Abstract

Made famous by Ernst Mayr (1961), the distinction between proximate and ultimate causation in biological explanation is widely seen as a key tenet of evolutionary theory and a central organizing principle for evolutionary research. The study of immediate, individual-level mechanistic causes of development or physiology (“proximate causation”) is distinguished from the study of historical, population-level statistical causes in evolutionary biology (“ultimate causation”). Since evolutionary developmental biology (evo-devo) is a field that explicitly uses so-called “proximate” sciences such as developmental biology, morphology, and embryology in the study of evolution, it challenges the standard construal of the proximate-ultimate distinction and its associated account of causation. The exact nature of the challenge and its ramifications for the viability of the distinction more broadly are contested, but these conceptual questions are central to the status and significance of evo-devo in contemporary evolutionary biology.