In the early twentieth century many scientists held the view that biologically distinct races existed. The races corresponded to the major continental regions of Africa, Europe, Asia and the Americas. These races were distinguished from each other based on a few visible traits such as skin color and hair texture. Black people were largely defined by their dark skin and sometimes frizzy hair. The belief at that time was that not only did the races differ in appearance but in behavior, intellect and origins. Some scientists such as Carleton S. Coon believed the different races to have evolved separately over millions of years and that racial differences were thus extremely significant.
Breakthroughs in genetics and the mapping of the human genome in the late twentieth century have helped dispel many of the earlier myths about race. Ninety-nine point nine percent of any one person’s DNA is exactly the same as any other person regardless of ethnicity. Identical twins, but not fraternal twins, are an exception as the their DNA is a 100% match. Of the remaining 0.1% variation, there is an 8% variation between ethnic groups within a race, such as between the French and the Dutch. Only 7% of all human genetic variation lies on average between major human races such as those of Africa, Asia, Europe, and Oceania.
Afri was the name of several peoples who dwelt in North Africa near the
provincial capital, Carthage. The Roman suffix “-ca” denotes “country or land”.
Other etymologies that have been postulated for the ancient name ‘Africa’:
* the Latin word aprica, meaning “sunny”;
* the Greek word aphrike, meaning “without cold.” This was proposed
by historian Leo Africanus (1488-1554), who suggested the Greek word phrike (f?, meaning “cold and horror”), combined with the negating prefix “a-“, thus indicating a land free of cold and horror.
The low level of genetic variation across populations surprised many in the scientific community. Scientists believe the reason for this low level of variation is because the entire world population of 6.5 billion is descended from a small group of people, probably numbering no more than 2,000, who lived in Africa 70,000 years ago.From this small group, an even smaller group left Africa to populate the rest of the world. The differences in physical appearance between the various peoples of the world is as a result of adaptations to the different environments that the early pioneers who left Africa made in order to conquer the new lands to which they traveled.
The African population retains the great degree of physical variation. Even though all Africans share a skin color that is dark relative to other peoples of the world, they actually differ significantly in physical appearance. Examples include the Dinka, some of the tallest people in the world and the Mbuti, the shortest people in the world. Others such as the Khoisan people have an epicanthal fold similar to the peoples of Central Asia. A recent study found that Sub-Saharan Africa has the highest skin color diversity within population.
Scientists now believe that humans first appeared in Africa between 100,000 and 200,000 years ago.Dark skin helped protect against skin cancer that develops as a result of ultraviolet light radiation, causing mutations in the skin. Furthermore, dark skin prevents an essential B vitamin, folate, from being destroyed. Therefore, in the absence of modern medicine and diet, a person with dark skin in the tropics would live longer, be more healthy and more likely to reproduce than a person with light skin. Scientists point to the fact that white Australians have some of the highest rates of skin cancer as evidence of this expectation.
Conversely, as dark skin prevents sunlight from penetrating the skin it hinders the production of vitamin D3. Hence when humans migrated to less sun-intensive regions in the north, low vitamin D3 levels became a problem and lighter skin colors started appearing.
The people of Europe, who have low levels of melanin, naturally have an almost colorless skin pigmentation, especially when untanned. This low level of pigmentation allows the blood vessels to become visible and gives the characteristic pale pink color of white people. The difference in skin color between black and whites is however a minor genetic difference accounting for just one letter in 3.1 billion letters of DNA.
