The Ohio Center for Ecology and Evolutionary Studies celebrated Charles Darwin's 200th birthday yesterday with a guest lecture that
challenged the human conception of race as it relates to skin color.
Nina Jablonski, professor and chair of anthropology at Pennsylvania State University, spoke to students and faculty on the evolution of human skin and skin pigments.
Skin color is not a unique attribute that can be used to define human races.... [Skin color] is a signature of
the environment in which our ancestors lived
Jablonski said.
Essentially, skin pigment has evolved depending on a people's proximity to the equator, where the sun's ultraviolet rays have more of an effect. Darker pigment evolved to better protect the body from the sun, and the lighter pigment evolved when people moved away from the equator.
Because skin color is related to human migration throughout time, it is not a permanent trait, Jablonski said.
In her research, she found that ultraviolet radiation levels and latitude directly affect the pigmentation of the skin. Ultraviolet rays exist in three forms: UVA, UVB and UVC. Although each form of ultraviolet radiation harms the body in different way, UVB
rays help with the production of Vitamin D in the skin. Vitamin D is good for calcium absorption, the growth and maintenance of bones as well as the maintenance of a strong immune system, Jablonski said.
A lack of sun exposure can cause Vitamin D deficiencies, and because the people who migrated from the equator were no longer exposed to as much sunlight, their bodies needed to find a way to compensate for the lack of Vitamin D. To maximize
Vitamin D production in the skin, de-pigmentation evolved.
Skin color is the most visible product of evolution by natural selection on the human body Jablonski said.
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Culture
Rachel Ferchak
