The Sun, and the Color of Our Skin

Of the many things we identify ourselves by, skin color seems to be one that is both obvious and persistent throughout history (whether for better or for worse).  We attribute a lot of things to the color of our skin.  We build communities, cultures and our identities around our skin pigmentation, but we are often slow to attribute this “important” aspect of our lives to the science and evolutionary principles that actually underlie it. 

While there have been many historical movements for and against varying skin shades, there always is little thought paid to the fact that skin color is very dependent on the ancient migration patterns of our ancestors and the ability our extinct primate predecessors to adapt to heat and sun exposure.  Some scientists believe that our very early ancestors had light skin, similar to that of chimpanzees.  However, their skin began to experience various pressures as they wandered out of the forest and began to populate the more sun-exposed savannas and fields.  In the harsher environment offered by the savanna, our ancestors experienced selection for more sweat glands and for the ability to spend more time foraging in the sun.

While most people recognize the existence of a skin color gradient based on global latitude, it wasn’t until tests were conducted by NASA in the 70s and 80s that we could for sure correlate the amounts of ultraviolet light that reach the planet’s surface with skin color.  These tests showed that areas closer to the equator received more ultraviolet radiation and those further from it received less, correlating with darker-colored skin near the equator and lighter skin away from it.  Furthermore it was found that skin color actually has a lot to do with the vitamins that humans receive.

 “Unfortunately” for the supremacists (of any kind), skin pigmentation has more to do with regulating ultraviolet penetration of the skin than it does with the capabilities and rights of a human.  Skin color adaptations have been shown to oscillate and occur rather rapidly on an evolutionary time scale.  Given this fact, it should be no surprise that they are currently changing and will continue to change as human migration is further facilitated by improved means of transportation.  We should also expect to see the effects of these adaptations on “displaced humans” who move to areas to which their skin is ill-equipped to handle the levels of ultraviolet radiation.  How do you guys think modern migration and spread of technology will affect the color of our future?

Skin color of indigenous populations vary with the levels of ultraviolet radiation they receive.

 -Matthew Moran

Jablonski, Nina, and George Chaplin. "The Evolution of Human Skin Coloration."Http://www.bgsu.edu. Bowling Green State University, 2000. Web. 15 Apr. 2012. <http://www.bgsu.edu/departments/chem/faculty/leontis/chem447/PDF_files/Jablonski_skin_color_2000.pdf>.

Kirchweger, Gina. "The Biology of Skin Color: Black and White." PBS. PBS, 2 Feb. 2001. Web. 16 Apr. 2012. <http://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html>.