EEB 2202 Lecture Notes - Lecture 8: Radiation Protection, Melanin, Probability Distribution
21 Feb 2017
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Document Summary
Biological race: a group of populations sharing certain biological traits that makes them distinct from other groups of populations, numbered of proposed human races have varied from 3 to more than 9 races. It is difficult in practice to apply concept to human populations because: The majority of genetic variation is shared among populations. Much of this variation is continuous (polygenic) Continuous variation: many traits that have been used to define race are continuously variable. It is difficult to divide a continuum into discrete units: decisions on divisions are thus often arbitrary. Skin color among indigenous peoples: great variation and overlapping, pigmentation by itself not a good trait to make divisions, not a pattern we would expect from isolation by distance (skin color) Adaptive reasons for skin color variations: hypothesis 1: skin color is related to uv radiation protection, hypothesis 2: skin color is related to vitamin d synthesis, most biologists accept uv radiation and skin color are related.
