Stages Leading to The Modern Synthesis

During the period 1915–1930, three key events occurred that enabled the reconciliation of MendelismMendelism and Darwinism: (i) Castle and Norton proved the effectiveness of natural selectionselectionnatural acting on small differences; (ii) Nilsson-Ehle and East showed that Mendelian heredityheredityMendelian could explain quantitative traits, and (iii) Morgan and his co-workers demonstrated that most mutations were small rather than drastic changes. The reconciliation of MendelismMendelism and Darwinism was done primarily by Fisher, Wright, and Haldane, and gave rise to the field of mathematical evolutionary (or population) genetics. The results obtained from this discipline constituted the modern synthesis, which was further strengthened by the investigation of field biologists working in related disciplines.