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2010-09-03 20:49:48
2010-09-03 20:49:48

When genus homo emerged in Africa, their original color was black. The melanin in their skin acted as protection against the high level of ultraviolet radiation in African equatorial regions. They later spread to almost every corner of the globe and developed into various forms of the genus homo.

As they moved away from tropical sunshine, the advantage of a dark skin diminished, and another factor came into play. One of the essential vitamins is vitamin D. Most vitamins must be in food. D is an exception; humans can make it in the skin if and only if they are exposed to good sunlight. It became an evolutionary advantage to lower the amount of melanin in the skin, and the nearer the poles, the more important to do so. The further from the equator, the lighter the skin.

This is not just some wild theory; a classic confirmation occurred in UK a few decades ago. A number of children in northern England were found to have rickets. This is a disease which makes children grow up bow-legged. It is a well known symptom of vitamin D deficiency. Rickets was once common in northern England, especially in poorer families. It had quickly been eliminated when manufacturers of flour were compelled to enrich it with vitamin D.

It had now reappeared suddenly, but only in the children of immigrants from India/Pakistan. These families mostly ate rice; when they did eat bread it was made from chapati flour, imported from India, and not enriched. When enrichment was made compulsory for imported flours, the rickets quickly stopped. Indian children still have dark skins, and northern England still has little sunshine, but vitamin D did the trick.

As to the disparity in numbers between blacks and whites, truly coal-black people are found in tropical regions that are open to the sun, not heavily forested areas, not 'jungle'. The proportion of earth's habitat meeting these criteria is remarkably small.

Furthermore, the introduction of the gene for pale skin and red hair has been credited to the Ice age Neanderthals who first populated the northern zones of Eurasia. Without this adaptation it would have been difficult for modern humans to thrive in the northern reaches of our planet. After the most recent Ice Age ended, the limited sun light in the region continued to favor the survival of modern humans with this genetic anomaly of light skin color.


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