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EvolutionPrinciples160-page9 - see the darker moths and the...

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Principles of Evolution - 9 Evidence for Natural Selection Darwin and Wallace had presented extensive examples of the variations observed in members of natural populations to propose their theory on origin of species by natural selection. To support this, Darwin also looked at artificial selection. Darwin was much taken with the selective breeding of domestic animals, and used that as evidence for how selection could result in numerous variations. He used the domestic dog as one example of artificial selection. Cabbage, Brussels sprouts, cauliflower, broccoli, kale and kohlrabi are all derived from the same mustard species. We also have evidences in nature that demonstrate how selection works. During the Industrial Revolution, soot from using coal coated and killed lichens on trees in England, darkening the bark. At that time, the peppered moth came in two variants: dark and light. On trees where soot was not evident, birds were able to
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Unformatted text preview: see the darker moths, and the lighter moths became more prevalent. In the industrial areas, the soot covered trees made the lighter form more visible to their predators, and the camouflaged darker variant became more abundant. Because the cause of the selection pressure was human impact on the environment, this is often called induced selection. Evidence demonstrating origins of variations that are passed from generation to generation accumulated in the late 1800s and continues today. A mutation in cockroaches that resulted in distaste for glucose resulted in populations resistant to a common roach treatment (a poison that contained glucose). It took only a few generations to accomplish this (thanks to the poison killing all roaches lacking the glucose distaste gene that ate the poison and the short generation time needed to build up populations with resistance). Pesticide resistance is common among insects....
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