Gene Flow Essay

889 Words4 Pages
Describe the effects of gene flow and selection on three important forms of biological variation. What effects of gene flow and selection may we see by the 22nd century (if we make it that far)? The definition of gene flow is the transfer of alleles of genes from one population to another.(Wikipedia ). Gene flow help human to exist for millions years, it used to help human lived in harsh environment and evolution. There are three examples shown below to explain how gene flow works and changed our body. Firstly, I would like to mainly talk about the convergent and divergent of human body hair. Darwin suggested that hairlessness was favored when men and women were picking sexual partners (Wade 24). Therefore, the proportion with less body hair attracted much mate, consequently, they would have more opportunities have descendants which have less body hair. Different from modern, the society our ancestors lived was polygamy, which means, the individuals with hairless may have a lot wife but the others may have no chance to breeds. The les body hair gene would from one to next generation with more and more proportion until all human are hairless. However, since the different area that our ancestors moved to, some of them lived in a hot environment and some settled at cold place, the divergent gene of body hair happened at different place. The population near to equator lived in hot environment which means they need less or no body hair to improve the ability of heat elimination of body skin. Oppositely, the population who lived far from equator, due to the colder environment and windy, they need more body hair to keep body energy. In addition, the different skin color is similar to the divergent of body hair. Actually, our ancestors are all dark skin color because the dark color could protect skin from the sun`s harmful radiation like ultraviolet rays. As the
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