BIO 2129 Final: BIO2129 Final Notes.docx
15 Dec 2014
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Background extinction happens over a long period of time. Almost every species that ever existed is now extinct. Under normal circumstances extinction rates are close behind speciation rates (when a new species arises). Genus are less likely to go extinct than a species. Species that go extinct always leave a daughter species behind containing its genes. Darwin assumed that species went extinct because of natural selection and the fact that they could have experienced competitive failure and died out. Because of random chance extinction can take place if birth rates are higher than death rates. The bigger the population size the smaller the chance of extinction. Smaller populations are more likely to go extinct than a larger one. When there is a small area for a species to live in, there is more of a chance they will go extinct.
