Are physical differences between races of people caused by sexual selection or environmental/climatic factors?
Most people define race by skin color. The secondary aspects of how people classify “race” are relatively minor. Remember we humans are 99.9% the same. The genes that make up ‘race” are only a few hundred out of millions. As for skin color: “In their analysis of human evolutionary history, Jablonski and Chaplin concluded that modern humans most likely evolved in the tropics, where they were exposed to high UV levels. But as they moved into regions away from the equator, where UV levels are lower, humans became fairer so as to allow enough UV radiation to penetrate their skin and produce vitamin D, the “sunshine vitamin,” also obtained from eating fish and marine mammals. Vitamin D is essential for maintaining healthy blood levels of calcium and phosphorous, and thus promoting bone growth. Skin color, according to Jablonski and Chaplin, basically becomes a balancing act between the evolutionary demands of photo-protection and the need to create vitamin D in the skin. One of the importan
