..., and also dark skin looks fiercest than the light ones and it is a good protection also against the wild animals.
PHOTOGRAPH BY SARAH LEEN, NATIONAL GEOGRAPHIC
Published March 7, 2014
When it comes to skin color, the idea that we're really all the same isn't just a utopian dream. A look at skin cancer from an evolutionary perspective suggests that maybe once we were all white; then we were all black; then some of us went back to white.
In a study published in Proceedings of the Royal Society B, Mel Greaves, professor of cell biology at the Institute of Cancer Research in London, looked at some 25 studies of skin cancer in albinos in Africa. Albinos have less melanin, a natural pigment that helps protect the skin against damage from the sun. The more melanin in the body, the darker the skin.
Greaves found that basal cell and squamous cell carcinomas are not relatively harmless diseases of old age. In African albinos, they kill early and quickly. Skin cancer prevention, he concludes, was a driving force in human evolution to dark skin. Other scientists, including Charles Darwin, have long dismissed skin cancer as a force in evolution because it typically strikes those past childbearing age.
Greaves, who studies the role that disease plays in human evolution, believes his study adds credence to the idea that when earlier hominids shed their shaggy hair about two million years ago, exposing their naked, pale skin to the sun on the sun-drenched savanna of Africa, natural selection favored those who had the darkest variations in skin color to protect against the ultraviolet radiation (UVR) that can cause skin cancer.
Much later, about 50,000 to 100,000 years ago, those who migrated to cold northern climates no longer needed that protection, and evolved back to pale skin. National Geographic talked with Greaves about his research.
You point to skin cancer as a reason that skin color evolved. Among cancers, is skin cancer unique in influencing evolutionary protections?
I can't think of any other cancer and circumstance that would have had a sufficiently large impact on survival and reproduction. You might think that pediatric cancers might have been subject to evolutionary selection, but my guess is that they have always been too rare to provoke protective selection.
Can you explain when and why our human ancestors became black?
The genetic evidence suggests that black skin became the norm in Africa some 1.2 million years ago, around the time that early humans were colonizing the savanna and had lost most of their body hair. Most investigators believe that black pigmentation was an essential adaption to protect naked, pale skin against solar ultraviolet radiation, which is high all year round near the equator.
There has been consensus on some of the life-threatening impacts of UVR via the skin. Ideas have included damage to sweat glands and degradation of folate and other essential nutrients in blood circulating through the skin.
But skin cancer has been universally rejected as a possible selective force for the adaptation of black skin. This is on the grounds that in modern-day Caucasians, it is usually benign or is lethal too late in life to influence evolution. In my paper I suggest this is taking cancer out of the relevant context and that the experience of African albinos illustrates very vividly what the impact of intense UVR might have been on early humans.
Why did some people then evolve back to the white skin that was originally underneath hominids' hair?
As our human ancestors migrated out of Africa, those that moved away from equatorial and tropical regions underwent positive selection for paler skin. This was in part due to the reduced pressure from UVR skin damage, but also because black skin became a disadvantage, possibly because [pale skin is better at generating vitamin D] and dark skin is more susceptible to frostbite.
So you're saying that skin cancer played a part in skin color: Humans were originally white under all their hair, then evolved to black a million or two million years ago, then 50,000 to 100,000 years ago some went back to white as they migrated farther north?
That's exactly what I am suggesting. But unless Jared Diamond and Darwin [two scientists who dismissed skin cancer as a factor in evolution] are right and skin color variation is just incidental and endorsed by sexual preferences, then there has to be an evolutionary logic.
Naturally there is considerable speculation in all of this debate, and coming up with a definitive, unambiguous explanation for events that happened millions of years ago is very difficult, if not impossible. We are trying to come up with the most plausible answer in the light of all the evidence available—which is the way science always works.
How is this theory plausible when Africa at that time was full of wild animals?, and white skin would have been a disadvantage at that time for lack of melanin and no fur. One thing I agree is about the first skin of blacks, I am black African, is white and if what this theory says were true I think the human race couldn't have had of being born.
I know for many people the Bible is a myth, but has reasonable things about the origins of all species on the earth.
God created all creatures with the seeds of its own species, that to me, means the first human had originally dark skinned and were born automatically with dominant genes and recessives genes that happens in black people, because on the opposite side could be eons until the black albinos mutate to a dark skinned not counting with the little chance of survival, and also that is why blacks vary from darkest to lightest skins tone.
I do not have a strong opinion but an opinion. I live at 66 degrees north and the indigenous peoples (including my wife) have a darker skin than Europeans of the same latitude. Folic acid supplements are routine for pregnancies this far north due to lack of vitamin D3 absorption due to the darker skin. The lighter Europeans have less of this problem locally.
My understanding is the migration paths from Africa led to intermingling with different groups of Neanderthals. The Neanderthals existed as an evolving species for over six times the span modern human have existed. 350,000 plus years versus 50,000. The skin color of the migrating people depended on which subgroup of Neanderthals they bred with.
The the late coming humans bypassed all the evolution accomplished by the established humans already evolved for the climate.
DNA shows the four percent Neanderthal derived genes mostly have to do with skin color. Carbohydrate processing is also prominent.
This seems reasonable or else why would all non African humans still have such a high percentage of identifiable Neanderthal DNA.
I am waiting for more information on the exact relationship but so far this satisfies me as a logical line of inquiry.
What the hell? This is pseudo-scientific bunk. Why are you printing this nonsensical trash? No reputable scientist in the world supports this ridiculous notion.
It makes even LESS sense than that pale-faced, hazel-eyed image of King Tutankhamen on the cover of NG a few years back.
You need to get your act together before you lose all semblance of any credibility you once had. FIRE the clueless editor who green-lighted this garbage!
National Geographic, I thought you were better than this. Clearly, you are a part of the world's "problem" and not its solution.
@Preston Garrison. I have a right to my opinion. And you have the right to disagree. It is my opinion: If the theory of color changing due to climate is fact, then there should be no browned toned Eskimos. For a person who is of African descent to have descendants who turn into white Caucasians just because they live in the Artic is absurd. (In my opinion) Papers on the genetics of skin color are full of peoples opinions.
Why assume that the original hairless human was white? Evidence? On the contrary, Neanderthal Man was tawny (recent finding). I have also read that 41,000 years ago, a cosmic blast of radiation affecting mankind around the Tropic of Cancer caused a genetic mutation which led to the survivors becoming white after about 2,000 years or about 70 generations.. White people include East Asians (who are whiter than Europeans), Central and West Asians. And Europe was uninhabitable until about 10,000 years ago because of the Ice Age which ended about 12,000 years ago.
Mel Greaves does not deserve the letters behind his name (although I didn't see any). This study is a complete waste of time and money for a study with such a skewed perspective. Major fail.
The Sun has been around forever and it has always been hot in the area the original man has came from,( If we did Evolve) why would we go from having hair in the heat to not needing it if it was protecting us from the sun?
I love science and I respect each individuals right to their opinion. I do not believe first of all that man evolved from a hairy creature into a man. And I do not believe that man evolved from black to white or white to black. I believe man was created as a man and has remained a man. He has evolved intellectually, spiritually, and in strength, valor, and agility. He has also de-volved in areas to numerous to mention. But the theory of color darkening and lightening does not seem probable to me, because there are too many races of people that are a number of shades in between black and white. In addition, races have more distinctions than just color. Browned skinned people have lived in polar regions for centuries. If this theory were true, they would be whiter than snow by now. By the same token, if fair skinned people who live in a sunny region tan to a brown color, they will not produce a black baby. If they are white, they will have a white child. I believe people adapt to the climate they live in, but I absolutely do not believe that they evolve into a different race, by virtue of the their location and the warmth of the sun. An albino child that is born to a black couple, typically has black features. There condition is an anomaly, they are a black person born without pigmentation. That is all. It is not any type of evolution.
Since I first learned about melanin in grade school, I have always believed that people were colored light or dark according to our surroundings. Africa's blazing sun developed dark skinned people to better survive and be productive in the heat and rays of the sun. If we "left Africa" and went to an area with less searing sun and heat (like Seattle with grey and cloudy skies all the time) then we would no longer need that melanin protection and our skin would lighten up (hence "turning white again"). People who are deprived of any sun for whatever reason are always pale and ghostly as well as sickly. People who get a little sun are just pale. People who worship the sun are always very dark complected. Never thought of the cancer aspect but that would make sense. This story excites me!!! I can't wait to show it to people I have shared my thoughts with!!!
The distortions Europeans have injected into world history leave the doors open to many a fanciful theory.
If fading to White skin was a necessity for survival in colder northern climes, then dark skinned peoples would have disappeared from Europe long before the historical age.
Reports from the Greeks, Romans and the Vatican archives proves they did not.
Many of the ancient Greeks themselves were Black,
this includes their gods as depicted in their artwork.
The Romans themselves stood on Etruscan ground,
many of whom were themselves Black or dark Brown.
in describing various of the tribes throughout Europe, particularly Predain (Britain) they spoke of the unusually dark complexion of some of the inhabitants.
As late as 2nd half of the last millenium reports refer to encounters with the "Arctic Twa" better known as Skraelings, they inhabited Northern Europe, Greenland, the Arctic Circle and N.E. coast of North America some of these reports are contained in letters in the Vatican archives dated between 1000 to 1632.
All of the major branches of humanity had / have a documented Black section.
Dark skin is not there to block the life giving rays of the sun, but to properly absorb it therefore gaining the beneficial properties of sunlight,
a lot more positive research needs to be done on sunlight, Black / Dark skin, Melanin and the pineal gland if we are to get a better understanding of humanity.
Man would have never "evolved" in the first place
if we were coming from White / Pink skin,
skin cancer would have done killed him off long before the process was complete.
There is no such thing as "white" skin and "black" skin in humans. Melanin is a brown pigment not black. Polar bears live in the Arctic and they have dark skin with light fur.
What of the White dove theory. Release a white dove in a population of other birds that are colored and the white dove is targeted for attack. In the case of the Human ancesters a white human would stick out more to other human and ape speicies and maybe targeted for attack. Selection has many factors, skin cancer, formation of vitamin D and frostbite are all sellection pressures.
What utter moronic publishing. This must be the understatement of the century. Pure junk for the masses. Is this article aimed at two years olds but ended up in the wrong section?
"Darwin and others said skin cancer couldn't influence the evolution of skin color. A new study makes the case that it did." I believe Darwin is correct, but not for the reasons he thinks he was. The relatively new field of epigenetics easily explains the expression of adaptive characteristics over generations. Simply stated, genes can express selectively by switching on or off in response to environmental pressures. This is adaptation, not evolution.
I don't understand how dark skin is seen as the result of evolution when all humans originated from Africa and had dark skin to protect themselves against the sun. As humans migrated away from the equator lighter skin evolved because highly pigmented skin wasn't needed to protect against the sun in regions where it was less intense. This is the scientific equivalent of cutting Asia in half so America can be in the middle of the map.
If the whites go back to black then why is it that their lips or mouth got thicken? Does color affects facial contour of an individual during the process of adaptation?
It almost sounds skin cancer is secondary to why some of us have darker skin than others. The last study I saw on skin color said the color was based on the production of Vitamin D. If you lived in a climate with a lot of sun you had darker skin so you don't produce too much Vitamin D. In the northern climates you need the lighter skin to produce more Vitamin D to compensate for the less light. This is alluded to in the article as well.
Eh. Just not sure about this. I'm very far from a scientist or anything close to it, but the subject has always interested me. So this may sound "stupid" but hear me out. There are many animals through out the plains of Africa that actually still get sun burnt / skin cancer because the skin under their fur is white. Many of the animals, such as elephants and hippos, need to case them selves in mud just to keep the harmful sun rays out. So why didn't they evolve through "natural selection" to have darker pigment to get rid of this problem, but humans did?
"Natural selection led to darker-pigmented skin in desert regions and white skin in temperate regions" would have been a better title, as it is it sounds like evolution had some kind of goal. And I agree with @Stefan Sobol - this needed more research? @Jean B, a scientific theory is quite strong and is backed with years of research; unless I am mistaken, science doesn't seek out "fact".
Poorly written title as it misrepresents natural selection.
Better would be,"Dark skin may have evolved because lighter-skinned people were more likely to die of skin cancer at a younger age."
Longer, yes, but more accurate.
@Philip Olson neanderthal man has been refuted. so has piltdown man, and nebraska man, and all the other farses that the evolutionary cult has come up with, the fossil record CLEARLY depicts creation NOT evolution. IF darwins theory is the standard then africans and dark skinned people are by laws of survival of the fittest AND melanin CLEARLY more superior right? this article is bs, we were dark then became light then went dark again? lol ok.
@Tiffany Anderson Based on your pontifical assertion. Well, what else could we need? An argument, evidence?
@Candra Cheers You have next to no idea of what you are talking about. Go read some papers on the genetics of skin color.
@Stacey Summers Actually for me, I have always known that darkness and lightness of skin color has something to do with preventing diseases from the sun, especially skin cancer. I didn't know that it is still being debated that dark skin color is an evolutionary trait against skin cancer, actually.
@Nat Turner This is mostly ideologically motivated twaddle. There is a lot actual science being done on skin color, and it is actually quite interesting. Much of it is freely available on the internet. Put your self serving ideology aside and read some of it.
@Nat Turner Dark skinned people in Mediterranean area might have come from intermarriage from people from Africa.
@Nat Turner consider however that this article is relating to humans prior to mass migrations. The black populations in greece and rome you mentioned may be the result of migration from the african continent across the mediteranean from egyptians.
@R. ClarkBut dark skinned is prone to frostbites and rickets. Therefore, it is safe to safe that in time, people with lighter complexions (maybe not as white as today) outlived the really dark ones and might have increased in number, until such time that people with even lighter skin emerged through natural selection. It might have been gradual that we as a species did not notice. This is why we do not have that is why oral traditions of stories and legends of dark ancestors or dark people living in the north. We, as a species, just didn't notice the evolutionary changes because it took time to change the entire population up north. :)
@Ben B. Could you elaborate more? Such strong opinions for someone who isn't going to take the time to support them.
@Steve Simmer I read that over 150 genes have been identified that influence eye, skin, and hair colors, so it isn't quite that simple (http://www.hudsonalpha.org/education/outreach/basics/eye-color). I read that melanin levels in a particular human population can probably go from light to dark, and vice versa, over the course of one thousand years, given the change in exposure to UVB light between northern latitudes and equatorial latitudes (http://chriskresser.com/the-latest-discoveries-in-evolutionary-biology-genetics-and-epigenetics). However, human melanin levels do not "switch", as the eye color of a fruit fly does, and then stays changed in later generations, by simply manipulating ambient temperature when the initial generation's eggs are in the embryonic stage (http://www.sciencedaily.com/releases/2009/04/090412081315.htm).
@Nicholas Balemezi This is why even in tropical countries, such as the Philippines, people from tribes in mountainous region, with less sun,have lighter complexions.
@Nicholas Balemezi white skin is very good at absorbing sunlight necessary for vitamin D production in climates that receive very limited sunlight. It is believed that white skin may also be attribute to mountainous areas as they have the sun set earlier due to the higher horizon line. think of Ireland and norway, very pale people from there....
@Nicholas Balemezi Vitamin D production in lower light areas?
@Brittany Jackson Apparently, sunlight destroys the body's reserves of folate, which is very important to cell growth and methylation. Sunlight/tanning-bed exposure during pregnancy significantly increase risks of birth defects (http://chriskresser.com/the-latest-discoveries-in-evolutionary-biology-genetics-and-epigenetics).
@Brittany Jackson I think the article is suggesting that there was a lighter skin under the body hair in earlier hominids but when body hair was "evolved off" (as our sweat facility and running improved), that lighter skin was an evolutionary disadvantage in the sunnier climes and selection favoured the darker skin...until there was migration out of Africa.
@Romeo Bombita facial features evolve separately due to different selective pressure but often are related to climate. Big noses are very usefull in colder climates for regulating the temperature of air intake.
@Felicia Faulkner You make a very good point. Because natural selection and evolution are quite complicated. Though, it is all aimed towards mating and handing down your genes to the next generation. This will mostly happen for those individuals who are best adapted to their environment (or sometimes just very lucky). Who is considered the best adapted depends on many factors which influence the final outcome. These can be solely internal or an environmental influence and they may interact with each other. Furthermore, not all answers to a problem are the same and sometimes a trade-off exists between certain factors.
In the article such a trade-off is described because a darker skin might prevent cancer but can also lessen the bodies abillity to produce vitamin D.
As an example of an alternative, if hippos venture out of the water during the day their skin will start producing a substance which is a comparable to sunblock in its function, it makes them look a little bit pinkish. Furthermore they evade the sun with how they behave, for they spend most of the day in the water and are much more active at night.
Elephants indeed use mud to prevent sunburn, but it serves further purpose in warding of insects and keeping the animal cool. We do not know how long they have shown this behaviour or what was the driving factor to developing it but one might hypothesise that the method was effective enough to prevent skin cancer. In this case the negative influence of cancer would not influence an animals chances of reproducing to the extent it did before, and might even inprove it with the added bonusses. Or it could be that elephants did develop darker skins but that there were to many side-effects which cancel out the single positive effect. Or maybe the possibility to get darker skin has never been an option because elephants do not show, have or have not evolved the physical ability.
I hope this gives you some answers.
@Preston Garrison @Nat Turner This twaddle, sir, is unfortunately the comment section... a land that is made of many theories... opinions... trolls... and sometimes hard fact. This person (Nat) is using knowledge that s/he has learned to state what a possible farce this is to people.
But this is not only the land of comments... it is the internet... a world where even the most believable articles could be fake beyond belief. Or distorted beyond repair.
As far as I know black history has been distorted and/or tossed to the side for centuries at a time. So the debate you two are having about the 'original skin' and the evolution of said skin is invalid unless someone pulls some live tests on skin out right now or gets serious and starts pulling quotes from other scientific articles.
And finally... you're not proving your point either. You can't debunk an idea without directing the person to the articles you are talking about. To be honest you're being just as ideological as the person you shot down. "Put your self serving ideology aside and read some of it." comes off as rude and arrogant. So please either prove your point or gtfo.
- sincerely a kid
@Preston Garrison @Nat Turner
I see many opinions here which I disagree with,
I don't resort as yourself to belittlement of the writer
to prove myself right,
who gave you the big stick to shake at those you don't agree with ?
whether I'm right or wrong I have a right to an opinion and
the right to express it.
I have read far more than you could credit me for and
I still hold the opinion that no hairy pink skinned ape shed it's skin and somehow survived at least hundreds of thousands of years until it became Black.
The skin cancer of which this article speaks would have wiped it out before it could fully stand erect,
much less people this equatorial continent.
White skin cannot go Black it can tan but does not hold the color.
Look at the Europeans of Azania or Australia or the southern states of America they are still White.
Southern Europeans are dark because of history not the climate.
Man is thought to have originated in the Great Rift Valley region,
this area straddles the equator.
Chancellor Williams in his ground breaking work entitled
"The Destruction of Black Civilization - Great Issues of a Race from 4500 BC to 2000 AD" pointed out that
bi-racial children of Black and White parentage quite often did not live to the age of 18 years old because of the great heat of the sun in some equatorial regions.
Albinos die relatively young in Africa due largely to skin cancer.
An issue which the scientists have yet to touch upon is the beneficial merit of Melatonin and
why it is mysteriously produced in the pineal gland.
"Melatonin controls pigmentation changes by aggregation of melanin into the melanocytes within the skin,
causing the skin to change color".
Maybe the calcified state of 80% of Europeans pineal gland is an avenue of research which the scientists have yet to take, or would you rule that out before the road is trodden ?
Flat earth people were afraid of falling off,
I would suggest that those with big sticks mind
they don't swish themselves.
@Richmond Acosta @Nat Turner
The first people found on all habitable lands are Black Africans,
my point is that in many cases they persisted well into historical times,
No doubt the intermarriage you speak have could have occurred on more than one occasion but that would not alter the fact of who the originals were, and
as pointed out, as late as Greek times,
the Pygmy were still extant and regarded as the Gods in many lands.
I state again, Light or White skin would not have survived in the equatorial regions to have become Black.
Had the first humans been other than Black the tradition of nakedness would not have caught on and persisted, for
as in the Middle East for instance, a tradition of swaddling would have become the norm from the earliest times.
If we are talking about humans then it’s the “Short Blacks” or so called Pygmy of whom we are speaking.
Greece being the older of the two nations you mention, sight the Pygmy as their gods if not even their ancestors.
Athens village, not the much later state, was founded about 1200 BC.
By then the Pygmy were no longer a dominant feature in Egypt, as when Pharaoh Seti II, also c 1200 BC, wanted to see the “sacred dance” he had to send south to the fabled land of Punt for a Pygmy to be brought to perform it.
We know that the Hyksos ruled Egypt from 1670 BC for a century, so it is safe to assume that even at that early date the Pygmy were not in situ.
My point being any out flows from Egypt or Africa those times would have essentially been taller Black peoples.
The antiquity of the Pygmy puts them in Australia, Japan, South China, Thailand India and a host of other lands long before those normally accepted as the 1st or indigenous, such as the Aborigine, the Ainu or the Dravidian.
White skin can tan, it cannot keep the color, it does not get Black. White skin along the equator could not have survived to become Black, the remains of the earliest man are always Black.
Melaninated skin absorbs the positivity of our life giving sun, and that is another great story yet to be told.
@Russ Nash @Brittany Jackson The article suggestion is just a suggestion. If you think about it there is no proof and it doesn't make any sense. what Brittany said was true and makes perfect sense. (If we did evolve) why would the body hair fall off in the heat, if it was protecting us? would cancer kill off before evolution? The sun has been around all the time, it didn't change so why we have evolved into something that would harm us from the start. And the oldest bones found are not from a white man but a black woman. Australia is hot and has white people. The tip of Africa is cool and has black people.
@C. Dufour Great answer!!
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