ABSTRACT
This chapter examines the influence of some ecological factors on the physical differences exhibited by the human populations of sub-Saharian Africa. Human physical characteristics are conditioned by two groups of factors, heredity and environment, the relative importance of which differ according to the characteristic under consideration. Protein deficiency is common among agricultural African populations, especially those whose diet consists mainly of vegetables that are poor in proteins. Pastoral populations, or those that carry on agriculture and cattle-herding simultaneously, find a vital source of proteins in beef and milk. The important factors of direct influence of the environment on the average stature of African populations remain to be studied, and it is to be hoped that the various investigations will furnish us with significant data on the equally important problem of environmental influence on the rhythm of growth. Sociological and ecological factors hinder the action of a whole series of hereditary pathological characteristics, to determine the extent of selection.
