NATURAL SELECTION


Website:
http://www.globalchange.umich.edu/globalchange1/current/lectures/selection/selection.html
http://evolution.berkeley.edu/evolibrary/article/evo_25
http://biologyeoc.wikispaces.com/NaturalSelection
http://biologyeoc.wikispaces.com/StructuralAdaptations

Natural selection was trying to support the concept of evolution. Charles Darwin formulated this theory, which tried to prove that adapted organisms survived longer, and the less adapted organisms died out due to the frequency of unfavorable traits that could not allow those organisms to sustain life in that environment. Darwin got his ideas together, into this theory of natural selection, which strived to prove evolution. Natural selection is composed of the following four aspects: variation, overproduction, limits on population growth, and differential reproductive success.



Variation basically tried to explain that there is always many traits in an population, because each individual has their own combination of traits. Some traits allowed organisms to sustain life in that environment, while others drastically decreased the organism’s chances of survival. Overproduction is basically that each species will produce more offspring, than can survive. Limits on population growth can basically be competition for resources, predation, unfavorable weather conditions, and other factors. Differential reproductive success is basically the individuals most adapted to the environment, are likely to reproduce, and survive. The individuals that are not adapted to the environment can produce inferior offspring, as opposed to the adapted individuals. When enough changes accumulate in separated populations, new species are produced. Darwin was motivated by the fact that he was intrigued by artificial selection. Artificial selection is basically forming an individual with only the desired traits, which is evident in many varieties of dogs. Thomas Malthus also played an essential role in Darwin’s theory, as well as Alfred Russel Wallace. Darwin was able to publish his book, On the Origin of Species by Natural Selection, in 1859. Natural selection was a theory, which intended on proving that evolution occurred. Darwin did not know the mechanism of inheritance within variation, so he was not able to properly explain it. Eventually Mendelian genetics was coupled with natural selection to form the synthetic theory of evolution, which was formed by the ideas of many scientists. Natural selection is an important defender of evolution.

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http://www.answersingenesis.org/assets/images/articles/ee/v2/darwin-journey.jpg
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http://www.fieldmuseum.org/darwin/home_images/main_pic.jpg