2. Effects of Humans on the Ecosystem Human activities can affect the quality and supply of renewable resources such as Land Forests Fisheries Air Fresh water

3. Copyright Pearson Prentice Hall Sustainable Development LAND Sustainable development: using natural resources without depleting them and without causing long-term environmental harm. Examples of environmental harm: soil erosion and desertification.

4. Land Resources Soil erosion: wearing away of surface soil by water and wind. Desertification: productive areas are turned into deserts. Caused by a combination of farming, overgrazing, and drought. Copyright Pearson Prentice Hall

5. Air Resources AIR The condition of the air affects people’s health. Smog: mixture of chemicals that occurs as a gray-brown haze in the atmosphere. Pollutants: harmful material that can enter the air, land, or water. Acid rain: nitrogen and sulfur compounds combine with water vapor in the air and form drops of nitric and sulfuric acids. Copyright Pearson Prentice Hall

6. Formation of Acid Rain Air Resources Emissions to Atmosphere Nitrogen oxides Sulfur dioxide Chemical Transformation Nitric acid Sulfuric acid Condensation Dry Fallout Particulates Gases Precipitation Acid rain, fog, snow, and mist Industry Transportation Ore smelting Power generation

7. Copyright Pearson Prentice Hall Freshwater Resources FRESHWATER Water is a renewable resource. Water can become polluted.

8. Freshwater Resources Sources of Water Pollution: improperly discarded chemicals that enter streams and rivers. wastes discarded on land that seep through soil and enter underground water supplies. domestic sewage containing compounds that encourage growth of algae and bacteria. sewage containing microorganisms that spread disease. Copyright Pearson Prentice Hall

9. Pollution POLLUTION Many forms of pollution can threaten biodiversity. One of the most serious problems occurs when toxic compounds accumulate in the tissues of organisms- Ex. DDT.

10. Copyright Pearson Prentice Hall Pollution DDT (a pesticide) has two hazardous properties: 1. It is nonbiodegradable (cannot be broken down). 2. Once DDT is picked up by organisms, it cannot be eliminated from their bodies. DDT has been banned in the U.S.!!!

11. Pollution When DDT enters food webs, it undergoes biological magnification. Biological magnification: concentrations of a harmful substance increase in organisms at higher trophic levels in a food chain or food web. Copyright Pearson Prentice Hall

12. Pollution Magnification of DDT Concentration

13. Copyright Pearson Prentice Hall Pollution Magnification of DDT Concentration

14. Copyright Pearson Prentice Hall Pollution Magnification of DDT Concentration

15. Copyright Pearson Prentice Hall Pollution Magnification of DDT Concentration

16. Copyright Pearson Prentice Hall Pollution Magnification of DDT Concentration

17. Pollution Copyright Pearson Prentice Hall Magnification of DDT Concentration