Mary J. West

Throughout his life, John Tyler Bonner contributed to major transformations in the fields of developmental and evolutionary biology. He pondered the evolution of complexity and the significance of randomness in evolution, and was instrumental in the formation of evolutionary developmental biology. His contributions were vast, ranging from highly technical scientific articles to numerous books written for a broad audience. This historical vignette gathers reflections by several prominent researchers on the greatness of John Bonner and the implications of his work.

Darwin proposed that evolutionary novelties are environmentally induced in organisms “constitutionally” sensitive to environmental change, with selection effective owing to the inheritance of constitutional responses. A molecular theory of inheritance, pangenesis , explained the cross‐generational transmission of environmentally induced traits, as required for evolution by natural selection. The twentieth‐century evolutionary synthesis featured mutation as the source of novelty, neglecting the role of environmental induction. But current knowledge of environmentally sensitive gene expression, combined with the idea of genetic accommodation of mutationally and environmentally induced change, supports a revival of Darwin's original theory that is consistent with modern molecular and population genetics. †To contact the author, please write to: Smithsonian Tropical Research Institute, c/o Escuela de Biología, Universidad de Costa Rica, Costa Rica; e‐mail: [email protected].