Clinal Variation In Skin Deep

Like a Rainbow

Race related social issues have made it virtually impossible to erase the color lines that exist in America and abroad. However, different skin colors and ethnic backgrounds has, since the beginning of human existence, made life much more interesting than it would have been had society been absent of such differences. Imagine life if all people were all the same throughout the entire world. It is my guess that life would be pretty boring. The questions at hand are how does the concept of race, as highlighted in the course text, and the principles of evolution relate to one another? And, how is the idea of clinal variation supported by Nina G. Jablonski and George Chaplin’s “Skin Deep” article? This essay will attempt to

First, to define cline, the text stated that cline is “A gradual change in some phenotypic characteristic from one population to the next” (Larsen 124). Phenotypes are physical expressions of genotypes as discussed in the text on page 44-45. In addition to the definition of cline, the text explained that skin pigmentation is a good example of clinal variation. “From equatorial to higher latitudes, skin color changes in a gradient from dark to light. …, but the single strongest factor in determining skin pigmentation is exposure to ultraviolet radiation” (Larsen 125). Similarly, the authors of the article “Skin Deep” noted that people with dark skin occupy areas most near to the equator, whereas people with light skin occupy areas near the poles. Furthermore, the article went to great lengths in describing how dark and light skin respond to UV radiation in that dark skin has more melonin to protect itself against harmful UV rays but cannot produce sufficient vitamin D, on the other hand, lighter skin lacks melonin sufficient enough to protect itself against harmful UV rays but can better produce vitamin D. This issue is correspondingly described in the text on page 142. In fact, on page 139, the text relied on Jablonski and Chaplin’s work to explain skin color, exposure to UV radiation, sun protection factors, melanocytes, melonin, and skin reflectance to address the topic of skin color just as the authors did in the article, so, the text and the article complement and support each other. Both discussions boiled down to how near or far people are from the equator or the poles. Overall, the human variation of skin color in both discussions is based primarily on geography, climate, and natural selection, which embody the cline