Geoff Brody Posted August 9, 2016 Posted August 9, 2016 Was it something like this: http://res.cloudinary.com/dk-find-out/image/upload/q_80,w_640/H_sapiens_male_f3_29189_h66jq4.png I heard that since we evolved in an infared environment, it was light and medium brown complexion, so I'm confused.
DrmDoc Posted August 9, 2016 Posted August 9, 2016 (edited) According to most reconstructions from the fossils of the earliest modern humans, whose continental origin is Africa, I think that is a very good approximation of their appearance. Edited August 9, 2016 by DrmDoc
Joshua Chasseur Posted August 9, 2016 Posted August 9, 2016 Is what is posted above with them having very dark skin accurate? According to most reconstructions from the fossils of the earliest modern humans, whose continental origin is Africa, I think that is a very good approximation of their appearance. In the link, they look like they have brown skin, but the post shows them with a darker complexion, so which one is more accurate?
DrmDoc Posted August 9, 2016 Posted August 9, 2016 (edited) Is what is posted above with them having very dark skin accurate? In the link, they look like they have brown skin, but the post shows them with a darker complexion, so which one is more accurate? Thriving in the open savannahs of Africa, I think the earliest modern humans were probably darker complexioned due to their likely heavy sunlight exposure and the extra protection to exposure that darker skin provides. Edited August 9, 2016 by DrmDoc
StringJunky Posted August 9, 2016 Posted August 9, 2016 Is what is posted above with them having very dark skin accurate? In the link, they look like they have brown skin, but the post shows them with a darker complexion, so which one is more accurate? They would have been all shades, just like they have today, but some more common than others
John Cuthber Posted August 9, 2016 Posted August 9, 2016 I heard that since we evolved in an infared environment, What does that mean?
Strange Posted August 9, 2016 Posted August 9, 2016 What does that mean? I think it means in an area with a fairly high level of UV.
sethoflagos Posted August 9, 2016 Posted August 9, 2016 As a relatively pale skinned person who has lived in the African equatorial belt for nearly 20 years, one of the really useful benefits of a dark skin that I envy is the ability to find shade and radiate excess body heat away quickly, especially in very humid conditions where sweating does nothing but dehydrate. In this environment, heat stress and dehydration can kill very quickly. Traditional forest peoples who rarely see direct sunlight are often among the typically darkest-skinned. So I find the solar exposure theories a bit of a simplification. Africa is far, far more varied in ecosystem diversity than is widely realised (Savanna? Which type of savanna?) and the genetic diversity both of living Africans, and our distant African common ancestors must reflect this. To some extent the question is silly. There is no genetic advantage in monochrome uniformity. So arguing about the precise shading of our ancestors tells us far more about our present than our past.
StringJunky Posted August 9, 2016 Posted August 9, 2016 (edited) Traditional forest peoples who rarely see direct sunlight are often among the typically darkest-skinned. So I find the solar exposure theories a bit of a simplification. Perhaps the advantage of dark skin, in a forest environment, is concealment or camouflage from prey/enemies and useful for stalking. As you say, they are amongst the darkest skinned and that would be a definite plus for merging with the shadowed areas. Edited August 9, 2016 by StringJunky
sethoflagos Posted August 9, 2016 Posted August 9, 2016 Perhaps the advantage in a forest environment is concealment or camouflage from prey/enemies and useful for stalking. As you say, they are amongst the darkest skinned and that would be a definite plus for merging with the shadowed areas. I spent a year in the middle of the Gabonese rainforest. Very strange environment. Not sure camouflage is that relevant in the forest providing you're not some luminous primary colour. Sound and smell are far more relevant for locating prey. I put some store in thermoregulation. Forest peoples hardly sweat at all. So it's clearly a significant evolutionary factor for them. But these processes are never simple. 1
StringJunky Posted August 9, 2016 Posted August 9, 2016 (edited) I spent a year in the middle of the Gabonese rainforest. Very strange environment. Not sure camouflage is that relevant in the forest providing you're not some luminous primary colour. Sound and smell are far more relevant for locating prey. I put some store in thermoregulation. Forest peoples hardly sweat at all. So it's clearly a significant evolutionary factor for them. But these processes are never simple. Interesting point about the heat dissipation properties of black skin; wasn't aware of that. Edited August 9, 2016 by StringJunky
DrmDoc Posted August 9, 2016 Posted August 9, 2016 Most paleoanthropologist agree that modern humans emerge in Africa about 200,000 years ago. Paleoclimatology suggests our African ancestors evolved amid tropic or near tropic conditions. When we couple the place of emergence of modern humans and their likely equatorial climate with contemporary evidence suggesting the equatorial origin of dark skin pigmentation, I believe we can only conclude that the earliest modern humans were singularly dark complexioned.
StringJunky Posted August 9, 2016 Posted August 9, 2016 Most paleoanthropologist agree that modern humans emerge in Africa about 200,000 years ago. Paleoclimatology suggests our African ancestors evolved amid tropic or near tropic conditions. When we couple the place of emergence of modern humans and their likely equatorial climate with contemporary evidence suggesting the equatorial origin of dark skin pigmentation, I believe we can only conclude that the earliest modern humans were singularly dark complexioned. No such thing as mutants then? You only have to find one example to prove your belief wrong that humans were "singularly" dark skinned..
Delta1212 Posted August 9, 2016 Posted August 9, 2016 No such thing as mutants then? You only have to find one example to prove your belief wrong that humans were "singularly" dark skinned.. I think that was singularly as in "particularly" not as in "solely." 1
StringJunky Posted August 9, 2016 Posted August 9, 2016 I think that was singularly as in "particularly" not as in "solely." I'm sure he will enlighten us as to his meaning.
DrmDoc Posted August 9, 2016 Posted August 9, 2016 (edited) No such thing as mutants then? You only have to find one example to prove your belief wrong that humans were "singularly" dark skinned.. I think the plight of albinos in Africa presently suggest the probability of earlier mutations; however, I firmly believe in what the science appears to suggest about the dark complexion of our African ancestors. Also, I'll try to find a link to research which suggest that generally lighter pigmentations occurred about 20,000 years after our ancestors exodus from Africa. Edited August 9, 2016 by DrmDoc
sethoflagos Posted August 9, 2016 Posted August 9, 2016 The overwhelming majority of human DNA diversity is amongst populations of African lineage. To try and categorise all that variability into a single phenotype is just plain wrong. Walk down any street in Africa and you will see just how wrong it is.
DrmDoc Posted August 9, 2016 Posted August 9, 2016 (edited) The overwhelming majority of human DNA diversity is amongst populations of African lineage. To try and categorise all that variability into a single phenotype is just plain wrong. Walk down any street in Africa and you will see just how wrong it is. Actually, the diversity in Africa today is not entirely representative of the population that left Africa for Europe 40,000 years ago. Also, I found this Live Science article discussing relatively recent evidence suggesting the gene for lighter skin evolved in Europe about 7,000 years ago. Edited August 9, 2016 by DrmDoc
sethoflagos Posted August 10, 2016 Posted August 10, 2016 Actually, the diversity in Africa today is not entirely representative of the population that left Africa for Europe 40,000 years ago. Also, I found this Live Science article discussing relatively recent evidence suggesting the gene for lighter skin evolved about 7,000 years ago. There is no single gene for lighter skin. Many Africans (my wife's family amongst them) have relatively pale complexions. 'Yellow' in local parlance. And this is not due to some 'back to Africa' travelling of a 'white' gene. It's undoubtedly been added to in various colonial expeditions, but the widespread occurrence of pale skin tones among ancient African lineages (the San peoples being an obvious example) suggest that other than the very blonde features of some Scandinavians (linked to a long history in ice age Europe), the diversity of human skin tone is within the normal variance of African populations. I don't present any academic research papers to support this point of view. Because as far as this particular subject is concerned, I'm not sure there are any that have not been corrupted by an agenda. Sorry to say.
DrmDoc Posted August 10, 2016 Posted August 10, 2016 There is no single gene for lighter skin. According to this article, that isn't exactly true. From the article: "...Basu Mallick and her colleagues took skin color measurements for about 1,228 individuals in Southern India. The researchers then conducted a genetic analysis and found that about 27 percent of the skin color variation was due to a variation in a skin pigmentation gene. Called SLC24A5, this gene codes for lighter skin and is present in almost 100 percent of Europeans."
sethoflagos Posted August 10, 2016 Posted August 10, 2016 According to this article, that isn't exactly true. From the article: "...Basu Mallick and her colleagues took skin color measurements for about 1,228 individuals in Southern India. The researchers then conducted a genetic analysis and found that about 27 percent of the skin color variation was due to a variation in a skin pigmentation gene. Called SLC24A5, this gene codes for lighter skin and is present in almost 100 percent of Europeans." Please don't try hinting that I'm attempting to mislead. There are many genes involved. You don't mention KITLG or ASIP for example, though these seem to have diverged a little since they left Africa and could have been used to support your position (whatever that is). But you also ignore MC1R, SLC24A2, TYR, HERC2, OCA2, and ATRN among others. No one is trying to say that Africans aren't typically darker on average than Europeans. Just that our common ancestors will have been genetically diverse, and will not have conformed in general to a particular stereotype.
DrmDoc Posted August 10, 2016 Posted August 10, 2016 (edited) Please don't try hinting that I'm attempting to mislead. There are many genes involved. You don't mention KITLG or ASIP for example, though these seem to have diverged a little since they left Africa and could have been used to support your position (whatever that is). But you also ignore MC1R, SLC24A2, TYR, HERC2, OCA2, and ATRN among others. No one is trying to say that Africans aren't typically darker on average than Europeans. Just that our common ancestors will have been genetically diverse, and will not have conformed in general to a particular stereotype. I'm not trying to hint anything. In your posted, you asserted that, "There is no single gene for lighter skin." The article I referenced verbatim appears to contradict your assertion. It referenced a "single gene" (SLC24A5) and none of the others you've listed above. If you'll select the link I provide, you will find that the article goes on say, "Lighter skin has less melanin, a pigment that blocks the sun's UV rays; the body uses these rays to make vitamin D. The SLC24A5 gene is linked to less melanin production, so the gene may have become more common in Europe because it allowed people's skin to make more vitamin D in the continent's low-light conditions." The article suggests that this particular gene was critical to the adaptation of low melanin production, which gives us our skin pigment. If you have references to the contrary, I suggest you post them here. Edited August 10, 2016 by DrmDoc
sethoflagos Posted August 10, 2016 Posted August 10, 2016 'There is no single gene for lighter skin' does not mean there are none, it means that there are many. I think you know this, The paper you quote does not deny it. And indeed goes on to state that that particular gene can only account for a fraction (27% was it?) of skin tone variation in European populations. So other controls must be involved, mustn't they? But we weren't discussing the skin tone of European populations were we? So I don't really see its relevance. Nor really do I see the point that you're trying to make with it. And when you say 'this particular gene........gives our skin its pigment', who exactly is the 'us'?
DrmDoc Posted August 10, 2016 Posted August 10, 2016 (edited) 'There is no single gene for lighter skin' does not mean there are none, it means that there are many. I think you know this, The paper you quote does not deny it. And indeed goes on to state that that particular gene can only account for a fraction (27% was it?) of skin tone variation in European populations. So other controls must be involved, mustn't they? But we weren't discussing the skin tone of European populations were we? So I don't really see its relevance. Nor really do I see the point that you're trying to make with it. And when you say 'this particular gene........gives our skin its pigment', who exactly is the 'us'? Humans, humanity, which one would you prefer? To not be misleading, that was "27% of skin color variations in Indians" specifically and was "present in 100% of Europeans" according to the article. Further, as I recall, your previous comments inferred a diversity of skin color has always existed among early modern humans in Africa as they presently do. I provided evidence suggesting the opposite with further evidence suggesting light skinned adaptations didn't arise until early humans reach low UV (European) climates. I believe that is how we engaged this exchange. Edited August 10, 2016 by DrmDoc
John Cuthber Posted August 10, 2016 Posted August 10, 2016 As a relatively pale skinned person who has lived in the African equatorial belt for nearly 20 years, one of the really useful benefits of a dark skin that I envy is the ability to find shade and radiate excess body heat away quickly, ,,, Radiative cooling is small at these sort of temperatures- especially when surrounded by stuff at similar temperatures. The rate of heat loss will depend (slightly) on how well the skin absorbs far infra red. That's not going to be closely correlated with colour which depends on how well it absorbs visible light.
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