Variation and Evolution in Plants: Progress During the Past Twenty Years

Abstract

Professor Dobzhansky's ``Genetics and the Origin of Species'' was a milestone of progress in our understanding of evolution for two reasons. On the one hand, it was the first book to synthesize into a coherent whole the basic facts about traditional and population genetics, chromosomal variation, and natural selection. It therefore represents the birth of the modern synthetic theory of evolution. In addition, it attracted the attention of many biologists trained in disciplines quite different from his own, who then extended the synthetic theory in a variety of different directions. The present author was stimulated to apply the theory to plants. Even more than by the book, I was inspired by many exciting discussions of evolutionary theory with Professor Dobzhansky himself. My own book (Stebbins, 1950) is now old enough to be almost obsolete, and various other commitments make a complete revision unlikely during the next few years. I should like, therefore, to dedicate to Professor Dobzhansky on his 70th birthday a discussion of some of the most important topics of my book, as they appear to me now, based upon my interpretations of research results and theoretical discussion which many evolutionists have published during the past twenty years.