Tell me about race...

[theyearthreethousand]

Specifically, why do we have different features?

[Odd_Nonposter]

A lot of it has to do with how people physically adapted to their environment. If you've studied animal adaptation, this might sound a little familiar. For example, skin color is largely a function of the intensity of the sunlight in a region where a group of people live, darker skin being more prominent closer to the equator because the increased sunlight causes skin damage. Lighter colors are more common in higher latitudes because of the lack of sunlight necessary to synthesize vitamin D. Other factors, such as the presence of certain predators, plants, diseases, or parasites in the area may favor greater athletic ability, certain blood disorders, differences in sensory perception, etc. Those without those traits in that particular area likely died out or otherwise failed to reproduce. Some of it is also likely to do with how isolated a group of people are. Limited gene pools are likely in more isolated areas, such as islands and mountainous areas. Limited gene pools often favor recessive traits and genetic diseases, such as the "blue mountain men" of Appalachia. They had been inbred to the point that a genetic anomaly that causes blue blood could show itself. Edit: Hey, same post count!

[Jeff777]

Variety is good and beautiful.

[Taosaur]

Some studies with foxes and dogs are suggesting that selection for tame (in humans think "civilized") behavior can itself lead to a wider variation in morphology in just a few generations. Humans all over the world have been subject to ever-increasing local selection on that basis as we've come to live in denser and denser concentrations. A recent survey of the Human Genome Project database found that the accumulation of selected traits in humans increased radically 40,000 years ago and again 10,000 years ago. I would speculate we have one of the more varied genomes of any single species this planet has ever seen, and it's bound to be expressed in our appearance.

[theyearthreethousand]

Variety is good and beautiful. I agree. but why are some eyes different, noses, lips? what is the evolution advantage, if any?

[Jeff777]

I agree. but why are some eyes different, noses, lips? what is the evolution advantage, if any? I'm going to paraphrase what I heard once. I had heard that the Negroid nose is wider(flatter?) than the Caucasoid/Europoid thin(pointy?) nose because Negroes had to breathe in more air in their climate or something like that. The Caucasians from the Caucaus mountains didn't have to breathe in that much air because of the freezing climates etc. This could also sum up skin pigmentation (colder/warmer temperatures and adaptability) as Odd Nonposter explained above. Not sure if this is the "end all answer" but I figured I'd just pass along what I had once heard.

[theyearthreethousand]

Thanks for your answer Jeff777 and everyone else. I really want to understand it. I have always wondered, but haven't asked because I don't want to appear racist in anyway - I have a genuine interest. Do you know why asians have double eyelids?