CH 1 APTER Science and the Environment CHAPTER 1

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11 Science and the EnvironmentC H A P T E R 1

1 Understanding OurEnvironment

2 The Environment andSociety

PRE-READING ACTIVITY

BookletBefore youread this chap-ter, create the

FoldNote entitled “Booklet”described in the Reading andStudy Skills section of theAppendix. Label each page ofthe booklet with a main ideafrom the chapter. As youread the chapter, write whatyou learn about each main idea on the appropri-ate page of the booklet.

More than 2,700 m (9,000 ft)above sea level, a forest ecologistis studying biodiversity in a CostaRican rain forest. To ascend to thetreetops, he shoots an arrow over abranch and hauls himself up withthe attached rope.

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4 Chapter 1 • Science and the Environment

OverviewTell students that this chapter pres-ents an overview of environmentalscience and the history of humansin the environment. To solve envi-ronmental problems, we must beable to identify causes and describesolutions. The chapter also exam-ines environmental science in asocial and economic context.

Using the FigureThe photograph shows a Frenchecologist in Costa Rica’s RioMacho rain forest preserve. Tellstudents that many of the plantsfound in the rain forest canopy seem better adapted for life in thedesert than in the rain forest. Askstudents to hypothesize why this is true. (The rainforest canopy hastrace amounts of soil, so there isnothing to hold water when it rains.This means that plants must beadapted to conserve water eventhough they are growing in some of the wettest places on Earth.) Sometypes of plants, called bromeliads,can catch and store their ownwater. Some of the largest bromeli-ads can hold many liters of waterand can support reproducing popu-lations of frogs. VisualLS

For information about videosrelated to this chapter, go togo.hrw.com and type in the keyword HE8 SENV.

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PRE-READING ACTIVITY

LS 4e Human beings live within the world’s ecosystems. Increasingly,humans modify ecosystems as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening current globalstability, and if not addressed, ecosystems will be irreversibly affected.(Section 1)

ST 2a Scientists in different disciplines ask different questions, use differentmethods of investigation, and accept different types of evidence to supporttheir explanations. Many scientific investigations require the contributions ofindividuals from different disciplines, including engineering. New disciplines ofscience, such as geophysics and biochemistry often emerge at the interface oftwo older disciplines. (Section 1)

SPSP 3a Human populations use resources in the environment in order tomaintain and improve their existence. Natural resources have been and willcontinue to be used to maintain human populations. (Section 1)

SPSP 6b Understanding basic concepts and principles of science andtechnology should precede active debate about the economics, policies, poli-tics, and ethics of various science and technology related challenges.However, understanding science alone will not resolve local, national, or globalchallenges. (Section 1 and Section 2)

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When someone mentions the term environment, some peoplethink of a beautiful scene, such as a stream flowing through awilderness area or a rain forest canopy alive with bloomingflowers and howling monkeys. You might not think of yourbackyard or neighborhood as part of the environment. In fact,the environment is everything around us. It includes the naturalworld as well as things produced by humans. But the environ-ment is also more than what you can see—it is a complex webof relationships that connects us with the world we live in.

What Is Environmental Science?The students from Keene High School in Figure 1 are searchingthe Ashuelot River in New Hampshire for dwarf wedge mussels.The mussels, which were once abundant in the river, are now indanger of disappearing completely—and the students want toknow why. To find out more, the students test water samplesfrom different parts of the river and conduct experiments. Couldthe problem be that sewage is contaminating the water? Or couldfertilizer from a nearby lawn be causing algae in the river to growrapidly and use up the oxygen that the mussels need to survive?Another possible explanation might be that a small dam on theriver is disrupting the mussels’ reproduction.

The students’ efforts have been highly praised and widelyrecognized. Yet they hope for a more meaningful reward—thepreservation of an endangered species. The students’ work is justone example of a relatively new field— thestudy of the impact of humans on the environment.

environmental science,

Objectives� Define environmental science, and

compare environmental sciencewith ecology.

� List the five major fields of studythat contribute to environmentalscience.

� Describe the major environmentaleffects of hunter-gatherers, theagricultural revolution, and theIndustrial Revolution.

� Distinguish between renewableand nonrenewable resources.

� Classify environmental problemsinto three major categories.

Key Termsenvironmental scienceecologyagriculturenatural resourcepollutionbiodiversity

S E C T I O N 1

Understanding Our Environment

Figure 1 � These students arecounting the number of dwarfwedge mussels in part of theAshuelot River. They hope that thedata they collect will help preservethis endangered species.

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OverviewBefore beginning this section,review with your students theObjectives in the Student Edition.This section describes the fieldsthat contribute to environmentalscience. It also explores the historyof humans in the environment and discusses the major problemsthreatening the environment today.

Ask students, “What is the envi-ronment?” Have students brain-storm answers. As a class, establisha working definition for the term.

IdentifyingPreconceptionsUnderstanding EnvironmentalProblems Ask students to listsome of the most significant envi-ronmental problems in the worldtoday. (Answers may include globalissues such as rain forest destructionor global warming.) Then ask stu-dents to name some environmentalproblems in your local community.Ask students to identify one of thelocal problems that is part of alarger global problem. For exam-ple, if smog is a problem in yourarea, students may point out thatautomobile emissions might alsocontribute to global warming.Then ask students to brainstormways that the local problem couldbe solved. (Ideas might include car-pooling or using mass transit when-ever possible.)

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MISCONCEPTION ALERT

Too Many or Too Few? Environmentalnews stories often focus on the efforts topreserve a threatened or endangered species.But sometimes the problem is the opposite—species can overpopulate an ecosystem.Species that are introduced from another location and then thrive in the absence ofpredators are called invasive species. Thezebra mussel is one example of an invasivespecies. The zebra mussel was introducedinto the Great Lakes near Detroit in 1989from the ballast of an ocean-going ship.Since then, it has spread through 23 states

and two Canadian provinces. Zebra musselscause $50 million to $100 million in dam-ages each year by blocking water intakesand outflows for power plants and watertreatment facilities. They continue to spread,and they pose a threat to many of the water-ways of North America. Have studentsresearch the effects of another invasivespecies, such as fire ants, killer bees,European starlings, or plants such as hydrillaand kudzu. Have students create a posterdemonstrating these effects, and have themshare what they’ve found with the class.

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The Goals of Environmental Science One of the major goals ofenvironmental science is to understand and solve environmentalproblems. To accomplish this goal, environmental scientists studytwo main types of interactions between humans and the environ-ment. One area of study focuses on how we use naturalresources, such as water and plants. The other area of studyfocuses on how our actions alter our environment. To study theseinteractions, environmental scientists must gather and analyzeinformation from many different disciplines.

Many Fields of Study Environmental science is an interdiscipli-nary science, which means that it involves many fields of study.One important foundation of environmental science is ecology.

is the study of how living things interact with each otherand with their nonliving environment. For example, an ecologistmight study the relationship between bees and the plants thatbees pollinate. However, an environmental scientist might investi-gate how the nesting behavior of bees is influenced by humanactivities, such as suburban landscaping.

Many other sciences contribute to environmental science. Forexample, chemistry helps us understand the nature of pollutants.Geology helps us model how pollutants travel underground.Botany and zoology provide information to preserve species.Paleontology, the study of fossils, can help us understand howEarth’s climate has changed in the past. Using such informationabout the past can help us predict how future climate changescould affect life on Earth. Figure 2 shows a few examples of dis-ciplines that contribute to environmental science.

How is ecology related to environmental science?(See the Appendix for answers to Reading Checks.)��Reading Check

Ecology

HistoryConnection to

Rachel Carson Alarmed by theincreasing levels of pesticides andother chemicals in the environ-ment, biologist Rachel Carsonpublished Silent Spring in 1962.Carson imagined a spring morn-ing that was silent because thebirds and frogs were dead afterbeing poisoned by pesticides.Carson’s carefully researchedbook was enthusiastically receivedby the public and was read bymany other scientists, as well aspolicy makers and politicians.However, many people in thechemical industry saw SilentSpring as a threat to their pesti-cide sales and launched a$250,000 campaign to discreditCarson. Carson’s research pre-vailed, although she died in1964—unaware that the bookshe had written was instrumentalin the birth of the modern envi-ronmental movement.

Figure 2 � Many Fields of Study

� This marine biologist (right) isstudying a marine mammal calleda manatee.

� This ornithologist (above) isstudying the nesting behavior ofseabirds called albatrosses.

Brainstorming Before coveringthe passage about the fields ofstudy that contribute to environ-mental science, ask students tocome up with their own list similarto Table 1. Write their responseson the board. Then have studentsread the passage, revisit their list,and decide if any of the fields of study should be removed or added to the list.

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Environmental News JournalsTo help students become aware ofenvironmental issues in your com-munity and around the world, havethem create a notebook of articlesfrom environmental news stories inmagazines, newspapers, and on theInternet. Have students make regu-lar additions to their journals. Forexample, have students search forstories that relate to each section inthis book. Before you introduceeach section, discuss student storieswith the class. Or, students couldorganize their journals accordingto your class syllabus. Students canalso supplement their journals withcritiques of the articles they read.

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkEcology is an important foundationof environmental science. The scienceof ecology helps environmental scientists to understand how humanactions affect living things and their environment.

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CareerCareerEnvironmental Scientist Environmental science is a broad field of study. Most environ-mental scientists choose to specialize in onefield, such as chemistry, botany, or geology.Environmental scientists also take classes inother fields of study to understand differentaspects of the field. Students who are inter-ested in pursuing a career in environmental science should consider attending schools that offer a wide variety of sciences and interdisciplinary study programs.

StrategiesStrategiesINCLUSIONINCLUSION

Have students look in magazines to findphotographs that show an environment.Have students glue each photograph to a separate index card to create postcards. Onthe back of the index card, students shouldwrite a short message to a friend or relativedescribing the environment and its plants andanimals. Lower-level students may simplylabel the plants or animals in the photographand dictate a story about the environment toanother student or into a tape recorder.

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Reading Organizer Tell students that theymay find it useful to make a concept map ofthe fields of study that contribute to environ-mental science. One idea for a concept map is to have environmental science in the centerand have the other fields of study as branches.Encourage students to make notes on the con-cept map to describe how the field of studyrelates to environmental science. VisualLS

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But studying the environment also involves studying humanpopulations, so environmental scientists may use information fromthe social sciences, which include economics, law, politics, andgeography. Social sciences can help us answer questions such as,How do cultural attitudes affect how people use the U.S. nationalpark system? or How does human migration from rural to urbanareas affect the local environment? Table 1 lists some of the majorfields of study that contribute to the study of environmental science.

Major Fields of Study That Contribute to Environmental Science

Geography is the study of the relationship between human populations and Earth’s features.Anthropology is the study of the interactions of the biological, cultural, geographical,and historical aspects of humankind.Sociology is the study of human population dynamics and statistics.

Social sciences arethe study of humanpopulations.

Biochemistry is the study of the chemistry of living things.Geochemistry, a branch of geology, is the study of the chemistry of materialssuch as rocks, soil, and water.

Chemistry is thestudy of chemicalsand their interactions.

Engineering is the science by which matter and energy are made useful tohumans in structures, machines, and products.

Physics is the study of matter and energy.

Geology is the study of the Earth’s surface, interior processes, and history.Paleontology is the study of fossils and ancient life.Climatology is the study of the Earth’s atmosphere and climate.Hydrology is the study of Earth’s water resources.

Earth science is thestudy of the Earth’snonliving systems andthe planet as a whole.

Zoology is the study of animals.Botany is the study of plants.Microbiology is the study of microorganisms.Ecology is the study of how organisms interact with their environment and each other.

Biology is the studyof living organisms.

Table 1 �

� This geologist is studying a volcano in Hawaii.

� This biologist is examining a plantthat was grown in a lab from just afew cells.

www.scilinks.orgTopic: Careers in

EnvironmentalScience

Code: HE80223

DiscussionWhat is Environmental Science?Tell students that one of the basicconcepts of environmental scienceis that everything is connected toeverything else. Have studentsbrainstorm some examples of thisconcept. Ask students the follow-ing focus question: “How is thisbasic concept related to the factthat it is often difficult for peopleto reach an agreement about envi-ronmental issues?” (Decisions thatinvolve the environment often involvemany different parties, and any deci-sion or action can have many conse-quences. Because people havedifferent priorities, reaching an agree-ment is often difficult.) Verbal

Vocabulary Many words in sci-ence have suffixes or prefixes thatare based on Latin or Greek rootwords. Even the names of the dif-ferent sciences are based on theseroots. One of the first things thatstudents may see when looking atthe names of the sciences in Table 1is that many of the sciences havethe suffix –ology, which means“the study of.” This suffix is basedon the Greek word logos, whichmeans “discourse.” Encourage stu-dents to find out the meaning ofother common suffixes and prefixesused in science and make a table of prefixes and suffixes in theirEcoLog. Students may want tomake this list at the back of theirEcoLog so that they may continueto add to it and refer to it through-out the course.

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Scientists as Citizens, Citizens as ScientistsGovernments, businesses, and cities recognize that studying ourenvironment is vital to maintaining a healthy and productive soci-ety. Thus, environmental scientists are often asked to share theirresearch with the world. Figure 3 shows scientists at a press con-ference that was held after a meeting on climate change.

Often, the observations of nonscientists are the first steptoward addressing an environmental problem. For example, middle-school students first noticed the appearance of deformedfrogs in Minnesota lakes. Similarly, the students at Dublin SciotoHigh School in Ohio, shown in Figure 3, study the habitat ofendangered box turtles every year. A habitat is a place where anorganism usually lives. The students want to find out how the tur-tles live and what factors affect their nesting and hibernation sitesin their habitat. The students track and map the turtles’ move-ments, measure atmospheric conditions, and analyze soil samples.These efforts matter, because the box turtle habitat is threatened.At the end of every year, the students present their findings to cityplanners, hoping to protect the most sensitive turtle habitats.

1. Describe the two main types of interactions that envi-ronmental scientists study. Give an example of each.

2. Describe the major fields of study that contribute toenvironmental science.

3. Explain why environmental science is an interdisci-plinary science.

CRITICAL THINKING

4. Making Comparisons What is the differencebetween environmental science and ecology?

5. Making Inferences Read the Ecofact. Propose asolution to prevent the environmental problems ofthe seaport of Troy described in the Ecofact.

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S E C T I O N 1 Mid-Section Review

Figure 3 � Environmental Scienceand Public Life Scientists hold apress conference on climate change(above). Students (right) are studyingthe movements of box turtles.

EcofactThe Fall of Troy Environmentalproblems are nothing new. Nearly3,000 years ago, the Greek poetHomer wrote about the ancientseaport of Troy, which was locatedbeneath a wooded hillside. TheTrojans cut down all the trees onthe surrounding hills. Without treesto hold the soil in place, rainwashed the soil into the harbor.So much silt accumulated in theharbor that large ships could notenter and Troy’s economy collapsed.Today, the ruins of Troy are severalmiles from the sea.

Group ActivityHold a Press Conference Whenscientists make important discover-ies, one way they announce theirfindings to the world is through apress conference. Have studentshold a press conference about anenvironmental news story. Selectseveral students to be the scientists.Ask the scientists to research a current environmental news story.They should plan a press confer-ence to present their findings. Havethe rest of the class represent themedia. They should prepare ques-tions for the scientists. After thepress conferences, the media groupshould write a short newspaperarticle describing the findings. Havethe groups change roles until every-one has had the opportunity to pres-ent and report on a scientific finding.

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Constructing Wildlife HabitatSpaces Habitat loss is one of thegreatest threats to plants and ani-mals in our environment. Studentscan help by constructing andmaintaining a habitat for wildlife.Habitat projects may be as simpleas planting a container garden toattract pollinators or putting up a bird feeder. If students have more space available, they couldconstruct a small marsh or pond.Students might even consider in-volving their school or communityin turning a vacant lot into wildlifehabitat. For more information andideas about constructing backyardhabitats, visit the National WildlifeFederation Web site.

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AAnnsswweerrss ttoo MMiidd--SSeeccttiioonn RReevviieeww1. The two main types of interactions that envi-

ronmental scientists study are how we useresources and how our actions affect the envi-ronment. A geologist might study how mineralresources are mined and used while a biologistmight study insect populations to see how pes-ticides affect the population.

2. The five major fields of study are biology, thestudy of living organisms; Earth science, thestudy of Earth’s nonliving systems and theplanet; physics, the study of matter andenergy; chemistry, the study of chemicals and their interactions; and social sciences, the study of human populations.

3. Answers may vary. Environmental science is acomplex field and many different sciences areneeded to understand the interactions of differ-ent parts of the environment.

4. Environmental science is the study of howhumans interact with the environment.Ecology is the study of how living things interact with each other and the nonlivingenvironment.

5. Answers may vary. Students might suggest thatregulations limiting logging in ancient Troycould have reduced soil erosion.


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Our Environment Through TimeWherever humans have hunted, grown food, or settled,they have changed the environment. For example, theland where New York City now stands was once anarea where Native Americans hunted game andgathered food, as shown in Figure 4. The environ-mental change that has occurred on ManhattanIsland over the last 300 years is immense, yet thisperiod of time is just a “blink” in human history.

Hunter-Gatherers For most of human history,people were hunter-gatherers, or people who obtainfood by collecting plants and by hunting wild animalsor scavenging their remains. Early hunter-gatherergroups were small, and they migrated from place to placeas different types of food became available at different times of the year. Even today there are hunter-gatherer societies in theAmazon rain forests of South America and in New Guinea, asshown in Figure 5.

Hunter-gatherers affected their environment in many ways.For example, some Native American tribes hunted bison, whichlive in grasslands. The tribes set fires to burn the prairies and pre-vent the growth of trees. In this way, the tribes kept the prairiesas open grassland where they could hunt bison.

In North America, a combination of rapid climate changes andoverhunting by hunter-gatherers may have led to the disappearanceof some species of large mammals. These species include giantsloths, giant bison, mastodons, cave bears, and saber-toothed cats.Huge piles of bones have been found in places where hunter-gatherers drove thousands of animals into pits and killed them.

Name two ways that hunter-gatherers affected theirenvironment.��Reading Check

Figure 5 � This modern hunter-gatherer group lives in New Guinea,a tropical island off the north coast ofAustralia.

Figure 4 � Three hundred yearsago, Manhattan was a very differentplace. This painting shows an areawhere Native Americans hunted and fished.

ComparisonTable

Create the Graphic Organizerentitled “Comparison Table”described in the Appendix. Labelthe columns with “Hunter-Gatherers,” “The AgriculturalRevolution,” and “The IndustrialRevolution.” Label the rows with“Characteristics” and “Effects onthe Environment.” Then, fill in thetable with details about the char-acteristics and the effects on the environment of each historical period.

DebateThe Extinction of LargeMammals At the end of the lastIce Age, many large mammalsbecame extinct in North America.Scientists are not exactly sure whythe large mammals went extinct,but the extinction of these animalscoincides with the arrival ofhumans. Divide students into two groups. Assign one group toresearch how people may havecaused the extinction of the largemammals, and assign the othergroup to research other possiblereasons for the extinctions. Afterstudents have gathered their infor-mation, set up a trial between thetwo sides. Verbal

Paired Reading Have studentswork in pairs to read this subsec-tion. Students should alternatebetween reading and listening.Have the student who is listeningmake notes about the importantideas in the paragraph. When thepairs are finished reading, they can compile their notes inan outline.

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AAnnsswweerr ttoo RReeaaddiinngg CChheecckkSample answer: Hunter-gatherersaffected their environment by setting fires to prevent the growth of trees and by overhunting speciesto extinction.

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MISCONCEPTION ALERT

The Purchase of Manhattan IslandAccording to popular legend, ManhattanIsland was purchased by the Dutch in 1626for $24 of beads. Several misconceptions areassociated with the story. First, the islandwas purchased with various items, notbeads. The value of the items that wereexchanged was approximately 60 guilders.In 1847, a historian converted 60 guilders to

dollars and got a value of $24. However, he did not adjust the amount for inflation.That $24 figure has persisted through theyears and is probably much less than theactual sum. Secondly, it is believed that theNative American Chief who “sold” theisland probably did not own the islandbecause many different tribes lived on theisland at the time.

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The Agricultural Revolution Eventually many hunter-gatherergroups began to collect the seeds of the plants they gathered and todomesticate some of the animals in their environment.is the practice of growing, breeding, and caring for plants and ani-mals that are used for food, clothing, housing, transportation, andother purposes. The practice of agriculture started in many differ-ent parts of the world over 10,000 years ago. This change hadsuch a dramatic impact on human societies and their environmentthat it is often called the agricultural revolution.

The agricultural revolution allowed human populations to growat an unprecedented rate. An area of land can support up to 500times as many people by farming as it can by hunting and gathering.As populations grew, they began to concentrate in smaller areas.These changes placed increased pressure on local environments.

The agricultural revolution also changed the food we eat. Theplants we grow and eat today are descended from wild plants.During harvest season, farmers collected seeds from plants thatexhibited the qualities they desired. The seeds of plants with largekernels or sweet and nutritious flesh were planted and harvestedagain. Over the course of many generations, the domesticatedplants became very different from their wild ancestors. For exam-ple, the grass shown in Figure 6 may be related to the grass thatcorn was bred from.

As grasslands, forests, and wetlands were replaced with farm-land, habitats were destroyed. Slash-and-burn agriculture, shownin Figure 7, is one of the earliest ways that land was converted tofarmland. Replacing forest with farmland on a large scale cancause soil loss, floods, and water shortages. In addition, much ofthis converted land was farmed poorly and is no longer fertile. Thedestruction of farmland had far-reaching environmental effects. Forexample, the early civilizations of the Tigris-Euphrates River basincollapsed, in part, because the overworked soil became infertilethrough salt contamination.

Agriculture

Figure 6 � This grass, called Eastern gama grass, is thought to be a relative of the modern corn plant.Native Americans may have selectivelybred a grass like this to produce corn.

Figure 7 � For thousands of yearshumans have burned forests to create fields for agriculture. In thisphoto, a rain forest in Thailand isbeing cleared for farming.

FIELD ACTIVITYFIELD ACTIVITY Germinating Corn Many peo-ple do not realize how easy it is togrow corn plants from unpoppedpopcorn kernels. This ancient grasswill sprout in a matter of days if itis watered frequently. Place a fewpopcorn kernels on a wet papertowel, and place the paper towelin a clear plastic cup so that thekernels are visible from the outside.Leave the cup on a windowsillfor several days and water it fre-quently. As your plant grows, see if you can observe any grasslikefeatures. Record your observationsin your EcoLog.

DiscussionSelective Breeding andDomestication Selective breedingis a process in which plants andanimals are bred to enhance spe-cific characteristics. Dogs, cats,cows, horses, pigs, turkeys, andchickens have been selectively bredfrom wild animals. Broccoli, cauli-flower, cabbage, kale, kohlrabi,and Brussels sprouts are domesticplants that are derived from thesame species of wild mustard plant.Dogs are a good example of selec-tive breeding. Some dogs, such asthe Australian shepherd were selec-tively bred to herd animals, whilethe husky was selectively bred topull a dog sled. This is why there issuch a great variety of dogs, fromChihuahuas to Great Danes, whichare both the same species. Have stu-dents select a domesticated plant oranimal of their choice and researchthe wild ancestors from which itwas bred. Logical

AAnnsswweerrss ttoo FFiieelldd AAccttiivviittyyAnswers may vary. Students shouldnotice some grass-like features in thecorn seedling.

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Math According to the World WildlifeFund, rain forests are being cleared at a rate of26 hectares per minute. Ask students to calcu-late how many hectares of rainforest are beingcleared in an hour, a day, and a year. (26 haper min � 60 min per hr � 1560 ha per hr;1560 ha per hr � 24 hr per day � 37,440 ha perday; 37,440 ha per day � 365 days per year �13,665,600 ha per year) To help studentsunderstand the size of the area, ask them tofind out the size, in hectares, of their countyand their state and compare that area to thearea of rain forest being cleared. LogicalLS

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Ancient Dogs Fossils of domesticated dogs dating from 11,000 years ago havebeen found in Iraq, and cultivated plantsdate back 10,000 years in the Americas.

BRAIN FOOD

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The Industrial Revolution For almost 10,000 years the tools ofhuman societies were powered mainly by humans or animals.This pattern changed in the middle of the 1700s with theIndustrial Revolution, which involved a shift from energy sourcessuch as animal muscle and running water to fossil fuels, such ascoal and oil. The increased use of fossil fuels and machines, suchas the steam engines shown in Figure 8, changed society andgreatly increased the efficiency of agriculture, industry, and transportation.

During the Industrial Revolution, the large-scale productionof goods in factories became less expensive than the local pro-duction of goods. Machinery reduced the amount of land andhuman labor needed for farming. As fewer people grew theirown food, populations in urban areas steadily grew. Fossil fuelsand motorized vehicles allowed food and other goods to betransported cheaply across great distances.

Improving Quality of Life The Industrial Revolution introducedmany positive changes. Inventions such as the light bulb greatlyimproved our quality of life. Agricultural productivity increased,and sanitation, nutrition, and medical care vastly improved. Tech-nologies such as the telephone and the portable computer, shownin Figure 9, enabled people to work and communicate more easilyfrom any location. Yet with all of these advances, the IndustrialRevolution introduced many new environmental problems.

In the 1900s, modern societies began to use artificial sub-stances in place of raw animal and plant products. Plastics andmany other artificial materials have made life easier. However, wenow understand some of the environmental problems they pre-sent. Much of environmental science is concerned with the prob-lems associated with the Industrial Revolution.

Identify three ways that the Industrial Revolutionchanged society.��Reading Check

Figure 8 � During much of theIndustrial Revolution, few limits wereplaced on the air pollution caused byburning fossil fuels. Locomotives suchas these are powered by burning coal.

Figure 9 � The invention of com-puters has improved the ways thatpeople work, learn, communicate,and entertain themselves.

DiscussionThe Information RevolutionToday, information is widely andquickly distributed via television,radio, and the Internet. Many peo-ple think that the InformationRevolution is a distinct phase ofhuman history while others arguethat the Information Revolution ispart of the Industrial Revolution.Ask students to voice their opin-ions on this topic. Verbal

Writing The Industrial Revolutionhas changed the standard of livingof most of the people on Earth. But have all the changes associatedwith the Industrial Revolutionimproved our quality of life? Askstudents to think about the effectsof the Industrial Revolution on theenvironment and quality of life.Have students make a list of thepositive and negative effects of theIndustrial Revolution and thenhave them use their lists to write ashort, persuasive essay stating theirposition. Logical

Discussion Ask students todebate what type of society theylive in today. Our society formedduring the Industrial Revolution,but elements of hunter-gatherersocieties and agricultural societiesalso influence our lifestyles. Askstudents, “Are we an agrariansociety or are we a hunter-gatherersociety?” We depend on agriculturefor food, but only a small percent-age of people are farmers. Most ofus go to stores and in a way, “huntand gather” food. Logical

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkSample answer: Switching from animal power to fossil fuels increased the efficiency of agricul-ture. Inventions such as the lightbulb improved our quality of life.Our increased use of artificial sub-stances such as plastics introducednew environmental problems.

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BUILDERSKILL

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GENERAL

CONNECTIONCONNECTIONREAL-LIFEREAL-LIFE

GENERAL

Building an Environmental ScienceLibrary Throughout the school year, ask students to help you create an environmentalscience library for their use and for the use of future students. Create a system of foldersto organize articles that relate to specifictopics. As a class, attempt to raise funds to purchase books from used book stores.Also, ask parents and community members

to help you procure books. A good set of field guides for your region will be a corner-stone for your environmental science library.Local museums, libraries, and universitiesmay also be willing to help. Museums oftenloan resource kits to classrooms. Finally, atthe end of the school year, students may be willing to contribute Portfolio materials tothe permanent collection.

GENERAL

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Lake Washington: An EnvironmentalSuccess Story

Figure 10 � This photograph wastaken in 1968 by the crew of Apollo8. Photographs such as this helped people realize the uniqueness of theplanet we share.

Seattle is located on a narrow strip

of land between two large bodies of

water. To the west is the Puget

Sound, which is part of the Pacific

Ocean, and to the east is Lake Wash-

ington, which is a deep freshwater

lake. During the 1940s and early

1950s, cities on the east side of Lake

Washington built 11 sewer systems

that emptied into the lake. Unlike

raw sewage, this sewage was treated

and was not a threat to human

health. So, people were surprised by

research in 1955 showing that the

treated sewage was threatening their

lake. Scientists working in Dr. W. T.

Edmondson’s lab at the University of

Washington found a bacterium,

Oscillatoria rubescens, that had never

been seen in the lake before.

Dr. Edmondson knew that in

several lakes in Europe, pollution

from sewage had been followed by

allowing it to build up in an

enclosed lake.

Cities around the lake had to

work together to connect their

sewage plants to large lines that

would carry the treated sewage to

Puget Sound. Because there was no

legal way for cities to connect plants

the appearance of O. rubescens. Ashort time after, the lakes deterio-

rated severely and became cloudy,

smelly, and unable to support fish.

The scientists studying Lake Wash-

ington realized that they were see-

ing the beginning of this process.

About this same time, Seattle

set up the Metropolitan Problems

Advisory Committee, chaired by

James Ellis. Dr. Edmondson wrote

Ellis a letter that explained what

could be expected in the future if

action was not taken. The best solu-

tion to the problem seemed to be

to pump the sewage around the

lake and empty it deep into Puget

Sound. Although this solution may

seem like it would save one body of

water by polluting another one, it

was actually a good choice. Diluting

the sewage in Puget Sound is less of

an environmental problem than

Spaceship EarthEarth has been compared to a ship traveling through space,unable to dispose of waste or take on new supplies as it travels.Earth is essentially a closed system—the only thing that entersEarth’s atmosphere in large amounts is energy from the sun, andthe only thing that leaves in large amounts is heat. A closed sys-tem of this sort has potential problems. Some resources are lim-ited, and as the population grows, the resources will be used. In aclosed system, there is also the chance that we will producewastes more quickly than we can dispose of them.

Although the Earth can be thought of as a complete system, envi-ronmental problems can occur on different scales: local, regional, orglobal. For example, your community may be discussing where tobuild a new landfill, or local property owners may be arguing withenvironmentalists about the importance of a rare bird or insect. Thedrinking water in your region may be affected by a polluted riverhundreds of miles away. Other environmental problems are global.For example, ozone-depleting chemicals released in Brazil maydestroy the ozone layer that everyone on Earth depends on.

DiscussionEarth as a Living Organism Inthe 1960s, a NASA scientist namedJames Lovelock was working todesign tests to search for life onMars. Lovelock started by trying to determine how Earth was differ-ent from Mars. His search for differences led him to study theatmospheres of both planets. Earthhas an atmosphere of 78 percentnitrogen, 21 percent oxygen, asmall amount of carbon dioxide,and other trace gases. The atmos-phere of Mars is 95 percent carbondioxide, and has traces of oxygenand other gases. His work showedthat processes on Earth regulatedand maintained the atmosphere in a way similar to the manner in which an organism would maintain conditions in its body.

This discovery led Lovelock to develop the Gaia hypothesis,which stated that Earth was aliving organism. Gaia was thename of the ancient Greek Earth-goddess. Lovelock published abook in 1979 called Gaia, A NewLook at Life on Earth. Since thattime, the hypothesis has beenwidely debated. Some people arguethat the hypothesis can be inter-preted literally, while others thinkthat it is a useful analogy to understand Earth’s systems as a whole. The theory is one way ofapproaching and trying to under-stand environmental problems.Discuss the Gaia hypothesis withstudents and have them form theirown opinions. VerbalLS



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� Lake Washington is now cleanenough for everyone to enjoy.

Po

pu

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(in

bill

ion

s)

1600 1700 1800 1900 2000

Year

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5.5

4.5

3.5

2.5

1.5

0.5

World Population: 1600–2000

Figure 11 � The size of the humanpopulation in 2000 was more than10 times larger than it was just 400years ago.

at the time, Ellis successfully worked

for the passage of a bill in the state

legislature that set up committees to

handle projects of this kind. News-

paper articles and letters to the edi-

tor addressed the issue. Public forums

and discussion groups were also held.

The first sewage plant was con-

nected in 1963. Today, the lake is

clearer than it has been since scien-

tists began their studies of the lake

in the 1930s. The story of Lake

moving the sewage. Legislators and

civic leaders addressed the legal

problems. Volunteers, local media,

and local activists provided public

education and pressed to get the

problem solved quickly. The clear,

blue waters of Lake Washington

stand as a monument to citizens’

desires to live in a clean, healthy

environment and to their ability to

work together to make it happen.

CRITICAL THINKING

1. Analyzing Processes Explainhow each person and group playeda crucial role in the cleanup of LakeWashington.

2. Analyzing Relationships Howwas the scientists’ work similar tothe work of the Keene High Schoolstudents you read about in thissection?

Washington is an example of how

environmental science and public

action work together to solve envi-

ronmental problems. Science was

essential to understanding a healthy

lake ecosystem, to documenting

changes that were beginning to

cause problems, and to making pre-

dictions about what would happen

if changes were made or if nothing

was done. Engineers offered practi-

cal solutions to the problem of

Population Growth: A Local Pressure One reason many environ-mental problems are so pressing today is that the agricultural rev-olution and the Industrial Revolution allowed the humanpopulation to grow much faster than it had ever grown before.The development of modern medicine and sanitation also helpedincrease the human population. As shown in Figure 11, thehuman population almost quadrupled during the 20th century.Producing enough food for such a large population has environ-mental consequences. In the past 50 years, nations have used vastamounts of resources to meet their need for food. Many of theenvironmental problems that affect us today, such as habitatdestruction and pesticide pollution, are the result of feeding theworld in the 20th century.

There are many different predictions of population growth forthe future. But most scientists think that the human populationwill almost double in the 21st century before it begins to stabi-lize. We can expect that the pressure on the environment willcontinue to increase as the human population and its need forfood and resources grows.

Using the FigurePopulation Growth October 12,1999 was the day designated bythe United Nations as the day thepopulation of Earth reached 6 bil-lion. Other world population mile-stones include 1 billion people in1804 and 3 billion people in 1960.Ask students what factors theythink will affect population growthin the future. Have students lookat Figure 11 and make their ownestimates of what the world popu-lation will be in 2050.

13

GENERAL

MISCONCEPTION ALERT

Rates of Human Population GrowthStudents may think that the human popula-tion will continue to grow at the same rateas it has in recent years. There is a widerange of estimates of population growth.Most estimates predict that human popula-tion size will level off by 2100. Demogra-phers make projections based mostly ontrends in fertility levels and the number ofpeople at various ages in the population.The UN estimates that as of 2000 about 9 billion people will live on Earth in 2050

given a worldwide average fertility rate of2.1 children per woman. Population esti-mates are �� about 2 billion if average fer-tility rates turn out to be �� 0.5 childrenper woman. Many other factors can influencepopulation growth rates, and it is difficultto take all the factors into account. Studentsshould also be aware that population growthestimates are averages of different populationgrowth rates from different regions. Someareas, such as Singapore and most of Europe,have negative population growth.

Lake Washington Dr.Edmondson found a bacteriumcalled Oscillatoria rubescens inthe waters of Lake Washington.When scientists look for a partic-ular organism or to determine theenvironmental health of a loca-tion, the organism is called anindicator species. Many differentindicator species are used forassessing water quality. Severaldifferent bacteria are used todetect sewage contamination,for example. The bacterium com-monly looked for are called E.coli. Their presence indicates thatthere is pollution from sewage.Sewage may also carry pathogensthat cause diseases such as hepati-tis, dysentery, and cholera. Notall indicator species are bacteria,and not all are used to detect con-tamination. Some indicatorspecies are used to find healthyenvironments. For example, sometypes of snails are only found inclean water, while other types ofsnails are only found in pollutedwater. Have students find outsome of the indicator species forbodies of water in your region.

AAnnsswweerrss ttoo CCrriittiiccaall TThhiinnkkiinngg1. The scientists found the evidence

that Lake Washington was get-ting polluted. The advisory com-mittee recommended changes inlocal laws. The citizens sup-ported changes and broughtattention to the issue. Law makers changed laws and engi-neers built new treatment plants.

2. Answers may vary.

hes08TE_c01_05-15_S1 8/24/06 8:50 AM Page 13

What Are Our Main Environmental Problems?You may feel as though the world has an unlimited variety ofenvironmental problems. But we can generally group environ-mental problems into three categories: resource depletion, pollu-tion, or loss of biodiversity.

Resource Depletion Any natural material that is used byhumans is called a Natural resources can beclassified as renewable and nonrenewable as shown in Table 2. Arenewable resource is a resource that can be replaced relativelyquickly by natural processes. Fresh water, air, soil, trees, andcrops are all resources that can be renewed. Energy from the sunis also a renewable resource. A nonrenewable resource is aresource that forms at a much slower rate than the rate that it isconsumed. The most common nonrenewable resources are miner-als and fossil fuels. Once the supply of a nonrenewable resourceis used up, it may take millions of years to replenish it.

Resources are said to be depleted when a large fraction of theresource has been used up. Figure 12 shows a mine where copper,a nonrenewable resource, is removed from the Earth’s crust.Some renewable resources can also be depleted. For example, iftrees are harvested faster than they can grow naturally in an area,deforestation will result.

Pollution One effect of the Industrial Revolution is that societiesbegan to produce wastes faster than the wastes could be disposedof. These wastes accumulate in the environment and cause pollu-tion. is an undesired change in air, water, or soil thatadversely affects the health, survival, or activities of humans or

Pollution

natural resource.

Figure 12 � More than 12 milliontons of copper have been minedfrom the Bingham mine in Utah.Once all of the copper that can beprofitably extracted is used up, thecopper in this mine will be depleted.

Renewable and Nonrenewable Resources

Renewable Nonrenewable

energy from the sun

water

wood

soil

air

metals such asiron, aluminum,and copper

nonmetallic ma-terials such as salt,sand, and clay

fossil fuels

Table 2 �

QuickLABClassifying ResourcesProcedure1. Create a table similar to Table 2.

2. Choose five objects in yourclassroom, such as a pencil, anotebook, or a chair.

3. Observe your objects closely,and list the resources that com-prise them. For example, a pen-cil is made of wood, graphite,paint, aluminum, rubber, andpumice.

4. Classify the resources you haveobserved as nonrenewable orrenewable.

Analysis1. What percentage of the resources

you observed are renewable?What percentage of theresources are nonrenewable?

2. Hypothesize the origin of threeof the resources you observed.If time permits, research the ori-gin of the resources you choseto find out if you were correct.

Tasmanian Tigers The lastknown Tasmanian tiger, shown in Figure 14, died in captivity atthe Holbart Zoo in Australia in1936. Since that time, there havebeen hundreds of reported sight-ings but no Tasmanian tigers have been captured or photo-graphed. It is possible that thislarge marsupial is still living in the forests of Tasmania. Have students find out about the statusof the Tasmanian tiger.



14

Tracking the Ivory-Billed WoodpeckerThe ivory-billed woodpecker, one of thelargest species of woodpeckers, lived forcenturies in the forests of Cuba and thesouthern United States. As a result of log-ging and habitat loss, the bird had not beenseen in the United States since the 1950s,and was considered to be extinct. However,in April of 1999 a college student on a

spring break hunting trip in southeasternLouisiana provided a reliable report of an ivory-billed woodpecker sighting. Severalgroups of researchers have searched this areaof Louisiana since the report, but unfortu-nately, the status of the ivory-billed wood-pecker remains unresolved. Encouragestudents to find out about the current status of the ivory-billed woodpecker hunt.

BRAIN FOOD

QuickLABSkills Acquired:• Classifying

• Identifying and RecognizingPatterns

AAnnsswweerrss1. Answers may vary.2. Answers may vary.

GENERAL

hes08TE_c01_05-15_S1 8/24/06 8:50 AM Page 14


other organisms. Human activities produce a greatdeal of pollution. Air pollution in Mexico City, asshown in Figure 13, is dangerously high, mostlybecause of car exhaust and industrial pollutants.

There are two main types of pollutants. Biode-gradable pollutants are pollutants that can be brokendown by natural processes. They include materialssuch as human sewage and food wastes. Degradablepollutants are a problem when they accumulate fasterthan they can be broken down. Pollutants that cannotbe broken down by natural processes, such as mer-cury, lead, and some types of plastic, are called non-degradable pollutants. Because nondegradablepollutants do not break down easily, they can buildup to dangerous levels in the environment.

Loss of Biodiversity The term refers to the num-ber and variety of species that live in an area. Earth has beenhome to hundreds of millions of species. Yet only a fraction ofthose species are alive today—the others are extinct. Extinction isa natural process, and several large-scale extinctions, or massextinctions, have occurred throughout Earth’s history. For exam-ple, at the end of the Permian period, 250 million years ago, asmuch as 95 percent of all species became extinct. So why shouldwe be concerned about the modern extinction of an individualspecies such as the Tasmanian tiger shown in Figure 14?

The organisms that share the world with us can be considerednatural resources. We depend on other organisms for food, forthe oxygen we breathe, and for many other things. A species thatis extinct is gone forever, so a species can be considered a nonre-newable resource. We have only limited information about howmodern extinction rates compare with those of other periods inEarth’s history. But many scientists think that if current rates ofextinction continue, it may cause problems for human popula-tions in the future. Many people also argue that all species havepotential economic, ecological, scientific, aesthetic, and recrea-tional value, so it is important to preserve them.

biodiversity

1. Explain how hunter-gatherers affected the environ-ment in which they lived.

2. Describe the major environmental effects of theagricultural revolution and the Industrial Revolution.

3. Explain how environmental problems can be local,regional, or global. Give one example of each.

4. Identify an example of a biodegradable pollutant.

CRITICAL THINKING

5. Analyzing Relationships How did the IndustrialRevolution affect human population growth?

6. Making Inferences Fossil fuels are said to be non-renewable resources, yet they are produced by theEarth over millions of years. By what time frame arethey considered nonrenewable? Write a paragraphthat explains your answer. WRITING SKILLS

S E C T I O N 1 Review

Figure 14 � The Tasmanian tiger,native to an island near Australia, wasdeclared extinct in 1986.

Figure 13 � The problem of air pol-lution in Mexico City is compoundedbecause the city is located in a valleythat traps air pollutants.

ReteachingNatural Resources Have groupsdiscuss the connection betweennatural resources and their clothes,the contents of their backpacks,and common objects in the class-room. Compile a list of group findings, and help students identifywhich resources are renewable andwhich are nonrenewable.

Quiz1. Explain the difference between

renewable and nonrenewable re-sources. (Renewable resources arereplaced relatively quickly by nat-ural processes. Nonrenewable re-sources form at a much slower ratethan the rate that they are used.)

2. Why is it important for environ-mental scientists to have a back-ground in many different fieldsof study? (Environmental scienceis interdisciplinary and many dif-ferent factors influence the qualityof the environment.)

Alternative AssessmentIdentifying Causes Provide stu-dents with a list of 20 environ-mental problems. Ask them toidentify each problem as an exam-ple of resource depletion, pollution,extinction, or a combination offactors. Then have them identify the scale of the problem—is itlocal, regional, or global? LogicalLS

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15

GENERAL

GENERAL

AAnnsswweerrss ttoo SSeeccttiioonn RReevviieeww1. Hunter-gatherers changed habitat to obtain

food, introduced new plants to areas and insome areas overharvested plants and animals.

2. Sample answers: One effect of the agricul-tural revolution was the conversion of forestland into agricultural areas. This processremoved the native plants and replaced themwith crops and domesticated animals. TheIndustrial Revolution changed the environ-ment by introducing pollution from industryand accelerating habitat destruction.

3. Environmental problems can be local,regional, or global based on the size of areathey directly affect. A local problem may bea factory that releases air pollutants in aneighborhood. A regional problem mightbe contamination of a river that many citiesdepend on for drinking water. A globalproblem might be the releasing of green-house gases that contribute to global warming.

4. Sample answer: Food wastes are biodegrad-able pollutants.

5. Sample answer: Rates of population growthincreased during the Industrial Revolutionbecause of improvements in healthcare andincreased food production.

6. Fossil fuels are considered nonrenewableresources because a human lifetime is thetimeframe used to evaluate the replacementrate of resources. Fossil fuels take millionsof years to form, and humans consumethem much faster than they are formed.


hes08TE_c01_05-15_S1 8/24/06 8:51 AM Page 15

When we think about environmental problems and how to solvethem, we have to consider human societies, how they act, andwhy they do what they do. One way to think about society andthe environment is to consider how a society uses commonresources. A neighborhood park, for example, is a commonresource that people share. On a larger scale, the open ocean isnot owned by any nation, yet people from many countries use theocean for fishing and for transporting goods. How do we decidehow to share common resources? In 1968, ecologist GarrettHardin published an essay titled “The Tragedy of the Commons,”which addressed this question.

“The Tragedy of the Commons”In his essay, Hardin argued that the main difficulty in solvingenvironmental problems is the conflict between the short-terminterests of individuals and the long-term welfare of society. Toillustrate his point, Hardin used the example of the commons, asshown in Figure 15. Commons were areas of land that belongedto a whole village. Anyone could graze cows or sheep on thecommons. It was in the best short-term interest of an individualto put as many animals as possible on the commons. Individualsthought, If I don’t use this resource, someone else will.

However, if too many animals grazed on the commons, the animalsdestroyed the grass. Then everyone suffered because no one could raiseanimals on the commons. Commons were eventually replaced by closedfields owned by individuals. Owners were careful not to put too manyanimals on their land, because overgrazing meant that fewer animalscould be raised the next year. The point of Hardin’s essay is thatsomeone or some group has to take responsibility for maintaining aresource. If no one takes that responsibility, the resource can be overusedand become depleted.

Objectives� Describe “The Tragedy of the

Commons.”� Explain the law of supply and

demand. � List three differences between

developed and developing countries.

� Explain what sustainability is, anddescribe why it is a goal of envi-ronmental science.

Key Termslaw of supply and demandecological footprintsustainability

S E C T I O N 2

The Environment and Society

Figure 15 � Hardin observed thatwhen land was held in common(left), individuals tended to grazeas many animals as possible. Over-grazing led to the destruction ofthe land resources. When com-mons were replaced by enclosedfields owned by individuals (right),people tended to graze only thenumber of animals that the landcould support.


16

OverviewBefore beginning this section,review with your students theObjectives in the Student Edition.This section explores the relation-ship between economics and theenvironment and discusses the roleof critical thinking in science.

Ask students to brainstorm a list ofthe ways that economics relates tothe environment.

IdentifyingPreconceptions Economic Value Students may notbe accustomed to thinking about theeconomic value of the environment.Write $33 trillion (33 followed by12 zeros) on the board. That figure,according to one scientist, is thevalue of the products and servicesprovided by Earth’s ecosystemsevery year. Have students brain-storm a list of services that Earth’secosystems provide. (processingwastes and providing food and air)

MotivateMotivate

Bellringer

FocusFocus

GENERAL

Transparencies

TT BellringerTT “The Tragedy of the Commons”

• Lesson Plan• Active Reading• Section Quiz GENERAL


Group Activity“Tragedy of the Commons” Game Dividethe class into two groups. Mark two largesquares on the floor in tape. Divide one of thesquares into several smaller sections. Have thefirst group stand around the large, undividedsquare. Take fifteen pennies and drop them inthe undivided square. Don’t tell students howmany pennies there are. Give the group theseinstructions:

• When I say “Go,” enter the square and pickup the pennies.

• I’ll trade one piece of candy for each pennypicked up in the 1st round.

• I’ll trade two pieces of candy for each pennyin the 2nd round.Say “Go” and keep time for one minute.

Have students turn in their pennies at the endof the minute. Because students cannot trustothers not to pick up the pennies, you will nothave to play the second one-minute round.Next, assign each student in the second group“ownership” of a particular section in thedivided square. Repeat your instructions.Have students play two rounds and then dis-cuss how this exercise relates to “The Tragedyof the Commons” and the conservation ofscarce natural resources.

2S E C T I O N

GENERAL

hes08TE_c01_16-21_S2 9/13/06 7:44 PM Page 16

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkThe price of oil illustrates the law of supply anddemand. In general, when the supply of oildecreases, the price of oil increases.


Earth’s natural resources are our modern commons. Hardinthought that people would continue to deplete natural resources byacting in their own self-interest to the point of society’s collapse.But Hardin did not consider the social nature of humans. Humanslive in groups and depend on one another. In societies, we cansolve environmental problems by planning, organizing, consideringthe scientific evidence, and proposing a solution. The solution mayoverride the interests of individuals in the short term, but itimproves the environment for everyone in the long term.

Economics and the EnvironmentIn addition to social pressures, economic forces influence how weuse resources. Many of the topics you will explore later in thisbook are affected by economic considerations.

Supply and Demand One basic rule of economics is thewhich states that the greater the demand for

a limited supply of something, the more that thing is worth. Oneexample of this rule is shown in Figure 16, which illustrates therelationship between the production of oil and its price over aperiod of 20 years. Many environmental solutions have to takethe relationship between supply and demand into account. Forexample, if the supply of oil decreases, we have three choices: paythe higher price, use less oil, or find new sources of energy.

Costs and Benefits The cost of environmental solutions can behigh. To determine how much to spend to control air pollution, a community may perform a cost-benefit analysis. A cost-benefitanalysis balances the cost of the action against the benefits oneexpects from it. The results of a cost-benefit analysis often dependon who is doing the analysis. To an industry, the cost of pollutioncontrol may outweigh the benefits, but to a nearby community, thebenefits may be worth the high price. The cost of environmentalregulations is often passed on to the consumer or the taxpayer. The consumer then has a choice. He or she can either pay for the more expensive product that meets environmental regulationsor seek out a cheaper product that may not have the same environmental safeguards.

Risk Assessment One of the costs of any action is the risk of anundesirable outcome. Cost-benefit analysis involves risk assessment,which is one tool that helps us create cost-effective ways to protectour health and the environment. To come up with an effective solu-tion to an environmental problem, the public must perceive the riskaccurately. This does not always happen. In one study, people wereasked to assess the risk from various technologies. The public gen-erally ranked nuclear power as the riskiest technology on the list,whereas experts ranked it 20th—less risky than riding a bicycle.

Use an example to illustrate the law of supply anddemand.��Reading Check

supply and demand,law of

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1980 1985 1990 1995 2000

Year

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World Oil Production

Co

st p

er b

arre

l (d

olla

rs)

Source: U.S. Department of

Energy.

Figure 16 � Between 1980 and2000, the production and price of oil changed dramatically. Thisgraph shows how, in general, theprice of a barrel of oil increased asthe production decreased.

MATHPRACTICEMarket EquilibriumIn economics, the point where supply and demand are in balance is known as marketequilibrium. In Figure 16, marketequilibrium for oil was reached in 1986. What was the cost of abarrel of oil in that year? Howmany barrels of oil were producedin that year? By how much did thecost of a barrel of oil decline from1981 to 1986?

Interpreting Statistics Oil Prices After reviewingFigure 16, students may think thatthe amount of oil production is the only factor that determines thecost of a barrel of oil. Ask them to think about other factors thatinfluence the cost of oil. The costof oil depends on many other fac-tors such as world demand, time ofyear, political influence, and artifi-cial market manipulation. Also askstudents to think about what fac-tors could be included in the costof oil but are not. (Sample answers:The cost of cleaning up oil spills,greenhouse gas emissions, or healthcare problems.) These costs arecalled externalities.

K-W-L To use the K-W-L strategy,ask students to make a chart intheir EcoLog. The chart shouldhave three columns, and each col-umn should be labeled “What youKnow,” “What you Want to know,”and “What you Learned.” Thenask students the following ques-tions to answer in the first column:“What is meant by supply anddemand? What is meant by cost-benefit analysis? What is riskassessment?” Tell students thatthese are ways that the environ-ment and resources are evaluatedby economists. Then ask studentsto fill in the second column. Afterstudents read the Economics andthe Environment subsection, havethem revisit their chart and fill inthe third column.

SKILLBUILDER

READINGREADING

TeachTeach

17

GENERAL

MISCONCEPTION ALERT

“The Tragedy of the Commons”Students may assume that because “TheTragedy of the Commons” is a parablethat it is a very simple theory that doesnot relate to real experiences. Explain tostudents that the opposite is true. Eventhough “The Tragedy of the Commons” issimple, the underlying concept applies tomany problems in environmental science.

AAnnsswweerrss$26 per barrel; 60,000 � 365 �21,900,000; $22

MATHPRACTICE

hes08TE_c01_16-21_S2 8/24/06 8:55 AM Page 17

Developed and Developing CountriesThe decisions and actions of all people in the world affect ourenvironment. But the unequal distribution of wealth andresources around the world influences the environmental prob-lems that a society faces and the choices it can make. The UnitedNations classifies countries as either developed or developing.Developed countries have higher average incomes, slower popula-tion growth, diverse industrial economies, and stronger socialsupport systems. They include the United States, Canada, Japan,and the countries of Western Europe. Developing countries havelower average incomes, simple and agriculture-based economies,and rapid population growth. Developed and developing coun-tries have different consumption patterns, as shown in Figure 17,which affect the environment in different ways.

Population and Consumption Most environmental problems can be traced back to two rootcauses. First, the human population in some areas is growingtoo quickly for the local environment to support it. Second,people are using up, wasting, or polluting many naturalresources faster than they can be replaced or cleaned up.

Local Population Pressures When the population in an areagrows rapidly, there may not be enough natural resources foreveryone in the area to live a healthy, productive life. Often, aspeople struggle for survival in severely overpopulated regions,forests are stripped bare, topsoil is exhausted, and animals aredriven to extinction. Malnutrition, starvation, and disease can beconstant threats. Even though there are millions of people starv-ing in developing countries, the human population tends to growmost rapidly in these countries. Food production, education, andjob creation cannot keep pace with population growth, so eachperson gets fewer resources as time goes by. Of the 5.2 billionpeople in developing countries, fewer than half have access toenough food, safe drinking water, and proper sanitation.

Figure 17 � A food market inPushkar, India is shown above.The food market shown belowis in Goleta, California, in theUnited States. How do thesetwo food markets show differingconsumption trends in Indiaand the U.S.?

GeofactMinerals of South Africa Theresources a country has are a resultof geologic processes. South Africa,for example, has some of the mostproductive mineral deposits in theworld. In fact, the country is nearlyself-sufficient in the mineralresources that are important tomodern industry. South Africa isthe world’s largest producer ofgold, platinum, and chromium.

Using the Figure Fresh Vegetables Figure 17shows two different vegetable mar-kets. One is in a developing nationwhile the other is in a developednation. Ask students the followingquestions, “What do you noticeabout the variety of vegetables ineach photograph? What do younotice about the packaging in eachmarket? Which market do youthink used more energy to get thevegetables to the market? Whichmarket do you think has the fresh-est vegetables?” Visual

Examining Food Packaging Askstudents to look at the food theyhave at home. Ask students to lookat how the food is packaged. Askstudents how much of the food isin cans, how much is in bags, andhow much is in boxes. Ask stu-dents, “How much of the packag-ing contributes to the waste wegenerate? What types of resourcesare used to make the packaging forfood? How does the packaginghelp the food?”

LS



18

GENERAL

GENERAL

StrategiesStrategiesINCLUSIONINCLUSION

Have students draw a timeline of the past200 years on a piece of unlined paper. Theyshould indicate on the timeline when fivespecies of animals became extinct. For each ofthe extinct species, students should includehabitats, last sightings, and possible reasonsfor extinction. Lower-level students should be

able to label dates the species became extinctand draw pictures or locate and print pic-tures of the species on the Internet. Theyshould staple or glue the pictures on thetimeline. Compile the timelines to share withthe class.

••GGiifftteedd aanndd TTaalleenntteedd

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Figure 18 � An ecological footprintis a calculation of the amount of landand resources needed to support oneperson from a particular country. Theecological footprint of a person in adeveloped country is, on average,four times as large as the footprint ofa person in a developing country.

Table 3 �

Indicators of Development for the United States, Japan, Mexico, and Indonesia

Measurement U.S. Japan Mexico Indonesia

Health life expectancy in years 77 81 71.5 68

Population per year 0.8% 0.2% 1.7% 1.8%growth

Wealth gross national product per person $29,240 $32,350 $3,840 $640

Living space people per square mile 78 829 133 319

Energy use per person per year (millions of Btu) 351 168 59 18

Pollution carbon dioxide from fossil 20.4 9.3 3.5 2.2fuels per person per year (tons)

Waste garbage produced per person per year (kg) 720 400 300 43

Consumption Trends For many people in the wealthier part of theworld, life is better than ever before. Many environmental problemsare being addressed. In addition, the population has stabilized or isgrowing slowly. But to support this quality of life, developed coun-tries are using much more of Earth’s resources than developingcountries are. Developed nations use about 75 percent of theworld’s resources, even though they make up only about 20 percentof the world’s population. This rate of consumption creates morewaste and pollution per person than in developing countries, asshown in Table 3.

Ecological Footprints One way to express the differences in con-sumption between nations is as an ecological footprint, as shown inFigure 18. An shows the productive area ofEarth needed to support one person in a particular country. It esti-mates the land used for crops, grazing, forest products, and hous-ing. It also estimates the ocean area used to harvest seafood and theforest area needed to absorb the air pollution caused by fossil fuels.

ecological footprint

0

5

10

15

20

25

30

35

India Mexico BritainU.S.

Eco

log

ical

foo

tpri

nt

(acr

es)

19

GENERAL

GENERAL

Ecological Footprints The Internet has anumber of different calculators for determiningecological footprints. Ask students to find atleast three of these calculators and determinetheir ecological footprint. Ask students howthe results from the different calculators com-pare. Ask students why they think these differ-ences occur.

GENERAL

Reducing Your Ecological FootprintYou can do many things to reduce yourecological footprint. You can eat locallygrown foods, eat less meat, carpool, ridepublic transportation, ride a bike, anduse lights and appliances that conserveenergy. Ask students to make a list offive things that they could do to reducetheir ecological footprint.

BRAIN FOOD

Using the FigureDeveloped Vs. DevelopingTable 3 shows indicators for development from four differentcountries. Ask students to comparethe life expectancy between thecountries and ask what they notice.Ask students, “Why do you thinkpeople in developed countries livelonger?” Next ask students to com-pare the other characteristics. Askstudents, “Does the living space tellyou anything about the conditionsthat people live in?” Note thatJapan has a high standard of livingbut also has the highest populationdensity. Finally ask, “What doesthe amount of waste generated perperson tell you about the differ-ences between developed anddeveloping nations?” Logical

Using the Figure Different Footprints Figure 18shows the ecological footprint for four countries. Ask students,“Which country has the largestecological footprint? Why do youthink the United States has thelargest ecological footprint? Whichregions of the United States havethe largest ecological footprints?Which regions have the smallestecological footprints?” LogicalLS

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Environmental Science in ContextAs you have learned, environmental problems are complex.Simple solutions are rare, and they sometimes cause more damagethan the original problem did. To complicate matters, in recentyears, the environment has become a battleground for largerissues that affect human societies. For example, how do you bal-ance the rights of individuals and property owners with the needsof society as a whole? Or, when economic or political refugeesemigrate—legally or illegally—what can be done about the dev-astation they may cause to the local environment? How dohuman rights relate to the environment?

Critical Thinking and the Environment People on any side of anenvironmental issue may feel passionately about their cause, andthey can distort information and mislead people about the issues.Research done by environmental scientists is often used to makepolitical points or is misrepresented to support controversial view-points. In addition to the scientific data, the economic dimensionsof an environmental issue can be oversimplified. To further com-plicate things, the media often sensationalizes environmentalissues. So, as you make your own decisions about the environ-ment, it is essential that you use your critical-thinking skills.

Learning to think critically about what you see in news-papers, on TV, and on the Internet will help you make informeddecisions. As you explore environmental science further, youshould remember a few things. First, be prepared to listen tomany viewpoints. People have many different reasons for theopinions they form. Try to understand what those reasons arebefore reacting to their ideas. If you want your ideas to beheard, it is important that you listen to the opinions of others, asshown in Figure 19. Also, identify your own bias. How does itaffect the way you interpret the issue?

FIELD ACTIVITYFIELD ACTIVITY Critical Thinking and the NewsFind a news article or watch anews broadcast about a currentenvironmental issue. In yourEcolog, write down your initialreaction including your thoughts,feelings, and questions.

Now, look or think again,and answer the followingquestions:• Did the report present differ-ent sides of the issue? Describethe sides.• Did the report seem to favorone side over the other? Howcould you tell?• Did the report use images,sounds, or words that made youfeel a certain way?• Did the report provide anyfacts that helped you form anopinion? Try to list the facts.• Were the sources of the factsprovided? Did the sources seemreliable?• Were the opinions of anyexpert scientists presented? Whowere the scientists?• Is there any information thatwas not provided that might beimportant? Give examples.• When you think about the issuemore, does your opinion change?

Figure 19 � Anyone can express anopinion on environmental issues atstate and local public hearings.

www.scilinks.orgTopic: Solving

Environmental

Problems

Code: HE81424

DiscussionEnvironmental Problems in YourNeighborhood Ask students toimagine what they would think ifthey heard that a major employerin their area was found to bedumping poisonous chemicals,which showed up in the localwater supply. Ask students, “Howwould you recommend solving theproblem?” Then tell students thatthe company has stated that if it isforced to clean up its operations, itwill simply close its plant and openone in another country that hasless-strict environmental controls.Ask students, “Does this informa-tion change your opinion aboutwhat should be done?” Point outthat knowing the best way to solveenvironmental problems is difficultbecause all possible actions oftenhave both positive and negativeconsequences.

Group ActivityTown Council Meeting Selectfive students to represent the towncouncil. Then, select a current envi-ronmental topic for your area. Pollremaining students in the class tosee if there are opposing viewpointsin the class. If not, assign studentsto one side or the other for the topic.Have students research their positionon the topic and prepare a 3 minuteaddress to the town council. Thetown council members should takenotes about each address. After allthe students have expressed theiropinions to the council, have thecouncil vote on the issue. Thenallow each member of the councilto state why he or she voted for acertain issue. Co-op Learning



20

GENERAL

Set Up A Recycling Program There aremany things that students can do to helpwork towards a sustainable world. Recyclingis one easy way to make a difference. Glass,plastic, paper, and aluminum are easy to recy-cle. Most communities have a recycling centerthat will accept these materials. The centeroften has information on what can and cannot

be recycled. Students could see that containersfor recyclable materials are placed on campus,or if the containers are already there, studentscould start a campaign to encourage otherstudents to use the containers. Recycling savesenergy and resources and reduces the amountof trash that goes to landfills.

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AAnnsswweerrss ttoo SSeeccttiioonn RReevviieeww1. Answers may vary. Mexico has characteris-

tics of developing and developed countries. 2. Answers may vary. Critical thinking is a

skill that enables one to evaluate ideas andinformation.

3. The law of supply and demand states that the greater the demand for a limited supplyof something is, the more the supply isworth. Oil is one example. When demandis high the price usually increases.

4. Answers may vary. There are many otherfactors that might affect the price of oil.The cost of shipping and transporting theoil may increase. The cost of finding anddrilling wells may increase the price. Stu-dents may also note that the majority ofoil producing nations are part of a tradeorganization called OPEC. OPEC can con-trol the price and production of oil.


Second, investigate the source of the information youencounter. Ask yourself if the authors have reason for bias.Also, question the conclusions that are drawn from data. Askyourself if the data support the claims that are made. Thinkcritically about information posted on the Internet—flashygraphics and persuasive text might be hiding a biased agenda.Finally, gather all the information you can before drawing aconclusion.

A Sustainable WorldDespite the differing points of view on the environment, mostpeople support a key goal of environmental science: achievingsustainability. is the condition in which humanneeds are met in such a way that a human population can sur-vive indefinitely. A sustainable world is not an unchangingworld—technology advances and human civilizations continueto be productive. But at the present time we live in a worldthat is far from sustainable. The standard of living in devel-oped countries is high because those countries are usingresources faster than they can be replaced.

The problems described in this chapter are not insurmount-able. Achieving a sustainable world requires everyone’s participa-tion. If individual citizens, industries, and governments cooperate,we can move toward sustainability. For example, you read abouthow Seattle’s Lake Washington is cleaner and healthier now thanit was 30 years ago. Another example is the bald eagle, whichwas once on the brink of extinction. Today bald eagles are mak-ing a comeback, because of the efforts to preserve their habitatand to reduce pollution from the pesticide DDT.

Nevertheless, our environmental problems are significant andrequire careful attention and action. The 21st century will be acrucial time in human history. We must find solutions that allowpeople on all parts of our planet to live in a clean, healthy envi-ronment and have the resources they need for a good life.

What is a sustainable world?��Reading Check

Sustainability

1. Describe three differences between developing anddeveloped nations using the examples in Table 3.Would you classify Mexico as a developing nation?Explain your answer.

2. Explain why critical thinking is an important skill inenvironmental science.

3. Explain the law of supply and demand, and give anexample of how it relates to the environment.

CRITICAL THINKING

4. Applying Ideas The law of supply and demand is asimplification of economic patterns. What other fac-tors might affect the cost of a barrel of oil?

5. Evaluating Ideas Write a description of “TheTragedy of the Commons.” Do you think thatHardin’s essay is an accurate description of the rela-tionship between individuals, society, and the envi-ronment? WRITING SKILLS

S E C T I O N 2 Review

Figure 20 � These high school stu-dents are taking action to improve theirenvironment. They are cleaning uptrash that is clogging an urban creek.

AstronomyConnection to

Another Earth? If the environ-ment on Earth changed drasti-cally, would we have anywhere togo? There are no other planets inour solar system with an adequaterange of temperatures, a breath-able atmosphere, or the resourcesneeded to sustain humans withour present technology. There maybe other planets like Earth in theuniverse, but the closest planetswe know of are in other solar sys-tems that are light-years away.

AAnnsswweerr ttoo RReeaaddiinngg CChheecckkIn a sustainable world, human needsare met in such a way that a humanpopulation can survive indefinitely.

Reteaching Critical Thinking and theEnvironment Have students writea one-page story or parable thatillustrates the need for critical-thinking skills in environmentalscience. Logical

Quiz 1. What is the connection between

economics and the environment?(Answers may vary. Studentsshould note that economic forcescontrol the way resources areused.)

2. Why do people in developingcountries tend to have a smallerecological footprint than peoplein developed countries? (Sampleanswer: In a developing country,most people do not drive cars andgenerally depend less on resourcesfrom distant areas. Most of theirfood comes from nearby farms.)

Alternative Assessment Newspaper Article Ask studentsto write a short newspaper edito-rial on whether or not it is impor-tant to reduce the overall size of acountry’s ecological footprint. Thearticles should contain a definitionof the term ecological footprintand should discuss the economicsof the resources involved.

LS

CloseClose

21

GENERAL

5. Answers may vary. “The Tragedy of theCommons” states that when land held incommon is used for grazing, people tendto overgraze the land. When land isdivided up and privately owned, peopletend not to overgraze the land. To someextent this is accurate. People tend to caremore for an area when it is under theirdirect control.

GENERAL

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HighlightsCCHHAAPPTTEERR

11 HighlightsC H A P T E R 1

1 Understanding OurEnvironment

2 The Environment and Society

Key Termsenvironmental

science, 5ecology, 6agriculture, 10natural resource, 14pollution, 14biodiversity, 15

Main Ideas� Environmental science is an interdisciplinarystudy of human interactions with the living andnonliving world. One important foundation ofenvironmental science is the science of ecology.

� Environmental change has occurred through-out Earth’s history.

� Hunter-gatherer societies cleared grasslandby setting fires and may have contributed tothe extinction of some large mammals.

� The agricultural revolution caused humanpopulation growth, habitat loss, soil erosion,and the domestication of plants and animals.

� The Industrial Revolution caused rapidhuman population growth and the increaseduse of fossil fuels. Most modern environmen-tal problems began during the IndustrialRevolution.

� The major environmental problems we facetoday are resource depletion, pollution, andloss of biodiversity.

law of supply and demand, 17

ecological footprint, 19

sustainability, 21

� “The Tragedy of the Commons” was aninfluential essay that described the relationshipbetween the short-term interests of the individ-ual and the long-term interests of society.

� The law of supply and demand states thatwhen the demand for a product increases whilethe supply remains fixed, the cost of the prod-uct will increase.

� Environmental problems in developed coun-tries tend to be related to consumption. Indeveloping nations, the major environmentalproblems are related to population growth.

� Describing how sustainability can be achievedis a primary goal of environmental science.

Alternative AssessmentConduct a Survey Suggest thatstudents work in pairs to developand conduct a survey to determinethe attitudes of family members,classmates, neighbors, teachers,and friends toward specific envi-ronmental issues. Encourage stu-dents to include their survey resultsin their EcoLog.


22

• Chapter Test• Chapter Test• Concept Review• Critical Thinking• Test Item Listing• Math/Graphing Lab• Research Lab• Consumer Lab• Long-Term Project

GENERAL

GENERAL

GENERAL

GENERAL

GENERAL


GENERAL

hes08TE_c01_22-25_HCR 8/24/06 9:03 AM Page 22

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

1. agriculture2. natural resource3. pollution4. ecological footprint5. sustainability

Use the correct key term to complete each of thefollowing sentences.

6. The_________ Revolution was characterizedby a shift from human and animal power tofossil fuels.

7. Resources that can theoretically last foreverare called __________ resources.

8. __________ is a term that describes the number and variety of species that live in an area.

Understanding Key Ideas9. An important effect that hunter-gatherer soci-

eties may have had on the environment wasa. soil erosion.b. extinction.c. air pollution.d. All of the above

10. An important effect of the agricultural revo-lution wasa. soil erosion.b. habitat destruction.c. plant and animal domestication.d. All of the above

11. Which of the following does not describe aneffect of the Industrial Revolution?a. Fossil fuels became important energy sources.b. The amount of land and labor needed to

produce food increased.c. Artificial substances replaced some animal

and plant products.d. Machines replaced human muscle and ani-

mal power.

12. Pollutants that are not broken down by natural processes are a. nonrenewable.b. nondegradable.c. biodegradable.d. Both (a) and (c)

13. All of the following are renewable resourcesexcepta. energy from the sun.b. minerals.c. crops.d. fresh water.

14. In his essay, “The Tragedy of the Commons,”one factor that Garrett Hardin failed to con-sider wasa. the destruction of natural resources.b. human self-interest.c. the social nature of humans.d. None of the above

15. The term used to describe the productivearea of Earth needed to support the lifestyleof one person in a particular country iscalleda. supply and demand.b. the ecological footprint.c. the consumption crisis.d. sustainability.

C H A P T E R 1

Root Words As you study it may be helpful tolearn the meaning of important root words. Youcan find these roots in most dictionaries. For example, hydro- means “water.” Once you learnthe meaning of this root, you can learn themeanings of words such as hydrothermal, hydrologist, hydropower, and hydrophobic.

STUDY TIP

ANSWERS

UUssiinngg KKeeyy TTeerrmmss1. Sample answer: Agriculture is the

practice of growing, breedingand caring for plants and ani-mals that are used for food,clothing, housing, transportation,and other purposes.

2. Sample answer: Naturalresources are either renewableor nonrenewable.

3. Sample answer: Toxic chemicalsreleased into the environmentcause pollution.

4. Sample answer: A developednation has an ecological foot-print that is about four timeslarger than a developing nation.

5. Sample answer: Sustainability isa goal of environmental science.

6. Industrial7. renewable8. Biodiversity

UUnnddeerrssttaannddiinngg KKeeyy IIddeeaass9. b

10. d11. b12. b13. b14. c15. b


23

Review

Section Questions1 1–3, 6–13, 16, 17, 21, 25–29,

31, 352 4, 5, 14, 15, 18–20, 22–24, 32–34,

36, 37

Assignment Guide

CCHHAAPPTTEERR

11


ReviewShort Answer16. Give an example of how environmental

science might involve geology and chemistry.

17. Can biodegradable pollutants cause environ-mental problems? Explain your answer.

18. In what ways are today’s environmentalresources like the commons described in theessay “The Tragedy of the Commons”?

19. How could environmental concerns conflictwith your desire to improve your standardof living?

20. If you were evaluating the claims made ona Web site that discusses environmentalissues what types of information would youlook for?

21. Can species be considered natural resources?Explain your answer.

Interpreting GraphicsThe graphs below show the difference in energyconsumption and population size in developedand developing countries. Use the graphs toanswer questions 22–24.

22. Describe the differences in the energy con-sumption and population growth of devel-oped and developing countries.

23. Do you think that the percentage of commer-cial energy consumed by developing countrieswill increase or decrease? Explain your answer.

24. Why is information on energy consumptionrepresented in a pie graph, while populationsize is shown in a line graph?

Concept Mapping25. Use the following terms to create a concept

map: geology, biology, ecology, environ-mental science, chemistry, geography, andsocial sciences.

Critical Thinking26. Analyzing Ideas Are humans part of the

environment? Explain your answer.

27. Drawing Conclusions Why do you think thatfossil fuels were not widely used until theIndustrial Revolution? Write a paragraphthat describes your thoughts.

28. Evaluating Assumptions Once the sunexhausts its fuel and burns itself out, it can-not be replaced. So why is the sun consid-ered a renewable resource?

29. Evaluating Assumptions Read the descrip-tion of the Industrial Revolution. Were allthe effects of the Industrial Revolution nega-tive? Explain your answer.

Cross-Disciplinary Connection30. Demographics Obtain the 1985 and 2000

census reports for your town or city. Lookfor changes in demographic characteristics,such as population size, income, and age.Make a bar graph that compares some of thecharacteristics you chose. How does yourcity or town compare with national trends?What might be some of the environmentalimplications of these trends?

Portfolio Project31. Make a Diagram Many resources can be

traced to energy from the sun. For example,plants living in swamps millions of years agoused energy from the sun to grow. Over time,some of these plants became coal deposits.When we burn coal today, we are usingenergy that radiated from the sun millions ofyears ago. Choose a resource, and create adiagram that traces the resource back toenergy from the sun.

READING SKILLS

WRITING SKILLS

C H A P T E R 1

Developing countries

32% Developing countries

Developed countries

Developed countries

68%

Commercial Energy Consumption

Population Size

Po

pu

lati

on

(in

bill

ion

s)

Year

1900 1950 20000

1

2

3

4

5

6

?

? ?SShhoorrtt AAnnsswweerr16. Sample answer: Geology might be

involved in environmental sciencebecause scientists might use geol-ogy to find out how different rocktypes might affect pollution flow.Chemistry might be involved inenvironmental science becausescientists might use chemistry toidentify how different chemicalsinteract in the environment.

17. Answers may vary. Biodegradablepollutants can cause environmen-tal problems if they accumulatein the environment and they donot degrade quickly enough.

18. Sample answer: The Earth’sresources are shared by everyone,if societies do not use resourcesresponsibly, the resources canbecome depleted or polluted.

19. Answers may vary. 20. Answers may vary. Students

might suggest looking at thesources for the information, thereferences provided, the presenta-tion of data, or the credentials ofthe author.

21. Sample answer: A species canbe a natural resource because aspecies is part of the environment.

IInntteerrpprreettiinngg GGrraapphhiiccss22. Developing countries have a

much higher rate of populationgrowth than developed countries.Developed countries use abouttwice as much energy as develop-ing countries, even though thepopulations of developed coun-tries are much smaller.

23. Developing countries will proba-bly consume a higher percentageof commercial energy over time,because population growth isincreasing in developing countries.


24

24. The pie graph represents part of a totalamount, while the chart of population sizeshows change over time.

CCoonncceepptt MMaappppiinngg25. Answers to the concept mapping questions

are on pp. 715–720.

CCrriittiiccaall TThhiinnkkiinngg26. Sample answer: Humans are part of the envi-

ronment because they are animals that useresources.

27. Sample answer: Fossil fuels were not widelyused before the Industrial Revolution because

there was not an efficient way to mine ortransport the fuels and there were not manymachines that could use fossil fuels.

28. Answers may vary. The sun is usually consid-ered a renewable resource because it isexpected to last for many, many futurehuman generations.

29. Sample answer: Many of the effects of theIndustrial Revolution were positive.Machines made many processes much moreefficient and reduced the need for humanlabor and animal power to do many tasks.The Industrial Revolution also improved thestandard of living.

ReviewCCHHAAPPTTEERR

11


MATH SKILLS

Use the table below to answer questions 32–34.

32. Analyzing Data Make a bar graph thatcompares the garbage produced per personper year in each country.

33. Making Calculations Calculate how muchgarbage is produced each year per squaremile of each country listed in the table.

34. Evaluating Data Use the information in thetable to evaluate the validity of the followingstatement: In countries where populationdensity is high, more garbage is producedper person.

WRITING SKILLS

35. Communicating Main Ideas Briefly describethe relationship between humans and the environment through history.

36. Writing Persuasively Write a persuasiveessay explaining the importance of science ina debate about an environmental issue.

37. Outlining Topics Write a one-page outlinethat describes population and consumptionin the developing and developed world.

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

Think about what you did this morning. Fromthe moment you got up, you were makingdecisions and acting in ways that affect theenvironment. The clothes you are wearing, forexample, might be made of cotton. Severalyears ago the fibers of cotton in your shirtmight have sprouted as seedlings in Egypt orArizona. The cotton seedlings were probablyirrigated with water diverted from a nearbyriver or lake. Chemicals such as pesticides,herbicides, and fertilizers helped the seedlingsgrow into plants. Furthermore, the metals inthe machines that harvested the cotton weremined from the Earth’s crust. In addition, thevehicles that brought the shirt to the storewhere you bought it were powered by fossilfuels. Fossil fuels came from the bodies of tinyorganisms that lived millions of years ago. Allof these connections can make environmentalscience a complex and interesting field.

1. According to the passage, which of thefollowing conclusions is true?a. Decisions we make in everyday life do

not affect our environment.b. Cotton comes from minerals in the

Earth’s crust.c. Many different things in the environ-

ment are connected and interrelated.d. There is no connection between a

cotton shirt and the resources neededto grow a field of cotton.

2. Which of the following statements best describes the meaning of the termirrigation?a. Irrigation is a connection between liv-

ing things in the environment.b. Irrigation is the artificial process by

which water is supplied to plants.c. Irrigation is the process of diverting

water from a stream or lake.d. Irrigation is the process by which cot-

ton seedlings grow into plants.

U.S. Japan Indonesia

People per 78 829 319square mile

Garbage produced 720 kg 400 kg 43 kgper person per year

READING SKILLS

CCrroossss--DDiisscciipplliinnaarryyCCoonnnneeccttiioonn30. Answers may vary. The change

in demographics will probablyshow change in population andincome levels. The change mayalso show an increase in age.Increased population affects theresources used, and increasedincome probably translates toa larger ecological footprint.

PPoorrttffoolliioo PPrroojjeecctt31. Sample answer: Trees grow

because they use the energy fromthe sun. Trees are cut down toburn as fuelwood. When wood isburned, the energy is released.

MMaatthh SSkkiillllss32.

33. U.S. 56,160 kg/mi2; Japan 331,600 kg/mi2; Indonesia 13,717 kg/mi2

34. The statement is false becausethe population density is high in Japan and Indonesia, yet thegarbage produced per person islower than the United States.

WWrriittiinngg SSkkiillllss35. Answers may vary. 36. Answers may vary. 37. Answers may vary.

RReeaaddiinngg SSkkiillllss1. c2. c


25

900800700600500400300200100

0U.S.

Garbage Produced per Person per Year

Japan Indonesia

Kilo

gram

s


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

1 How do scientists characterize a nonrenewable resource?A. a resource that is used by humansB. a resource that cannot be replacedC. a resource that can be replaced relatively

quicklyD. a resource that takes more time to

replace than to deplete

2 Which of the following is an importantfoundation of environmental science? F. ecologyG. economicsH. meteorologyI. political science

3 Which of the following phrases describesthe term biodiversity?A. species that have become extinctB. the animals that live in an areaC. species that look different from one

anotherD. the number and variety of species that

live in an area

4 Energy from the sun, water, air, wood, andsoil are all examples of what kind ofenergy?F. ecological energyG. organic energyH. renewable energyI. solar energy

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

5 Pollution is created when societies producewastes faster than they can be disposed of.Identify the two main types of pollutants.

6 Economic forces influence the use of natural resources. One rule of economics is the law of supply and demand. Analyzehow economic forces affect the usage ofnonrenewable resources.

Reading SkillsDirections (7–9): Read the passage below. Thenanswer the questions.

Early hunter-gatherer groups began to col-lect the seeds of the plants they gathered andto domesticate animals in their environment.This practice of agriculture started in manyparts of the world more than 10,000 yearsago, and had such a dramatic impact onhuman societies and their environment that itis often called the agricultural revolution. Anarea of land could now support up to 500times as many people by farming than it couldby hunting and gathering. As populationsgrew, they began to concentrate in smallerareas.

As grasslands, forests, and wetlands werereplaced with farmland, habitat was destroyed.In addition, much of the converted land wasfarmed poorly and became infertile. Thedestruction of farmland had far-reaching environmental effects.

7 The practice of gathering seeds and domesticating some animals led to A. a reduction in the kinds of food

people ateB. the extension of the prairies as open

grasslandC. the disappearance of some species of

large mammalsD. a growth in population at an

unprecedented rate

8 In what ways did the agricultural revolution increase pressure on local environments?

9 What happened to human populations asthey became larger?F. They began to concentrate in smaller

areas.G. They remained dispersed.H. They became hunter-gatherers.I. Most became extinct.

Interpreting Graphics

A.B.C.D.

F.G.H.I.

A.B.C.D.

F.G.H.I.

26

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

Standardized Test Prep

26 Chapter 1 • Standardized Test Prep

10. D11. H12. B13. G

Answers1. D2. F3. D4. H5. The two types of pollutants are biodegradable and

nonbiodegradable. 6. Answers will vary. See Test Doctor for detailed

scoring rubric.7. D8. Answers will vary. See Test Doctor for detailed

scoring rubric.9. F

Question 6 Full-credit answersshould include the followingpoints:

• as nonrenewable resourcesbecome scarce, their costs rise

• as the cost of a resource rises,people look for alternatives thatare cheaper and more readilyavailable

Question 8 Full-credit answersshould include the followingpoints:

• the agricultural revolutionallowed populations to grow inlocalized areas

• the larger populations used moreresources than the smallerhunter-gatherer groups

• using more resources put morepressure on the environment toreplace, or find replacements for,the used resources

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TestWhen reading a graphthat shows a changein some variable overtime, keep in mind thatthe steepness anddirection of a curveindicate the relativerate of change at agiven point in time.

Interpreting Graphics

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

0 Population growth can result in what ethical environmental problem,addressed by ecologist Garrett Hardin in “The Tragedy of the Commons”?A. the conflict between water resources and industrial growthB. the conflict between forest resources and the lumber companiesC. the conflict between political interests and international energy useD. the conflict between individual interests and the welfare of society

The line graph below shows the world population between the years 1600and 2000. Use this graph to answer questions 11 and 12.

World Population (1600–2000)

q What was the total population increase between the years 1600 and1900?F. 0.6 billionG. 0.9 billionH. 1.0 billionI. 1.5 billion

w If the rate of growth from 1900–1950 had been the same as the rateof growth from 1950–2000, what would the world population havebeen at the end of the century?A. more than 7 billionB. more than 10 billionC. more than 15 billionD. more than 20 billion

e Which of the following characterizes the environmental consequencesof the current population trend?F. More people mean more housing construction.G. The need for food and resources is growing rapidly.H. The standard of living has risen around the world.I. There is no connection between population growth and

environment.

Po

pu

lati

on

(in

bill

ion

s)

1600 1700 1800 1900 2000

Year

6.5

5.5

4.5

3.5

2.5

1.5

0.5

27

Standardized Test Prep

Chapter 1 • Standardized Test Prep 27

Question 11 Answer H is correct.You can determine differences invalues by identifying each value onthe y-axis, which corresponds to aspecific value, and then subtractingthe smaller values from the larger.Answers F and G are too small,and answer I is much too large.

Question 12 Answer B is correct.To estimate a value, studentsshould draw a best-fit line from apoint near where the data ends tothe point they are trying to pre-dict. To estimate the value asked inthe question, students should esti-mate the slope of the line from1950–2000. Then replace theactual line from 1900–1950 withthe new line. Identify where theline ends (the population of 1950under the new conditions). Thenapply this line again to the periodbetween 1950 and 2000 to identifywhat the population in the year2000 would have been under thenew conditions.

Students struggling with this typeof question may benefit from prac-ticing producing their own linegraphs. For example, ask studentsto draw two line graphs. The firstshould have a constant slopethroughout. The second shouldhave one slope for the first half,and then double the slope for thesecond half. Ask student to com-pare the two graphs.

hes08TE_c01_26-27_STP 8/24/06 1:37 PM Page 27

Exploration LabField Activity

CCHHAAPPTTEERR

11What’s in an Ecosystem?How well do you know the environment around your home orschool? You may walk through it every day without noticing mostof the living things it contains or thinking about how they survive.Ecologists, on the other hand, observe organisms and seek tounderstand how they interact. In this lab, you will play the role ofan ecologist by closely observing part of your environment.

Procedure1. Use a tape measure or meter stick to measure a 10 m � 10 m

site to study. Place one stake at each corner of the site. Loopthe string around each stake, and run the string from onestake to the next to form boundaries for the site.

2. Survey the site, and then prepare a site map of the physicalfeatures of the area on the poster board. For example, showthe location of streams, sidewalks, trails, or large rocks, andindicate the direction of any noticeable slope.

3. Create a set of symbols to represent the organisms at yoursite. For example, you might use green triangles to representtrees, blue circles to represent insects, or brown squares torepresent animal burrows or nests. At the bottom or side ofthe poster board, make a key for your symbols.

4. Draw your symbols on the map to show the location and rela-tive abundance of each type of organism. If there is not enoughspace on your map to indicate the specific kinds of plants andanimals you observed, record them in your notebook.

5. In your notebook, record any observations of organisms intheir environment. For example, note insects feeding onplants or seeking shelter under rocks. Also describe thephysical characteristics of your study area. Consider the following characteristics:a. Sunlight Exposure How much of the area is exposed to

sunlight?b. Soil Is the soil mostly sand, silt, clay, or organic matter?c. Rain When was the last rain recorded for this area? How

much rain was received?d. Maintenance Is the area maintained? If so, interview the

person who maintains it and find out how often the site iswatered, fertilized, treated with pesticides, and mowed.

e. Water Drainage Is the area well drained, or does it havepools of water?

f. Vegetation Cover How much of the soil is covered withvegetation? How much of the soil is exposed?

6. After completing these observations, identify a 2 m � 2 marea that you would like to study in more detail. Stake outthis area, and wrap the string around the stakes.

Objectives� Survey an area of land and deter-

mine the land’s physical featuresand the types of organisms thatlive there.

� Identifypossible relationships between theorganisms that live in the area ofland you surveyed.

Materialshand lensmarkers or felt-tip pens of

several different colorsnotebookpen or pencilposter boardstakes, (4) string, about 50 mtape measure or metric ruler

optional materials: field guides toinsects or plants

USING SCIENTIFIC METHODS

Exploration Lab: FIELD ACTIVITYC H A P T E R 1

� Marking a Site Use stakes andstring to mark a site that you willobserve in detail.

WHAT’S IN ANECOSYSTEM?

Teacher’s Notes

Time Requiredone or two 45-minute class periods

Lab Ratings

TEACHER PREPARATION

STUDENT SETUP

CONCEPT LEVEL

CLEANUP

Skills Acquired• Measuring• Collecting Data• Communicating• Predicting

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

MaterialsThe materials listed are enough fora group of 3 to 4 students.

E A S Y H A R D

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Tips and TricksBefore you perform this lab, obtain as manyfield guides about the natural history ofyour region as possible. Local libraries andused book stores should have these guides.The Internet should also offer information.Encourage the groups to study the field guidesbefore performing the lab, so that they do notgo into the field “blind.” Award points togroups that use the field guides to correctlyidentify plants and animals in their plots.

Encourage groups to survey terrain that hasa variety of features. Wooded, hilly areas aregood spots for this lab. If you have additional

time for this activity, have groups switch plotsuntil each group has surveyed every plot. If yousave the results of this lab from year to year,students can compare the changes over time.

Pick a site that is fairly undisturbed. Tie 10 m sections of string to the stakes ahead of time because setting up the plot can betime-consuming. Use a hammer to secure thestakes into the ground. Before beginning theactivity, discuss with students what organismsthey might expect to find at their site, howthose organisms might interact, and what abiotic factors might come into play.

hes08TE_c01_28-29_Lab 8/24/06 9:07 AM Page 28


7. Use your hand lens to inspect the area. Be careful not to dis-turb the soil or the organisms. Then record the types ofinsects and plants you see.

8. Collect a small sample of soil, and observe it with your handlens. Record a description of the soil and the organisms thatlive in it.

Analysis1. Organizing Data Return to the classroom, and display your

site map. Use your site map, your classmates’ site maps, andyour notes to answer the followingquestions. Write your answers inyour notebook.

2. Analyzing Data Write one para-graph that describes the 10 m �10 m site you studied.

3. Analyzing Data Describe the 2 m � 2 m site you studied. Is this site characteristic of the larger site?

Conclusions4. Interpreting Conclusions What

are the differences between theareas that your classmates stud-ied? Do different plants andanimals live in different areas?

5. Making Predictions As the seasons change, the types oforganisms that live in the areayou studied may also change.Predict how your area mightchange in a different season orif a fire or flood occurred. If possible, returnto the site at different times throughout the year and record your observations.

� Site Maps Your site map shouldbe as detailed as possible, and itshould include a legend.

1. Asking Questions Based on what you have learned, thinkof a question that explores how the components of the areayou observed interact with each other. For example, youmight want to consider the influence of humans on the site;study a particular predator/prey relationship; or explore theeffects of physical features, such as water or sunlight, on thegrowth or behavior of organisms. Write a description ofhow you would investigate this topic. WRITING SKILLS

Extension

AAnnsswweerrss ttoo AAnnaallyyssiiss2. Answers may vary. Students

should note types of foliage, ani-mals and inorganic characteristics.

3. Answers may vary.

AAnnsswweerrss ttoo CCoonncclluussiioonnss 4. Answers may vary. 5. Answers may vary.

AAnnsswweerrss ttoo EExxtteennssiioonn 1. Answers may vary.

29

• Datasheets for In-Text Labs• Lab Notes and Answers


Jim WatsonDalton High School

Dalton, Georgia

CLASSROOM

TESTED& APPRO

VED

Holt Lab Generator CD-ROM

Search for any lab by topic, standard, difficulty level, or time.Edit any lab to fit your needs, orcreate your own labs. Use the LabMaterials Quicklist software tocustomize your lab materials list.

hes08TE_c01_28-29_Lab 8/28/06 11:56 AM Page 29

CHICKEN OF THE TREES In the stillness of predawn, the airwarms over the Carara BiologicalPreserve in Costa Rica. Severalthousand eggs in sun-heated incuba-tors just below the surface of theEarth stir in response. Within theseeggs are tiny iguanas—lizards thatwill eventually emerge, grow to alength of 1.5 m to 2.0 m (5 ft to 6.5ft), and weigh up to 6 kg (13 lb).

What’s going on here? Well,these giant lizards are being raisedso that they can be released intothe rain forest. It’s part of a projectled by German-born scientist Dr.Dagmar Werner. Her goal is tohelp restore an iguana populationthat has been severely reduced inthe past several decades.

The lizard has suffered from theeffects of hunting, pollution, andhabitat destruction by people whoclear the rain forest for farming.Prime iguana habitat is at the edgeof the forest—where a combinationof open areas, scrub, and treesoccur. Historically, these areas arethe type of habitat that humans

most often destroy when convert-ing forestland to farmland. Peoplecut down the forest at its edges—which just happens to be primehabitat for iguanas and otherplants and animals.

Back at the IguanaRanchDr. Werner’s “iguana ranch” preserve has artificial nests wherefemales can lay their eggs in apredator-free environment. Afterthey hatch, the young lizards areplaced in a temperature- andhumidity-controlled incubator andgiven a special diet. As a result, theiguanas grow faster and strongerand are better protected frompredators than their noncaptivecounterparts.

In the first five years of herproject, more than 80,000 iguanaswere released into the wild.Ordinarily, less than 2 percent ofall iguanas survive to adulthood inthe wild, but Dr. Werner’s iguanashave a 77 percent survival rate.Dr. Werner knows this becauseafter she releases the iguanas intothe rain forest, the lizards aretracked and monitored to deter-mine whether they have success-fully adapted to life in the wild.

Passing It OnSince the 1980s, Dr. Werner hasimproved the iguanas’ chances ofsurvival by breeding them andreleasing thousands of young igua-nas into the wild. But Dr. Wernersoon realized that this effort wasnot enough, so she began trainingother people to do the same.

Because she knew there was notime to lose, Dr. Werner took animmediate and drastic approach tosolving the problem. She combinedher captive-breeding program atthe preserve with an education pro-gram that shows farmers that thereis more than one way to make aprofit from the rain forest. Instead

� These are iguanas at the CararaBiological Preserve in Costa Rica.

CHICKEN OF THE TREES

BackgroundThe green iguana (Iguana iguana)is found throughout CentralAmerica. In some parts of its habi-tat, it has been hunted to extinc-tion. The green iguana has beenused for centuries as a food source.It is called chicken of the trees orgallina de palo in Spanish. Thename comes from the fact thatiguanas have a white meat thattastes like chicken. The demand foriguanas and iguana eggs for foodhas caused them to nearly becomeextinct.

Releasing the iguanas into thewild is a key part of Dr. Werner’sprogram. Attempting to raise theiguanas to a marketable size in captivity would be a costly processbecause iguanas constantly needfood and require large habitats.By releasing the iguanas into thewild, much of the expense isreduced. However, to increase theproductivity of the iguanas, feedingstations are set up in the jungle.

By supplying extra food forthe iguanas—broken rice, meat,bone, fish meal, papayas, mangos,bananas, avocados, and a varietyof leaves and flowers—many moreiguanas can grow to maturity thancould be naturally supported by thehabitat. In fact, scientists estimatethat 6 to 10 times more iguanas canbe raised by supplied food.

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Making a DifferenceMaking a Difference


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AAnnsswweerrss ttoo WWhhaatt DDoo YYoouu TThhiinnkk??Dr. Werner’s project helps the iguanas because ittakes hunting pressure off the iguana population.Her program helps the local farmers because itincreases their income and prevents habitatdestruction. Dr. Werner’s larger goals are for theprotection of the environment. She is workingtoward sustainable use of the forest resources.

What Do You Think?How does Dr. Werner’s projectprotect iguanas and help localfarmers too? Why do you thinkthat she trains farmers to raiseand value iguanas—what couldher larger goal be? Can youthink of a similar project thatwould be suitable for your area?

of raising cattle (and cutting downrain forest to do so), she encour-ages local farmers to raise iguanas,which can be released into the wildor sold for food. Known as the“chicken of the trees,” this lizardhas been a favored source of meatamong native rain-forest inhabi-tants for thousands of years.

Not only do farmers profitfrom the sale of iguana meat, theyalso produce iguana leather andother handicrafts from the lizard.

Fundación Pro IguanaVerdeWith Dr. Werner’s methods, farmerscan release many iguanas into thewild and earn a good living. Butconvincing farmers to use her meth-ods hasn’t been easy. According toDr. Werner, “Many locals have

never thought of wild animals ascreatures that must be protected inorder to survive. That’s why somany go extinct.” To get her mes-sage across, Dr. Werner has estab-lished the Fundación Pro IguanaVerde (the Green IguanaFoundation). This organizationsponsors festivals and educationseminars in local communities.These activities promote the tradi-tional appeal of the iguana, increasecivic pride in the animal, and

heighten awareness about theiguana’s economic importance.

By demonstrating that the needsof all concerned parties can be metwhen attempting to save an endan-gered species, Dr. Werner has revo-lutionized the concepts of speciespreservation and economic devel-opment. This hard-working scien-tist has hit upon a solution thatmay encourage farmers throughoutCentral America to “have theirlizards and eat them too.”

� Dr. Werner and an associate dis-cuss how the iguana can be farmed.

� Dr. Werner has established aninnovative way to raise the numberof iguanas living in the wild.

Sustainable DevelopmentDr. Werner’s iguana ranch is justone example of a sustainable development project run by a non-governmental organization (NGO).One goal that most sustainabledevelopment projects share isencouraging local support andinvolvement in the project. If aproject is supported by the localpopulation the project is morelikely to match the needs of thepopulation and to be economicallysustainable. Students may be inter-ested in finding out about otherNGOs that are working on envi-ronmental issues. One notableorganization is Ashoka, based inArlington, Virginia. Ashoka locatesand supports individuals calledsocial entrepreneurs. Like businessentrepreneurs, social entrepreneurshave developed innovative, patternbreaking ideas that would producemaximum results for a minimumof investment. Social entrepreneurs,however, focus on areas such ashealthcare, the environment, andhuman rights. Worldwide, Ashokasupports nearly 1,000 social entre-preneurs. Students may be inter-ested in finding out more aboutAshoka or another NGO thatoffers internships or other careeropportunities.

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CH 1 APTER Science and the Environment CHAPTER 1

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Transcript of CH 1 APTER Science and the Environment CHAPTER 1