Politically Incorrect Curiosity

Ever since childhood, there have been a few things I've always wondered about concerning humanity. There is no politically correct way I can express this curiosity, so I will preface it by saying that no prejudicial judgement of any particular human group is intended, but that it is simple curiosity.

Humanity has three major racial groups: whites, blacks, and asians. In two of these groups, among those who are racially unmixed, there is uniformity of hair and eye color, and hair texture. Both groups have naturally black hair and dark brown eyes, with black people having curly/kinky hair and asian people having straight hair. Among whites, however, there is a great deal of variety in these three traits: hair can be black, plus various shades of brown, red, or blond. Hair texture can be straight, wavy, or curly. Eye color can be brown, blue, green, or hazel.

Why do these various combinations exist in whites, where they do not in the other two races? Because all three races can have black hair and brown eyes, it would seem as if this is a strong human genetic preference. What purpose do such traits serve?

Some racial variations have easily explained reasons. Black people, who originated in Africa's hot climate, have dark skin as a protection from the sun. Whites, who originated in colder climates, have lighter skin in reaction to that.

But the reasons for hair and eye traits aren't so obvious. I've yet to find any lengthy explanation for why variations exist in whites, but not in the other two races.

Another thing I've wondered is why humans did not advance technologically at the same pace all over the planet. When Europeans first came to North America, they had brick buildings, written language, universities, ships, carriages, and so on. The Native Americans they encountered had none of these things, not even the wheel. Some cultures to this day live at a stone age level. I'd always wondered why this was so, as I was sure that people all over the planet were equally intelligent.

Fortunately, I have some of the answers for this particular question, as I encountered the book John Sherck mentioned in a recent blog entry: "Guns, Germs, and Steel" by Jared Diamond, which explains why societies around the globe have developed at different paces. I'm hoping to one day find something written about the first topic I mentioned.