Influence of Genetic Systems on Geographical Distribution

Abstract

The purpose of this paper is to examine the problem of the geographical distribution of species from the point of view of species borders and their rupture. Our speculations will be limited to cross-fertilizing species inhabiting continental areas. The writer is well aware of the complexities exhibited by living organisms in relation to their environments, the diverse methods of dispersal of individuals, and the difficulty inherent in any attempt to force these complexities to conform with any simple scheme. Indeed, the writer is at times astounded by his own presumptiousness in writing on a topic so complex and so remote from his particular field of study. He can only hope that these remarks will add somewhat to the understanding of geographical distributions, and therefore to our understanding of race and species formation, by indicating similarities in the underlying causes of distribution patterns where perhaps these similarities have previously been...