 This relationship, whereby biodiversity progressively arose from changes in development, was already anticipated by Johann F. Meckel (1812) and Richard Owen (1837), who parallelized ‘transmutations’ of embryonic forms and transmutations of species. Also Darwin (1837) describes the genesis of individuals as a ‘shortened repetition’ of morphological changes during phylogeny. From the end of the 19th century this view of development as a recapitulation of evolution became problematic (see Rasmussen 1991). First, during this time the view of a linear evolution from invertebrates over vertebrates to humans was increasingly questioned. Second, based on comparative studies of cell lineages across different taxa in the 1890s, scholars criticized that not only adult organisms but their developmental pathways evolve, too. For example, in 1898, embryologist Edmund B. Wilson (1898) was using homologous patterns of embryonic cell division to unite taxa, while embryologist Frank R. Lillie (1898) studied differences in these patterns to show the origins of evolutionary adaptations. These studies were (at least to some part) in conflict with Haeckel’s recapitulationism, as they saw ontogeny not as sufficiently explained by historical causes, but rather in need of independent mechanistic laws operating on physical properties of the ontogenetic material (see Guralnick 2002). In addition, this cell lineage research suggested that Haeckel’s law on the relationship between development and evolution should be inverted, as cell lineages evolve over evolutionary time. In more general terms, this means that development does not merely mimic evolution. Rather, it is a source of variation and thus a cause of evolution and adaptation: “ontogeny does not recapitulate phylogeny, it creates it” (Garstang 1922: 81). In short, evolution proceeds through modifications of development.