Why Variation in Skin Color is of No Use in Defining Human Races, Essay Example
Genetic adaptations are optimal for ensuring genetic variety and survival within a given environment. Although cultural factors will play a role in the way humans modify the environments in which they live, variations in skin color are a direct result of the genetic adaptations that are dependent upon environmental survival. Variations in genetics appear to be the result of both adaptations and acclimatizations, which are both affected by cultural factors, such as nutrition and stress (Genetics and Evolution, nd). It is through these genetic mutations or productions of altered genes, that the survival of a species is more likely to flourish when faced with environmental changes. However, the genetic adaptations that are reflective of geographical location and indicate distinct racial group, all compose a single species and maintain that species’ identity through the flow of genes among their populations (Human Variation, 2008). These distinctions are often identified through physical traits, such as the adaptive response that either increases or decreases the melanin in the skin, which acts as a protective barrier from otherwise harmful ultraviolet radiation. Although both dark and light skin individuals share an equal amount of melanocytes, which are the skin cells that produce melanin, the amount of melanin found in the skin is a direct result of evolution and migration. Scientific evidence suggests that our first spices evolved in equatorial Africa, indicating that dark skin was the original human skin tone. As the human species migrated further from the equator, the production of vitamin D, which is synthesized in lower layers of skin when a precursor of the vitamin is activated by UV radiation, could not manufacture a sufficient amount of vitamin D for normal bone growth and maintenance. So adaptations causing the development of lighter skin tones would be a reproductive advantage, which over time, would develop as a common inherited trait (Human Variation, 2008).
Skin color is a trait of continuous variation, with various shades of light and dark and only four blood type variations. These factors offer no conclusion in defining human race. The human species cannot be divided into distinct subgroups based on biological differences, and since we are a single species with extensive gene flow, our variable traits are distributed as clines, with no clear-cut boundaries (Human Variation, 2008). The exchange of genes within the human species prevents any group of humans from being isolated long enough to evolve the distinct differences sufficient for semi-species status. Phenotypic features can be influenced by multiple genes, environmental factors, and natural selection. When scientists genetically compared samples from traditional racial groups, they determined that the groupings accounted for only around five percent of genetic variation existing between major population groups (Human Variation, 2008). The nature of genetic variation that influences phenotype may indicate geographic location due to the processes of evolution. This can be seen in skin color, blood type, and other physical features that are characteristic of climate and location. However, only a few genetic variants are unique to any one population, indicating that they are not characteristic of those populations. There is almost no set of African genetic variation not shared by some other population or group. For example, Europeans and Native Americans do not have a genetic racial identity because their genetic variants are found somewhere in Africa (Human Variation, 2008). As with phenotypic features, variation and regional differences in genes do not translate into biologically racial groups and may just be a cultural or societal classification based upon biological variation and human diversity. Because the human species cannot be categorized into a distinct group of biological races, it appears evident that racial variations based upon biological classification does not translate into any distinct racial category, and therefor; does not exist as a biological trait.
(Author’s name(s)) (nd). Genetics and evolution: Human adaptation and variation. (City: Publisher).
(Author’s name(s)) (2008). Human variation: Biological diversity and race. (City): McGraw-Hill.
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