CHAPTER SECTION 1 An Interconnected · PDF fileSECTION 1 An Interconnected Planet continued ... we use them up, or deplete them, ... of nutrients and the flow of energy in an ecosystem

Name Class Date

SECTION

1 An Interconnected PlanetThe Environment

As you read this section, keep these questions in mind:• How are humans and the environment connected?• What is the difference between renewable resources and

nonrenewable resources?• How can the state of the environment affect a person’s health

and quality of life?

KEY IDEAS

How Are Humans and the Environment Connected?

Humans are a part of the environment. We dependon the environment for food, water, air, shelter, fuel,and many other resources. However, human actionscan affect the quality and availability of these importantresources. The study of the impact of humans on theenvironment is called environmental science.

All parts of Earth are connected. The environmentprovides us with resources, and it is affected by ouractions. As the human population increases, our impacton the environment increases. We need to learn about ourconnection with Earth so that we can care for the environ-ment. With this knowledge, we can be sure we do not useup or damage the resources we all need to survive.

What Are Earth’s Resources?Humans live in almost every ecosystem on Earth.

As the human population grows, we use more and moreresources. Humans today consume far more resourcesthan our ancestors did. What are these resources?

We can classify Earth’s resources into two groups:renewable and nonrenewable. Some examples of thesetwo groups of resources are listed in the table below.

Renewable resources Nonrenewable resources

wind energy oil

solar energy coal

fresh water natural gas

trees and other living things precious metals and minerals

READING TOOLBOXCompare As you read this section, make a Venn diagram to compare renewable and nonrenewable resources. In your Venn diagram, be sure to include examples of each.

READING CHECK

1. Define What is environmental science?

READING CHECK

2. Identify What are the two main groups of natural resources?

CHAPTER 6

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Interactive Reader 55 The Environment

Name Class Date

An Interconnected Planet continuedSECTION 1

RENEWABLE RESOURCESRenewable resources are natural resources that

can be replaced at the same rate at which we use, orconsume, them. Water is an example of a renewableresource. However, many renewable resources are beingused up or damaged faster than they can be replaced.In these cases, such resources become nonrenewable.

Windmills such as these use energy from the wind to produce electricity. Wind energy is a renewable resource.

NONRENEWABLE RESOURCESNonrenewable resources are natural resources that

form much more slowly than we consume them. In otherwords, we use them up, or deplete them, more quicklythan they can be replaced.

Most of our energy today comes from fossil fuels.Fossil fuels formed from the remains of organisms thatlived millions of years ago. We are using fossil fuels muchfaster than they form. Thus, Earth’s supply of fossil fuelsis decreasing and will be gone one day. Coal, oil, andnatural gas are examples of fossil fuels.

How Does the Environment Affect Our Health?

Damaging the environment can harm or destroyresources, such as air, water, and food, that we needto survive. The table below describes some effects of adamaged environment on human health.

Human action Effect

Cutting down trees increased number of landslides and floods which can cause injuries and deaths

Polluting air headaches, nausea, respiratory infections; may cause lung cancer and heart disease

Polluting water birth defects, cancer, and the spread of infectious diseases such as cholera

3. Infer Is water always a renewable resource? Explain your answer.

4. Identify What is the function of these windmills?

READING CHECK

5. Explain Where did the fossil fuels that we use today come from?



Name Class Date

Section 1 ReviewSECTION VOCABULARY

fossil fuel a nonrenewable energy resource formed from the remains of organisms that lived long ago; examples include oil, coal, and natural gas

1. Explain How does a growing human population affect resources?

2. Apply Concepts Complete the table below to identify each resource as renewableor nonrenewable. For renewable resources, indicate if the resource couldbecome nonrenewable.

Resource Renewable or nonrenewable?

Trees Renewable; could become nonrenewable

Gold

Sunlight

Fish

Clean air

Steel

3. List What are three examples of fossil fuels?

4. Explain Why is natural gas a nonrenewable resource?

5. Apply Concepts Identify one nonrenewable resource that you used today.

6. Identify Name two environmental disturbances that can affect our health.



Name Class Date



Environmental IssuesThe EnvironmentCHAPTER 6

SECTION

2

As you read this section, keep these questions in mind:• What are the effects of air pollution?• How might burning fossil fuels lead to climate change?• What are some sources of water pollution?• Why is soil erosion a problem?• How does ecosystem disruption affect humans?

KEY IDEAS

What Are the Effects of Air Pollution?Natural processes, such as volcanic activity, can affect

air quality. However, human activities cause most airpollution. For example, when power plants and vehiclesburn fossil fuels for energy, they release pollutants. Theseinclude carbon dioxide (CO

2), sulfur dioxide (SO

2), and

nitrogen oxides (NO2

and NO3).

Some problems caused by air pollution are listedbelow:

• causes acid rain

• causes respiratory problems in humans

• damages the ozone layer

• leads to changes in global temperatures

ACID RAINAcid rain is precipitation that has an unusually

high concentration of sulfuric or nitric acids. Acid raindamages forests and lakes and the organisms that livein these habitats.

OZONE LAYERThe ozone layer protects life on Earth from some

of the sun’s damaging ultraviolet (UV) rays. Chemicalscalled chlorofluorocarbons (CFCs) have damaged theozone layer. CFCs are human-made chemicals that areused as coolants in refrigerators and air conditioners.They are also used in spray cans. Today, many countrieslimit or forbid the use of CFCs.

READING TOOLBOXOutline As you read this section, make an outline to summarize the information. Use the header questions to help you organize your outline.

READING CHECK

1. List Identify three pollutants that are released when fossil fuels are burned.

READING CHECK

2. Explain Why do many countries limit or forbid the use of CFCs?

Name Class Date



SECTION 2 Environmental Issues continued

How Can Air Pollution Cause Climate Change?Air pollutants may be a cause of global warming.

Global warming is the gradual increase in the averageglobal temperature.

GREENHOUSE EFFECTWhy does the inside of a car become so hot on a bright

sunny day? As sunlight passes through the windows,the seats and other objects send out, or radiate, energyback toward the glass. However, the radiated energy isin a different form (heat) than the sunlight energy. Heatenergy becomes trapped because it cannot pass throughthe windows as easily as light energy.

Earth’s atmosphere acts much like the windows of acar. In this process, known as the greenhouse effect,gases in the atmosphere trap heat energy that is radiatedfrom Earth’s surface. The gases that trap energy radiatingfrom Earth are called greenhouse gases. CO

2and water

vapor are two examples of greenhouse gases.

Radiation from the sun passes through the atmosphere and warms Earth’s surface.

1

2 Heat radiates from Earth. Some of this heat escapes into space.

3 Greenhouse gases absorb some of the heat and radiate it back to Earth.

GLOBAL WARMINGWithout the greenhouse effect, Earth would be too

cold to support life. However, Earth’s average globaltemperatures have been rising rapidly for many decades.

Burning fossil fuels increases the amount of CO2

in the atmosphere. Larger amounts of CO2

and othergreenhouse gases in the atmosphere trap more heat,which can lead to global warming. The effects of suchclimate change include changing sea levels, powerfulstorms, and droughts.

READING CHECK

3. Explain Why does sunlight energy pass through car windows, but the energy radiated from objects inside the car does not?

4. Explain Do greenhouse gases trap all the energy radiated from Earth? Explain your answer.

READING CHECK

5. List Identify three effects that climate change may cause.

Name Class Date




What Causes Water Pollution?Every person needs 20–70 L of clean water each day

for drinking, washing, and other needs. Unfortunately,many sources of water are polluted. Water pollution cancome from fertilizers and pesticides, livestock farms,industrial wastes, septic tanks, landfills, and runoff fromroads.

Industrial waste

WastewaterplantUrban pollutants

Municipalwell

LandfillRoadsalt

Hazardous wasteinjection well

Petroleumstorage tank

Lawnfertilizer

Watertable

Septicsystem

Percolation

Aquifer

RunoffPesticides

Privatewell

Pollutants on Earth’s surface run off the land and into groundwater and other water systems.

What Is Soil Erosion?Without fertile soil, we cannot grow crops to feed

ourselves or the livestock we depend on. The processesthat form just a few centimeters of fertile soil can takethousands of years. However, this important resource canbe depleted or harmed much more rapidly. The greatestthreat to soil is soil erosion. Erosion is the process inwhich wind, water, or gravity carries materials such asrocks or soil from one place to another.

Roots of trees and other plants help hold soil togetherand protect it from erosion. If these plants are removed,the soil may erode easily. Many farming methods can alsolead to soil erosion. For example, plowing loosens thetopsoil and removes plants that hold the soil in place. Asa result, wind and rain can wash away or blow away thetopsoil. Farmers and scientists are working to developfarming methods that help conserve fertile soil.

6. Identify On the figure, circle all the possible sources of water pollution shown.

7. Infer Why can the water in a well far from a source of pollution be polluted?

8. Apply Concepts Isfertile soil a renewable or a nonrenewable resource? Explain your answer.

Name Class Date




How Does Ecosystem Disruption Affect Us?As the human population has grown, we have

disrupted or damaged many ecosystems. Ecosystemdisruption can affect humans and other organisms. Someof the effects on humans are listed below:

• loss of biodiversity

• decrease in food supplies

• loss of potential cures for diseases

• disruption of the balance of ecosystems that supportsall life

LOSS OF BIODIVERSITY AND EXTINCTIONBiodiversity is the variety of organisms in a given

area. Ecosystem disruption can decrease biodiversity.How does this decrease in biodiversity affect the functionof an ecosystem? Every species plays a role in the cyclingof nutrients and the flow of energy in an ecosystem.Species depend on one another. One lost species maylead to the loss of others.

Extinction is the death of every member of a species.When a species becomes extinct, an important link in afood web disappears. We also lose the benefits and theknowledge we might have gained from studying the species.

HABITAT DESTRUCTIONPeople have cleared many forests for farmland,

pastureland, or timber. The process of clearing forestsis called deforestation. As forests disappear, theorganisms that live there also disappear. Today, habitatdestruction causes more extinctions than any otherhuman activity.

INVASIVE SPECIESHumans have disrupted ecosystems by bringing in,

or introducing, nonnative species. Some introducedspecies become very successful in their new habitats.Their success may cause some native species to leave anarea or become extinct. Many invasive species can alsocause damage that costs the public millions of dollarseach year. For example, zebra mussels in the Great Lakesclog the pipes of water-treatment facilities.

Debate Many zoos try to breed endangered species, or species that may soon become extinct. They hope to increase the number of individuals of each species. With a partner, debate how effective this plan may be. Will increasing the number of individuals solve the problem of extinction?

READING CHECK

9. Describe What effect can invasive species have onnative species?

Name Class Date



Section 2 ReviewSECTION VOCABULARY

acid rain precipitation that has a pH below normal and has an unusually high concentra-tion of sulfuric or nitric acids, often as a result of chemical pollution of the air from sources such as automobile exhausts and the burning of fossil fuels

biodiversity the variety of organisms in a given area, the genetic variation within a population, the variety of species in a community, or the variety of communities in an ecosystem

deforestation the process of clearing forests

erosion a process in which the materials of Earth’s surface are loosened, dissolved, or worn away and transported from one place to another by a natural agent, such as wind, water, ice, or gravity

extinction the death of every member of a species

global warming a gradual increase in averageglobal temperature

greenhouse effect the warming of the surface and lower atmosphere of Earth that occurs when carbon dioxide, water vapor, and other gases in the air absorb and reradiate infrared radiation

1. List Identify three effects of air pollution.

2. Explain How do increased CO2

levels in the atmosphere lead to climate change?

3. Explain Why is soil erosion a problem for humans?

4. Describe How does deforestation affect biodiversity?

5. Explain Why can the loss of one species lead to the loss of other species?

Name Class Date

As you read this section, keep these questions in mind:• How do conservation and restoration solve environmental issues?• What are three ways that people can reduce the use of

environmental resources?• How can research and technology affect the environment?• How do education and advocacy play a part in preserving the

environment?• Why is it important for societies to consider environmental impact

when planning for the future?

KEY IDEAS

Why Are Conservation and Restoration Important for the Environment?

Two major techniques for solving environmentalproblems are conservation and restoration. Conservation

involves protecting natural habitats. Restoration involvescleaning up and restoring damaged habitats.

Conservation is the best way to solve environmentalproblems because it prevents them from happening. Forexample, parks, nature preserves, and wildlife refugesprotect areas where many species live.

Restoration reverses damage to ecosystems. A recentproject to clean Boston’s harbor is an example ofrestoration. For more than 200 years, the city dumpedsewage directly into the harbor. The wastes causeddisease, and most of the marine life disappeared. Tosolve the problem, the city built a sewage-treatmentfacility. Since then, the harbor waters have becomecleaner, and plants and fish have returned.

How Can We Conserve Resources?Our impact on the environment depends on how many

resources we use. We can conserve resources in threemain ways:

• reduce the amount of resources, such as water andfossil fuels, that we use

• reuse products rather than throw them away

• recycle wastes rather than make products from rawmaterials

Environmental SolutionsThe Environment

SECTION

3CHAPTER 6

READING TOOLBOXUnderline As you read thissection, underline the mainidea of each paragraph orsubsection. Review thesemain ideas after you read.With a partner, comparewhat you underlined.

Discuss Consider the case ofsewage in Boston’s harbor.In a small group, discusshow a conservation approachwould have differed from arestoration approach. Wasa conservation approachpossible in this case? In thefuture, can the city of Bostonuse conservation instead ofrestoration?

READING CHECK

1. List What are the threemain ways we can conserveresources?



Name Class Date

Environmental Solutions continuedSECTION 3

READING CHECK

2. Identify What two things can you reduce to conserve resources?

3. Identify RelationshipsHow are reducing resource use and recycling related?

REDUCE You can help conserve resources by reducing the

amount of a resource you use and the amount of wasteyou produce. For example, low-flow toilets and showerheads can help reduce the amount of water you use. Youcan use ceramic plates instead of paper ones to reducethe amount of wastes you produce.

REUSE Many people throw items away even though they

are still useful. Reusing items saves both money andresources. For example, you can use plastic bags andutensils several times instead of just once. You can reuseplastic shopping bags to carry groceries or your lunch.

RECYCLE The process of using old, used materials to make new

products is called recycling. Recycling provides thefollowing benefits:

• Using old materials to make new products generallycosts less than making products from raw materials.

• Recycling uses less energy than making an item fromraw materials.

• Because recycled materials are not put into landfills,recycling can also help prevent pollution.



When we recycle, we send fewer items to landfills.

Name Class Date




How Can Technology and Research Help the Environment?

Advances in technology have lead to the productionof cars and the development of industry. Both of theseprocesses have contributed to the problem of pollution.However, technology can be part of many environmentalsolutions. Technology and research can help protect theenvironment by providing:

• cleaner sources of energy

• better ways to deal with waste

• improved methods for cleaning up pollution

ADVANCES IN TECHNOLOGYSolar panels, hybrid cars, and scrubbers are three

examples of technologies that can help limit pollution.Solar panels use energy from the sun to generateelectricity. Solar panels generate electricity withoutproducing pollution. Using solar energy also helpsconserve fossil fuel resources.

Using solar panels to generate electricity helps us use fewer fossil fuels.

Hybrid cars use a combination of batteries andgasoline as energy sources. A hybrid car uses less fueland releases less pollution than a typical car.

Scrubbers are devices that reduce harmful sulfuremissions from factory smokestacks. Scrubbers havedecreased emissions of sulfur dioxide, carbon monoxide,and soot from factories by more than 30%.

READING CHECK

4. Identify What are two benefits of using solar energy to generate electricity?

READING CHECK

5. Explain How do hybridcars help us conserve resources?

Name Class Date




RESEARCHING SOLUTIONSScientists and engineers must determine the cause

of an environmental problem before they can propose asolution. Research is necessary to develop technologiesthat can help solve these problems. Researchers usescientific methods to study an environmental problem.After they analyze a problem, they propose a solution.Their proposals must consider the costs, risks, andbenefits of a particular solution.

How Do Education and Advocacy Help the Environment?

Conservation groups, individuals, and governmentsmust cooperate to solve environmental problems.Education and advocacy help more individuals playa role in this process.

EDUCATIONEducation helps make people more aware of

environmental problems and how they can help solvethem. Some environmental education happens in schools.However, people can learn about the environment in otherways, too. For example, some people travel to coral reefsor rain forests to learn about those ecosystems. Whenpeople travel to learn about an environment or to helpconserve an environment, it is known as ecotourism.

ADVOCACYGiving support, or advocating, for efforts to protect

the environment can help more people become involved.Conservation groups work to help educate people,protect land, and influence laws. Some groups advocatefor the environment internationally. Others advocate forthe environment close to home.

How Should We Plan for the Future?What will our planet look like in 50 years? Will we still

have the resources we need to live? If we plan carefully,we can avoid damaging the environment, and we can solveenvironmental problems. For example, people in StatenIsland, N.Y., are planning to turn a landfill into a park.We need to study the effects of certain activities, such asdevelopment, to protect our resources for years to come.

READING CHECK

6. List What are three factors a proposal for an environmental solution must consider?

Debate Ideas Many people think ecotourism is a good way to educate people about the environment. However, some people think ecotourism can cause problems. In a small group, discuss possible ways ecotourism might both help and harm an environment.

READING CHECK

7. Identify What are three roles conservation groups may play in advocating for efforts to protect the environment?

Documents

CHAPTER SECTION 1 An Interconnected · PDF fileSECTION 1 An Interconnected Planet continued ... we use them up, or deplete them, ... of nutrients and the flow of energy in an ecosystem