ANTHROP 2E03 Lecture Notes - Lecture 11: Melanin, Zygosity, Vasodilation
9 Apr 2018
School
Department
Course
Professor
Document Summary
Gradual change in frequency of a trait or allele in populations dispersed over geographical space. When modern humans migrated out of africa, they began to occupy regions with lower uv radiation. Protective high melanin levels no longer necessary: less risk of skin cancer, sunburn and folate destruction. Vitamin d is essential for normal bone growth and mineralization. Lack of vitamin d causes rickets in children bones become soft. Can lead to reduced reproductive fitness, especially in females: pelvic deformations from growing up with a lack of vitamin d. In our body, vitamin d is synthesized through the action of uv radiation. Vitamin d is necessary for a proper absorption of calcium, which is important for bone and teeth growth. In environments with low uv radiation: dark skin would be harmful. Thus, there was likely a selective pressure for a lighter skin pigmentation in regions farm from the equator, with low uv radiation.
