ANTH 103 Lecture Notes - Lecture 5: Galactose, Human Skin Color, Radiation Protection
Document Summary
Color is due to the amount of melanin and melanosomes produced in melanocytes. Human skin color variation follows pattern of uv radiation levels; skin color varies depending on power of uv rays geographically. Too much uv radiation can damage skin cells not protected by melanin/melanosomes. Some uv exposure is necessary to catalyze vitamin d production in the skin. Vitamin d deficiency can cause rickets (disorder where bones are poorly minimalized, bowed legs) Variation is the result of two competing selective pressures: uv radiation protection in the tropics, adequate uv exposure for vitamin d synthesis. Not at all, everything is not separate it overlaps; not a spider chart, one of those overlapping circle charts. 6-10% of genetic variation occurs between major races or groups with shared ancestry. 90-94% of this variation occurs within each race or geographical group. There is less genetic variation between everyone in the world than than there is in certain places (ex.
