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The story of the development of the synthetic theory of evolution, named from Julian Huxley 's contribution, Evolution The Modern Synthesis (1942), has been told many times, notably in Mayr (1982) and in the collective work, Mayr and Provine (1980). As Mayr has frequently emphasised, population thinking - seeing anagenesis as the establishment of new forms in interbreeding populations - plus the biological species concept, traceable to John Ray in the seventeenth century (Ray 1686; see Chapter 14), were necessary before the theory could be developed. Theoretical population genetics - the mathematical modelling of genes in populations – was developed with different emphases by Fisher, Haldane, and Sewall Wright. Contemporary with them, Chetverikov and his colleagues in Russia were not only developing parallel ideas but testing them on wild populations of the fruit-fly Drosophila, Morgan 's choice of experimental animal. Dobzhansky, not a member of Chetverikov 's group but strongly influenced by them, continued his work in the United States in a series of papers on D. pseudoobscura from 1938 to 1976 and also produced what is usually considered the first great book of the synthesis, Genetics and the Origin of Species, in 1937. The others usually recognized are Huxley 's; Mayr 's Systematics and the Origin of Species (1942); Rensch (1947), translated in its second edition as Evolution Above the Species Level (1959); and Simpson 's Tempo and Mode in volution (1944), considerably changed (Gould 1980c) and reissued as The Major Features of Evolution (Simpson 1953). [ABSTRACT FROM AUTHOR]

In Chapters 2 and 3, I set out to suggest that the theory that evolution has occurred is the explanans of the phenomenon of natural classification (the explanandum). We also saw that the hierarchical pattern of classification, apart from being the normal way in which classifications of objects are presented, is the result, at least historically, of an accepted method. That method, described in Chapter 6, is logical division. But since the time of Darwin and Wallace, the resulting hierarchy has been regarded as the natural pattern. Most methods of classifying organisms are therefore designed to produce a divergent hierarchy not just for convenience but because it is presumed to correspond to a real phenomenon in nature. But classifications depend on characters possessed by the objects to be classified. Thus if the natural arrangement of organism is a divergent hierarchy, there must be an underlying divergent hierarchy of characters, and there should be something more to a character correctly uniting two species than a coincident resemblance. Behind the idea that one is dealing with the “same” character in two species, or higher taxa, is the concept of homology. Thus as natural classification is logically prior to phylogeny, homology is perhaps to be regarded as logically prior to natural classification. It is not the case, however, that the concept of homology arose before that of natural classification in the history of systematics. [ABSTRACT FROM AUTHOR]