Modern Synthesis

The Modern Synthesis is the mid-twentieth-century union of Charles Darwin's natural selection with Gregor Mendel's rules of inheritance, resolving a divide between naturalists who studied selection in wild populations and geneticists who studied heredity in the laboratory, a divide this atlas's own Lamarckian Inheritance entry already traces back to Mendel's rediscovered rules supplying a mechanism for heredity around 1900. Ronald Fisher's and colleagues' mathematical work founded population genetics, showing that Mendelian inheritance and gradual selection were not in conflict but were exactly the mechanism selection needed; Theodosius Dobzhansky's 1937 book Genetics and the Origin of Species then brought that mathematics together with direct field evidence of genetic variation in wild fruit fly populations, widely credited as the synthesis's founding text. By the 1940s the once-separate fields of genetics, paleontology, and field naturalism shared a single working framework for how evolution occurs, still the basic model modern evolutionary biology builds on.