Skin Color: Handy Tool for Teaching Evolution?
ScienceDaily (Feb. 20, 2011) — Variations in skin color provide one of the best examples of evolution by natural selection acting on the human body and should be used to teach evolution in schools, according to a Penn State anthropologist.
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Source: Scientific American
"There is an inherent level of interest in skin color and for teachers, that is a great bonus -- kids want to know," said Nina Jablonski, professor and head, Department of Anthropology, Penn State. "The mechanism of evolution can be completely understood from skin color."
Scientists have understood for years that evolutionary selection of skin pigmentation was caused by the sun. As human ancestors gradually lost their pelts to allow evaporative cooling through sweating, their naked skin was directly exposed to sunlight. In the tropics, natural selection created darkly pigmented individuals to protect against the sun.
Ultraviolet B radiation produces vitamin D in human skin, but can destroy folate. Folate is important for the rapid growth of cells, especially during pregnancy, when its deficiency can cause neural tube defects. Destruction of folate and deficiencies in vitamin D are evolutionary factors because folate-deficient mothers produce fewer children who survive, and vitamin D-deficient women are less fertile than healthy women.
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Read more here/Leia mais aqui: Science Daily
