S K I N

The evolution of the different skin tones is thought to have occurred as follows: the haired primate ancestors of humans, like modern great apes, had light skin under their hair. When Hominids evolved relative hairlessness (the most likely function of which was to facilitate perspiration) , they evolved dark skin, needed to prevent low folate levels since they lived in sun-rich Africa. (The skin cancer connection is probably of secondary importance, since skin cancer usually kills only after the reproductive age and therefore does not exert much evolutionary selection pressure.) When humans migrated to less sun-intensive regions in the north, low vitamin D3 levels became a problem and light skin color re-emerged. (sexual selection and diet may well have played a part in the evolution of skin tone diversity, as well)