Natural Selection and Morphological Variability: The Case of Europe from Neolithic to Modern Times'

Abstract

THE QUESTION OF THE INTRASPECIFIC differentiation of mankind may be answered in two ways. The first answer is a typological one, based on the assumption that evolutionary forces, especially natural selection, do not act upon man now that he is equipped with culture as an adaptive mechanism. Hence the human races developed in the Paleolithic have remained unchanged up to our time, and all the changes in the phenotypic characteristics of populations are due to gene flow and environmental factors only. The second answer takes into account all the phenomena known to population genetics, as well as knowledge of cultural evolution and the interrelations between man and the environment he creates. It is obvious that in this concept there is no room for speculation about an absence of biological evolution caused by cultural development. Man is continuously adapting to his environment, both biologically and culturally, but cultural change is at the same time change in the environment, demanding further adaptation. Hence he has to adapt biologically both to the natural environment and to the environment created by socioeconomic progress. It seems that natural selection is the main mechanism responsible for the origin and maintenance of man's variability. Although numerous attempts have been made to show substantial effects of genetic drift or inbreeding on human populations, only a few rather exceptional cases of isolates, on islands, in high mountains, etc., have been found. Obviously these populations are not typical for our species at any level of cultural development. Moreover, it seems that considerable exchange of genes between populations is the normal state of human breeding groups and isolation is mostly relative, due to distances (cultural and/or geographic) separating population clusters. Hence in this paper we will deal with the effects of natural selection on inter- and intragroup variability in man. The operation of natural selection on man may be arbitrarily