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Unformatted text preview: Chapter 9 72 % of worlds birds are headed for extinction Local Extinction: species is no longer found in an area, but found elsewhere in the world Ecological Extinction: few members are left; no longer play its ecological role Biological Extinction: no loner found anywhere on Earth Endangered species: few individual survivors that species could soon BECOME extinct Threatened species: still abundant but declining Key deer are nicotine addicts killed by cars Identified 1.8 million species Earth estimated to have 4 million to 100 million species Current rate of extinction is 100 times the background extinction rate 30,000 of worlds species are listed as endangered We should prevent extinction because of the economic and ecological services they provide and because they have a right to exist regardless of their usefulness. 90% of leading prescription drugs came from wild organisms Recreational pleasure watching wildlife Int rinsic (existence) value: based on species inherent right to exist and play its ecological...
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This note was uploaded on 01/30/2010 for the course BIOL 6 taught by Professor Petersen during the Fall '08 term at Mt. SAC.
- Fall '08