answer:I doubt that white people evolved from black people to help deal with the cold. It is more likely that we turned white in cooler climates, because sun stroke and heat related health problems had been removed, and so natural selection was no longer favoring high amounts of melanin. If we had evolved to deal with cold, we would probably have wider nostrils more similar to that of a neandarthal, to help us prevent sweating when we run, as sweat would freeze on us and cause us to die from cold more often We would probably also all be fat, or if not fat, at least capable of remaining healthy while fat, as fat and hair are often natures first choice for insulation. Life did start in Africa, and the first humans most probably were black, and whites probably did evolve in cooler climates, but the color of the skin is probably more to do with mother nature saving time by cutting corners, I doubt the color of the skin would have much effect on insulation. Then again, its just an educated guess. EDIT: I ruled out turning white for camuflage purposes, due to our predatorial nature, however it could have some minor significance, probably a bigger influence that the cold.