Chapter 6

Humans in the Biosphere

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6-1 A Changing Landscape

!● All organisms share Earth’s limited resources ● Understanding how humans interact with the

biosphere is crucial to protecting these resources

● Human activities that have changed the biosphere: hunting & gathering, agriculture, industry & urban development

6-2 Renewable & Nonrenewable Resources

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6-2 Renewable & Nonrenewable Resources

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Sustainable Use

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Land Resources

● land for cities & suburbs ● raw materials for industry ● food crops which grow best in fertile soil

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Sustainable Use Strategies

● contour plowing ● leave stems & roots from previous years

crops in place ● harvest mature trees selectively ● plant, manage, harvest and replant tree farms

in places where forests have already been cut ● Breed new, faster-growing tree varieties that

produce high quality wood

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Deforestation in the U.S.

• 2010- U.S. had 751,255,000 acres of forested lands

• Between 1990 and 2010 the U.S lost an average of 949,750 acres of forest each year and added 18,995,000 acres of forested land

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Ocean Resources

● major source of food/protein (fish) ● many species are being overfished ● approximately 2,215 species are listed as

endangered or threatened

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Air Resources

● Preserving air quality remains a challenge

Smog- Los Angeles California

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Acid Rain

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Water Resources

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Sustainable Use Strategies

● limit the catch of fish populations stressed by overfishing

● use technology to control emissions from factory smokestacks

● strict automobile emission standards ● clean air regulations ● protect natural systems involved in the water

cycle (wetlands) ● water conservation

6-3 Biodiversity “Species Richness”

The Value of Biodiversity • ecosystem stability • sources of food • provides us with medicine • provides us with industrial products • economic resources (eco-tourism)

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Biological Magnification

• widespread use of DDT (pesticide) threatened fish-eating birds with extinction (osprey, pelican & bald eagle)

• began showing up in the tissues of humans

• banned in the U.S in the early 1970’s

• bird populations have recovered

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!!!

Introduced/Invasive Species

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NYS Invasive Species

Emerald Ash BorerEurasian Milfoil

Purple Loosestrife

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Conserving Biodiversity

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6-4 Charting a Course for the Future

● Ozone Depletion ● Global Warming ● The Value of a Healthy Biosphere

Ozone Depletion

Ozone = Earth’s sunscreen

Main cause = CFC’s

Worldwide CFC production ended in the mid 1990’s

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Effects of Ozone Depletion

● skin cancer ● damage eyes (cataracts) ● decrease an organism’s resistance to disease ● damage tissue in plants & phytoplankton in

oceans

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Antarctic Ozone Hole

Global Warming/Climate Change

Global Emissions of Greenhouse Gases

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Melting of Arctic Sea Ice

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Effects of Global Warming

● ice melting worldwide (mountain glaciers, ice sheets covering Antarctica & Greenland, and Arctic Sea ice)

● rise in sea level ● animal and insect migration ● storms becoming stronger ● floods and droughts becoming more common ● less fresh water will be available ● spread of diseases like malaria ● ecosystems will change

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What Can We Do?

● reduce greenhouse gas emissions by burning less fossil fuels

● reduce energy consumption ● be energy efficient ● preserve and grow forests ● invest in new infrastructure ● upgrade existing highways and transmission

lines

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Hydrofracking

● large amounts of water combined with smaller amounts of chemicals and sand are pumped under high pressure into a drilled gas well

● this forces the rock to open up along tiny existing fractures allowing gas to flow more freely into the well

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Preserving Resources

1. Reduce: use less resources (walk rather than drive, use energy efficient appliances, etc.)

2. Reuse: use resources several times (use dishes instead of paper plates, etc.)

3. Recycle: use resources in a different product (recycle metal, plastic, glass)