Yoshinari Yoshida

Biologists often study particular biological systems as models of a phenomenon of interest even if they already know that the phenomenon is produced by diverse mechanisms and hence none of those systems alone can sufficiently represent it. To understand this modeling practice, the present paper provides an account of how multiple model systems can be used to study a phenomenon that is produced by diverse mechanisms. Even if generalizability of results from a single model system is significantly limited, generalizations concerning specific aspects of mechanisms often hold across certain ranges of biological systems, which enables multiple model systems to jointly represent such a phenomenon. Comparing mechanisms that operate in different biological systems as examples of the same phenomenon also facilitates characterization and investigation of individual mechanisms. I also compare my account with two existing accounts of the use of multiple model systems and argue that my account is distinct from and complementary to them.

Although there are many historical and philosophical analyses of evolutionary developmental biology (EvoDevo), its development in the 1980s, when many individual or collective attempts to synthesize evolution and development were made, has not been examined in detail. This article focuses on some interdisciplinary studies during the 1980s and argues that they had important characteristics that previous historical and philosophical work has not recognized. First, we clarify how each set of studies from the 1980s integrated the results or approaches from different biological fields, such as paleontology, developmental genetics, comparative morphology, experimental embryology, theoretical developmental biology, and population genetics. Second, after close examination we show that the interdisciplinary studies during the 1980s adopted different and conflicting views of genes, such as developmental-genetic, epigenetic, or population-genetic ones. We conclude that EvoDevo in the 1980s was a motley aggregation of various kinds of local integration. Finally, we discuss the implications of our analysis by comparing these early EvoDevo studies with those of the Modern Synthesis and with the present state of EvoDevo.