Why we don't grow blue or green or... hair or skin?

Discussion in 'Human Science' started by Shadow1, Jul 28, 2010.

  1. Shadow1 Valued Senior Member

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    why humans don't get born with hair colors like green, blue, or other colors, also skins,
    there was a hall family in europe, their skin is blue, and close to violet.
     
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  3. spidergoat Valued Senior Member

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    I dated a girl with green skin.
     
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  5. Shadow1 Valued Senior Member

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    lol

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    i think you sleeped with her too much.

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    that's why she's green.
     
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  7. spidergoat Valued Senior Member

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    Yes I did, but that wasn't the issue. Some people have a kind of algae growing under their skin. It's not harmful at all or contagious. It was just some green patches on her back.
     
  8. Emil Valued Senior Member

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    Maybe because we are not poisonous? :scratchin:
     
  9. Randwolf Ignorance killed the cat Valued Senior Member

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    You can grow blue skin by messing with the wrong type of silver:
    Let me know how that works out for you...

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  10. river-wind Valued Senior Member

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    Interesting question. Green and blue aren't common pigments in mammals, so I'd venture it's a result of our early shrew-like ancestors either losing pigment, or there not ever existing such pigments in our ancestry.

    Birds seem to be the most complex animals with a really wide variety of pigmentation, and their likely evolutionary connection to lizards would seem to be the reason why - yellows and oranges and reds are pretty common in lizards as well.

    Can anyone think of a mammal or direct mammal ancestor that had dramatic pigmentation outside of gray/brown/black/orange?


    edit we go:
    http://www.fasebj.org/cgi/content/abstract/5/14/2902
    "Visible pigmentation in mammals results from the synthesis and distribution of melanin in the skin, hair bulbs, and eyes. The melanins are produced in melanocytes and can be of two basic types: eumelanins, which are brown or black, and phaseomelanins, which are red or yellow."

    http://shkrobius.livejournal.com/176833.html
    "Frogs have green rods in its retina; turacoverdin is found in the feathers of some touracos; there are green pigments in certain moths; a green pigment colouring the bug Psylla mali on apple trees is formed by symbiotic bacteria; a green pigment has been found in the integument of the lugworm, Arenicola; there are green schemochrome which color the polychaete worms Eulalia viridis and Phyllodoce viridis, and there is a dark-green schemochrome in the entomostracans Triops and Cypris....

    The rest [of the animals] have never learned how to produce other pigments than yellow, brown, and red.... Green lizards, parrots, and frogs are as dedicated melanin producers as the mammals. Their green originates through Tyndall scattering by microcrystals. The reflected light is enriched in blue and it becomes green when filtered by an overlayer of a yellow pigment, such as pteridine. Blue and green irises in our eyes originate through the same effect, so the mammals have not fully forgotten the trick. Cold blood animals rely on stacks of DNA base guanine in their reflective cells (iridophores) to produce this incoherent scattering effect. The birds and mammals do not have these guanine filled iridophores, as they have lost the ability to produce the stacked guanine granules. Instead, the birds make nanosize air vacuoles and channels in the beta-keratin of their feather barbs"
     
    Last edited: Jul 28, 2010
  11. Randwolf Ignorance killed the cat Valued Senior Member

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    Well, you've heard of "blue balls", right?

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    It would seem that Vervet Monkeys have a permanent case of it... Quite a bright blue as well, wouldn't you say?
     
  12. Shadow1 Valued Senior Member

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    what about the blue people that i mentioned, i mean, they are blue, and they're not sick, or infected, or have a bacterias, they are just blue, try to see it in google

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  13. Shadow1 Valued Senior Member

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    lol
     
  14. Shadow1 Valued Senior Member

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    that's not what i meant ..

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  15. Anti-Flag Pun intended Registered Senior Member

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    Forget uncommon, IIRC there are no naturally green or blue mammals at all.
     
  16. river-wind Valued Senior Member

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    That is both a great find, and perfectly hilarious. I wonder where the blue comes from.

    That actually reminded me of another primate w/ blue coloration: the baboon

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    edit: according to the textbook "Animal bichromes and and structural colors", both of these cases are due to Tyndal light scattering:
    http://books.google.com/books?id=tt...AEwBA#v=onepage&q=blue pigment baboon&f=false


    That is due to the intake of colloidal silver; they are blue, but they are not producing the blue color internally.

    edit2: or it could be http://en.wikipedia.org/wiki/Methemoglobinemia I had forgotten about that condition.
     
    Last edited: Jul 29, 2010

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