The RED Man In North America for 50,000 years?

[Colter]

Bill Nye (The Science Guy) was on CNN Saturaday night, explaining the radical implications of finding evidence of human habitation and tool use in S. Carolina dating back 50,000 years. It doesn't just affect the concept of when the red man came to the Americas, but also

1. The theory of the origin of race. If humans in N. America stayed red-skinned over this period of time, then skin color is probably not an evolutionary adaptation to sun light exposure at different latitudes. So when and why did differentiation into races occur?

2. The time frame in which "modern" humans migrated out of Africa, and when civilization developed. In the future, the Urantia Book view of these matters may not seem so different from that of the mainstream.

[Jose]

It remains to be seen whether the date of 50,300 years actually applies to a human-tended fire, or to a natural fire. It's probably actual ashes, though.

Even though we don't have enough data to decide one way or the other, your questions are still interesting.

1. The theory of the origin of race. If humans in N. America stayed red-skinned over this period of time, then skin color is probably not an evolutionary adaptation to sun light exposure at different latitudes. So when and why did differentiation into races occur?

I don't see any reason to discard the idea that melanin is an adaptation to UV exposure. What's interesting is that, as we migrated from Africa to Asia, and [at some time, by some means] to North America, then south to Central and South America, we went through different UV-irradiation zones. In equatorial Africa, there's a lot of UV. Melanin is advantageous. In northern latitudes, there's a lot less. Too much melanin is dis-advantageous, so mutations were selected for that decreased our constant-output of melanin. In migrating back south into high-UV zones, we picked up new mutations that gave us more melanin expression--but not strict reversal of the original mutations. Instead, we picked up a really good tanning response. [My personal experience with this is that I burn easily, and tan slowly, being of Scottish heritage. My son has a modicum of Tarahumare heritage, and he tans darkly and quickly.] Whether there were people in South Carolina 50,000 years ago doesn't really change the dynamics, or the molecular biology of UV sensitivity. After all, we presume that dark skin was the original human condition in Affrica; selection has maintained it for at least 200,000 years. Selection has maintained light skin in northern Europe for probably 100,000 years. Why not allow selection to maintain a pretty-good tanning response for 50,000 years?

It's also worth pointing out that the genetic data indicate that there is more genetic diversity among humans in Africa than in the rest of the world combined. The genetic data indicate that one of the African lineages gave rise to all of the rest of us (the ones who walked north, rather than south or west). I rather like this. It means our made-up notion of "race" is entirely without merit. We'd have to say, instead, that there might be 4 races in Africa, and one of those races includes Africans, Asians, Europeans, and everyone else. Cute.

2. The time frame in which "modern" humans migrated out of Africa, and when civilization developed. In the future, the Urantia Book view of these matters may not seem so different from that of the mainstream.

I'm not sure there's anything here that's relevant to the Urantia Book, but its proponents will find something (just as proponents of the Bible can find "accurate predictions" of things in their book). Still, finding 50,000 year-old habitation sites tells us, at best, when humans got here, not when they left Africa. Between the date of 200,000 years in Africa, and 50,000 years in South Carolina, there's still a couple of years in between when they could have been moseying along on their way here. For civilization, of course, we'd need more than a fire pit--so I think we're stuck with the known ruins for that timepoint.

As I recall, the traditional view is that we reached South America some 13,000 years ago, but some evidence suggests occupation at 40,000 years. This would be consistent with that age, and would still be consistent with the migration from Africa to the Americas. Perhaps they got their feet wet on the land bridge, though.

But again, much depends on what the deposit turns out to be. If it's not a result of human activity...

[2 and 92]

Do not forget that skin tone is also a sexually selected trait. It is not only a UV protection, but in some areas, your skin color is as important to your getting a mate as feather color is to birds.

[Jose]

Do not forget that skin tone is also a sexually selected trait. It is not only a UV protection, but in some areas, your skin color is as important to your getting a mate as feather color is to birds.

Excellent point, 2 and 92. I've also thought that endlessly-growing hair must be, too, since most mammals have hair that reaches a certain length and then stops. We do too, everywhere except our heads. Along with it is an inordinate concern about what our hair looks like. I bet our concern about having "good skin" is related to selection for skin tone. Interesting.

[Lotan]

Among the Inuit, where a relatively spherical body shape is a survival advantage, relatively spherical women are (or at least were) prized for their beauty. At least if Peter Freuchen is to be believed.

[potwalloper.]

I bet our concern about having "good skin" is related to selection for skin tone. Interesting

A good point. A recent study by Craig Roberts and his team at Newcastle University, UK, found that women find the skin of men with a healthier set of genes more attractive. Specifically the team looked at three of a key set of immune system genes called the MHC genes. Scientists currently believe that having a mixture of different versions of these genes makes a person better able to fight off infection. When the team asked 50 women to rate the attractiveness of 92 male faces they found that the women preferred men with different versions of all three genes. Amazingly they got similar results when they only showed the women a small piece of skin from the man's cheek. The study is to be published shortly in Evolution and Human Behaviour and was reported in summary in New Scientist on 30 October.

[Colter]

I bet our concern about having "good skin" is related to selection for skin tone. Interesting

A good point. A recent study by Craig Roberts and his team at Newcastle University, UK, found that women find the skin of men with a healthier set of genes more attractive. Specifically the team looked at three of a key set of immune system genes called the MHC genes. Scientists currently believe that having a mixture of different versions of these genes makes a person better able to fight off infection. When the team asked 50 women to rate the attractiveness of 92 male faces they found that the women preferred men with different versions of all three genes. Amazingly they got similar results when they only showed the women a small piece of skin from the man's cheek. The study is to be published shortly in Evolution and Human Behaviour and was reported in summary in New Scientist on 30 October.

Interesting, as a male I've always been kind of turned off by fake tans on women. The look orange like the Umpa Lumpas of Willie Wonka fame.

[loki]

One should also consider the possibility of migratory european tribes, i.e. Kennewick Man, marching across the steppes in search of food. An intermingling of the races/sub-species would explain the differences; height, bone structure, skin tone..., between the south american indians and those of the north.