Extremphiles
Essay Preview: Extremphiles
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All issues that pertain to human evolution have been hotly contested and spark great ranges of emotions in people. In this article the differences in human skin color are explored. Different ethnic groups have evolved different skin colors as a result of climate and the need to balance the absorption of harmful UV rays and vitamin D. This issue holds important health implications, as well as promising mankind a better understanding of itself.
Human skin color is dependent upon melanocytes which control the release of melanin, the human skin pigment. Melanin shields skin cells from UV rays which can mutate DNA in the skin cells. It also works inside the human body to neutralize free radicals. Scientists have found the effects of Melanin by working with the bald spots of chimpanzees, and the harmful effects of UV radiation have been well documented. In humans, lighter-skinned people are more susceptible to a deficiency in Vitamin B folate.
It is believed that Africa is the cradle of human health, and the African sun posed a harsh obstacle for human evolution. Humans evolved a dark skin color to protect from the harsh African sun, and the UV rays it produces. It follows that human skin color is a function of the climate, and as people spread out form Africa the more temperate climates was conducive to a lighter skin color. This is because as well as shielding UV rays the melanin also blocks the absorption of vitamin D. Vitamin D is essential for human life, and the only mineral in the human body not gained through ingestion. Scientists feel that some UV rays are beneficial for the human body while a large amount would be detrimental. In addition to climate, gender also has an affect on skin color. Women tend to be lighter skinned, because they use more vitamins in pregnancy, and need to absorb more vitamin D than males.
The implications of this knowledge are important in that in the modern age so many peoples of different races