Ernst Mayr and the History of Evolution

Thus, evolutionary biology around 1930 found itself in a curious position. It faced two major seemingly unsolved problems: the adaptive changes of populations and the origin of biodiversity. Two large and very active groups of evolutionists worked on these problems. One of these groups consisted of the population geneticists. As summarized in the works of Fisher, Haldane, and Wright, this group had solved the problem of gradual evolution of populations through natural selection. But they had not made any contribution to the problem of how species arise (speciation)--that is, to the problem of the origin of biodiversity. The other group of evolutionists consisted of the naturalists (taxonomists). Although unaware of the solution to the problem of gradual adaptive evolution, they had solved the open problems of the evolution of biodiversity through the contributions of the European naturalists Wagner, Jordan, Poulton, Stresemann, and Chetverikov. Thus, by 1930, the two great problems of evolutionary biology had been solved, but by different groups whose accomplishments were unknown to one another. . .Fortunately, there was one evolutionist who had the background to be able to resolve the conflict between the geneticists and the naturalists. It was Theodosius Dobzhansky.* He had grown up in Russia as a naturalist and beetle taxonomist, but, in 1927, he joined Morgan's laboratory in America where he became thoroughly familiar with population genetics. He was ideally suited to show that the findings of the population geneticists and those of the European naturalists were fully compatible and that a synthesis of the theories of the two groups would provide a modern Darwinian paradigm, subsequently referred to as the "Evolutionary Synthesis." . . .By the end of the 1940s the work of the evolutionists was considered to be largely completed, as indicated by the robustness of the Evolutionary Synthesis. But in the ensuing decades, all sorts of things happened that might have had a major impact on the Darwinian paradigm. First came Avery's demonstration that nucleic acids and not proteins are the genetic material. Then in 1953, the discovery of the double helix by Watson and Crick increased the analytical capacity of the geneticists by at least an order of magnitude. Unexpectedly, however, none of these molecular findings necessitated a revision of the Darwinian paradigm--nor did the even more drastic genomic revolution that has permitted the analysis of genes down to the last base pair.