Talk:Human skin color/Archives/2011/July

Evolution of Skin Color

"By 1.2 million years ago, shortly after the final speciation of homo sapiens from homo ergaster" UMM, since when did homo sapiens speciate 1.2 million years ago? Even if you consider the Archaics as subspecies of homo sapiens - which many anthropologists do not - they did not exist until 500,000 years ago. Anatomically modern humans, homo sapiens or homo sapiens sapiens if you prefer, have been earliest recorded about 200,000 years ago. 1.2 million years ago homo erectus and homo antecessor were walking the Earth. Succubus MacAstaroth (talk) 10:15, 1 April 2011 (UTC)

"The leading explanation is that skin color adapts to sunlight intensities which produce vitamin D deficiency or ultraviolet light damage to folic acid.[4] Other hypotheses include protection from ambient temperature, infections, skin cancer or frostbite, an alteration in food, and sexual selection.[5]" What about predation? Dark-skinned bands of humans that wandered into tundras, for example, would have been easily detectable by predators, with those possessing lighter-skinned mutations or albinism having an advantage for long-term survival. Are humans so pompous as to believe we have always been on top of the food chain? 68.208.127.1 (talk) 04:13, 28 July 2011 (UTC)

new theory

What about the new theory that melanin is an anti-infection agent and that rather than people evolving lower melanin in order to let in more light, they did it because they weren't as healthy and so couldn't afford the metabolic cost of melanin production? According to this theory, melanin corresponds to humidity levels (which many viruses and bacteria depend on) instead of light levels. --Ark

Hum, -- never came up in my immunology, antomomy or human evolution classes and I can't find anything about it on Google either. It does sound interesting. Do you have a webpage or better yet a peer-reviewed journal article to point me to for more information? --maveric149, Tuesday, June 11, 2002

Heh. It came up either in Scientific American or New Scientist. Probably sometime in the last year. In the last two years definitely. :)

Basically it was speculation based on some preliminary finding. I don't remember what the finding was though. I just mentioned it because like you said, it's so interesting. -- Ark

Cool I try to find it. It's probably a bit too new and unvarified to include in this article though. --maveric149

I remember seeing a little article in New Scientist at least five and probably ten or more years ago on this. One point that I did remember was the comment about there often being a concentration of melanin around that particular part of the anatomy where, as they say, "the Sun don't shine". This fits with the antiseptic hypothesis, and not with the solar radiation/vitamin D/sunburn theory. Of course, there could be some truth in both theories. --ADM

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What does this mean?

In general, people with recent ancestors in sunny regions have darker skin than people with recent ancestors in regions that lack much sunlight.

Was the above sentence intended to support idea that acquired characteristics can be inherited? I thought Lysenkoism had been thoroughly discredited. --Ed Poor 19:59 Sep 6, 2002 (UCT)

I think you can get that with usual natural selection arguments. White skin is more susceptible to skin cancer, so you could eliminate them from the gene pool because of that.AstroNomer (Who is not a biologist and is just waving hands)

• I also am not a biologist. However, my understanding is:
  • If you are born light-skinned in a region with intense sunlight levels, your chances of skin cancer are much greater. Ergo genes for fair skin are much less likely to be passed on. There are probably other factors like increased vulnerability to disease as a result that would intensify this.
  • If you are born dark-skinned in a region with low sunlight levels, your body doesn't synthesize as much of a certain nutrient (vitamin D?), which is best catalyzed by sunlight on skin. Ergo, your resistance to disease and such goes down, and again, your genes are far less likely to be passed down through the generations.
• Over many generations this dual selection effect may lead to the grouping of prevalent skin colors according to the amount of sunlight received by, oh, the past few hundred generations in a given locale. -- April

Right, I understand about the "genes being passed on" part. And it accords with ethnographical observations of Northern Europeans being light-skinned and equatorial Africans and Caribbeanns being dark-skinned.

My confusion was about the "recent ancestors" claim in the sentence I first quoted way above. I'd like to revise it so it doesn't give the impression that the process takes place over a couple of generations. Doesn't it take centuries before we start to see any significant differences? --Ed Poor

I see what you mean. Probably he was meaning e.g. african-americans: they have "recent ancestors" from Africa, that were dark skinned because they had had lots of ancestors living there. There is a step missing in the chain.AstroNomer

• Going out on a limb here, with my shaky bio knowledge, but I'd guess that the genes for most skin levels would be present, if not common or commonly expressed, in just about any population. So if two groups of humans colonize a high-sunlight planet and a low-sunlight planet, and then are cut off from intermarriage outside the group, we'd start seeing significant changes between the populations in... well, if you take a "generation" as about 20 years... at a very rough guess, maybe a few centuries?

• I suspect that by "recent" the person was thinking "hundreds or thousands of years in the same place" as opposed to, say, ten thousand to a hundred thousand years, which is (I think) the scale of many major population migrations. Add a lot of caveats that I could be talking complete nonsense here, 'cause I'm far from expert. :) -- April

I thought of "recent ancestors" as not more than 4 generations back, like my great-great-grandparents, who are Polish and Russian Jews (on my mother's side). Thanks for the scientific help. I think I have enough information to edit the article.

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What means "The lighter skin of women results either from sexual preference or from the higher calcium needs of women during pregnancy and lactation."??? Can I see the ``sexual preference of a woman in her skin color?

There has been no proven correlation between lighter skin and gender, in any culture or race. Beauty standards in the modern age, a byproduct of colonialism, are purely cultural.

In addition, Vitamin D in high levels is toxic, such that people with melanin were at a biological advantage in high-sunlight areas in their ability to regulate, thus prevent over-production of, the vitamin.

  -M

What he is trying to say is that women with lighter skin are supposedly prettier. He should look at Beyonce Knowles and reconsider. Cameron Nedland 03:33, 29 December 2005 (UTC)

There is a school of thought suggesting that light skin, blond hair, and pale blue eye color arose in part among European populations during the last Ice Age as a way for females to attract males. The lighter-skinned females stood out from the others and were more "exotic," hence more desirable as mates. There is solid evidence that there was a gender imbalance in Europe at that time (for varous reasons), and that strong males were in shorter supply. So in addition to other environmental factors selecting for light skin, demographics may have also played a role. Sociobiologists can see in populations today that small numbers of different looking females are viewed as particularly attractive sex partners by dominant males. On study in Finland showed that while racist views were quite prevelant in the overrall population, the small population of young black and asian women resident there received a higher degree of sexual advances from Finnish males than the average young ethnic Finn did; the "exotic" theory at work.

In general, however, given the smaller number of very light-skinned females in most societies, it will be these who are considered the most attractive, Beyonce notwithstanding.

Recent studies on internet pornography tend to support this. Both black and white males are drawn in far greater numbers to websites featuring light-skinned, white girls. There are, of course, sites featuring Latinas and black women, but far fewer. None of this is politically correct, of course, and most scientists won't touch these issues. I work in a related field myself, and I admit that I won't sign my name here because of the fear of being labelled racist, etc.

I don't think any of that means that light-skinned females are "better" than dark-skinned females, etc. That's not what it's about. And cultural factors are obviusly involved too. But there is quite a bit of rather dry evidence to support that in general, males in most populations are somewhat "hard-wired" to prefer light-skinned gals over dark-skinned ones.

Let's put it this way. As any biologist will tell you (and I'm one), all animals use visual markers and signals to attract and select mates, and obervation of any species will identify certain physical characteristics, especially marking and color patterns, that invariably attract more attention. Humans are no different. Difficult for us to talk about or admit given the way that "race" has negatively impacted so many people throughout the world. But from a cold scientific standpoint, it's true.

no dear its not true white people like whites and dark people like darks naturally. asians prefer asians but when whites are always humiliating black people(dont deny it )and all other people like asians and other races and due to increasing domination of your culture(north america and europ)by goods,advertisements,movies etc yes they prefer their child be one of you and belong to you (better race) sorry im very frank but just look at mis world selection they selected a blond girl in my country no one think that she is better than others or even beauteful.my people (in your opinion of cours uncivilized!!!)dont like very thin and very white girls they call them corps (you know dead body is bloodless and white!)and light eyes have always been the symptom of villainy! sorry i dont want to insult you but it was like this.

Wow, eye colour as an indicator of "villainy"; this is a whole new level of racism.86.144.145.48 (talk) 10:33, 19 July 2011 (UTC)

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Why/how is it that the Tasmanian Aborigine, a population isolated for thousands of years so far south, retained such dark skin? Tasmania is as close to the South Pole as Southern Europe, mid-North-America, or Japan is from the North, and the populations of those areas were much lighter. -- stewacide 20:39, 18 Mar 2004 (UTC)

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I'm a tad confused as well. For vitamin D production, the amount of time spent in the sun is trivial -- say, about 15 minutes/day, for a light-skinned person. For a dark skin person, they might need 6 times that -- Say, an hour and a half. Thus, the skin-color/vitamin D link seems a tad weak. I believe Darwin wanted to chalk skin color up to sexual selection. The Tasmanians have been isolated in Tasmania for thousands of years -- the disappearance of the Tasmanian-Australia landbridge is known. At the same time, the retreat of the glaciers from northern Europe happened later. But the typical northern European has light skin, Tasmanians have dark skin.

The climate in Tasmania is only marginally colder than the coastal temperate areas of mainland Australia (for example Melbourne and Sydney) and Aboriginals on Mainland Australia mainly lived in those cooler temperate areas and not in the deserts until Europeans arrived.

Article explains examples such as Tasmanian skin color when it mentions the Aleut exception; Tasmania is a small island, so the indigenous diet was likely high in fish, which canceled out the need for light skin to produce vitamin D. Also, the idea that Aboriginals in Australia didn't live in the desert until the Europeans arrived is erroneous. Archaeological evidence puts occupation of the desert at several thousand years.DayBaye (talk) 21:35, 18 December 2008 (UTC)

Edit war

It seems like a so-called edit war has been started, wherefore I create this discussion. The same is the case with the article Sun tanning.

According to my view, these articles lack nuances and attempt to give an impression of that tanned colour completely has taken over 'the exclusivity' and that all persons in the Western world consider tanned skin colour as e.g. «fashionable, healthy, and luxurious».

The article should be nuanced by including various temporary considerations of the concept of tanned skin. It should preferrably come from reliable scientific research. It is too silly when the formulations in the text appear like they have been taken from a fashion and lifestyle magazine.

--- Aaemn784 (talk) 17:55, 21 April 2011 (UTC)

I have rather asked for editor assistance, since users seem to place their personal opinions and agendas before science.

http://en.wikipedia.org/wiki/Wikipedia:Editor_assistance/Requests#Edit_Disagreement_in_.27Human_skin_color.27_and_.27Sun_tanning.27

--- Aaemn784 (talk) 14:30, 22 April 2011 (UTC)

Agreed, the section on skin tanning is very unbalanced ("tanned skin has become more desirable in both men and women"). Personally, I think skin tanning (and especially the use of sunbeds) is vulgar and the result ugly. The classical view is that fair skin is beautiful, and there is no evidence suggesting this is no longer the case. TuriTerj (talk) 19:44, 3 July 2011 (UTC)

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Help with an user that modifies the article in a wrong way

I pray the moderators of Wikipedia to forbid the user 111.94.228.121 to modify the position of East Asian in Phototype II. The sources added by user 111.94.228.121 say that East Asian People belong to Phototype IV (see Sources 52, 53, 54 in notes) but he put East Asians in Phototype II. I corrected the error committed by user 111.94.228.121 and I told him that his sources say the opposite of what he asserts. Now, I'm wondering if he can read or understand English... I don't know... but I'm sure that he is in error (see his sources). So, I ask your help to lock the East Asian position in Phototype IV in the article. Also scientifical articles and essays (see Jablonski and Chaplin) say that skin reflectance of Europeans (also Southern Europeans) is higher than that of East Asian (so the skin of europeans is lighter). Also, Japanese people have values very similar to those of Philipino people and Vietnamese people. Europeans range is from 62 to 69, East Asian range is from 50 to 59: so, it is impossible that East Asians are of Phototype II (the phototype of Central and, partially, Northern Europeans) when East Asians are darker than Southern europeans, that are of Phototype III. So, I believe that the personal beliefs and racist east-asian supremacism of user 111.94.228.121 must be stopped.

Thanks for attention, regards — Preceding unsigned comment added by 80.182.11.166 (talk) 11:36, 22 July 2011 (UTC)