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Why do black people have a black skin? It should be the opposite.

 
 
Reply Fri 11 Jan, 2013 09:41 am
Black people in Africa are exposed to sun too much and therefore their skin should be reflecting the sunlight so that their skin will be protecting itself against the bad impacts of the sunlight on the skin. In order to reflect the sunlight, the skin should be white. And, when the skin is white, it will be protected against the sunlight because it will be diverting the sunlight away from the skin.

In cold areas such as Europe, people need the sunlight but they don't have a black skin. That's a problem. They need the sunlight because they need to feel warm in cold Europe. A black skin would be absorbing the light and when the light is absorbed it's converted into energy that we call warmness. And warmness make you feel warm and this process of feeling warm would be possible only by possessing a black skin.

The skin color thing should have been as I described above. Why is it the other way around?
 
ossobuco
 
  2  
Reply Fri 11 Jan, 2013 09:44 am
@cicibebe,
http://en.wikipedia.org/wiki/Melanin
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dalehileman
 
  0  
Reply Fri 11 Jan, 2013 01:53 pm
@cicibebe,
Very interesting Cis that you should so inquire because I've often wondered the very same. Doubtless …….'s link above explains it but doesn't meet the requirements of your Average Clod (me). So for the benefit of those unwilling to root the basics someone qualified in the ability might condense the Wiki in short sentences of common terms
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ossobuco
 
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Reply Fri 11 Jan, 2013 02:08 pm
quoting wiki -
Melanin i/ˈmɛlənɪn/ (Greek: μέλας - melas, "black")

Production of melanin is induced by UVB-radiation simulated by DNA, which is also a photoprotectant.[1] The photochemical properties of melanin make it an excellent photoprotectant. This is because it efficiently absorbs harmful UV-radiation (ultraviolet) and transforms the energy into harmless heat.[2][3][4] This occurs by means of a process called "ultrafast internal conversion". This property enables melanin to dissipate more than 99.9% of the absorbed UV radiation as heat[5] (see photoprotection). This prevents the UVB radiation damage that is responsible for the formation of malignant melanoma and other skin cancers.
dalehileman
 
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Reply Fri 11 Jan, 2013 02:14 pm
@ossobuco,
Thank you for that quote, ……, but it doesn't much help. For instance, the implication seems to be that the color of "black" skin is caused by inherent melanin

Cis, help me out here
ehBeth
 
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Reply Fri 11 Jan, 2013 02:16 pm
@dalehileman,
Think of melanin as a darkly-toned, built-in, sunscreen.
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ehBeth
 
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Reply Fri 11 Jan, 2013 02:18 pm
@dalehileman,
http://www.skincancer.org/prevention/skin-cancer-and-skin-of-color

Quote:
BIOLOGY 101

Human skin is comprised of three layers: the epidermis, dermis, and fat. Cells in the epidermis (the outermost layer of skin) called melanocytes produce melanin, the pigment that gives skin and eyes their color.

The more melanin the melanocytes produce, the darker the skin pigmentation.

Melanin helps protect the skin against effects of the sun such as skin cancers and premature aging.

In African American skin, melanin provides a sun protection factor (SPF) approximately equivalent to 13.4, compared to 3.4 in white skin.

This discrepancy illustrates why skin cancer is more prevalent in Caucasian people; it is, in fact, the most common type of malignancy in the US among Caucasians.

Their inherently light skin color and low amounts of melanin leave them vulnerable to the sun’s carcinogenic (cancer-causing) ultraviolet rays. UV light, also emitted by tanning beds/lamps, is, in many cases, the causative culprit of skin cancer in Caucasian Americans
Walter Hinteler
 
  1  
Reply Fri 11 Jan, 2013 02:32 pm
@ehBeth,
This research - Genetic evidence for the convergent evolution of light skin in Europeans and East Asians - might be interesting.
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dalehileman
 
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Reply Fri 11 Jan, 2013 02:41 pm
@ehBeth,
Thanks Beth for that quote. So it is melanin and it's inherent

But still then we wonder about the evolution of white, as above by Walt
DrewDad
 
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Reply Fri 11 Jan, 2013 03:18 pm
@dalehileman,
Evolution isn't interested in perfect solutions (which would be reflecting all of the bad radiation). Evolution is about "organisms this trait survive longer, and breed better."

Melanin is good enough at blocking dangerous radiation long enough for people to reproduce and protect their progeny.

(Meanwhile, regular sunlight has to be allowed through, for Vitamin D, vision, etc.)
ossobuco
 
  1  
Reply Fri 11 Jan, 2013 04:02 pm
@DrewDad,
Not to be corrective, as I know you know this, DD, and is probably what you meant - evolution is not a one word persona; it is a process, rather beautiful to me, in its ways and manifestations.

Catholics, of which I used to be one, admitted it. The original designer and the followup process were ok to them.

If I'd have been a hippie/boomer, I'd have called it a long time happening. But: I'm older and gruffer.
0 Replies
 
Setanta
 
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Reply Fri 11 Jan, 2013 04:08 pm
The melanocytes also give off heat, which is an advantage in warm climates, but a disadvantage in cold climates. Evolution would have selected for fewer melanocytes in "white people" in cold climates, such as the periglacial steppes and forests where our European ancestors lived tens of thousands of years ago.
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Foofie
 
  0  
Reply Fri 11 Jan, 2013 09:52 pm
Black skin allows Africans to not die from vitamin D poisoning. White skin allows Caucasians not to get rickets, by getting enough vitamin D from their skin producing the vitamin.

The theory of evolution says we adapt to that which helps us survive.
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dalehileman
 
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Reply Sat 12 Jan, 2013 12:24 pm
@cicibebe,
Cis I am wondering whether our participants have satisfied our curiosity and if so can you condense it for the Average Clod (me)
cicibebe
 
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Reply Sat 12 Jan, 2013 12:28 pm
@dalehileman,
You must wait for it. I have to read all documents that people share here. It'll take some time because I'll have to look words in dictionaries. You know, English is not my first language.
dalehileman
 
  -1  
Reply Sat 12 Jan, 2013 12:40 pm
@cicibebe,
Quote:
You must wait for it…... It'll take some time…….
Your patience is indeed commendable

Quote:
You know, English is not my first language.
As I very much admire your ambition and determination, Cis, far exceeding my own efforts for instance to learn Japanese when I was stationed there, and forgive if I've asked this before--but without revealing anything critical I wonder if you'd mind disclosing something about yourself; age, sex, ed., occup, nationality, family, ambitions, motives, etc. Even a separate OP
0 Replies
 
 

 
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