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Leaving a Mark on the World

Have you ever seen very old photographs of the town or city in which you now live? Has your area changed? Perhaps there are more buildings or roads than there were many years ago. Maybe your town or city has more trees and flowers now than it had years ago. Humans, like all organisms, have an effect on their environment.

Section 6-1

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1. Choose an animal other than a human and describe at least two ways in which it may change its environment.

2. What events might have led to the changes that occurred in your town or city?

3. What positive effect have humans had on their environment? What negative effect have humans had on their environment?

Section 6-1

Interest Grabber continued

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6–1 A Changing LandscapeA. Earth as an Island

B. Human Activities

C. Hunting and Gathering

D. Agriculture

1. From Traditional to Modern Agriculture

2. The Green Revolution

3. Challenges for the Future

E. Industrial Growth and Urban Development

Section 6-1

Section Outline

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HumanActivities

that have changed the biosphere include

may have once caused often relies on the methods of thehave resulted in

which increased

Food supply Pesticide use Monocultureuse

Hunting andgathering Agriculture

Industrial growth

Urbandevelopment

Extinctions oflarge animals

Greenrevolution

High standardof living

Increasedpollution

Section 6-1

Concept Map

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Where Do Natural Resources Come From?

Natural resources are materials that are supplied by nature. A renewable resource is one that is replaceable. A nonrenewable resource is one that cannot be replenished by natural processes. Once a nonrenewable resource is used up, it is gone forever.

Section 6-2

Interest Grabber

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1. Examine the list of natural resources shown below. Then, classify each natural resource as either renewable or nonrenewable.

a. Woodb. Fossil fuelsc. Aluminumd. Woole. Gold

2. Describe the impact that the loss of nonrenewable resources would have on the environment.

Section 6-2

Interest Grabber continued

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6–2 Renewable and Nonrenewable ResourcesA. Classifying Resources

B. Sustainable Development

C. Land Resources

D. Forest Resources

E. Fishery Resources

1. Overfishing

2. Sustainable Development

3. Aquaculture

F. Air Resources

G. Freshwater Resources

Section 6-2

Section Outline

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World Fish Catch World Fish Catch per Person

Tot

al C

atch

(mill

ion

tons

)

Am

ount

of

Fis

h pe

r P

erso

n(k

ilogr

am

s)Year Year

Section 6-2

Growth of Fish Catch

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Emissions to AtmosphereNitrogen oxidesSulfur dioxide

Chemical TransformationNitric acid

Sulfuric acid

PrecipitationAcid rain, fog,snow, and mist

Dry Fallout

Condensation

particulates, gases

Industry Transportation Ore smelting Power generation

Section 6-2

Figure 6-12 The Formation of Acid Rain

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What Is Biodiversity?

Biodiversity is the sum total of the variety of organisms in the biosphere. Sometimes humans can reduce biodiversity, which is considered a natural resource.

Section 6-3

Interest Grabber

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1. List three ways in which other organisms have proved to be a benefit to humans.

2. Compare biodiversity with other natural resources, such as wood and fossil fuels. Do you think biodiversity is a renewable or a nonrenewable resource? Explain your answer.

3. What can be done to preserve the biodiversity of organisms?

Section 6-3

Interest Grabber continued

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6–3 BiodiversityA. The Value of Biodiversity

B. Threats to Biodiversity

C. Habitat Alteration

D. Demand for Wildlife Products

E. Pollution

F. Introduced Species

G. Conserving Biodiversity

1. Strategies for Conservation

2. Challenges in Conservation

Section 6-3

Section Outline

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Insects

BacteriaFungi

Plants

Protists Other Animals

54.4%

4.2%

18%

3.4%0.3%

19.7%

Section 6-3

Species Diversity

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Fish-Eating BirdsMagnification ofDDT Concentration

10,000,000

100,000

10,000

1,000,000

1

1000

LargeFish

Small Fish

Zooplankton

Producers

Water

Section 6-3

Figure 6-16 Biological Magnification of DDT

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How Much Should It Cost?

You may have read that when something becomes hard to obtain, its price usually increases. Such is the case for materials like gold and diamonds, which are nonrenewable resources. Using similar thinking, some researchers believe that all the valuable services provided by a healthy ecosystem should be assigned a dollar value.

Section 6-4

Interest Grabber

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Rank the following items in order of their importance to you. Then, next to each item, write down how much you would be willing to pay for it.

1. Fresh, clean drinking water

2. Clean air to breathe

3. An endangered plant containing a substance that can cure cancer

4. Gas for your family car

Section 6-4

Interest Grabber continued

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6–4 Charting a Course for the FutureA. Ozone Depletion

B. Global Climate Change

1. Evidence of Global Warming

2. Possible Effects of Global Warming

C. The Value of a Healthy Biosphere

Section 6-4

Section Outline

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Cover CropsLegumes, grasses, and othercover crops recycle soil nutrients,reduce fertilizer need, andprevent weed growth.

Controlled GrazingBy managing graze periods and herddensities, farmers can improve nutrientcycling, increase the effectiveness ofprecipitation, and increase the carryingcapacity of pastures.

Biological Pest ControlThe use of predators and parasitesto control destructive insectsminimizes pesticide use as well ascrop damage

Contour PlowingContour plowing reduces soil erosion from land runoff. On hilly areas, plowing is done across the hill rather than straight up and down.

Crop RotationDifferent crops use and replenish different nutrients. By rotating crops, the loss of important plant nutrientsis decreased.

A B C

Yr. 1

Yr. 2

Yr. 3

Section 6-4

Sustainable Agriculture

corn

corn

corn

alfalfa

alfalfa

alfalfa

oats

oats

alfalfa (plowed in)

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Solar energy

Production of oxygen

Storage and recycling of nutrients

Regulation of climate

Purification of water and air

Storage and distribution offresh water

Food production

Nursery habits for wildlife

Detoxification of human andindustrial wasteNatural pest and disease controlManagement of soil erosionand runoff

Section 6-4

Figure 6-22 Ecosystem Services

Video

Click the image to play the video segment.

How Does Everything Fit?

Interactive test

Articles on natural resources and pollution

For links on sustainable agriculture, go to www.SciLinks.org and enter the Web Code as follows: cbn-2061.

For links on biodiversity, go to www.SciLinks.org and enter the Web Code as follows: cbn-2063.

For links on global warming, go to www.SciLinks.org and enter the Web Code as follows: cbn-2064.

Go Online

Interest Grabber Answers

1. Choose an animal other than a human and describe at least two ways in which it may change its environment.

Sample answers: A beaver both removes wood from a forest and dams a body of water. A dog digs a hole and may damage plants, but also may unearth worms and turn the soil.

2. What events might have led to the changes that occurred in your town or city?

Sample answers: increase or decrease in population and industry.

3. What positive effect have humans had on their environment? What negative effect have humans had on their environment?

Humans preserve, conserve, and restore the natural environment as well as construct facilities that improve human health. Humans pollute the air, water, and land with materials that can harm humans and other organisms.

Interest Grabber Answers

1. Examine the list of natural resources shown below. Then, classify each natural resource as either renewable or nonrenewable.

a. Wood Renewable; new trees can be grownb. Fossil fuels Nonrenewable; once depleted they are gonec. Aluminum Nonrenewable; although recyclable, once depleted the resource is gone

d. Wool Renewable; sheep can grow new fleecee. Gold Nonrenewable; once gold ores are depleted no more gold can be made

2. Describe the impact that the loss of nonrenewable resources would have on the environment.

Sample answers: fossil fuels; limited energy, which impacts on industry, quality of life, economy; gold and aluminum; decrease in components for technology, which also impacts on industry, quality of life, economy.

Interest Grabber Answers

1. List three ways in which other organisms have proved to be a benefit to humans.

They provide food, medicine, building materials, and clothing.

2. Compare biodiversity with other natural resources, such as wood and fossil fuels. Do you think biodiversity is a renewable or a nonrenewable resource? Explain your answer.

Nonrenewable, because once species of organisms are extinct, they cannot be brought back to life by any natural processes.

3. What can be done to preserve the biodiversity of organisms?

Students may suggest protecting endangered species and ecosystems.

Interest Grabber Answers

Rank the following items in order of their importance to you. Then, next to each item, write down how much you would be willing to pay for it.

1. Fresh, clean drinking water

2. Clean air to breathe

3. An endangered plant containing a substance that can cure cancer

4. Gas for your family car

Students’ answers will depend on how important the items are to them.

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