The white man closely related to reproduction ability of the complexion bears the inferior position obviously

The white man closely related to reproduction ability of the complexion bears the inferior position obviously
What color is skin of the chimpanzee born? " It is certainly black! " Perhaps you will answer without thinking. In fact what you saw is the color of chimpanzee's hair . Keeping an eye on face, sole of the little chimpanzee,etc. has no part covered by the hair, you will see its skin color is actually very light.
East African several million year ago, salute we with the ancestors and the ancestors of chimpanzee of mankind but don't, go on different evolution roads. We can imagine, look and present chimpanzee of the human ancestor are a bit similar, also the dark hair is covering the light-colored skin. As the human ancestor takes off the hair, turn into " L The naked ape " ,The light-colored skin has been totally exposed, just turned into at the same time " L White ape " . But, why today the African aboriginal's skin colors are all very dark, that is called overstating " L The black person " R (used at the end of a special alternative, or rhetorical question)?
The depth of the complexion mainly depends on black and plain amount and size in the skin. Under the ultraviolet stimulus in the sunshine, quantity and size of the black plain particle will increase, the only so-called quilt is tanned . It is sun-proof frost in nature that human body make to be black and plain, are used for absorbing the ultraviolet ray in the sunshine. If ultraviolet ray is not shielded, not only will burn the skin, the more serious one is, will damage DNA in skin cells, and then bring out malignant skin carcinoma - black plain tumour. The intersection of complexion and shallow getting easy skin carcinoma, for example American 10 times of the Afro-American's in dark plain morbidity of tumour in white man.
Obviously, the human ancestor must protect skin against the injuring of strong sunshine in Africa behind taking off the hair. The answer seems apparent and apt to see: The complexion of the human ancestor becomes deep, is resulted from natural selection, in order to prevent skin cancer. But this answer has a loophole . Skin carcinoma usually will take place after the damage of suffering the ultraviolet ray year in year out, the patient has often already entered reproduction period while breaking out, have already left the offspring, and the natural selection is through controlling the offspring amount to contribute, the impact on skin carcinoma patient is very small.
The person's fecundity that other factors let the complexion be simple exerts a tremendous influence, the natural selection will just have ample scope for abilities. Discover, if the person with simple complexion is exposed to the strong sunshine, folic acid in the blood will be destroyed, the content drops rapidly. Folic acid is a kind of B clan vitamin, it is the indispensable composition when the cell division formates DNA, any physiological course of involving cells and proliferating fast needs folic acid, folic acid lacks will influence a lot of physiological functions. Say, lack the production that folic acid will influence the sperm in the body to the man. Come, say to woman, lack folic acid, can result in, miscarry in the body when being pregnant, let foetus appear the nerve in charge of the defect, do not have brain child or backbone to split to give birth to (The vertebra was not totally closed ) Baby . All these directly relate to level of reproduction ability, let the complexion have obvious reproduction inferior position simply, this may be the main reason that the human ancestor's complexion is deepened.
More than ten ten thousand years ago, the modern's ancestor goes out of Africa, spread to world all parts gradually. When the human ancestor migrates to the high latitude area, the complexion has become the question. In the intersection of high latitude and district, the sunshine is not strong then in district as low latitudes, UV radiation quantity is greatly reduced, it is very limited that it is usually regarded as the natural suncream and played a protection that gets role that black, too many and harmful to health instead. Originally, though ultraviolet ray will destroy folic acid, damage the skin, also have an essential function: Stimulate synthetic vitamin D of skin. It is synthetic by the skin under the ultraviolet stimulus that vitamin D that the human body needs probably has 90%, 10% left Just absorb from the meal.
Complexion dark people this pieces of question at tropical regional life, though ultraviolet ray deceive, usually shield mostly, but that small part slipping through the net has already used synthetic vitamin D enough. But they have reached the high latitude area, it is unable to get abundant ultraviolet rays. Vitamin D helps the intestine to absorb calcium, phosphorus, if lack vitamin D in the body, can then result in, lack calcium, phosphorus in the body, influence growth of skeleton, appear rickets, this kind of disease will present in infant and pre-school children period. If women lack vitamin D in Childhood, will enable the pelvis deformity and will have difficult labour later.
So in the high latitude area, the complexion has become serious existence inferior position deeply, the human complexions of these areas become light gradually. As an evidence of this view, in all crowds, women's complexion is generally lighter than the male one, their usually lacking about 3%-4% black in skin, though people often think this is a fact that men had partiality for simple complexion women (evolutionism calling this choice) ,But its deep reason may be so large as to have something to do with women's demand for calcium of reproduction age more, especially in gestation and nursing period, women's demand for calcium is larger, so women are relatively simple, it is for letting more ultraviolet rays penetrate the skin, make more vitamin D.
Perhaps you will expect, there is one this view against the example: Of Innewrt living around the Arctic Circle (Called the Eskimo in the past ) Complexion as Nordics shallow . But the intersection of Innewrt and people eat the ocean fishes and oil of seal in a large amount, the food is rich in vitamin D, meet their demands enough already, so the intersection of they and complexion it thes shallow pressure to be then loud. Moreover Innewrt to move northwards before about 5000 year in people, complexion of them have no enough time, happen, evolve.
Over several hundred years, the mankind has recured and migrated big worldwide, a lot of crowds with simple complexion have migrated to the tropical area, but a lot of crowds with deep complexion migrate to the high latitude area. Evolution which meet the local climate of having no time to happen of their complexion even more. Moreover, the result of the natural selection is not always perfect, even a aboriginal, also there are a lot of people that will lack vitamin D or folic acid. Actually these people should be eliminated by the natural selection, but the civilized society did not allow everything " L Comply with the nature " . Advising children, pregnant woman to supplement vitamin D preparation, the pregnant woman supplements folic acid preparations, have become the current methods of medical circles of various countries. But medical science propose, can not guarantee everybody can observe, it adds nutrient to be one effective cheap measure too in daily food. Today, the milk that developed countries such as U.S.A.,etc. sold generally add vitamin D, and the U.S. government requires all grain products to add folic acid from January of 1998 by force even more. Modern medical science lets the mankind have ability to resist natural selection, can benefit everyone, but its realization, need approval and participation of the whole society. With the intersection of health and enhancement of consciousness, people
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