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Ecology week 3 Human Impact on the Environment

Ecology week 3 Human Impact on the Environment

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Ecology week 3 Human Impact on the Environment

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  1. Ecology week 3Human Impact on the Environment

  2. Humans in the Biosphere • Like all organisms, we humans participate in food webs and chemical cycles. • Among human activities that affect the biosphere are hunting and gathering, agriculture, industry, and urban development.

  3. Humans in the Biosphere • By the end of the last ice-age – about 11,000 years ago – humans began the practice of farming, or agriculture • Monoculture, fertilizers, and the green revolution.

  4. Industrial growth and urban development • Human society and its impact on the biosphere (Earth) were transformed by the industrial revolution (1800’s) • Dense human communities produce waste that must be disposed of. • Certain industrial processes pollute air water and soil.

  5. Renewable and Nonrenewable resources • Environmental goods and services may be classified as either renewable or nonrenewable • Renewable resources: can regenerate if they are alive or can be replenished by biological cycles if they are non-living (abiotic), but they are not necessarily unlimited. “ex: freshwater” • Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air, and fresh water. • Soil erosion? • Desertification?

  6. Renewable and Nonrenewable resources • Nonrenewable resources: are those that cannot be replenished by natural processes • Fossil fuel • Coal • Oil • Natural gas • Nuclear energy???

  7. Renewable and Nonrenewable resources • Deforestation • Overfishing (aquaculture) • Air resources (smog, pollutant, acid rain) • Freshwater resources

  8. Effects of Acid Rain

  9. Biodiversity • Biodiversity is the sum total of the genetically based variety of all organisms in the biosphere • Biodiversity is one of Earth’s greatest natural resources. Species of many kinds have provided us with foods, industrial products, and medicines – including painkillers, antibiotics, heart drugs, antidepressants, and anticancer drugs

  10. Rosy Periwinkle (used to treat certain cancers)

  11. Biodiversity • Human activities can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments • Demand for wildlife products???

  12. Pollution • DDT • Biological magnification??? • Chloroflorocarbons (CFC’s) & the ozone layer. • UV ~ skin cancer, phytoplankton?

  13. Ozone Layer (O3) • Many scientists are concerned about the thinning of the OZONE layer.

  14. How Populations Grow • Exponential growth • Bacteria • Humans • Logistic growth • Carrying capacity • Predator / Prey relationships • Human population

  15. Human PopulationIssues

  16. The end