Does the Melanin Pigment of Human Skin Have Adaptive Value?: An Essay in Human Ecology and the Evolution of Race

Abstract

The widely accepted idea that melanin pigment in human skin protects against sunlight, and that this has bearing upon adaptation to life in the tropics and the distribution of races, is examined in terms of its physical and physiological aspects. Regarded in such terms the concept appears to have little merit. It is concluded that whereas the pigment may have a slight adaptive value as regards some aspects of the organism-environment relationship, it may be non-adaptive as regards others; and the respective values may depend upon various complicating factors of the, environment. Moreover, the distribution of races according to skin color does not appear to conform well to what would be expected from the spectral distribution of sunlight.