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Author Topic:   Skin colors and latitude
macaroniandcheese 
Suspended Member (Idle past 2720 days)
Posts: 4258
Joined: 05-24-2004


Message 46 of 65 (161376)
11-19-2004 1:58 AM
Reply to: Message 44 by mark24
11-18-2004 4:32 PM


Re: An Interesting Find
there are no original indigenous groups like that... however, the people in non-indigenous areas are moving in those directions.

This message is a reply to:
 Message 44 by mark24, posted 11-18-2004 4:32 PM mark24 has responded

Replies to this message:
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mark24
Member (Idle past 3987 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 47 of 65 (161385)
11-19-2004 3:26 AM
Reply to: Message 46 by macaroniandcheese
11-19-2004 1:58 AM


Re: An Interesting Find
Bren,

there are no original indigenous groups like that... however, the people in non-indigenous areas are moving in those directions.

Where? And why are there no indigenous populations where this occurs?

As explained previously, & you agreed, skin colour is not sex-linked, therefore when a dark skinned man mates with a light skinned female the offspring is in general inbetween as regards skin colour. This is in evidence in countries like the Dominican Republic where most of the population is a light cross between european whites & black negro. If your hypothesis were true the men would be black & the females white. They aren't, they have become homogenised.

Mark

This message has been edited by mark24, 11-19-2004 03:28 AM


There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 46 by macaroniandcheese, posted 11-19-2004 1:58 AM macaroniandcheese has responded

Replies to this message:
 Message 49 by Parsimonious_Razor, posted 11-19-2004 1:21 PM mark24 has responded
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contracycle
Inactive Member


Message 48 of 65 (161388)
11-19-2004 4:18 AM
Reply to: Message 40 by macaroniandcheese
11-18-2004 3:35 PM


Re: An Interesting Find
quote:
i'm not talking about popular culture in america.

And I was not talking about popular culture IN AMERICA either. Britain colonised huge chunks of the planet, and it is hardly as if prior to the invention of celluloid there were no depictions of people. There was plenty of poster art alone, for example, that propagated the dance-hall culture and could easily have had much the same role as modern hollywood (if rather less intensely).

As was mentioned above, the Victorian and prior aesthetic for the upper classes was to appear pale, and be therefore definitely not be identified as one of the "horny-handed sons of toil", tanned by wind and sun.

I find it prima facie plausible that men on aggregate are darker than women in a given population, but cannot see how this can give rise to a specifically white local population alone. Because if lightness of tone is a female sexual signifier, and so is darkness in men (the tall, dark stranger of fiction one presumes), then the next generation should show much the same dimorphism, not be driven down only one path.


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Parsimonious_Razor
Inactive Member


Message 49 of 65 (161494)
11-19-2004 1:21 PM
Reply to: Message 47 by mark24
11-19-2004 3:26 AM


Re: An Interesting Find
A trait doesnt have to be sex-linked genetically to be sexualy dimorphic. I quoted some research in the post above that showed relative lightness and darkness of skin is linked to hormones. Testosterone is linked to darker skin and estrogin to lighter skin. There also appears to be a sexual preference of men for the lighter skin and hair tones for women with in ones group.

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Replies to this message:
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macaroniandcheese 
Suspended Member (Idle past 2720 days)
Posts: 4258
Joined: 05-24-2004


Message 50 of 65 (161499)
11-19-2004 1:41 PM
Reply to: Message 47 by mark24
11-19-2004 3:26 AM


Re: An Interesting Find
you don't pay much attention to people do you?

This message is a reply to:
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macaroniandcheese 
Suspended Member (Idle past 2720 days)
Posts: 4258
Joined: 05-24-2004


Message 51 of 65 (161500)
11-19-2004 1:43 PM
Reply to: Message 49 by Parsimonious_Razor
11-19-2004 1:21 PM


Re: An Interesting Find
that's what i've been saying all along...

This message is a reply to:
 Message 49 by Parsimonious_Razor, posted 11-19-2004 1:21 PM Parsimonious_Razor has responded

Replies to this message:
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mark24
Member (Idle past 3987 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 52 of 65 (161512)
11-19-2004 2:00 PM
Reply to: Message 50 by macaroniandcheese
11-19-2004 1:41 PM


Re: An Interesting Find
Brennaki,

you don't pay much attention to people do you?

What are you talking about? I have directly challenged you on this more than once, & you accuse me of not paying attention? Draw a line under it.

You have claimed that male preference for light skin & vice versa for females is somehow able to lead to entire populations of light or dark skins? I have been alluding to this problem since you broached the subject, how can this occur? If you have light females & dark males how will all males end up light as in europeans, or vice versa in africans? I have seen the evidence that others have presented on sexual dimorphism as regards skin colour, but still fail to see how this leads to an entire population being light or dark.

Contracycle put it better than I could:

I find it prima facie plausible that men on aggregate are darker than women in a given population, but cannot see how this can give rise to a specifically white local population alone. Because if lightness of tone is a female sexual signifier, and so is darkness in men (the tall, dark stranger of fiction one presumes), then the next generation should show much the same dimorphism, not be driven down only one path.

Do you understand this? It explains the appearance & maintenance of the sexual dimorphism, but in no way explains a directional shift that would drive the entire population lighter or darker.

Mark


There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 50 by macaroniandcheese, posted 11-19-2004 1:41 PM macaroniandcheese has responded

Replies to this message:
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Parsimonious_Razor
Inactive Member


Message 53 of 65 (161513)
11-19-2004 2:01 PM
Reply to: Message 51 by macaroniandcheese
11-19-2004 1:43 PM


Re: An Interesting Find
The studies that I have read all say that on average women are lighter then men cross culturally. If estrogin, as it appears to be, is truly linked to lighter skin tones then it makes perfect since. Her at the Univeristy of New Mexico a lot of studies have been done and are being done right now about attractivness ratings and assesments. Men prefer women with strong estrogin signals.

Aoki, 2002 cited above talks about how the theory of vitamin D and rickets acting as a natural selective pressure for lighter skin isn't with out its criticisms. Most serious metastudies on the topic find strong evidence for a wide range of proxmiate and ultimate causes. UV protection is included in these but so is pathogen resistence, immuno system aiding, sexual selection, dominate mating systems in the society and a range of early enviormental cues both in the womb and once the child is born. There are VERY few things in evolution that can be summed up nice and tidy with a singal selective agent. Skin color isn't one of them.


This message is a reply to:
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Parsimonious_Razor
Inactive Member


Message 54 of 65 (161514)
11-19-2004 2:05 PM
Reply to: Message 52 by mark24
11-19-2004 2:00 PM


Re: An Interesting Find
The research that I have seen suggest that there may be strong natural selection pressures for dark skin everywhere. In more northern climates the natrual selection pressure maybe reduced to the point that sexual selection could drive the population to lighter skin tones. If there is strong selective pressure on women for lighter skin tones and, as you have said, there is no sex linked genes wouldn't the men in such a population also proceed to get lighter? I have not seen any evidence that there is sexual preference for DARKER men, but also have seen no convincing evidence that there is preference for lighter men.

The only sexual selection pressure that seems related to darkening up people is in highly polygamous societies which push for massive testosterone due to intragender mate competition. If the natural selection pressures for darker skin is reduced and there is minimal male-male competition, I don't see why sexual selection on females for lighter skin wouldn't lead to whole populations becoming lighter.


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 Message 52 by mark24, posted 11-19-2004 2:00 PM mark24 has responded

Replies to this message:
 Message 56 by mark24, posted 11-19-2004 2:22 PM Parsimonious_Razor has responded

  
mark24
Member (Idle past 3987 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 55 of 65 (161515)
11-19-2004 2:07 PM
Reply to: Message 49 by Parsimonious_Razor
11-19-2004 1:21 PM


Re: An Interesting Find
Hi Parsimonious,

Thanks for your information.

I have the same conceptual problem as contracycle with the sexual selection of males for light females, & females for dark males being able to produce a directional pressure in one way or the other. Surely it would simply maintain sexual dimorphism as is in the next generation?

Mark


There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 49 by Parsimonious_Razor, posted 11-19-2004 1:21 PM Parsimonious_Razor has not yet responded

  
mark24
Member (Idle past 3987 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 56 of 65 (161520)
11-19-2004 2:22 PM
Reply to: Message 54 by Parsimonious_Razor
11-19-2004 2:05 PM


Re: An Interesting Find
PR,

I have not seen any evidence that there is sexual preference for DARKER men

Yes, that makes sense, but it also contradicts Brennakimi who maintains that there is sexual preference for darker men among females. Regardless, I'll take your word over hers unless she can produce evidence to support this.

but also have seen no convincing evidence that there is preference for lighter men.

But assuming random sorting during meiosis it wouldn't matter, if one sex had a preference, & the other didn't either way, then there would be a directional pressure in favour of that sex across the population as a whole.

Mark


This message is a reply to:
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Parsimonious_Razor
Inactive Member


Message 57 of 65 (161549)
11-19-2004 4:40 PM
Reply to: Message 56 by mark24
11-19-2004 2:22 PM


Re: An Interesting Find
quote:
Yes, that makes sense, but it also contradicts Brennakimi who maintains that there is sexual preference for darker men among females. Regardless, I'll take your word over hers unless she can produce evidence to support this.

There have been some studies that suggest perhaps there is a preference of women for lighter colors in men as well. This is related back to the idea of neotony. That humans seem to prefer characteristics in mates that are usually associated with juvinial traits in other primates. But the problem with female preference is that it is far from constant. There is a major shift between what a women likes and dislikes across their cycle. One change that applies here would be during peak fertility points there is a preference for more testosteronized men, but during extended sexuality a preference for much more estroginzed men. So any study that wanted to look at female preference for skin color would have to take cycle effects into account, and I havent seen any such study. The only one saw a slight preference for lighter skin tones but there was no account taken for cycle effects. Untill that is done I remain agnostic one way or another.

But there does appear to be SOME evidence for male-male competition leading to darker skin. This is more to do with higher testosterone being favored in more polygamous systems.

quote:
But assuming random sorting during meiosis it wouldn't matter, if one sex had a preference, & the other didn't either way, then there would be a directional pressure in favour of that sex across the population as a whole.

So if the women were recieving sexual selection pressure to become lighter, and there was no longer a strong natural selection pressure to maintain darker skin you would expect them to become lighter and lighter. If there was a genetic component beyond sensitivity to estrogin levels then the sons as well as the daughters would be lighter, so perhaps the whole population would move towards lighter skin.


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macaroniandcheese 
Suspended Member (Idle past 2720 days)
Posts: 4258
Joined: 05-24-2004


Message 58 of 65 (161699)
11-20-2004 12:14 AM
Reply to: Message 53 by Parsimonious_Razor
11-19-2004 2:01 PM


Re: An Interesting Find
quite so. i was simply trying to add another piece to the puzzle since everyone had decided that the only differentiation or skin tone was caused by uv exposure ... which conveniently saves everyone from sounding racist in any way. i think it's quite stupid to bother avoiding sounding like anything... people who make accusations of such are simply looking for trouble.

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Replies to this message:
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macaroniandcheese 
Suspended Member (Idle past 2720 days)
Posts: 4258
Joined: 05-24-2004


Message 59 of 65 (161712)
11-20-2004 12:39 AM
Reply to: Message 52 by mark24
11-19-2004 2:00 PM


Re: An Interesting Find
the descent of man, and selections relating to sex.

darwin wrote it about twelve years after he whote his more famous book... it entirely discounts natural selection as a cause of racial variation amongst humans.

the below information is paraphrased from the third chimpanzee which i already suggested you read.

tasmanians have very dark skin and their area recieves very little sunlight. (btw. australian aborigines and their tasmanian compatriots have lived there for 50,000 years. more than long enough to adapt to the lower uv since most europeans have been in their indigenous home much less time. par example. scandinavia has only been inhabited for 9,000 years.)
no one in the new world has very dark skin immaterial of uv exposure.
parts of asia with excessive uv exposure boast only medium-toned peoples.
"when one takes cloud cover into account, the world's most dimly lit areas, recieving a daily average of under 3.5 hours of sunlight, include parts of equatorial west africa, south china, and scandinavia, inhabited respectively by some of the world's blackest, yellowest, and palest peoples!" (diamond 115).
in the solomon islands (sorry. i thought it was new guinea... wrong place it's been a while since i read it.) there are indigenous people with very dark skin and very light skin living within short distances of each other.


This message is a reply to:
 Message 52 by mark24, posted 11-19-2004 2:00 PM mark24 has responded

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contracycle
Inactive Member


Message 60 of 65 (162287)
11-22-2004 9:03 AM
Reply to: Message 58 by macaroniandcheese
11-20-2004 12:14 AM


Re: An Interesting Find
quote:
i think it's quite stupid to bother avoiding sounding like anything... people who make accusations of such are simply looking for trouble.

Really? The theosophists claimed the dark-skinned people were less spiritually developed than light skinned people, rather similar to certain Fascist ideas. It is not stupid to seek to AVOID sounding like a reflexive racist and ensure that your analysis is actually grounded in fact when there is so much history of exactly this sort of argument being put forward for supremacist reasons.

So if I understand the argument being put forward here then, it is that masculine darkness arises mainly from male-on-male competition, and that in the ABSENCE of polygynous social arrangements, this competition will be muted, resulting in male selection for female lightness more or less alone.

Is there any evidence indicating that the population groups which became white caucasians were the earliest developers of monogamy? That would seem to be the implicaitons of the argument.

As an alternate hypothesis, I would suggest the same result would be achieved by the conversion of women to chattel property, in that their ability to select their mates would be radically curtailed, leaving male-selection-for-lightness to operate without a counter-selection by women.


This message is a reply to:
 Message 58 by macaroniandcheese, posted 11-20-2004 12:14 AM macaroniandcheese has responded

Replies to this message:
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