Nina Jablonski says that differing skin colors are simply our bodies' adaptation to varied climates and levels of UV exposure. Charles Darwin disagreed with this theory, but she explains, that's because he did not have access to NASA.

We have lots in common with our closest primate relatives. But comparatively, humans seem a bit... underdressed. Instead of thick fur covering our bodies, many of us mainly have hair on top of our heads— and a few other places. So, how did we get so naked? And why do we have hair where we do? Nina G. Jablonski explores the evolution of human hai...