How much time did it take for Black people to evolve White in colder places?

Question

IF SKIN COLOR is related to environment (weather) and We all come from Africa. Then, How much time did it take for Black people to evolve White in colder places?

Hello, I'm a student . Thank you for the answers.

(if any grammar mistakes.. sorry.. i'm learning :D).

If you know about sites related to this let me know

1. Some say EVOLVE is not the word - I am ESL student ..What is the proper word then?

2. This is about A theory :"HUman Origins : Africa" http://en.wikipedia.org/wiki/Recent_single-origin_hypothesis

Answer 1

Actually, it was a genetic mutation that's responsible for fair skin. It's not an automatic response to the environment, so it cannot be predicted how long this adaptation would take. What we do know is that this single mutation responsible for blondes occurred in the Baltic Sea district sometime after 35,000 BC. Because of genetic drift and mixing with the general population, blonde people will become extinct in a few centuries. Today, there is very little evolutionary pressure to maintain this mutation, as even dark skinned people can do very well in northern climes, because it's not expected that they'll live in the wild.

Addendum: That is, unless man tinkers with his own genes, in which case not only we'll have lots of blondes, we'll have lots of pink, blue, and green glowing people as well. Hey, we've already got green glowing fishes from such genetic manipulations today! Today, fishes, tomorrow, women!

A site? This wiki article should be a good place to start.

2nd Addendum: Other "fair skinned people" like Asians and American Indians are not called WHITES! They have their own genetic mutations responsible for their skin color, but the fact remains that all the European WHITES stem from a single genetic mutation.

3rd Addendum: Is "evolve" the right word? Yes it is. "Evolve" does not mean, "change into a higher or more perfected state". It means a genetic change which is reinforced by environmental pressures. Having a light skin was an adaptation in low-light latitudes, just like dark skin was an adaptation in overly sunny tropical latittudes. Remove this environmental pressure, and skin differences in the human race will gradually diminish. An important point frequently lost on people: Evolution does not necessarily mean speciation. Phenotypical changes can occur within a given species.

Answer 2

Just some more info....quite a few Africans are born with white skin. They are either albinos or simply do not have the dark pigmentation.

They have problems with skin cancer caused by the sun's rays which normal skinned Africans do not have.

And.. the soles of an African's feet are white, presumably because that part of the body is not exposed to the sun and therefore needs no protection.

Humans have therefore adapted ( evolved ) to the different climates they live in.

Answer 3

Skin exposure to uv light assists in the production of vitamin D and as humans moved out of Africa they had an advantage being lighter skinned because of the vitamin D position. Innuit populations have a diet rich in Vitamin D from the liver of fish and arctic mammals and have less need for skin produced Vit. D
The answer appears to be about 40,00 years and it is estimated that the population of Australia will be predominantly dark skinned as they adapt to the high uv levels, over about 40k years

Answer 4

I don't know why you are receiving hostile answers! But yes if theory of evolution is correct and we all descend from Africa, with our skin becoming whiter as we moved out of Africa across to other cooler continents, then I would imagine this took a good few hunderds of thousands of years at least for a lighter skinned race to emerge. I don't know exactly how long though I am afraid!

Answer 5

Mitochondrial "Eve" was about 70,000 years ago... but the cultural revolution was, maybe, 50,000 years ago.
The answer: we don't really know, but it was almost certainly less than 50,000 years.

Another possibility, which most people will find unpalatable, is that there was might have been some gene flow in Europe from Neanderthals, and that light skin coloring might have come from them. This is unlikely at best, since our species didn't retain some of the other distinguishing characteristics of the robust Neanderthals.

Answer 6

Homo sapiens entered Europe about 40,000 years ago.
people crossed to North America about 10,000 years ago so the difference between Native Americans and Asians is about that long. Skin colour hasn't been preserved in fossils.

Answer 7

I dont have an answert but i think it is humerous that white people get so angry when faced with the fact that they could possibly share origin with a culture they have spent thier whole life trying to prove that they are better than simply because they have pale skin...
some people will never learn, but hopefully, they will die out soon and the world will be a better more tolerant place.

Answer 8

Darn good question! Maybe they started out white in Africa and the Africans that stayed there got darker.

Answer 9

Good question - I've always wondered that! And how long did it take? - Hasn't it happened in other animals too, eg. snow leopards? Hope you get an answer! xx

Answer 10

First of all I am amazed by the stupid ignorant, childish minds that actually know how to use a computer.

Skin color is due primarily to the presence of a pigment called melanin . Both light and dark complexioned people have this pigment. However, two forms are produced--pheomelanin , which is red to yellow in color, and eumelanin , which is dark brown to black. People with light complexioned skin mostly produce pheomelanin, while those with dark colored skin mostly produce eumelanin. In addition, individuals differ in the number and size of melanin particles. The latter two variables are more important in determining skin color than the percentages of the different kinds of melanin. In lighter skin, color is also affected by red cells in blood flowing close to the skin. To a lesser extent, the color is affected by the presence of fat under the skin and carotene , a reddish-orange pigment in the skin.

Melanin is normally located in the epidermis , or outer skin layer. It is produced at the base of the epidermis by specialized cells called melanocytes
Nature has selected for people with darker skin in tropical latitudes, especially in nonforested regions, where ultraviolet radiation from the sun is usually the most intense. Melanin acts as a protective biological shield against ultraviolet radiation. By doing this, it helps to prevent sunburn damage that could result in DNA changes and, subsequently, melanoma --a cancer of the skin. Melanoma is a serious threat to life. In the United States, approximately 54,000 people get this aggressive type of cancer every year and nearly 8,000 of them die from it. Those at highest risk are European Americans. They have a 10 times higher risk than African Americans.

Ultraviolet radiation reaching the earth usually increases in summer and decreases in winter. The skin's ability to tan in summertime is an acclimatization to this seasonal change. Tanning is primarily an increase in the number and size of melanin granules due to the stimulation of ultraviolet radiation.
Skin Color Distribution Around the World

Before the mass global migrations of people during the last 500 years, dark skin color was mostly concentrated near the equator and light color progressively increased further away, as illustrated in the map below. In fact, the majority of dark pigmented people lived within 20° of the equator. Most of the lighter pigmented people lived in the northern hemisphere north of 20° latitude.

Such a non-random distribution pattern of human skin color was predicted by Wilhelm Gloger, a 19th century naturalist. In 1833, he observed that heavily pigmented animals are to be found mostly in hot climates where there is intense sunshine. Conversely, those in cold climates closer to the poles commonly have light pigmentation. The relative intensity of solar radiation is largely responsible for this distribution pattern.

There are exceptions to Gloger's rule in the animal kingdom. In some cases, these are due to the fact that the survival value of having a camouflaged body can be more important than the selective pressures of ultraviolet radiation. Among humans, mate selection preferences may counter some of the evolutionary trend in skin color predicted by Gloger. The Inuit case described earlier suggests that diet may also be a significant factor in some societies. In the United States today, milk is regularly fortified with vitamin D to reduce the likelihood of children having calcium deficiencies. Despite this effort, some segments of the population still have high rates of calcium deficiency--especially African Americans and the elderly.

Humans have spent most of their history moving around. To do that, they've had to adapt their tools, clothes, housing, and eating habits to each new climate and landscape. But Jablonski's work indicates that our adaptations go much further. People in the tropics have developed dark skin to block out the sun and protect their body's folate reserves. People far from the equator have developed fair skin to drink in the sun and produce adequate amounts of vitamin D during the long winter months.

Jablonski hopes that her research will alert people to the importance of vitamin D and folate in their diet. It's already known, for example, that dark-skinned people who move to cloudy climes can develop conditions such as rickets from vitamin D deficiencies. More important, Jablonski hopes her work will begin to change the way people think about skin color. "We can take a topic that has caused so much disagreement, so much suffering, and so much misunderstanding," she says, "and completely disarm it."

The final answer is that this is a natural selection pressure that has taken tens of thousands of years.