Why do we have different SKIN COLOR?

Anthropologist Nina Jablonski, Ph.D. theorizes in a film by TED (2009), that variations in human skin are adaptive traits that correlate closely to geography and the sun's ultraviolet radiation, not race.

"Over the course of evolution, human ancestors became bigger and more active as they moved into hot, open environments in search of food and water. In these places, one big challenge was keeping cool. The adaption they made was to increase the number of sweat glands on their skin while at the same time reducing the amount of their body hair. With less hair, perspiration could evaporate more easily and cool the body more efficiently. But this less-hairy skin was a problem because it was exposed to a very strong sun, especially damages the body. The solution was to evolve skin that was permanently dark so as to protect against the sun's more damaging rays." explains Dr. Jablonski

"As some groups moved into regions farther from the equator where UVR (Ultra Violet Radiation) levels are lower, natural selection favored lighter skin, which allowed enough vitamin D-forming UVR to penetrate their skin." Jablonski continues.

It can be seen in the image Holding Hands, the variations of skin color within the human race.

Holding Hands