Human of light skin

Discussion in 'Human Science' started by timojin, Nov 23, 2016.

  1. timojin Valued Senior Member

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    You are making the assumption that "The first Homo sapiens arose in Africa, where they needed protection from the sun. " were of dark skin
     
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  3. timojin Valued Senior Member

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    Could you please check this up. I am not sure the test for genome that far is accurate
     
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  5. Fraggle Rocker Staff Member

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    If their skin were as light as mine (I'm about as white as the Queen's hiney), most of them would have died of skin cancer before reaching puberty.

    Sure, it's not inconceivable that of the few who survived, some would have had offspring with a mutation for darker skin. With a little luck, a few of the next generation would have had even darker skin. If this continued for several more generations, a population that looked a lot like modern Africans would have arisen.

    But what are the odds? We're talking about a rather small community, most of whose members were suffering in constant pain from sunburn. A disease, a dry year without enough food, or an attack by lions could have killed off the entire tribe. (Remember, our ancestors had lost the ability to quickly climb into the trees for safety a few million years earlier. They traded their prehensile toes in favor of bipedal walking!)

    But sure, you might be right. We don't have any DNA that old to study. On the other hand, it's more likely that as they lost the full-body coat of fur that protected their chimpanzee ancestors from sunburn, a mutation arose for darker skin.
     
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  7. sculptor Valued Senior Member

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    arboreal = trees = shade
     
  8. Fraggle Rocker Staff Member

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    Sure, but with our huge brains, Homo sapiens is an obligate carnivore. There's not enough protein in nuts and seeds to maintain these brains. So our ancestors simply had to be hunters.

    We've seen this go the other way in dogs. When the more curious wolves decided to try living among us, they had to adapt to the lower-protein diet of a scavenger. One of the major differences between the wolf (Canis lupus lupus) and the dog (Canis lupus familiaris) is that the dog has a smaller brain that can survive on a lower-protein diet.

    Our own Paleolithic ancestors had to spend considerable time under the African sun, in order to hunt down enough meat to survive. And of course once they discovered the twin technologies of farming and animal husbandry (which, taken together, comprise agriculture) that heralded the dawn of the Neolithic Era, they had to spend rather a lot of time out under the sun.
     
  9. sculptor Valued Senior Member

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    You got a thing for vegans?
     
  10. timojin Valued Senior Member

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    Why are you equating African have to have dark skin,
     
  11. Fraggle Rocker Staff Member

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    Uh... because that's where our species, Homo sapiens, arose. The first modern humans lived in Africa for many thousands of years before they developed the tools and technology to build boats, which they used to venture out into the other continents. The first Homo sapiens came into existence about 200,000 years ago, but it was about 140,000 years later when their descendants finally discovered how to build boats sturdy enough to cross the Red Sea.

    Nature helped them in that enterprise, because the planet was undergoing an ice age. So much of the Earth's water was trapped in the glaciers and the polar caps, that sea level was at least 100ft (30m) lower than it is today. So the Red Sea was much narrower than it is today--a shorter journey in a rickety boat!
     
  12. timojin Valued Senior Member

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    Why did they have to cross the red sea , they just could have followed the Nile river , they would have water and not go through salty water, They could go to Lavant or stay in North Africa then cross at Gibraltar.
     
  13. Ophiolite Valued Senior Member

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    I've never typed on a medium, though I did once write a poem on a clairvoyant.
     
  14. rpenner Fully Wired Staff Member

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    Your article suggests that the African population lost protection from the sun from their body hair and the forest and went through a population bottleneck with only dark skin followed by a period with a lower bound of about 1.2 million years when only mutations which didn't change skin color were tolerated. Thus, according to your article, dark skin prevailed as common to all humanity for at least a million years as the ancestral genotype before some modern humans left Africa between 50,000 and 130,000 years ago.

    As this thread is in the science section of the forum, this is a factual claim raised by sculptor's source which can't be disputed by lay opinions.
    See Site Policy on the Science subforums.

    Modern humans clearly aren't arboreal, notwithstanding the trope of suburban children wanting treehouses.
     
  15. Fraggle Rocker Staff Member

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    Ardipithecus is the last ancestor of modern humans who was arboreal, and even he could not actually live in the trees. He did not have a full set of prehensile toes like the modern non-human apes and all other living primates. His feet had been reshaped for bipedal walking, with only the hallux ("big toe") retaining its ability to grab a branch. He and his family could easily climb up into the trees if predators approached, but they could not sleep up there.

    The tradeoff, of course, is that he could walk long distances to find food, and use his arms to carry it back to camp--a camp near a tree so the females could climb out of danger with their babies.
     
  16. RuneSpider Registered Senior Member

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    57
    I'm sorry, is that addressed to me?
    You refer to sculptors link supporting his claim, but I was the one stating that dark skin was the default, and light skin the more recent adaption.
    Apologize for any misunderstanding.
     
  17. rpenner Fully Wired Staff Member

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    I'm using shorthand to point out that sculptor's article in post #15 supports your claim in post #35, not his post in #33. The inference to be made about sculptor was left unwritten as an exercise for the reader, but is hinted at again by the last line of my previous post suggesting that sculptor has grossly mischaracterized modern humans who live in Africa.
     
    Last edited: Jan 4, 2017
  18. RuneSpider Registered Senior Member

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    57
    Should h
    Should have registered with my usual handle of Keenidiot. Oh well.
    I thought so, but wanted to be sure.
     

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