Straight Hair

According to the recent single origin hypothesis, anatomically modern humans (Homo sapiens) arose in East Africa approximately 200,000 years ago (Tishkoff, 1996). Then, ~150,000 years later, modern humans began to expand their range to regions outside of (and within) this continent (Tishkoff, 1996). Among those in the group which left... Read More

According to the recent single origin hypothesis, anatomically modern humans (Homo sapiens) arose in East Africa approximately 200,000 years ago (Tishkoff, 1996). Then, ~150,000 years later, modern humans began to expand their range to regions outside of (and within) this continent (Tishkoff, 1996). Among those in the group which left the African continent, their skin had developed the ability to manufacture vitamin D (which was essential for bone development) upon exposure to UV light (Jablonski, 2006). However the UV light of northern regions was too weak to penetrate the highly pigmented skin of the initial migrants in order to provide enough vitamin D for healthy bone development (Jablonski, 2006). Malformed bones in the pelvic area were especially deadly for women because they interfered with the successful delivery of babies; leading to the death of both the mother and the infant during labor. See Less