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Chapter 55

Chapter 55. Humans in the Environment. Biological diversity Variety of organism considered at three levels Genetic diversity Species diversity Ecosystem diversity Decreasing worldwide. Extinct species All members of the species are dead Endangered species

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Chapter 55

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  1. Chapter 55 Humans in the Environment

  2. Biological diversity • Variety of organism considered at three levels • Genetic diversity • Species diversity • Ecosystem diversity • Decreasing worldwide

  3. Extinct species • All members of the species are dead • Endangered species • In imminent danger of extinction • Threatened species • Population is quite small, but extinction is less imminent

  4. An extinctspecies

  5. Four causes of declining biological diversity • Most significantly, habitat loss and fragmentation • In addition, pollution, introduction of invasive species, pest and predator control, and commercial activity

  6. Percentage of imperiled U.S. species that are threatened by various human activities

  7. Conservation biology • Study of how humans affect organism • Development of ways to protect biological diversity

  8. Habitat destruction

  9. Biodiversity hotspots

  10. In situ conservation • Efforts to preserve biological diversity in the wild • Ex situ conservation • Efforts to preserve biological diversity in human-controlled settings

  11. Endangered Species Act (ESA) • Authorizes the U.S. Fish and Wildlife Service to protect bio-diversity domestically and abroad • CITES • International organization to protect species from illegal international wildlife trade

  12. Illegal commercial harvesting

  13. Organisms listed as endangered or threatened in the U.S., 2003

  14. Forests provide many ecosystem services • Watershed protection • Soil erosion prevention • Climate moderation • Protection from flooding • Wildlife habitat • Greatest problem is deforestation

  15. Deforestation

  16. Greenhouse gases • Carbon dioxide • Methane • Surface ozone • Nitrous oxide • Chlorofluorocarbons • Causes greenhouse effect and global warming and enhanced greenhouse effect

  17. Mean annual global temperature,1960 to 2002

  18. Surface Ozone • Ozone (O3) is a form of oxygen • Human-made pollutant in lower atmosphere • Occurs naturally in the stratosphere

  19. Ozone destruction in the stratosphere • Amount of ozone in the stratosphere is declining (ozone depletion) • Large areas of ozone thinning over Antarctica and the Arctic • Excessive exposure to UV radiation linked to human disease, i.e., skin cancer

  20. Increase in greenhouse gases, preindustrial to present

  21. Enhanced greenhouse effect

  22. UV radiation and the ozone layer

  23. Ozone thinning

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