Origin of "Racial" Traits

Great Debates
1

I was reading this thread asking why do the Chinese have epicanthic folds.

Cecil was cited that it was either an environmentally induced selection or on accident.

John Mace reported correctly that this trait can be seen in the Khoi-San people of southern Africa as well.

It is widely speculated that the Khoi-San best represents the origin of the human race. I once saw a program on TV discussing the genetic history of mankind, and in summary, pointed out that these people exhibited various morphological traits that can be found throughout the “races”. This is in keeping with the tracing of human migration history. Black people’s ancestors migrated to Australia and environs. Yellow people’s ancestors migrated to the east coast. Red people’s ancestors migrated to Siberia and on to the Americas. White people migrated to cental Asia and back west to Europe.

Visual morphological differences among the isolated groups of mankind became quite distinct yet genetic research has proven that

  1. There is far more genetic differences among chimpanzees than among humans.

  2. There is more genetic differences among the people of sub Sahara Africa than between the “races”

Certainly this is evidence that man originated in Africa. Speculation is that man only left Africa around 60,000 years ago.

I can’t believe that migratory man evolved specific traits based on his environment. That is the environment selected him. Does anyone believe today that a black baby can’t survive to reproduce in Nunavut? Mankind had the ability to contol his environment ever since he had the brains common to us all.

He also had the ability in various degrees at various times to control other humans through warfare , banning, and sacrifice. Furthermore, he had the imagination to question his existence, and at best without science could only attribute it to much higher powers.

Over thousands of years different morphological traits can appear within a species. In the northern coast of British Columbia there is an area where about 10% of the black bear population is actually white. The local native people have long referred to them as spirit bears. Clearly, they have applied a religous connotation. Yet bears are not human. They do not develop a hatred for other bears of their species because they look different. But humans do. And humans will question its significance. Our recent history is proof of that.

Imagine a tribe in Africa where white babies suddenly appear and start to become more prevalent. Several years of drought, and the elders are looking for answers. Why are the gods angry with them? What’s changed? Could it be that the gods are angry because we are developing white people amongst us. Lets expel them. And so the new white tribe wends it way through the hostile tribes of Africa and finds an opening north of the Red Sea. It was a difficult journey and their hardships were attributed to the people among them who had epicanthic folds and angering the gods.

It wasn’t only whites that were expelled. As Africa became heavily populated, there certainly could have been all black tribes forced out of their homelands in search of their new territory. In fact they were probably first. Hugging the southern coast all the way to Australia leaving behind their relatives along various locations. When the whites migrated out of Africa, they avoided the blacks by migrating eastward toward cental Asia leaving their relatives all over before continuing on in various directions.

So somewhere in eastern Asia a tribe was born where the founding father and mother had epicanthic folds. They were isolated and the majority of the tribe had them. There was a drought so they sacrificed their children who did not have epicanthic folds to appease the gods.

In summary, I postulate that our " superficial’ racial differences are not at all environmentally induced or accidental as Cecil suggests. It is human kinds intelligence but limited knowledge that has given us religion and our subsequent hatred of others who look different.

Please discuss.

2

Your theory relies on sudden mutations - not the long arch of small incremental evolutionary changes.

Dark skin in very sunny climates makes sense - just as pale skin in less sunny climates makes sense. The human migration out of Africa into Northern Europe took a long time - the environmental impact upon appearance most like occurred over a long time as well.

In addition, human communities when such differences were evolving were relatively isolated and inbred. Any mutations which were not “snuffed out” had a chance of replicating more effectively and becoming common to the population.

I do agree that the sudden appearance of recessive traits, ie albinos, could be selected out due to superstition.

3

I don’t have a lot of time right now, so let me address this one point since it seems to be the point of origin of your confusion. Evolutoin is not digital-- ie, no one would claim that people* with black skin could not survive in the arctic. The argument is that lighter skin provides a statistical advantage for survival (and subsequent reproduction) in the arctic over darker skin. Even a slight increase in survival rate (ie, a few percent) by one trait can make that trait pervasive in a population over 10s of 1000s of years.

You are aslo making WAY too sweeping a statement in your last sentence. Humans have been able to **mitigate **environmental factors, but certainly not to **control **our environment. Even today, that would be an outlandish claim.

*for this discussion we are both talking about primitive hunter/gatherer type populations. Obviously, a technologically advanced population would be under less environmentally selective pressure.

4

Whose confused might be debatable. Let me point out that the people of the far north are darker skinned than the people of the more temperate climates. So much for statistical advantage.

Humans have contolled their immediate environment for 10s of millenia evidenced by their survival in more hostile environments than present in the tropics. Their survival depended on clothing and housing to control thier environment or mitigate their environment if you prefer. I’d say the ability to protect themselves from their environment is way more significant than skin tone.

Just how has modern technology suddenly given the black man an equal chance to the white man to survive the temperate regions of the world?

5

Lets assume that it was an original black tribe in Africa that migrated out. At some time either a sudden mutation occured to provide one white baby. Several decades later their were more white babies. Now suddenly the black members of the tribe couldn’t reach their reproductive age?

Or lets assume that the skin tone changed gradually. Black babies were less able to reach reproductive age. The whiter you were the more likely you would reach puberty?
I wish to add in support of my theory that the morphological differences in the species of homo sapiens occured over 10s of thousands of years. Such changes within a species over such a short time are only more evident in dogs and domesticated livestock species. These animal examples are a result of the hand of man, not environment, so why not attrbute the “racial” differences to the hand of man?

6

I don’t understand what you mean by “all of a sudden” the black babies couldn’t reach their reproductive age because of the presence of white babies.

Hunter-gatherer societies often lived on the edge of famine. They did expose babies that they decided were not worth the effort of feeding. It is logical that those with undesirable characteristics or deemed unhealthy would be abandoned. It doesn’t make sense that the majority would decide that their characteristics were unworthy of survival.

7

You can “point it out”, but you’d be wrong. Certainly there are instances of people with relatively darker skin in the far north and relatively lighter skin in the south, but ON AVERAGE the opposit is true. But, why don’t you give us your data. What is the relative frequency of the alleles for darker skin pigmentation vs ligher skin pigmintation over the globe? Please include your cite along with your data.

Absolutely. But that doesn’t mean that skin tone has NO effect. Again, you seem to be hunting for a digital answer-- either 100% or 0%. Things don’t work that way. No doubt some populations lacked the technology to survive in the arctic and either adapted by developing new technology or died out. Just as some populations increased or decreased due to physiological factors.

I don’t undertand your point. Are you suggesting that the advances in technology over the last say, 5,000 years has had no effect on mitigating environmental factors for survival? The shear size of the human population at persent woud seem to contradict that.

8

How long do you think it has taken to develop different breeds of dogs? This happens on the order of 100s of years, not 1,000s and not 10s of 1000s. The changes seen in modern human populations occured over a time frame 3 orders of magnitide greater (100x) than that time frame over which different dog breeds emerged (thru slective breeding).

9

See http://www.backintyme.com/Essay021215.htm
This includes global maps of skin tone

Seems like latitude has no bearing on selecting for skin tone.

I didn’t say that. I am contesting skin tone as a factor in survival is as irrelevant today as it was 40,000 years ago.

10

Actually, the archeological evidence is that dogs have been domesticated long past a thousand years. So knock off one order of magnitude.Genetic evidence would suggest even a 100,000 years for the origin of the dog. Secondly, the reproductive cycle for the dog is one order of magnitude shorter. Clearly man’s intervention in the selection process is far more intense and deliberate for his animals than for his fellow human beings so you can chalk up one further order of magnitude.

11

And you’re wrong. Consider Australia, home to the highest rates of skin cancer in the world. In the absence of sunscreen and advanced oncology, do you really think that fair-skinned Aussies wouldn’t be at a survival disadvantage relative to their dark-skinned compatriots? And for the inverse, look the consequences of vitamin D deficiency. Mmm, rickets! What fun. While Inuit and Siberian populations might be darker than northern Europeans, they’re a heck of a lot lighter than sub-Saharan Africans.

12

And isn’t that due to the recent man induced ozone depletion? Just wondering though, do you have stats on differing skin cancer rates for whites and Aborigines or Maoris? I never use sunscreens. I don’t believe early man was much on wearing a bikini and sunbathing either.

I used to have cod liver oil to combat rickets, but now we have vitamin D enriched milk. I also understand that many non-caucasians are lactose intolerant. Do all African Americans drink milk and if not, how do they combat rickets?

13

I was under the impression that the diet of the Inuit and Siberian compensates for the extra pigmentation; which is why they don’t need to be fair skinned.

14

What about the North American Indian and non coastal Siberian?

15

More or less. This is actually spelled out in substantial detail in grienspace’s cite containing the maps of skin tone. It talks all about vitamin D synthesis and the like, and it addresses most of his questions about how current patterns of skin tone could have evolved. I suspect he didn’t actually read it.

16

Yes I did, and that hypothesis doesn’t convince me. As a European born, why was the use of cod liver oil so prevalent in the 50s. Wasn’t I white enough?

With regard to holmes, I would further ask of what relevence is skin cancer anyway, which usually takes hold and kills past the reproductive age.

17

It appears that I was wrong about skin cancer being a selective force due to relatively late age of onset, as pointed out. The article talks about folic acid synthesis, and cites studies that support its claim. As for cod liver oil usage, your question seems misguided in at least two respects. First, evolutionary theory makes no predictions about cultural fads. And second, no one has ever said that evolution leads to organisms that are ideally adapted to their environments, just better than existing alternatives. Pale-skinned people may well still be vulnerable to vitamin-D deficiency (I’m no expert), making fish oil supplements a good idea, even if pale skin provides an advantage in this respect. That is, it makes people less susceptible to rickets, not impervious to rickets.

Why aren’t you convinced by the essay’s hypothesis, exactly? It struck me as pretty convincing.

18

Did you read the conclusion Gorsnak?

I’m not entirely dismissing the hypothesis. I’m just excited by my own. I don’t think my hypothesis is falsifiable, though I realize it might not be provable either.

19

Errr. Falsifiability is a good thing. It means that a hypothesis is responsive to evidence. Your hypothesis requires a lot of ad hoc assumptions and doesn’t provide any explanation for correlations between skin tone and environment. Their hypothesis explains both why there is usually a correlation between levels of UV radiation and skin tone, and why there are two major exceptions to this correlation.

20

Australian aborigines are at high risk of skin cancer. I do not have statistics how much more/less likely they are to be at risk than white/paler skinned people.

Two things should be borne in mind:

  1. Many aboriginal people today are mixed race, and have lighter skin than their forebears, which means less natural defence to the sun (melanin).

  2. The ozone hole. Talking to older-generation, (white) Australians, they will tell you that in their childhood they could spend hours in the sun, whereas today people burn in under an hour.

So that change in the environment has come within a couple of generations.