How the Sun Created Race (and Kinky Hair)

The paradox between the positive and negative effects of the sun is at the root of humanity’s wide range of skin colors. Races that have traditionally lived in the glare of the equatorial sun have darker skin that offers natural sun protection. But here’s the curious bit: If you follow the tree of humanity back far enough, you’ll find that we all have relatively dark-skinned ancestors. The lightskinned people of today descended from mostly European races that lost their built-in sunscreen over generations of life in colder, dimmer lands. The obvious question is why. After all, if the sun is so dangerous, surely everyone can use a bit of natural sunblock.

The going theory is that when dark-skinned people moved north and south, their natural sunscreen starved them of vitamin D. But the genetic misfits with light skin absorbed more sun, providing the vitamin D they needed, and they thrived. The sun played the same role in shaping humanity’s hair. Races that needed sun protection developed UV-scattering Afro hair to shield their scalps. Races that needed more vitamin D developed straight, kink-free hair that allows light to pass through to the skin below. In other words, if the sun wasn’t harmful, no one would sport dark skin. And if vitamin D wasn’t important, there would be no white people.

Source of Information : Oreilly - Your Body Missing Manual