The Sources. Formation of the Concept of Directed Evolution in the Nineteenth Century

Abstract

The pre-history of the concepts of directed evolution is represented by treatises of the authors who worked in the first half of the nineteenth century (Jean-Baptiste Lamarck, Georges Cuvier, Giovanni Batista Brocchi and others). They contained ideas related to spontaneous evolution, constraints on variation and the similarity of lifecycles of species and those of individuals. In the second half of the nineteenth century the concept of directed evolution was developed by Albert von Kölliker, Carl Nägeli, Edward Cope, Alpheus Hyatt, Wilhelm Haacke and Theodor Eimer, who worked more or less independently of each other. Each of these authors can be credited with being, in some respect, the pioneer of orthogenesis. The first works dealing with directed evolution were disconnected, and we cannot find in them the first wording of this concept, however hard we might try. This elusive concept can be deduced from the context of the writings of several authors, who claimed that organisms changed spontaneously in definite directions and denied the leading role of natural selection. As for the rest, their ideas had little in common.