d. can migrate hundreds of kilometers each

summer.

15. A biome that has a large amount of rainfall,high temperatures, and poor soil is aa. temperate woodland.b. temperate rain forest.c. tropical rain forest.d. savanna.

16. The two main factors that determine whereorganisms live area. soil type and precipitation.b. temperature and precipitation.c. altitude and precipitation.d. temperature and latitude.

17. Which of the following biomes containslarge trees?a. savannab. temperate rain forestc. chaparrald. desert

18. The most common types of plants in thetaiga biome area. deciduous trees.b. short shrubs.c. coniferous trees.d. grasses.

C H A P T E R 6

Concept Maps Remembering words and under-standing concepts are easier when information isorganized in a way that you recognize. For exam-ple, you can use key terms and key concepts tocreate a concept map that links them together ina pattern you will understand and remember.

STUDY TIP

ANSWERS

UUssiinngg KKeeyy TTeerrmmss1. Sample answer: A biome is a

large region characterized by aspecific type of climate and cer-tain types of plant and animalcommunities.

2. Sample answer: Climate refers to weather conditions in an areaover a long period of time.

3. Sample answer: Epiphytes growon tall trees in the canopy forsupport.

4. Sample answer: Tundra is abiome dominated by grasses,lichens, and herbs and is pri-marily located north of theArctic Circle.

5. Sample answer: Permafrost is alayer of soil beneath topsoil thatis permanently frozen.

6. The canopy is the main layer oftrees in a forest. The understoryis below the canopy and extendsto shorter plants and shrubs onthe ground.

7. Latitude is the distance from theequator. Altitude is the heightabove sea level.

8. Chaparral has moderately warmtemperatures all year and is dry.The desert is drier and is hotterin the summer.

9. Tropical rain forests are locatednear the equator and maintain arelatively constant warm temper-ature year-round. Temperatedeciduous forests are generallylocated between 30° and 50°north latitude and have extremeranges of temperatures.

UUnnddeerrssttaannddiinngg KKeeyy IIddeeaass10. d11. b12. c13. c14. d15. c16. b17. b18. c


175

ReviewCCHHAAPPTTEERR

66

Section Questions1 1, 2, 7, 16, 21, 24–26, 32–332 3, 6, 9–11, 15, 17–19, 23, 29, 303 4, 5, 8, 12–14, 20, 22, 27, 28, 31

Assignment Guide


Read the passage below, and then answerthe questions that follow.

1.

a.b.c.d.

2.

a.

b.

c.

d.

34.

35.

36.

37.

Savanna

Temperate grasslandTemperate forest Desert

Temperate

Tropical

Subarctic

Arctic

Taiga

Tundra

Tropical rain forest Desert

DryWet

Hot

Dec

reas

ing tem

per

atur

e

Col

d

Decreasing moisture

ReviewSShort Answer19. Unlike the jungles you see in movies, the

floor of an undisturbed tropical rain forestusually has little vegetation. Explain why itlacks vegetation.

20. What is the relationship between root sys-tems and erosion in a grassland ecosystem?

21. How might a mountain affect where particu-lar types of biomes are located?

22. Well-preserved mammoths have been foundburied in the tundra. Explain why the tundrapreserves animal remains well.

23. How does deforestation contribute to achange in climate and increase the chance offloods in a biome?

Interpreting GraphicsUse the diagram below to answer questions24–26.

24. Why are tall trees found in the taiga but notin the tundra?

25. As moisture decreases, what happens to theamount of vegetation in an area?

26. What does the diagram tell you about thetemperature of and precipitation in temper-ate grasslands?

Concept Mapping27. Use the following terms to create a concept

map: threats to an ecosystem, erosion, over-grazing, logging, grasslands, rain forests,tundra, deserts, oil extraction, and irrigation.

Critical Thinking28. Comparing Processes American prairies and

Asian steppes contain different plant speciesbut are dominated by grasses. Write a shortparagraph that explains why the two grass-lands contain different species but the sametypes of plants.

29. Classifying Information Read the descrip-tion of tropical rain forests in this chapter,and list two factors that are responsible forthe biodiversity of this biome. Describe tworeasons for the decline of tropical rainforests.

30. Analyzing Relationships If you took a popu-lation of squirrels from the southeasternUnited States and introduced them into aCentral American rain forest, they wouldprobably not survive. Why do you think thesquirrels would not survive even though theyare naturally adapted to life in a forest?

31. Making Inferences How might prairie firesset from natural and human causes haveaffected the evolution of fire resistance inprairie grasses?

Cross-Disciplinary Connection32. Geography Use a world map to find loca-

tions of the various biomes. Then, make aposter that contains photos or illustrationsof plants and animals native to each biome.

Portfolio Project33. Food Webs in Your Biome Do a special proj-

ect on the ecosystems in your biome. Use fieldguides to find out what plants and animalslive in your biome. Then, draw a food webthat shows how organisms in each ecosystemcould be related.

READING SKILLS

WRITING SKILLS

C H A P T E R 6?

? ?SShhoorrtt AAnnsswweerr19. The rain forest floor lacks veg-

etation because the soil is poor innutrients and receives very littlesunlight.

20. Large root systems hold soil inplace and prevent erosion.

21. Biomes vary in climate, and theclimate gets colder with increas-ing altitude. So, different biomesare located in different altitudesacross a mountain.

22. Permafrost in the tundra can preserve organisms such as amammoth because the cold temp-eratures and frozen ground pre-vent and slow bacterial activity.Therefore, a mammoth wouldnot decompose quickly if buriedin the tundra.

23. A decrease in the number of trees will cause less carbon to be absorbed and stored. This will lead to an increase in carbondioxide, a greenhouse gas thatcan cause warmer temperatures.A decrease in the number of treesalso leads to flooding because the trees are no longer there to absorb and store water.

IInntteerrpprreettiinngg GGrraapphhiiccss24. Cold temperatures and limited

precipitation exclude most treesfrom tundra.

25. The amount of vegetationdecreases.

26. Temperate grasslands have moderate temperature and precipitation.

CCoonncceepptt MMaappppiinngg27. Answers to the concept mapping

questions are on pp. 715–720.


176

CCrriittiiccaall TThhiinnkkiinngg28. Similar environments led to the evolution of

similar organisms with similar characteristicsand strategies, even though the species live indifferent locations.

29. Answers may vary. Two factors that areresponsible for the biodiversity of this biomeare constant warm temperatures and largeamounts of annual rainfall. Deforestationcaused by logging and agricultural operationscontributes to the decline of tropical rainforests.

30. The squirrels are not adapted to the rain forest, so they may not be able to eat or

compete for the food that is available. Thedisplaced squirrels are also not adapted toconstant high temperatures, high humidity,and high precipitation.

31. Frequent fires may have increased the evolu-tionary pressure for prairie grasses to evolvefire resistance.

CCrroossss--DDiisscciipplliinnaarryy CCoonnnneeccttiioonn32. Answers may vary.

PPoorrttffoolliioo PPrroojjeecctt33. Answers may vary.

ReviewCCHHAAPPTTEERR

66


Read the passage below, and then answerthe questions that follow.

The Tropics and other regions of high biodi-versity include some of the economically poor-est countries on Earth. These countries aretrying to use their natural resources to buildtheir economies and to raise the standard ofliving for their citizens. Several conservationstrategies offer ways for developing countriesto benefit economically from preserving theirbiodiversity.

For example, in a debt-for-nature swap,richer countries or private conservationorganizations pay some of the debts of adeveloping country. In exchange, the devel-oping country agrees to take steps to protectits biodiversity, such as setting up a preserveor launching an education program for itscitizens. Another idea to help local peoplemake money from intact ecosystems is to setup a national park to attract tourists. Peoplewho want to see the ecosystem and itsunique organisms will pay money for natureguides, food, and lodging. This idea is calledecotourism.

1. The main objective of both a debt-for-nature swap and ecotourism is a. economic gain.b. education of citizens. c. preservation of biodiversity.d. Both (a) and (c)

2. According to the passage, which of thefollowing statements is true?a. Regions of high biodiversity are not

worth saving.b. Intact ecosystems are ecosystems that

are most developed.c. A debt-for-nature swap is an example

of international compromise.d. Launching education programs for citi-

zens does not help protect ecosystems.

MATH SKILLS

Use the table below to answer quesions 34–35.

34. Making Calculations What percentage oftropical rain forest is being destroyed eachyear in country A? in country D?

35. Interpreting Statistics According to thetable, which country’s tropical rain forestwill be completely destroyed first? Whichcountry’s rain forest will be completelydestroyed last?

WRITING SKILLS

36. Communicating Main Ideas Describe theimportance of conserving the biomes of theworld. What can you do to help conserve theworld’s biomes?

37. Writing From Research Choose one biomeand research the threats that exist against it.Write a short essay that describes the threatsand any actions that are being taken to helpsave the biome.

Amount of Tropical Rainforest

Amount ofAmount of annualtropical rain deforestation

Country forest (km2) (km2/y)

A 1,800,000 50,000

B 55,000 3,300

C 22,000 6,000

D 530,000 12,000

E 80,000 700

READING SKILLS

MMaatthh SSkkiillllss34. 50,000 � 1,800,000 � 100% �

2.8% in country A; 12,000 �530,000 � 100% � 2.3% incountry D

35. The tropical rain forest in country C will be completelydestroyed first. The tropical rain forest in country E will becompletely destroyed last.

WWrriittiinngg SSkkiillllss36. Each biome represents a wealth

of adaptations and biologicalvariety. Losing any biome wouldrob the world of that evolution-ary history and diversity. Biomescan be conserved in part by thedevelopment of sustainable for-estry and agriculture and by set-ting aside areas for preservation.Support of international conser-vation and human rights organi-zations can also help to preservebiomes.

37. Answers may vary.

RReeaaddiinngg SSkkiillllss1. d2. c


177


C H A P T E R 6 Standardized Test PrepUnderstanding ConceptsDirections (1–4): For each question, write on aseparate sheet of paper the letter of the correctanswer.

1 Which of the following describes a biome?A. all the areas on Earth that are life-

supportingB. weather conditions in an area for a

specific time periodC. a region characterized by specific climate

and organism communitiesD. an area where the animal population

interacts with its abiotic environment

2 What type of forest has the greatest biodiversity?F. taiga forestG. temperate deciduous forestH. temperate rain forestI. tropical rain forest

3 What is the diversity of the species in anarea dependent on?A. plant lifeB. rainfallC. sunlightD. temperature

4 What are the main factors that determineweather?F. altitude, latitude, precipitation,

temperatureG. altitude, latitude, precipitation,

vegetationH. air currents, altitude, temperature,

vegetationI. air currents, precipitation, temperature,

vegetation

Directions (5–6): For each question, write a shortresponse.

5 A temperate grassland is a biome that isdominated by grasses and that has very fewtrees. How are temperate grasslands threat-ened by overgrazing?

6 Compare and contrast the tundra anddesert biomes.

Reading SkillsDirections (7–8): Read the passage below. Thenanswer the questions.

When rain falls on a forest, much of the rainis absorbed by plant roots and transpired intothe air as water vapor. The water vapor forms rain clouds. Much of the water in the cloudswill fall as rain somewhere downwind fromthe forest. Clearing the trees results in defor-estation, which can change the climate.

Deforestation led to the disastrous floodingof the Yangtze River in China in 1998. More than 2,000 people died in the floods,and at least 13 million people had to leavetheir homes. It is estimated that 85 percent of the forest in the Yangtze River basin hasbeen cut down. So the millions of tons ofwater these trees once absorbed now flowsfreely down the river and spreads across thefields into towns during the seasonal monsoonrains.

7 How could future flooding on the YangtzeRiver be avoided?A. replanting cropsB. rebuilding homesC. replanting treesD. rebuilding walls

8 Examine the climate change produced bydeforestation.

Directions (9): Read the passage below. Thenanswer the question.

Tropical rain forests are located in a beltaround the Earth near the equator. The climateis ideal for a wide variety of plants and ani-mals. In tropical rain forests, different types ofplants grow in different layers. The main lay-ers above the forest floor are, in order fromtop to bottom, the emergent layer, the canopy,and the understory.

9 Which layer of a tropical rain forestreceives the least sunlight, and why?

178

Estimated TimeTo give students practice undermore realistic testing conditions,allow them 30 minutes to answerall of the questions in this practicetest.

178 Chapter 6 • Standardized Test Prep

Standardized Test Prep

10. I11. C12. G13. A

Answers1. C2. I3. B4. F5. Answers will vary. See Test Doctor for detailed

scoring rubric.6. Answers will vary. See Test Doctor for detailed

scoring rubric.7. C8. Answers will vary. See Test Doctor for detailed

scoring rubric.9. The forest floor receives the least sunlight,

because the other layers block most of it.

Question 5 Full-credit answersshould include the followingpoints:

• overgrazing causes increased soilerosion

• increased erosion reduces theoverall health of the soils whichmakes it harder for grasses togrow


• both desert and tundra have lowannual precipitation

• temperatures in the desert arehigher than in the tundra


• deforestation reduces rainfall,making the climate drier

• trees absorb carbon dioxidefrom the atmosphere

• when there are less trees, morecarbon dioxide remains in theatmosphere, which affects tem-perature

hes08TE_c06_178-179_STP 8/25/06 4:51 PM Page 178

TestWhen several ques-tions refer to the samegraph, table or map,answer the questionsyou are most sure of first.

Interpreting GraphicsDirections (10–13): For each question below, record the correct answer ona separate sheet of paper.

Different scientists classify biomes in different ways. The map below showsone way to classify the biomes in Africa. Use this map to answer questions10 through 13.

Biomes of Africa

0 What can be inferred about the biomes of Africa?F. Africa has a large concentration of tropical rain forests.G. Africa has a limited number of plant and animal communities.H. Africa has all types of plant life because of the many diverse

biomes.I. Africa has large desert areas that get less than 25.0 cm of precipita-

tion a year.

q Which biome covers the most surface area in Africa?A. desert C. MediterraneanB. highland D. steppe

w According to the map, which of the following determines the characteristics of a biome?F. geographic borders H. longitudeG. latitude I. the Indian ocean

e What geographic features are near 10°N, 40°E?A. mountains C. riversB. plains D. volcanoes

LEGEND

Humid tropicalTropical savannaDesertSteppeMediterraneanMarine west coastHighland

N

W E

S

1,000 Kilometers

1,000 Miles500

500

0

0

SCALE

10°E

0°10°W

20°W

Equator

20°N

30°N

20°S

10°S

10°N

30°S 40°E

50°E

INDIANOCEAN

ATLANTICOCEAN

RED SEA

Tropic ofCancer

Tropic of Capricorn

MEDITERRANEANSEA

179

Standardized Test Prep

Chapter 6 • Standardized Test Prep 179

Question 12 Answer G is correct.Students struggling with this typeof question may benefit from prac-ticing using the process of elimina-tion. Each incorrect choice can beidentified by imagining what amap would look like if each condi-tion was true. For example, if lati-tude was the determining factor,then biome boundaries would runparallel, or close to parallel, withlatitude lines (as they do).

Question 13 Answer A is correct.Students struggling with this typeof inference question may benefitfrom practicing parsing outdescriptive titles. For example, thebiome type at the given coordi-nates is described as highlands.Ask students what conclusionsthey can draw from the specifictitle highlands. If they are stillstruggling, tell students to breakthe word into its two roots,“high” and “lands.”

hes08TE_c06_178-179_STP 8/25/06 4:51 PM Page 179

4.

a.

b.

c.

d.

e.

Analysis1.

2.

Conclusions3.

4.

1.

Extension

CCHHAAPPTTEERR

66Identify Your Local BiomeIn what biome do you live? Do you live in a temperate deciduousforest, a desert, or a temperate grassland, such as a prairie orsavanna? In this lab, you will explore certain characteristics ofthe biome in which you live. With the information you gather,you will be able to identify which biome it is.

Procedure1. Use a globe or atlas to determine the latitude at which you

live. Record this information.

2. Consider the topography of the place where you live. Studythe contour lines on a map or surface variations on a globe.What clues do you find that might help identify your biome?For example, is your area located near a mountain or anocean? Record your findings.

3. Prepare a climatogram of your area. A climatogram is agraph that shows average monthly values for two factors:temperature and precipitation. Temperature is expressed indegrees Celsius and is plotted as a smooth curve. Precipitationvalues are given in centimeters and are plotted as a histogram.

To make a climatogram of your area, obtain monthlyaverages of precipitation and temperature for one year fromyour local TV or radio weather station. Make a data table,and record these values. Next, draw the vertical and hori-zontal axes of your climatogram in your notebook or ongraph paper. Then, show the temperature scale along thevertical axis on the right side of the graph and the precipita-tion scale along the vertical axis on the left side of thegraph. Show months of the year along the horizontal axis.Finally, plot your data.

Objectives� Collect information from interna-

tional, national, and local resourcesabout the biome in which you live.

� Performfield observations to identify thename of the biome in which you live.

Materialsbinoculars (optional)

field guide to local flora and

fauna

globe or atlas

graph paper (optional)

notebook

pencil or pen

ruler

USING SCIENTIFIC METHODS

Exploration Lab: FIELD ACTIVITYC H A P T E R 6

Tem

pera

ture

(˚C

)

–60

–40

–20

0

20

40

–50

–30

–10

10

30

Months

DJ F M A M J J A S O N0

10

20

30

40

50

5

15

25

35

45

Pre

cip

itati

on

(cm

)

Austin, Texas (2000)

� Climatograms The temperatureand precipitation for Austin, Texas isshown in this climatogram.

IDENTIFY YOUR LOCALBIOME

Teacher’s Notes

Time Requiredone 45-minute class period

Lab Ratings

TEACHER PREPARATION

STUDENT SETUP

CONCEPT LEVEL

CLEANUP

Skills Acquired• Classifying• Collecting Data• Inferring• Interpreting• Organizing and Analyzing Data

The Scientific MethodIn this lab, students will:• Make Observations• Ask Questions• Analyze the Results• Draw Conclusions

MaterialsThe materials on the student pageare enough for a group of fourstudents.

E A S Y H A R D

Tips and TricksIf you are near a university or college, contactthe biology department, and ask if a professoror student would be willing to help your stu-dents identify the local flora and fauna.Climatograms will probably be influenced byhuman habitations and roads. These structurescan elevate ambient temperature. Therefore,students’ climatograms may not match any inthe chapter. Have students identify organismsliving in natural vegetation as well as those living in human habitation. Have them recordthe differences in their lab write-up.

180


Exploration LabField Activity

hes08TE_c06_180-181_Lab 8/25/06 9:44 AM Page 180


4. Go outside to observe the plants growing in your area. Bringa field guide, and respond to the following items in yournotebook. a. Sketch or describe as many plants that are common in

your area as you can. Use your field guide to identify each of these species.

b. Describe three or more adaptations of each plant to thelocal climate.

c. Which of the plants that you observed are native to yourarea? Which have been introduced by humans? Which ofthe introduced plants can survive on their own in localconditions? Which of the introduced plants requireextensive human care to remain alive?

d. Look for evidence that animals have left behind—footprints, nests, dens or burrows, hair or feathers,scratches, or urine markings. Sketch or describe as manydifferent animal species as possible. Identify each speciesby using your field guide.

e. Describe three or more adaptations that each animal hasdeveloped in order to survive in local climatic conditions.

Analysis1. Analyzing Data Compare your local climatogram to the

biome climatograms shown in this chapter. Which biome hasa climatogram most similar to your climatogram?

2. Analyzing Results Consider your latitude, topographicalfindings, and observations of local plants and animals.Combine this information with your climatogram, and deter-mine which biome best matches the area in which you live.

Conclusions3. Evaluating Results Does your climatogram match any of the

seven major terrestrial climatograms shown in the chapter?Explain how any differences between your biome and thebiome in the chapter that your biome most clearly matchesmight influence the adaptations of local animals and plants.

4. Applying Conclusions Organisms create features of thebiome in which they live. What features of your biome arecreated by the organisms that live there?

1. Classifying Information Name the three plant adaptationsand the three animal adaptations that you observed.Explain in detail how each of these adaptations meets theconditions of your biome.

Extension

� Biomes These two cities are locatedin two different biomes. Stamford,Vermont (top) is located in a temper-ate deciduous forest, and Tucson,Arizona (bottom) is located in a desert.

AAnnsswweerrss ttoo AAnnaallyyssiiss1. Answers may vary.2. Answers may vary.

AAnnsswweerrss ttoo CCoonncclluussiioonnss3. Answers may vary.4. Answers may vary but may

include dams, dens, burrows, or other features.

AAnnsswweerrss ttoo EExxtteennssiioonn1. Answers may vary.

181

Lowell S. BaileyBedford - N. Lawrence

High SchoolBedford, Indiana

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A LITTLE PIECE OF CAJUN PRAIRIECajun prairie is a distinct grassland,named for the settlers who livedthere. It once covered more than2.5 million acres of southwestLouisiana. Today, only about 100acres of Cajun prairie remain. If the work of two biologists andmany volunteers pays off, how-ever, a little piece of Cajun prairiewill always exist in Louisiana.

“I think that saving Cajunprairie is important because once itis gone, you cannot bring it back,”says Charles Allen, a retired profes-sor from the University of Louisi-ana and the botanist for Louisiana’sFort Polk. “There are plants andanimals there that have never beentested for uses by humans. Wecould be losing a plant that wouldcure cancer, or provide food orfiber,” he says.

Allen and biologist MalcolmVidrine, a professor of biology at Louisiana State University inEunice, have been working foralmost two decades to restoreCajun prairie.

Although Cajun prairie and the tallgrass prairies of the Mid-west both belong to the temperategrassland biome, Cajun prairie soilhas unique characteristics. It is

made of tight, heavy clays thatformed as a result of coastal flood-ing and rains. This soil, combined with frequent light-ning fires, makes it difficult for treesto grow but easy for prairie plants to flourish.

Settling on the PrairieIn the mid-1700s, many French Aca-dians, also known as Cajuns, arrivedin Louisiana from Nova Scotia,Canada. They sustained themselvesfor over 100 years by fishing, hunt-ing, and some farming. They alsosustained their environment becausetheir lifestyle caused little damage tothe prairie.

The establishment of the rail-road in the late 1800s brought newsettlers to farm the rich land. Thesesettlers brought with them new,more intensive agricultural practicesand established herds of cattle thatovergrazed the vegetation. By the early 20th century,most of the Cajun prairie had disappeared.

Today, the Cajun prairie eco-system is labelled as “imperiledglobally” by the Nature Conser-vancy, an organization dedicated to preserving natural communities.There are now fewer than 100 acresof Cajun prairie left in Louisiana. The railroad led to the near dis-appearance of the prairie, but ithas also played an important role

� Charles Allen is shown here collecting seeds from a compassplant at a Cajun prairie remnant.The leaves of the compass plantface east to catch the sun.


� Cajun prairie, preserved on this 10-acre site,once covered nearly 10 percent of Louisiana. What Do You Think?

The Eunice Cajun PrairieRestoration Project


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Making a DifferenceMaking a Difference

A LITTLE PIECE OF CAJUNPRAIRIE

BackgroundThe original human inhabitants ofthe prairie in southwest Louisianawere the nomadic Attakapas peo-ples. In the second half of the 18thcentury, Acadians arrived inLouisiana. The Acadians wereFrench settlers who were forced toleave Nova Scotia by the colonialBritish government because of theirreligion and culture. Some of theexiled Acadians returned to France.Those who settled in Louisianabecame known as Cajuns.

The Cajuns lived in relative isolation in Louisiana for about100 years. During this time, otherparts of Louisiana developedquickly. By the mid-1800s, thepopulation of New Orleans wasincreasing quickly and the foodsupply could not keep up. At thetime, agricultural goods had to betransported by boats throughlakes, swamps, and rivers.

Transporting food became easierwhen a railroad was built betweenTexas and Louisiana. After the railroad was built in the 1880s,developers began to buy the prairielands and build towns, includingEunice, Louisiana. Many farmersfrom the prairies in the Mid-westrelocated to grow rice on theCajun prairie. They brought withthem new, more intensive agricul-tural practices and technologies,which led to the destruction of theprairie biome.

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A LITTLE PIECE OF CAJUN PRAIRIE

Settling on the Prairie

AAnnsswweerrss ttoo WWhhaatt DDoo YYoouu TThhiinnkk??Answers will vary. Factors that may have led tothe loss of local habitats include rapid populationgrowth, the construction of new homes andinfrastructure, logging, mining, farming, and pollution. It is possible for people to settle in a habitat and minimize their impact on the land if they do not use the resources in their environment faster than the resources can berenewed. The Cajuns were able to sustain themselves on the prairie without destroying the habitat by practising low-impact farming,fishing, and hunting.


What Do You Think?Are there threatened habitatsin your area? What factors do you think led to the loss of these habitats? Is it possiblefor people to settle in a habitatwithout having a negativeimpact? How were the Cajunsable to sustain themselves onthe prairie without destroyingthe habitat?

in saving the last remaining piecesof prairie. The remaining prairie ismostly in remnants of small, nar-row strips along railroad right-of-ways. Because the railroad ownedthese pieces of land, they werenever farmed.

The Eunice Cajun PrairieRestoration ProjectIn the late 1980s, Allen and Vidrinelocated as many remnant strips asthey could. They chose 10 of thestrips and studied them carefully.They found almost 500 species ofplants in the 10 strips.

The Eunice Cajun Prairie Restor-ation Project began in the summerof 1988. Its goal was to restore andpreserve a small Cajun prairie in thecity of Eunice, Louisiana.

A 10-acre site in Eunice wasmowed, and herbicide was used todestroy the nonnative vegetation.Volunteers from local elementaryand high schools collected bags of seeds from Cajun prairie plants

growing in the remnant strips. Thatwinter, controlled burns were usedto prepare the site. On a designatedplanting day, the students spreadthe seeds they had collected. Thesite was then lightly tilled. Sod wasremoved from the remnant stripsand replanted at the Eunice siteduring the next three seasons.

Restoration is an ongoing effort.Yearly controlled burns maintainthe habitat. The fires destroy shrubsand trees, but do not kill most ofthe prairie plants. Spot herbicidesare used on the more pervasive non-native species, such as the Chinesetallow tree, the most threateningnonnative species for the prairie.The seeds of this tree are easilyspread when birds eat the seedsand deposit them in droppings.

Today, nearly 300 native Cajunprairie species, including little blue-stem, Eastern gama grass, blazingstars, and hairy sunflower, have been reestablished at the site. Aswell, the rare wild coco orchid

(Eulophia ecrista) has been found at the site. This is a very positivesign because few of these orchidshave been found in the remnantstrips or in Louisiana. Much of the Eunice site is now almost com-pletely Cajun prairie.

� To maintain the habitat, volun-teers remove nonnative vegetationsuch as this vasey grass.

� Volunteers such as these students used seeds and sodgathered from remnants to create a new Cajun prairiehabitat in Eunice, Louisiana.

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The Native Prairie BankPrairie lands once covered millionsof acres of North America. Forexample, in the state of Minnesota,there were once 18 million acres of prairie. Today, less than one percent of Minnesota’s tallgrassprairie exists. Across the UnitedStates, there are ongoing efforts toprotect prairie remnants.

To encourage such efforts, thestate legislature created the NativePrairie Bank program in 1987.This program helps landownersprotect native prairie located on their properties. Prairie has survived on some farms in areaswhere the land is too rocky or hillyto plow. Landowners with suchremnants on their farms can register their properties in theNative Prairie Bank and receivepayment for preserving their nativeprairies, while continuing to owntheir properties. The program pro-tects the land from development orfarming.

Have students find out moreabout the Native Prairie Bank. Do similar programs exist forthreatened habitats in their state?Challenge students to come upwith a way to raise awarenessabout these programs.

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