Here you find some nice charts from this article about human skin color evolution roots. The research has been done by some Norwegian scientists that discussed some interesting hypothesis for the human race evolution patterns. Too bad there is no clear reference to the missing link between apes and human with the aquatic apes theory, that I found really fascinating and plausible.
Also check out Frank W Sweet’s Knol about skin color.
Here’s another nice draw from the same study, analyzing a possible distribution of the different human species in space and time. Anyway I really miss the speech of Elaine Morgan so I’m going to post the video at the end of this post.