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u10a1 Life in the Universe Review Assignment
Finance & Accounting
Pages 4 (1004 words)
4. Why is the theory of evolution so critical to our understanding of the history of life on Earth? Explain how evolution proceeds by natural selection, and what happens to DNA that allows species to evolve. Some 99.9 percent of all the species that have ever lived are now extinct.
Evolution is a natural phenomenon. Natural selection is the reason why evolution happens. In its most basic form, evolution is genetic change within a population - specifically changes in the allelic frequencies of said population. Genetic drift, natural selection, mutation, and migration these are the basic mechanisms of evolution. Evolutionary thought can be traced back to classic Greece, but it is most commonly associated with Charles Darwin. Darwin only described one of the mechanisms that now are known to guide evolution: Natural Selection. He also put forward his idea that all the species have originated from a common ancestor and changed over time to the present situation. Natural Selection is the process by which favorable heritable traits become more common in successive generations of a population and unfavorable heritable traits become less common due to differential reproduction. That is: given a certain population, those individuals who are more fit to the selective pressure(s) by their habitat will leave more descendants than those less fit. This means that for Natural Selection to act, a population must be composed by individuals that differ in their traits. Evolution is the explanation for the development, adaptation and diversity of life, as well as the morphological similarities between different kinds of life. ...
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