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Thoeries Of Evolution Essay example

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Thoeries of Evolution

Evolution is the process by which living organisms originated on earth and have changed their forms to adapt to the changing environment. The earliest known fossil organisms are the single-celled forms resembling modern bacteria; they date from about 3.4 billion years ago. Evolution has resulted in successive radiations of new types of organisms, many of which have become extinct, but some of which have developed into the present fauna and flora of the world (Wilson 17).
Evolution has been studied for nearly two centuries. One of the earliest evolutionists was Jean Baptiste de Lamarck, who argued that the patterns of resemblance found in various creatures …show more content…

Evolution proceeds by the natural selection of well-adapted individuals over a span of many generations, according to Darwin's theory(Microsoft 96).
The parts of Darwin's theory that were the hardest to test scientifically were the interferences about the heritability of traits because heredity was not understood at that time. The basic rules of inheritance became known to science during the turn of the century, when the earlier genetic works of Gregor Mendel came to light. Mendel had discovered that characteristics are transmitted across generations in discrete units, known as genes that are inherited in a statistically predictable fashion. The discovery was then made that inheritable changes in genes could occur spontaneously and randomly without regard to the environment. Since mutations were seen to be the only source of genetic novelty, many geneticists believed that evolution was driven onward by the random accumulationof favorable mutation changes. Natural selection was reduced to a minor role by mutationist such as Vries. Morgan, and Bates.
While mutation was replacing Darwinism, the leading evolutionary theory, the science of population genetics was being founded by Sewall Wright, J.B.S.
Haldine, and several other geneticists, all working independantly. They
developed

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