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Unformatted text preview: Observed Speciations Speciation has been observed. In the plant genus Tragopogon , two new species have evolved within the past 50-60 years. They are T. mirus and T. miscellus . The new species were formed when one diploid species fertilized a different diploid species and produced a tetraploid offspring. This tetraploid offspring could not fertilize or be fertilized by either of its two parent species types. It is reproductively isolated, the definition of a species. Extinction -- Decreasing Biological Diversity Ordinary Extinction Extinction is the ultimate fate of all species. The reasons for extinction are numerous. A species can be competitively excluded by a closely related species, the habitat a species lives in can disappear and/or the organisms that the species exploits could come up with an unbeatable defense. Some species enjoy a long tenure on the planet while others are short- lived. Some biologists believe species are programmed to go extinct in a manner analogous to organisms being destined...
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This note was uploaded on 11/14/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.
- Fall '10