Natural Selection Summary

Natural Selection Summary - nature do the selecting. 6....

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1 Introduction to Anthropology On the Origin of Species by Means of Natural Selection or The Preservation of Favored Races in the Struggle for Life Summary of Darwin’s theory of evolution through natural selection: 1. Despite the many similarities of individuals in a species, there is enough variety among them. Except for identical twins, no two individuals are exactly alike. 2. All species are capable of producing offspring at a faster rate than food supplies. 3. Because in each generation more individuals are produced than can survive, owing to limited resources, there is competition between individuals. 4. Those individuals that possess favorable variations or traits have an advantage over individuals that do not possess them. The individuals with the advantage are more likely to survive, or live longer, and produce offspring than are others. 5. The environmental context determines whether or not a trait is beneficial. The mechanisms of
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Unformatted text preview: nature do the selecting. 6. Because individuals possessing favorable characteristics contribute more offspring to the next generation than do others, over time, such traits become more common in the population, less favorable traits are not passed on as frequently and become less common. 7. Over long periods of geological time, successful variations accumulate in a population, so that later generations may be distinct from ancestral ones. 8. Geological isolation may also lead to the formation of new species. As populations of a species become geologically isolated from one another, for whatever reason, they adapt to different environments. Example: the 13 species of Galapagos finches, descended from a common ancestor on the South American mainland....
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