Winner
Diverse in Unity
I have found a pretty interesting article on the net some time ago and I feel like sharing it with the rest of the forum
The article is rather long so I'll sum up the conclusions. For those who want to learn more, read the article. It's not that long.
Basics:
- human skin colour doesn't depend so much on sunlight as previously thought (Europe is about the only place on Earth where very light skin is the norm - why?)
- instead, the process of evolution of different skin tones had been influenced by sexual preferences combined with different environmental conditions in which various human populations lived
- generally speaking, there are feminine and masculine traits which are more desirable, more attractive to the opposite sex
- women with lighter skin are generally more attractive to men while men with darker skin are more attractive to women (explained in the article)
- human skin color variance between sexes is very low
Thus:
- populations where (largely) monogamous men choose mates from a larger pool of available women are evolving towards lighter skin colour
- populations where women's preferences play a significant role are evoloving towards darger skin colour
Why is Europe largely white?
- The natural conditions in Europe during Ice Ages were difficult for humans; living in sub-arctic tundra-like environment leads to a disproportionately higher male mortality (freezing, hunting accidents etc.) which leads to a higher percentage of females in the population (explained in much more detail in the article).
- In these living conditions, polygyny (= men have more than one wife) is not sought after, because women are of lesser value - their traditional role in hunter-gatherer society (gathering berries and stuff like that) is ill-suited to environment where there is practically nothing to be gathered for most of the year. Women thus contribute little or nothing in terms of food. Logically, men don't want to take more than one wife, because only exceptional hunters can obtain enough food to sustain more wives.
- In a situation when there is a small number of males who are choosing a single wife from a large number of available women, they're likely to choose the ones with physical traits they find attractive - like the lighter skin colour.
- Since skin colour variance between sexes is low, it's likely that the skin colour of women they chose was genetically determined.
- And so, when this process continues for long enough, genes making people's skin lighter become more common in the society. Gradually, light skin becomes a norm.
- When the ice ages ended, this selective process ended with them - but the light skin colour has remained.
Why aren't the North American native people/Eskimos white too?
- They arrived to Americas by the end of the last major glaciation, so the process probably didn't have enough time to lighten their skin (explanation in the article)
OK, so why are most Africans black?
- In Africa, the value of women was much higher - there was plenty of things they could gather and bring back home, therefore it was desirable for a man to have more than one wife because they produced surplus food and he didn't have to hunt so much (I am oversimplifing it now).
- Because it was so good to have more wives, men competed for them: they had to look masculine enough to attract them and to intimidate other men. And since the skin colour variance between sexes is low, this resulted in genetic darkening of equatorial Africa's populations. Note that the original South African populations were not nearly as dark as the Bantu populations which replaced them in most of Southern Africa later on.
...
The end
I hope that all racists out there are red with rage and fuming by now - you see, light skin colour really isn't a sign of biological superiority 
The article can be found here.
(I won't quote it all because there are pictures and charts, so just click on the link.)
