exploring science and the environment t -...

Chapter

Exploring Science andthe Environment

The photo on the left shows a tiny model of Earth undera magnifying glass. You have probably used a similartool to study small living things. Of course, you cannot

really see the whole Earth through a magnifying glass. However,many scientists do study planet Earth very carefully. Earth ismade of many parts that interact, including living things. Theresult is a constantly changing planet. In Chapter 1, you willlearn how living things depend on Earth's environment. Youwill also find out how scientists study interactions betweenEarth and its living things.

Organize Your Thoughts

Environment

• Parts of the environment• Environmental challenges

Environmental

Science

• Scientific method• Science and society

Goals for Learning

To understand that environmental science includesmany different areas of study

To describe the major things that all living things needto survive

To explain how life on Earth has changed over time

To describe five major environmental problems

To list and describe the steps in the scientific method

To explain why science is important to society

Lesson Introducing Environmental Science

Objectives

After reading thislesson, you shouldbe able to+ define

environmentalscience andapplied science

+ describe thenatural environmentand the builtenvironment

+ list differentareas of studyimportant toenvironmentalscience

OrganismA living thing; one ofmany different formsofhfe

EnvironmentalscienceThe study of howliving things, includinghumans, interact withtheir environment

Environment

An organism's naturaland human-madesurroundings

Think about some of the advances in science that havehappened in the last decade. Scientists have developed newways to track organisms, or living things, such as whales andbutterflies. They have designed cars that run on both gas andelectricity to save energy. They have even discovered new plantsand animals that no one has ever seen before. These are just afew examples of what scientists are learning about the earth.

Science and the EnvironmentAll of these discoveries show environmental science at work.Environmental science is the study of how living things,including humans, affect and interact with their environment.The environment is an organism's natural and human-madesurroundings. Environmental scientists work to understand theenvironment in order to solve environmental problems. Theyalso try to prevent new problems from happening in the future.

The environment has two major parts, the natural environmentand the built environment. The natural environment is oftencalled nature. The built environment includes what humanshave made, such as roads and buildings. The environment alsoincludes the relationships among living and nonliving things.Environmental scientists study both the natural environment andthe built environment to understand how they affect each other.

Language ArtsThe word environment comes from the French word virer,which means "to turn." The word environ means to encircle,or surround.

Chapter 1 Exploring Science and the Environment

NaturalenvironmentAll living and nonlivingthings found in nature

BuiltenvironmentWhat humans havemade, such as roads andbuildings

Natural resourceA material fount! innature that is usefulto humans

Applied scienceA field of study that usesscientific knowledge tosolve practical problems

Environmental science builds on many other areas of science.These areas include biology, earth science, chemistry, physics, andthe social sciences. It explores how people use natural resources,such as water, plants, coal, and soil. Unlike many other sciences,environmental science is an applied science. That means its goalis to provide practical solutions to environmental problems.Environmental scientists look for ways people can interact withthe environment without harming it.

Map Skills: Physical Map of the United States

One way to learn about the physical environment is throughmaps. A physical map shows natural features, such as mountainsand rivers. It also shows elevation, which is the height abovesea level. The colors on the map represent different ranges ofelevations. Notice that the units are in meters. Use the map andthe legend to answer the questions below.

1. What natural resource is shown in blue?

2. What color represents the highest elevations?

LEGEND

Land Elevation in Meters

-100 to 700

701 to 1,200

1,201 to 2,000

2,001 to 4,400

3. Which mountains are taller: the Rocky Mountains or theAppalachian Mountains? How do you know?

4. What is the elevation range of most of the southeasternUnited States?

5. What body of water does the Mississippi River empty into?

Exploring Science and the Environment Chapter I 3

CultureThe languages, religions,customs, arts, and dressof a people

Researchand Write

With a partner,choose an area ofscience listed in thislesson. Researcha scientist in thisarea who hasadded to people'sunderstanding ofthe environment.Create a posterthat displays yourfindings.

There are many kinds of environmental scientists. They havedifferent backgrounds and different points of view. Some areconservation biologists who study living things and how toprotect the environment. Others are earth scientists who studyair, water, and land systems. Some are social scientists, such asgeographers and anthropologists. These scientists look at differentcultures, among other things. Cultures are the languages,religions, customs, arts, and dress of a people. All of these thingshelp determine how people relate to the environment.

Different areas of science within environmental science arelisted in Table 1.1.1. They are followed by some real-lifeexamples of environmental scientists.

Table 1.1.1 Different Areas of Science WithinEnvironmental Science

Area of science

Biology

Ecology

Zoology

Botany

Ethology

Microbiology

Earth science

Geology

Climatology

Hydrology

Meteorology

Paleontology

Chemistry

Biochemistry

Geochemistry

Geography

Anthropology

Sociology

Demography

Definition

The study

The studyand their

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

The study

of living things

of interactions between living thingsenvironment

of animals

of plants

of animal behavior

of microorganisms

of the planet over time

of the solid parts of the earth

of climate

of the earth's water systems

of the earth's air and weather

of fossils and prehistoric life

of matter and how it changes

of the chemistry of living things

of the chemistry of the earth

of places, people, and cultures

of human cultures

of human societies

of population dynamics

4 Chapter I Exploring Science and the Environment

Link to >->->-

Biology

Though WangariMaathai is abiologist/ she wonthe Nobel Prize forPeace. Nobel Prizesare also awarded forphysics, chemistry,medicine, literature,and economicsciences.

Wangari Maathai is a biologist.She is the first African womanto win the Nobel Peace Prize.For more than 30 years, shehas worked with communitiesthroughout Africa to plant trees.The trees provide resources forcommunities and help preventsoil from washing away. Herwork has also provided jobs formany poor people in Africa.She has shown firsthand howa healthy environment canimprove the quality of life.

Figure 1.1.2 In 2004, WangariMaathai received the Nobel PeacePrize for her work.

Jason Clay is an anthropologist who works to reduce the impactof food production. He is researching ways to grow shrimp andsalmon that do not harm the environment. He is also workingto protect the fish in oceans and rivers.

Eric Dinerstein is a conservation biologist. He is working toprevent rhinoceroses, tigers, pandas, and other large animalsfrom disappearing. In the past 50 years, the numbers of theselarge animals have decreased. Dr. Dinerstein is trying to protectthe land they need to survive.

Figure 1.1.3Eric Dinerstein traveledto China to study giantpandas and helppreserve their habitat.

Exploring Science and the Environment Chapter I

All of these scientists ask questions and conduct research tolearn how people and the environment interact. They sharetheir findings with others, including other scientists andthe public. Scientists build on what others have discoveredbefore them to make new discoveries. In this textbook, youwill read about how science helps people learn more aboutthe environment.

Express Lab 1

Materials* paper

+ pencil

Procedure1. Look around your

classroom. Observe andwrite down the things thatsurround you.

2. Identify which naturalresources might have beenused to make these things.

3. List all the natural resourcesthat you identified.

Analysis1. Which natural resources

are used to constructbuildings?

2. Which natural resources onyour list will be used up oreaten? One example is anapple someone brought forlunch.

3. Which natural resourcesdo you share with otherstudents? One example isthe water in the drinkingfountain.

Chapter I Exploring Science and the Environment

Lesson 1 R E V I E W

Word Bankapplied science

built environment

environmentalscience

On a sheet of paper, write the words from the Word Bank thatcomplete each sentence correctly.

1. Buildings, roads, schools, and bridges are examplesof the .

2. The study of how living things interact with theirsurroundings is .

3. A(n) is an area of study designed to help solvepractical problems.

On a sheet of paper, write the letter of the correct answer.

4. Which of the following is not a natural resource?

A soil B water C roads D plants

5. Which of the following areas of science might study a pastsociety's relationship with the environment?

A ecology C chemistryB climatology D anthropology

6. The _ _ is often referred to as nature.

A natural environment C built environmentB environmental science D tropical rain forest

Critical ThinkingOn a sheet of paper, write the answers to the followingquestions. Use complete sentences.

7. As an applied science, what is the main goal ofenvironmental science?

8. Name a natural resource and one reason that it isimportant to people.

9. List three different areas of science that are part ofenvironmental science. How do they each relate tothe environment?

10. Give two examples of the types of work environmentalscientists do.

Exploring Science and the Environment Chapter 1

Lesson A Living Planet

Objectives

After reading thislesson, you shouldbe able to+ list the things that

organisms needto survive

+ explain wheremost of Earth'senergy comesfrom

+ describe howwater, oxygen,energy, andnutrients areimportant

CellThe basic unit of life

DissolveTo break apart

Researchand Write

Use the Internet toresearch anotherplanet. Write areport explaininghow its conditionswould make itdifficult for humansto live there.

Earth is the only planet in the universe known to support life.It is home to gigantic blue whales and bumblebee bats the sizeof a dime. It is home to tiny mosses and giant redwood trees.All of these organisms need certain things to survive, includingwater, oxygen, and energy.

The Importance of WaterSea jellies, often called jellyfish, have bodies that are more than95 percent water. These creatures live in the ocean, pushedalong by currents and wind. They have a bell-shaped bodyand thin, dangling arms. Unlike true fish, jellyfish do not havebackbones. Instead, they are related to corals and sea anemones.Without water, sea jellies could not exist.

Water is important for people, too. Each person needs to drinkabout 1.9 liters of water every day to stay healthy. In the UnitedStates, each person uses about 379 liters each day. This water isused in many ways, such as for drinking, bathing, and flushingtoilets. In other areas of the world, there is not enough wateravailable. More than 2 billion people do not have enough waterfor drinking or cleaning.

Take a BreathAnother thing that organisms need to live is oxygen. When youtake a breath, you bring oxygen and other gases into your lungs.The oxygen is picked up by chemicals in your blood. It travelsto all of your body's more than seven trillion cells. Cells are thebasic units of life that make up all living things. Oxygen helpsthe cells get the energy they need from food. When you breatheout, you give off carbon dioxide as a waste product.

Oxygen can dissolve, or break apart, in water. Many organismsthat live in water, such as fish, use gills to absorb this oxygen.Gills are organs that allow fish to breathe underwater. Likepeople, fish need oxygen to get energy from food.


EnergyThe ability to do work;found in many differentforms

ReproduceTo breed and produceoffspring

ElectromagneticradiationRadiation that is madeup of electric andmagnetic waves

NutrientA chemical organismsneed to grow

SpeciesA group of organismsthat can breed witheach other

Liters, kilograms,and metersare metricmeasurements.Appendix A onpages 502 and 503shows how theseand other metricmeasurementscan be convertedto customarymeasurements,such as gallons,pounds, and feet.

The Energy ConnectionAll life needs energy, which is the ability to do work. Withoutenergy, organisms could not grow, move, think, or heal.Organisms also need energy to reproduce, which means tobreed and produce offspring. Organisms get the energy theyneed from their environment. Where does the earth's energycome from? Almost all of Earth's energy comes from the sun. Ittravels from the sun in waves, such as heat waves and light waves.These waves are types of electromagnetic radiation.

When sunlight strikes the earth, most of it bounces back intospace as heat waves. Enough makes it to Earth to provide theenergy organisms need to live. Some sunlight is absorbed intothe water and ground. Some is absorbed by animals in the formof heat. Plants use some to make food.

Energy is never created or destroyed. It just changes form asit moves through living systems. You will learn more aboutenergy in Chapters 2 and 7.

What We Need to SurviveLiving things need water, oxygen, energy, and nutrients,which are chemicals needed for growth. Each species has itsown specific set of needs. A species is a group of organismsthat can breed with each other. Each species also has differentrequirements for where it can live. Frogs and willow trees areexamples of species that need a wet environment. Some species,such as parrots and orchids, thrive in environments that stayhot all year. Other species, such as tigers and eagles, need a lotof open space to find enough food. Some species, such as snowleopards and snowy owls, do best in cold, snowy weather.

Link to >*>^>^

Physics

Electromagnetic radiation moves by electromagnetic waves.Electromagnetic waves are different than many other types of waves.They do not need a medium, such as air or water, to move through.This is how electromagnetic radiation can move through outer space.

Exploring Science and the Environment Chapter 1

PesticideAny chemical used to

kill or control pests

Science |Myth

Myth: Radiation isalways dangerous.

Fact: Radiationis the release ofenergy. Sometypes of radiation,such as nuclearradiation, arestrong enoughto harm humans.Most types ofradiation areharmless. Forexample, you areable to see thanksto light radiation.Heat radiationkeeps you warmin winter. Radiationis also used totreat cancer.

Environmental scientists study what organisms need tosurvive. They explore how living things interact with theirenvironment. They also study how organisms interact with theliving and nonliving parts of their environment. For example,farmers use pesticides on their crops. These poisonouschemicals can harm more than just the pests. In many cases,pesticides have poisoned birds and even humans. It is difficultto know exactly how changes in the environment will affectdifferent organisms. That is one of the reasons environmentalscience is so important.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *Achievements in Science

Silent SpringAt first, the development of the pesticide DDT was celebratedby the public. In fact, a Swiss chemist received a Nobel Prizein 1948 for his discovery of the pesticide properties of DDT.The chemical promised to greatly decrease the populations ofdisease-carrying mosquitoes. Few people imagined that thischemical could harm the environment.

A biologist named Rachel Carson became concerned aboutthe effects of DDT and other pesticides. She and several otherbiologists noticed that birds were dying in areas where DDT wasbeing used. These scientists eventually began their own researchon the pesticide. In 1962, Carson published the research resultsin her book Silent Spring. The book revealed how DDT waskilling many more organisms than anyone had thought. She alsoexplained how destroying large numbers of animals would affectthe environment.

Silent Spring made people realize that using chemicals couldhave negative effects on the environment. In response, the U.S.government investigated DDT and banned its use in 1 972. Thisaction helped start the environmental movement. You will learnmore about DDT in Chapter 3.

10 Chapter 1 Exploring Science and the Environment

Lesson 2 R E V I

Word Bankenergy

organisms

pesticides

On a sheet of paper, write the word from the Word Bank thatcompletes each sentence correctly.

1. Birds, fish, and trees are all examples of .

2. Many different activities, such as dancing and talking,require _ .

3. Farmers use _ _ to control unwanted organismson crops.

Choose the term from Column B that best matches the phrase inColumn A. Write the letter of your answer on a sheet of paper.

Column A

4. these organs help fishget oxygen from the water

5. electric and magnetic waves

6. chemicals that help plantsand animals grow


7. Describe what would happen if living things ran outof oxygen.

8. What is the relationship between oxygen and food in thehuman body?

9. Explain where most of Earth's energy comes from and howit travels to Earth.

10. Why is Earth the only planet in the universe with life?

Column B

A electromagnetic radiation

B gills

C nutrients

Exploring Science and the Environment Chapter 1 11

Lesson A Short History of Life on Earth

Objectives

After reading thislesson, you shouldbe able to

+ discuss how life onEarth has changedover time

+ describe thelifestyle of hunter-gatherers

+ explain howthe AgriculturalRevolutionchanged theworld

+ describe howthe IndustrialRevolution hasaffected theenvironment andpeople's lives

Homo sapiensThe scientific name formodern humans

Hunter-gathererA person who hunts,gathers food, and movesfrom place to place tosurvive

Scientists estimate that the earliest life forms appeared on Earthabout 3.5 billion years ago. It took another 3 billion years forhuman history to begin. Based on recent discoveries, scientiststhink the first humans emerged more than 100,000 years ago.These early humans, who were called Cro-Magnons, were thefirst Homo sapiens. They made and used tools, created art, andhunted to find food.

From the beginning, humans depended on the environmentto survive. They also affected their environment in manyways, just as they do today. Over time, human societies havefound three main ways to survive. One way was as hunters andgatherers. Another was by farming the land. A third was byusing machines to produce what people need.

Living Off the LandThe first humans lived in small groups. As the seasons changed,they moved from one place to another to find food. They werecalled hunter-gatherers. This means they survived by huntinganimals and collecting plants to eat. When one place ran out offood, they moved to another area.

People lived as hunter-gatherers for most of human history.Hunter-gatherers knew a lot about their environment. Theyknew which plants could be eaten and where to catch animals.This information was passed down from one generation tothe next.

Many of the early hunter-gatherer tribes were very small innumbers. The effect they had on their environment waslimited. As their numbers increased, so did their impact onthe environment. Scientists believe that some tribes mighthave hunted certain species faster than they could reproduce.This could have helped to wipe out giant bison and otherlarge animals.


AgricultureAnother word forfarming

AgriculturalRevolutionA period in history

when hunter-gathererslearned to farm andraise animals for food

CycleA repeating pattern

LandscapeThe characteristics of

the land

Math Tip

To estimate means

to make a close

calculation of anamount.

Today, only a few hunter-gatherer societies exist. However,many people still hunt for food and collect berries andother plants.

The Agricultural RevolutionAbout 11,000 years ago, a huge change took place in hunter-gatherer societies. Some of the tribes started planting seeds andgrowing crops. They also started raising animals that couldprovide them with food and clothing. Instead of moving whenthe seasons changed, people started to stay in one place.

Agriculture, also called farming, allowed people to raise morefood. Farming supports around 500 times more people thanhunting and gathering, using the same space. With better cropsand the invention of the plow, there was enough food to supporteven more people. The number of humans quickly increased.

Historians call this period of time the Agricultural Revolution.The Agricultural Revolution changed people's diets. Peoplestarted eating grains, such as wheat, barley, rice, and corn.Beans were also an early crop. Many of the grains people eattoday came from these early wild plants.

The Agricultural Revolution also changed how people lived.Farming communities began to thrive. People worked togetherto build cities. However, as more people lived in smaller areas,they faced new problems. For the first time, they had to dealwith getting rid of waste and keeping water supplies clean.The Agricultural Revolution also started a cycle, or repeatingpattern, of environmental change that continues today.Farming has completely changed the landscape in most partsof the world. Chapters 8, 10, and 11 will discuss more about theeffects of farming on the environment.


Mass-produceTo produce in largequantities usingmachines

IndustrialRevolutionA period in historywhen humans startedusing machines toproduce food andother products

HabitatThe place where anorganism lives

PollutionAnything added to theenvironment that isharmful to living things

The Industrial RevolutionIn the mid-1700s, another revolution took place. Thisrevolution was run by machines. Before that, agriculture andmanufacturing were accomplished by people and animals. Withthe invention of the steam engine, factories could mass-produceclothes, building materials, and equipment. To mass-produceis to produce in large quantities using machines. Machines alsohelped make farming and transportation more efficient. Withmotorized farm equipment, more land could be farmed usingfewer people.

The Industrial Revolution, as it was called, caused far-reachingchanges. On the positive side, fewer people were needed toproduce the goods that people needed. Goods are items peoplebuy, like beds, cars, and televisions. These goods also cost lessbecause many could be made at once. Many new inventionsmade people's lives easier. Electric lights, automobiles, andcomputers are just a few examples.

The Industrial Revolution also created new environmentalproblems. Large-scale farming led to a loss of habitat, orliving space, for many wild animals. Pollution from farms andfactories increased. Pollution is anything humans add to theenvironment that is harmful to living things. In cities, air andwater pollution became serious problems. Machines requiredmore and more energy and resources. All this has led to anumber of environmental problems.

Social Studies

The steam engine is commonly believed to be the invention thatstarted the Industrial Revolution. The first working steam enginewas developed by Thomas Savery. This engine used coal to heatwater into steam. The force of the steam moved the machine'sdifferent parts. This steam engine, the "Miner's Friend," was usedto pump water out of coal mines.


Math Tip

The amount oftime that humanshave been on Earthis relatively short.Humans have onlybeen around for100,000 out of4,600,000,000years, or just 0.02percent of Earth'shistory.

One of the biggest side effects of the Industrial Revolutionwas the increase in population. Since the 1800s, the humanpopulation has climbed from 1 billion to more than 6billion. This has put a number of different pressures on theenvironment. You will learn more about population problemsand solutions in Chapter 6.

Environmental science focuses on solving the environmentalproblems that have increased since the Industrial Revolution.The timeline in Table 1.3.1 shows how much time has passedsince the earth formed. By comparison, the changes humanshave caused are recent events.

Table 1.3.1 Timeline

4.6 billion years ago



650 million years ago






3.5 million years ago

100,000 years ago

10,000 years ago

4,500 years ago

650 years ago

270 years ago

230 years ago

Earth and planets formed

Earth's crust hardened

first life in the oceans; photosynthesisbegins

first multicellular organisms appear

first land plants appear

mass extinction (99 percent of lifedisappears)

age of the reptiles begins

continents drift apart

age of dinosaurs ends with massextinction (70 percent of lifedisappears)

first prehumans appear

first Homo sapiens appear

first record of human history

pyramids were built

Black Death

beginning of the Industrial Revolution

birth of the United States



Word BankAgricultural

Revolution

habitat

IndustrialRevolution

On a sheet of paper, write the word or words from the WordBank that complete each sentence correctly.

1. About 11,000 years ago, during the _ , people startedplanting crops and raising animals.

2. Many goods and services today are a result of the __.

3. A(n) is the place where an organism lives.


4. Farming supports over 500 times as many people as .

A hunting and gathering C searching and movingB industry D raising cows

5. Which of the following did not happen as a result of theIndustrial Revolution?

A The world's population decreased.B The world's population increased.C More goods and services became available.D Pollution increased.

6. During the Agricultural Revolution, provided power.

A animals C machinesB computers D plants

Critical ThinkingOn a sheet of paper write the answers to the followingquestions. Use complete sentences.

7. How did hunter-gatherers survive when they ran out offood in one location?

8. Compare the Agricultural Revolution and the IndustrialRevolution.

9. Describe one way that farmers affect the environment.

10. What are some ways the Industrial Revolution affectedthe environment?


I N V E S T I G A T I O N 1

Materials

460 pennies

timeline on page 15

4 index cards

marker

Understanding Earth's HistoryEarth was created approximately 4.6 billion years ago.However, life did not appear until over one billion yearslater. Even after the first basic signs of life, it took overthree billion more years for the first pre-humans toappear. This lab will help you visualize periods of timeduring Earth's long history.

Procedure1. Place the pennies in one large pile. These pennies

represent Earth's history.

2. Mark the index cards A, B, C, and D.

3. Divide the pennies into two piles. Put 110 penniesin Pile A and 350 pennies in Pile B. Pile A representsthe time period from Earth's creation to theappearance of life. Pile B represents the time periodfrom the appearance of life to the present time.

4. Take 65 pennies from Pile B and place them in PileC. This third pile shows how long organisms withmore than one cell have existed.

5. Take one penny from Pile C and place it in Pile D.This represents the last 10 million years of Earth'shistory. The time period since Homo sapiensappeared would be one-hundredth of this penny.

Continued on next page


Cleanup/DisposalReturn the pennies to your teacher.Wash your hands with soap andwarm water.

Analysis1. How would you represent recorded

human history using these pennies?

2. How would you represent the pointwhen dinosaurs became extinct?

Conclusions1. How many years does each

penny represent?

2. What type of life has been presentthrough most of Earth's history?

Explore FurtherCreate your own timeline by using ameter stick and a piece of tape. Measureout the amount of time for each eventfrom left to right.

Table 13.1 Timeline

4.6 billion yean, ago









3.5 million years ago

100,000 years ago

10,000 years ago

4,500 years ago

650 years ago

270 years ago

230 years ago

Earth and planels formed

Earth's crust hardened

first life in the oceans; photosynthesis begins

first multicellular organisms appear

first land plants appear

mass extinction (99 percent of life disappears)

age of the reptiles begins

continents drift apart

age of dinosaurs ends with mass extinction

(70 percent of life disappears)

first prehumans appear

first Homo sapiens appear

first record of human history

pyramids were built

Black Death

beginning of the Industrial Revolution

birth of the United States


Lesson Introducing Environmental Challenges

Objectives

After reading thislesson, you shouldbe able to

+ describe asustainable society

+ list fiveenvironmentalchallenges

+ explain why valuesare importantto solvingenvironmentalproblems

DiversityVariety

EcosystemAll of the living andnonliving things foundin an area

SustainablesocietyA society where currentneeds are met whilepreserving naturalresources and systemsfor future generations

Global

For most of human history, people have believed the earthhad unlimited natural resources. There were huge forests andoceans, as well as fertile soils where crops could grow. Therewas also an amazing diversity, or variety, of wildlife. Today,however, people are using many resources faster than they canbe replaced. As a result, pollution and overuse are harmingmany of the world's ecosystems. An ecosystem is made up ofall the living and nonliving things in an area. When part of anecosystem is harmed, the entire system is affected.

Protecting ecosystems is only one goal of environmentalscience. One of the most important goals of environmentalscience is to create a more sustainable society. A society is agroup of people who share a common culture. A sustainablesociety works to meet the needs of the current generation whilepreserving resources for future generations. The natural systemsthat support life on Earth arc also protected. However, there area number of environmental challenges that prevent societiesfrom becoming sustainable.

Major Environmental ChallengesSome environmental challenges arc global and affect the wholeworld, such as rising temperatures. Others are regional, suchas an oil spill that affects the ocean near several countries.Environmental challenges can also be local. Examples wouldinclude chemicals polluting a local lake or trash littering anearby park.

Affecting the entire world

Regional

Affecting part of theworld, such as a country

LocalAffecting a certain place

Technology and Society

As technology advances, so does people's ability to deal withenvironmental challenges. For example, wireless technologymakes it possible to monitor pollution levels around the world.

Exploring Science and the Environment (.Kapler I 19

CategoryA group

OverconsumptionUsing more resourcesthan can be replaced

Global warmingAn increase in Earth'saverage surfacetemperature

Global, regional, and local environmental problems can be putinto several categories, or groups.

A Growing Population. More than 6.4 billion people live onEarth. Each year, that population increases by about 85 millionpeople. That is like adding another New York City each monthor another India every nine years. Experts estimate that by2050, the population could grow to more than 9 billion. BothChina and India already have populations of over a billion.This worldwide population increase has put pressure on theenvironment. You will learn more about population issues andhow population affects the environment in Chapters 6 and 11.

Using Too Many Resources. Population growth is directlyconnected to overconsumption. When people use naturalresources, they consume them. Overconsumption means usingmore resources than can be replaced.

Natural resources include everything people get from theenvironment that helps them survive. They include things suchas water, air, wood, food, coal, oil, gas, minerals, and metals.Overconsumption will be discussed in more detail in Chapter 6.

Pollution and Climate Change. The use of resources produceswaste. You have probably seen examples of this waste whereyou live. It can be waste in the air from burning trash. It canbe chemicals spilled along the coast, or overflowing dumps.Sometimes people cannot see the waste, but its harmful effectsshow it is there. Poisonous chemicals in the water or air cancause health problems for humans and animals. Too much heatin the water can kill fish.

All of these are examples of pollution. Since the IndustrialRevolution, the amount of pollution has increased along withthe human population. Global temperatures are also rising, ina trend called global warming. Global warming is an increasein Earth's average surface temperature. This is partly caused byincreased amounts of carbon dioxide escaping into the air. Youwill learn more about pollution in Chapters 8, 9, and 10.


BiodiversityThe variety of life onEarth; another namefor nature

ExtinctWhen no members of aspecies remain

ValueWhat is important toa person

Loss of Biodiversity. Biodiversity is the variety of life on Earth.It includes all the living things on the planet, from trees totigers. Loss of biodiversity is another serious problem. Manyspecies have already become extinct in the past 200 years. Whena species becomes extinct, it no longer exists.

Today, many species and ecosystems are in danger of becomingextinct. You will learn more about loss of biodiversity inChapters 4 and 12.

Unequal Division of Resources. Earth's natural resourcesare not spread out evenly. Some countries have many naturalresources and others have only a few. Some countries have muchhigher populations per square kilometer than other countries. Allthis adds up to some countries having more wealth per personthan others.

People living in wealthier countries often use a greater share ofEarth's natural resources. On average, people from the UnitedStates use more resources than people from any other country.These resources make life easier for people living in the UnitedStates. However, this unequal resource use can create hardshipsin other parts of the world. More than half of the people in theworld do not have what they need to survive. They do not haveenough food or clean drinking water. They also lack healthcare, jobs, and education. People in less wealthy countries oftenoveruse local resources because they have no other choice. Thisputs more pressure on the environment.

The Role of ValuesScientific research can help people understand more aboutenvironmental problems and possible solutions. Researchcan help people understand the possible results of differentdecisions. However, scientists usually do not tell people what todo. They leave those decisions to society. Decisions about theenvironment often involve values. A value is what is importantto a person. Values are shaped by people's view of the world.


Values play an important role in creating a sustainable globalsociety. They help people decide what to do. How will asolution affect people's lives? Will it hurt some people morethan others? Is the solution fair? How will it affect people inthe short-term? How will it affect future generations? Peoplemaking environmental decisions need to think about what ismost important.

In this textbook, you will find out more about these majorenvironmental challenges. You will learn what problemsscientists have discovered and what creative solutions theyhave found. You will also see how you can help create a moresustainable world. Learning more about these issues and gettinginvolved in your community are both important. In these ways,you can help protect the environment.

» * • » * • » * • » » • » • • » » • » » • » » • » * • » * • » * • » * • * * • • * • * » •

Science in Your Life

Consumer Choices:Reducing Global WarmingThe amount of carbon dioxide releasedinto the air increases each year. This trendbegan during the IndustrialRevolution. Carbon dioxide isone possible cause of globalwarming, an increase in globaltemperatures. Many scientistsare working to reduce theamount of carbon dioxide beingreleased. You can also makechoices at home that can helpreduce global warming.

ENERGY USAGECompare (he Energy Use of this Refrigerator

wHh Others before you Buji

™^^i

Carbon dioxide is released when fuels suchas oil, coal, and gasoline are burned. Theelectricity that you use probably comes froma power plant that burns these fuels. Youcan lower the amount of carbon dioxidethat goes into the air by using less electricity.

Appliances that use less energy can reduceyour electricity use. Most products havelabels that list their energy use. A flat-screen computer monitor uses less than

half the electricity of a cathoderay tube monitor. Front-loadingwashing machines use lessenergy than those that loadfrom the top. It also helps tokeep size in mind. An oversizedair conditioner or refrigeratorwastes energy and money. Bychoosing an energy-efficientproduct, you can make adifference every day.

1. How does reducing the use of electricityhelp reduce global warming?

2. What are two ways you can reduce youruse of electricity?



Word Bankextinct

overconsumption

values

^̂ ^̂ ^̂ ^


1. Using more resources than the environment can support iscalled

2. A species that is

3. People use their

has no more living members,

to make decisions.

On a sheet of paper, write the letter of the answer thatcompletes each sentence correctly.

4. The population of Earth grows by about _ _ each year.

A 8 million B 18 million C 80 million D 8 billion

5. Pollution problems in your neighborhood are_ problems,

A national B local C regional D global

6. is any human-caused change in the environmentthat harms living things.

A Energy B Pollution C Diversity D Farming


7. Describe how overconsumption harms the environment.

8. Explain how the division of resources can influence howdifferent societies affect the environment.

9. What role do values have in finding solutions toenvironmental problems?

10. Explain why it is important for people to work for asustainable society.

Exploring Science <tinl the Environment Chapter I 23

How Science Works

Objectives

After reading thislesson, you shouldbe able to+ understand why

scientists use thescientific method

+ define each stepof the scientificmethod

Coral bleachingA process in whicha coral dies and

turns white

AlgaeTiny organisms thatmake their own food

ScientificmethodA series of steps used totest possible answers to

scientific questions

BiasA persona! beliefthat can affect anexperiment's results

In the late 1980s, scientists and underwater divers noticedthat many coral reefs were dying. When corals are understress, they turn white. This is known as coral bleaching. Ithappens because of the algae that live in the coral. Algae aretiny organisms that make their own food. They give corals theirbright colors and also provide them with food. When coralsare stressed, they expel the algae, almost like spitting them out.Without their food source, the corals start to die. All that is leftare the white skeletons that once housed tiny, living corals.

When scientists first noticed the problem, they started askingquestions. What was causing the increased stress? Why did ithappen in only some places? How could they stop it?

The Scientific MethodLike all scientists, environmental scientists follow a process toanswer questions and find solutions. This process is called thescientific method. Scientists may skip steps or not follow stepsin order, but they all use this process.

Scientists use the scientific method for many reasons. The stepshelp make sure that people's biases do not affect the results oftheir research. Scientists anywhere in the world should have thesame results if they repeat the experiment. Science depends onfacts that can be tested and retested by other scientists.

The scientific method requires that scientists use manyskills. These skills include predicting, observing, organizing,classifying, modeling, measuring, inferring, analyzing, andcommunicating. The steps of the scientific method are:

1. Observation2. Question

3. Hypothesis4. Experiment5. Analysis6. Communication


Figure 1.5.1 shows the steps in the scientific method. You willlearn about each step below.

TheScientific Method

Figure 1.5.1 The scientific method is a constant cycle scientists useto find answers to many questions.

Observation. You perform this step without even being awareof it. Look at your classmates and all the objects in the room.The first step is simply looking at the world around you,watching life. While scientists are watching, or observing, theymay see something they do not understand. If it interests them,they move to the next step of the scientific method.

In the example above, people observed that coral reefs wereturning white. This led many scientists to start asking questionsabout why.

Question. When scientists see something they do notunderstand, they ask a question. Environmental scientistsask questions about how living things interact with theirenvironment. They work to find answers to questions like,"Why are frogs and toads around the world disappearing?" or"Why are so many children in cities having trouble breathing?"Once environmental scientists have questions, they can beginlooking for answers.


HypothesisAn educated guess;also the third step ofthe scientific method(plural: hypotheses)

Field studyA study conducted in anatural environment

Control groupThe group in anexperiment that has novariable changed

ExperimentalgroupSimilar to the controlgroup, except for thevariable being tested

VariableWhat is tested inan experiment

Hypothesis. A hypothesis is an educated guess. After askinga question, scientists try to guess the right answer. Scientistsmake their guesses based on what they already know. They alsoread what has been published about the topic or collect otherinformation. Scientists then use experiments to see if theyare right.

Here is an example. A scientist's hypothesis might be that coralsdie if ocean temperatures rise more than 1.5°C. This statementcould be tested in a lab using corals from around the world.

Experiment. An experiment is used to test whether a hypothesisis correct. Environmental scientists perform many differentkinds of experiments. The kind they perform depends on thequestion they are trying to answer. Scientists might conduct asurvey, an experiment, or a field study to gather information. Afield study is conducted in a natural environment.

Scientists design experiments to test possible answers to thequestion. There are two groups in a scientific experiment: acontrol group and an experimental group. In the controlgroup, nothing is changed. The experimental group is similar tothe control group, except for one part that is changed. That partis called the variable. Scientists control the variables in theirexperiments to get information they can use.

For example, an environmental scientist might want to testthe hypothesis above. It states that corals will die if oceantemperatures rise more than 1.5°C. To test this hypothesis, thescientist would put corals of the same species into two groupsof tanks. Both groups of tanks would be the same size and havethe same amount of seawater in them. Then the scientist wouldraise the temperature of the water in one group of tanks 1.5°C.The water in the other group of tanks would stay the sametemperature. The scientist would then record what happened tothe corals.


DataInformation collectedduring experiments

AnalysisThe process of making

sense of an experiment'sresults; also the fifth stepof the scientific method

InternetA worldwide network ofcomputers

ScientificjournalA science magazine

Scientists usually perform their experiments many times.They need to be sure that they gel a similar answer every time.They also need to keep track of all the data, or information,they collect. Scientists use different tools to keep track ofinformation, such as computers and calculators. They also usespecial equipment tha t is designed for their experiments. Mathis also important in experiments. Scientists use math to gatherdata, analyze data, and communicate results.

Analysis. Analysis is the process of making sense of the results.Scientists look at the information and ask questions: Doesthe information collected support the hypothesis? Were thereany unexpected results? If the results do not agree with thehypothesis, scientists may ask a different question. Sometimesthe results answer the question but do not agree with thehypothesis. A hypothesis is an educated guess and can bewrong. The answers scientists find often lead to more questions.Say that scientists discovered that raising the water temperature1.5°C caused corals to die. Then the scientists might ask whatcaused the ocean to become warmer.

Communication. After scientists have tested their hypothesisand checked their results, they share their results. Otherscientists may be interested in the same questions. Scientistsuse the Internet to share their data. The Internet, a worldwidenetwork of computers, helps scientists communicate.

Scientists also communicate their methods and results inscientific journals. Scientists publish their results in journalsthat arc reviewed and read by other scientists. These journalshelp scientists keep up on advances in science. By publishingthe results of their research, scientists contribute to what isknown about a subject.

Exploring Science tinti the Environment Chapter I 27

Sharing data not only allows others to know what one scientistdid. It also allows scientists to review the data and check formistakes. It also allows other scientists to suggest new questionsor interpret the data in a different way. Environmental scientistsshare their data to help other scientists working on similarproblems. When more scientists study a question, it increasesthe chances that it can be answered.

A Y-« A Y A Y •< A Y « A Y •< A Y •« A Y •< AT

Science at Work

Field Research TechnicianField research technicians run experimentsand gather data. They often set upexperiments and make observations outsidethe laboratory. Field research techniciansusually work with a professor or a chiefresearcher throughout the experiment.

Field research technicians must mastermany skills. Before setting up anexperiment, the technician must oftenresearch past experiments and techniques.The technician writes up the experimentalprocedure and sets up the experiment.Often a field investigation takes severalweeks, or even months, to run. During thattime, the technician runs the experimentand collects data. Then the technician helpsto analyze the data and write up the results.

It is common for a field research technicianto have a bachelor's degree or be workingtoward one. However, many field researchtechnicians have only an associate's degree.



Word Bankcontrol group

data

hypothesis

On a sheet of paper, write the word or words from the WordBank that complete each sentence correctly.

1. The in an experiment has no variable changed.

2. Forming and testing a is an important part of thescientific method.

3. Information collected from experiments and research iscalled .


4. Which of the following is not a step in the scientific method?

A observation C copyingB experiment

5. A scientist who is

D analysis

experimental data checks to see ifit supports the hypothesis.

A communicating C creatingB questioning D analyzing

6. Scientists publish their results in scientific journals and onthe Internet to their results.

A questionB analyze

C communicateD check

Critical ThinkingOn a sheet of paper, answer the following questions. Usecomplete sentences.

7. Describe how a scientist develops a hypothesis to test.

8. How does the control group help scientists test a hypothesis?

9. What should a scientist do when an experiment does notsupport a hypothesis?

10. Describe one method that a scientist could use to keeptrack of experimental data.


DISCOVERY I N V E S T I G A T I O N 1

Materials

safety goggles

lab coat or apron

2 plastic cups

20 bean seeds

potting soil

water

vinegar

lamp

paper towels

eyedropper

Using the Scientific MethodScientists answer questions and solve problems in anorderly way. They use a series of steps called the scientificmethod. How can you use the scientific method toanswer questions? You will find out in this lab.

Plants need several things to grow well. Among themare light, space, and air. Also, plants require liquid, butthe amount and type of liquid used can vary. Howimportant are these variables for plant growth?

Procedure1. In a small group, discuss the question in the

second paragraph above. Then write a hypothesisthat you can test with an experiment. Choose onevariable to test: amount of light or water, or thetype of liquid used.

2. Write a procedure for your experiment, includingany Safety Alerts. Use materials from the Materialslist. The experiment should take eight days tocomplete.

3. Be sure your experiment changes, or tests, onlyone variable at a time. Include a control group inwhich you do not change any variables.

4. Draw a data table to record your data foreight days.

5. Have your entire procedure approved by yourteacher. Then carry out your experiment.


Cleanup/DisposalBefore leaving the lab, clean up yourmaterials and wash your hands.

Analysis1. What variable did you change in

this experiment?

2. What changes did you see amongthe bean seeds after Day 4? Whatchanges did you see after Day 8?

Conclusions1. Was your hypothesis supported by

the results of your investigation?Explain.

2. What problems did you have inperforming the experiment? Whatpart of the procedure would youchange to be more successful?

Explore FurtherIn your group, discuss the variables ofplant growth that you did not test. Pickone of these variables to investigate inthe future. Write a procedure to carryout your investigation.


Lesson Science and Society

Objectives

After reading thislesson, you shouldbe able to+ list three

characteristics ofa good scientist

^ define theory andprinciple andgive an exampleof each

+ describe whyenvironmentalscience isimportant tosociety

TheoryA well-tested hypothesisthat explains many

scientific observations

PrincipleA basic law or truth

Science is important to human society. It provides informationthat helps people make better decisions. It helps peopleunderstand what effect decisions can have today, as well asin the future.

Theories and PrinciplesScientific information is based on centuries of work. It isthrough sharing information that human knowledge grows. Asnew evidence is discovered, scientific ideas and theories maychange. A theory is a well-tested hypothesis that explains manyscientific observations. One example is the theory of gravity.With so much evidence, there is almost no chance that thistheory could be proved wrong.

Scientists often add to the understanding of a theory. This mayrefine the theory, but not prove it wrong. Theories are believed tobe some of the greatest achievements in science. They show howfar humans have come in understanding how the world works.

After years of research, some theories can become principlesof science. A principle is a statement of a basic law or truth.Principles about the laws of motion have been tested andretested. Scientists will tell you, though, that even principlesmay be questioned. Everything can change as humans learnmore about the universe.

Science Myth

Myth: Theories are scientific ideas that are often proven wrong.

Fact: For an idea to become a theory, it must be tested andproven repeatedly. Scientific theories are supported by evidenceand accepted by other scientists.


SkepticalQuestioning or doubting

EthicsA set of moral principles

MoralHelping to decidebetween right or wrong

ObjectiveNot influenced bypersonal feelings or

opinions

SubjectiveInfluenced by personalfeelings or opinions

Many universitiesand research labshave an ethicistworking there.Ethicists make sureexperiments do notharm people or theenvironment.

What Makes a Good Scientist?Good science depends on good scientists. A good scientist maybe described as curious, honest, patient, and creative.

Many people become scientists because they are curiousabout the world. They start by asking questions. They are alsoskeptical, meaning they do not just accept all that they reador hear. If something does not seem to make sense, they willquestion it. Being skeptical also means that scientists constantlyquestion their own beliefs, research methods, and results. Thisquestioning leads to more knowledge and understanding.

Ethics also are an important part of science. Ethics are a set ofmoral principles that help a person decide what is right. Theyare guidelines for how a scientist should act. Scientists must behonest about what they learn and what it means. Sometimesthis is difficult. People who pay them or work with them mightbe expecting different results. For example, the results of anexperiment might show that a scientist's hypothesis was wrong.The scientist might want to change his or her results to appearcorrect. A scientist must remember that honesty is critical togood science.

Patience is another characteristic of a successful scientist.Good science takes time. Most of the changes in people'sunderstanding of the world happen in bits and pieces. Majorchanges in thinking have happened, but discovery is usually aslow process. Each new finding adds another piece of the puzzleof how the world works.

Scientists also try to be objective when making observations orcollecting data from experiments. That means that they focuson facts and scientific measurements. They try not to includepersonal feelings or opinions, which are subjective. Althoughno one can be completely objective, scientists try not to bebiased. They need to make sure their observations are accurate.Subjective observations are important in art, music, andliterature, but not in science.


ConsequenceThe effect of an action

Environmental Science and SocietyEnvironmental scientists often work on issues, or problems, thataffect people and society. They might focus on issues such as:

+ How to create new energy sources that do not pollute

^ How to provide clean water to the billions of people whoneed it

+ How to provide enough food for Earth's 6.4 billion peoplewithout harming the environment

+ How to protect wild tigers or reintroduce wolves intoYellowstone National Park

Environmental scientists do not make decisions for society.Instead, they provide information to the members ofgovernments, communities, and businesses who makedecisions. This information can help people understand thepossible consequences, or effects, of different actions. It caninfluence people's decisions about how they interact with theenvironment. In this way, environmental scientists can makea difference.

Figure 1.6.1 Environmental scientists work to find solutions toproblems that affect society.


EnvironmentaljusticeDealing withenvironmental problemsin a way that treatspeople equally

Environmental JusticeEnvironmental problems also create many social problemsaround the world. Environmental justice means dealing withenvironmental problems in a way that treats everyone equally.

Knowing the consequences of decisions helps to answermany questions:

^ How will the solution affect people's daily lives?

+ Will it hurt some people more than others?

+ Is the solution ethical?

^ How will it affect people in the short-term?

+ How will it affect people in the future?

In a world that practices environmental justice, all of thesequestions would be equally important. Every environmentaldecision would try to balance the positive and negative effectsfor all groups. These groups include people from differentcountries and people who make different amounts of money.They also include people of different races and people withdifferent backgrounds. The whole world benefits wheneveryone is treated equally.

Technology and Society

The catalytic converter was invented in 1976. It reduces theamount of pollution that is released by an automobile's exhaustsystem. The converter changes engine exhaust into harmlessmaterials. This helps reduce the amount of dangerous pollutionin the air.



Word Bankprinciple

subjective

theory

A disorganizedB honest


1. A is a well-tested explanation that helps explaina variety of scientific observations.

2. A person's feelings or opinions help them makejudgments.

3. "Energy cannot be created or destroyed" is abecause it is a basic law of science.


4. Which of the following characteristics does not help ascientist perform good science?

C curiousD skeptical

5. A scientific theory be disproved.

A cannot C mightB should not D will always

6. are moral principles that guide people's actions.

A Objectives C EthicsB Relationships D Theories

Critical ThinkingOn a sheet of paper, answer the following questions. Usecomplete sentences.

7. Which two characteristics of a good scientist do you thinkare most important? Explain your answer.

8. How are scientific principles and theories different?

9. Explain why it is important for scientists to be as objectiveas possible when doing research.

10. Give an example of how science works to improve society.


ENVIRONMENTAL ISSUES IN THE WORLD

A Cleaner AmericaThe U.S. EnvironmentalProtection Agency (EPA)started in 1970. Its job is toprotect human health andthe environment. Before1970, the U.S. governmenthad few laws againstreleasing harmful chemicalsinto the environment. As aresult, the EPA had to cleanup a lot of pollution.

The EPA's headquartersare in Washington, D.C.Approximately 18,000 EPAemployees work throughout the UnitedStates. Some workers research ways toreduce air and water pollution. Otherworkers run educational programsfor communities and businesses. EPAworkers also measure pollution comingfrom businesses and make sure theyfollow environmental laws.

The EPA runs several types of wasteprograms. These programs make surethat dangerous chemicals are disposed ofproperly. Chemicals such as paint thinnerand gasoline can pollute water and soil.That means these chemicals must bedisposed of differently than other wastes.

The EPA also gives money and directionto help repair areas damaged bypollution. Through this effort, pollutedland becomes a place where people canlive and work again.

1. What is the mission of theEnvironmental Protection Agency?

2. Describe two services that theEPA provides.

3. How might the environmentbe different if the EPA had notbeen established?


Chapter 1 S U M M A R Y

Environmental science draws on manydifferent sciences to help solve theworld's environmental challenges.

The environment has two parts: thenatural environment and the builtenvironment.

Living things have basic needs,including energy, oxygen, nutrients,and water. In addition, living thingsalso need shelter, space to raise theiryoung, and a place to live.

Almost all energy comes from the sun.

Scientists estimate that the earliest lifeforms appeared about 3.5 billion yearsago. Humans emerged about 100,000years ago.

Human societies first survived ashunters and gatherers. Later societieslearned to farm and use machines toproduce goods and services.

Since the 1800s, the world populationhas grown from 1 billion people tomore than 6 billion.

In a sustainable society, naturalresources are used in ways that ensurethat there will be enough for currentand future generations.

Environmental problems includepopulation growth, overconsumption,pollution, climate change, biodiversityloss, and unequal distribution ofresources.

Scientists use the scientific method tounderstand the universe.

A theory is an idea explaining manyevents that has been tested andretested. A principle is a basic law ofscience.

Vocabulary

AgriculturalRevolution, 1 3

agriculture, 1 3algae, 24analysis, 27applied science, 3bias, 24biodiversity, 21built environment, 3category, 20cell, 8consequence, 34control group, 26coral bleaching, 24culture, 4cycle, 1 3data, 27

dissolve, 8diversity, 19ecosystem, 19electromagnetic

radiation, 9energy, 9environment, 2environmental

justice, 35environmental

science, 2ethics, 33experimental group,

26extinct, 21field study, 26global, 19

global warming, 20habitat, 14Homo sapiens, 1 2hunter-gatherer, 12hypothesis, 26Industrial Revolution, 1 4Internet, 27landscape, 1 3local, 19mass-produce, 14moral, 33natural environment, 3natural resource, 3nutrient, 9objective, 33organism, 2overconsumption, 20

pesticide, 10pollution, 14principle, 32regional, 19reproduce, 9scientific journal, 27scientific method, 24skeptical, 33species, 9subjective, 33sustainable society, 1 9theory, 32value, 21variable, 26


Chapter 1 R E V I E W

Word BankAgricultural

Revolution

applied science

built environment

electromagneticradiation

energy

Homo sapiens

hunter-gatherers

hypothesis

IndustrialRevolution

natural resources

nutrients

organisms

overconsumption

pesticidesscientific method

species

sustainable society

theory

Vocabulary ReviewOn a sheet of paper, write the word or words from the WordBank that best complete each sentence.

1 - The includes buildings where people live, work,and play.

2. Environmental science is called a f n ) becausescientists apply scientific knowledge to solveenvironmental problems.

3. Soil, water, and plants are all examples of Earth's

4. Two organisms that can breed together and produceoffspring belong to the same _ .

5. It changes forms, but is never created or destroyed.

6. Most living things on Earth need water, energy, _ , andoxygen to survive.

7. Environmental science studies the interaction between_ and their environment.

8. Heat waves and light waves are types of .

9. When farmers use __ _ on their crops, they can harmmore than just the pests.

10. The scientific name for humans is

., who lived off the land and11. The first humans weremoved from place to place to find food.

12. During the _ , people started raising crops and animals.

13. During the _ , machines were used to provide goodsand services to society.

14. Afn) is one that uses resources in a way that meetsthe needs of current and future generations and otherliving things.

Continued on next page


Chapter 1 R E V I E W - continued

15. When people use more resources than the environmentcan support, it is called ....

16. The is a series of steps that scientists follow to testpossible answers to scientific questions,

17. An educated guess in science is called a(n) .

18. A(n) has been well-tested and makes sense of agreat variety of scientific observations.

Concept ReviewOn a sheet of paper, write the letter of the answer thatcompletes each sentence correctly.

19. The human population has grown from 1 billion in the1800s to more than billion today.

A 2 B 6 C9 D 1 2

20. A road is part of the

A applied environment C organic environmentB natural environment D built environment

21. are basic laws or truths that have been tested andretested over time.

A Variables C ValuesB Principles D Hypotheses

22. The Industrial Revolution increased the amount of _released into the air.

A carbon dioxide C oxygenB ozone D water vapor



23. List each step of the scientific method along with a shortdescription of what happens during the step. Then explainwhy scientists use the scientific method.

24. Describe how people's lives changed as a result of theIndustrial Revolution.

25. Describe five major environmental problems.

When studying for a test, work with a partner to write yourown test questions. Then answer each other's questions.Check your answers.

Exploring Science and the Environment Chapter ! 41

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