Anthropologists and geographers have exposed the relationship between skin color and spatial layout (Jablonski and Chaplin 2002). Darker-skinned individuals are found closer to the equator than lighter-skinned populations (Jablonski and Chaplin 2002). Having darker skin was originally thought to be associated with an evolutionary defense mechanism regarding protection against skin cancer (Jablonski and Chaplin 2002). However, further research suggests that skin pigmentation depends on natural selection responsible for regulating UV radiation (Jablonski and Chaplin 2002). The evolution of early humans was necessary to preserve optimal body temperature and thus avoid overheating (Jablonski and Chaplin 2002). The body began to adapt by increasing the number of sweat glands and decreasing hair production, thereby establishing a cooler body temperature (Jablonski and Chaplin 2002). When humans began to have bare skin, melanin pigments formed and created a barrier against harmful cancerous UV rays (Jablonski and Chaplin 2002). Melanin absorbs UV energy and counteracts UV damage by neutralizing free radicals (Jablonski and Chaplin 2002). Our earliest ancestors, called Homo sapiens, evolved around 120,000 years ago in Africa (Jablonski and Chaplin 2002). Homo sapiens had dark skin pigments and therefore high levels of melanin, which blocked most ultraviolet rays from penetrating their skin (Jablonski and Chaplin 2002). Long-term exposure to UV rays can damage DNA and lead to cancer (Jablonski and Chaplin 2002). Therefore, dark pigments were an evolutionary adaptation to the high temperatures of the equator (Jablonski and Chaplin 2002). Additionally, darker pigments protect... middle of paper... and heritage. Works Cited Jablonski, NG 2002. “The Naked Truth.” Scientific American 42-49. Print. Lin, JY and DE Fisher. 2007. “Biology of melanocytes and skin pigmentation. » Nature 445.7130: 843-50. Print. Mas, JS, CO Sanchez, G. Ghanem, J. Haycock, JA Lozano Teruel, JC Garcia-Borron, and C. Jimenez-Cervantes. 2002. “Loss-of-function variants of the human melanocortin-1 receptor gene in melanoma cells define structural determinants of receptor function.” European Journal of Biochemistry 269.24: 6133-141. Print.Rees, JL “The genetics of skin and hair pigmentation in humans.” » University of Edinburgh: UK 842-843 (2003)Valverde, P., E. Healy, I. Jackson, JL Rees and AJ Thody. 1995. “Melanocyte-stimulating hormone receptor gene variants are associated with red hair and light skin in humans.” » Natural Genetics 11.3: 328-30. Print.