Humans in the Biosphere Chapter 6

1. Humans in the BiosphereChapter 6 Dr. Donna Howell Biology I Blacksburg High School

2. Our Ecosystem • Human activities that affect the biosphere are: • Hunting and gathering • Agriculture • Industry • Urban development

3. Hunting and Gathering • The hunger-gatherer way of life makes relatively few demands on the environment. • However, the use of technology does: guns, automobiles, tools, etc.

4. Agriculture • The Green Revolution is an effort to create sustainable agriculture • Purpose was to increase the world’s food supply

5. Agriculture • Ecological challenges: • Pest control • Finding irrigation water

6. Industrial Growth • Growth of industry has led to problems: • Pollution of air, water, and soil • Need for energy

7. Urban Development • Problems associated with: • Waste disposal • Consumes farmland and natural habitats • Stress on animal populations

8. Resources • Environmental goods and services may be classified as • Renewable • Nonrenewable

9. Renewable Resources • Renewable resources are those that can be regenerated or replenished in a reasonable amount of time. • Ex: land, forests, fisheries, air, water

10. Nonrenewable Resources • Nonrenewable resources are those that cannot be regenerated or replenished in a reasonable amount of time. • Ex: fossil fuels

11. Sustainable Development • A way of using natural resources without depleting them, and of providing for human needs without causing long-term damage to the environment.

12. Land Resources • Plowing the land removes roots that hold soil in place, causing erosion. • Contour plowing reduces erosion.

13. Forest Resources • Deforestation is the loss of forests by human activities. • Leads to severe erosion. • Replace trees, produce faster growing trees via breeding.

14. Fishery Resources • Overfishing is harvesting fish faster than they can reproduce. • Affects other species in lakes, streams, oceans also. • Aquaculture, limits on catch

15. Air Resources • Condition of air affects organism’s health. • Smog, pollution and acid rain are problems • New technology to control emissions

16. Freshwater Resources • Pollution of water can affect our health • Includes waste such as chemicals, sewage, fertilizers, etc. • Conservation, protection via filtering

17. Biodiversity • Biodiversity is the sum total of all organisms in the biosphere. • One of Earth’s greatest natural resources • Provide drugs, food, etc.

18. Biodiversity • Human activity can reduce biodiversity by altering habitats, over hunting, adding waste, and introducing foreign species.

19. Biodiversity • Pollution greatly reduces biodiversity. • DDT was a problem. • Rachel Carson wrote about in “Silent Spring” • Discussed biomagnification.

20. Biological Magnification • Biological magnification is when concentrations of harmful substances increase in organisms in the higher trophic levels in a food chain.

21. Introduced Species • Invasive species are those that are introduced into new habitats, and they reproduce quickly. • Harm existing species, and alter niches.

22. Introduced Species • Zebra mussels came over in 1980’s from Europe. • Spread through Great Lakes and rivers. • Driving other native species to extinction.

23. Data Gathering • Researchers collect data on systems to help monitor effects of humans on environment. • Two are ozone layer and global climate system.

24. Ozone Depletion • 20-50 km above Earth, O3 is found. • Protects us from harmful UV rays. • Scientists are finding a hole in ozone caused by CFC’s.

25. Global Climate Change • Scientists are concerned with global warming. • Partially due to burning of fossil fuels. • Ice caps melting, sea levels rising, could cause extinctions.

26. The End