Impact of Humans

1. Impact of Humans

2. Impact of people on Earth—pages 143-160 • Urban development—consumes farmland and natural habitats. • Can place additional stress on animal and plant populations • Industrial growth—certain kinds of industrial processes pollute air,water, and soil.

3. Impact • Pollution—harmful material that can enter the biosphere through land, air, or water

4. Biological Magnification • Biological magnification—concentrations of a harmful substance increase in organisms at higher trophic level • Example: DDT and the near extinction of the California condor • Chemical enters water supply and progresses up the food chain

5. Impact • Ozone depletion—beginning in the 1970s the hole found in the ozone layer has grown larger and lasted longer • Causes: CFCs (chlorofluorocarbons) can linger for more than a century • Effects: Global warming • The increase in the average temperature of the biosphere

6. Impact • Renewable resources—can regenerate if they are alive or can be replenished by biochemical cycles if they are nonliving • Not unlimited • Nonrenewable resources—cannot be replenished by natural processes

7. Impact • Biodiversity—the sum total of the genetically based variety of all organisms in the biosphere • One of the earth’s greatest natural resources • Conservation—the wise management of natural resources