George Gaylord Simpson, Ph.D. (Geology, Yale University, 1926), was Professor of Geosciences at the University of Arizona from 1968 until his retirement in 1982. Previously was Curator of the Museum of Comparative Zoology at Harvard University 1959–1970, Curator of the Department of Geology and Paleontology at the American Museum of Natural History 1945–1959, and Professor of Zoology at Columbia University.
He was awarded the Linnean Society of London's prestigious Darwin-Wallace Medal in 1958. Simpson also received the Royal Society's Darwin Medal 'In recognition of his distinguished contributions to general evolutionary theory, based on a profound study of palaeontology, particularly of vertebrates,' in 1962. In 1966, Simpson received the Golden Plate Award of the American Academy of Achievement.
An excellent work in evolutionary theory. Simpson was an important figure in the development of neo-Darwinian thinking. Here, he focuses on "tempo and mode," how quickly evolution occurs and how it occurs. Historically, this is a key work to explore if one is interested in the development of evolutionary theory in the 20th century.
With this classic text, Simpson established paleontology as absolutely relevant to evolution as envisioned in the Modern Synthesis. Simpson's is the first to examine these issues in light of population genetics and is justly considered a foundational test of the Modern Synthesis.
It is very enlightening to read Simpson now, particularly how thoroughly he examined rate variation in numerous evolutionary lineages, estimated variation in rates (with new terminology not subsequently adopted) and anchored it to explicit mechanisms, and to contrast it with the straw man that punctuated equilibrium was at its very birth, variation in evolutionary rates drastically simplified into a non-phenomenon bereft of reasonable mechanism. Simpson already laid out mechanisms for rapid evolution and anchored them to numerous evolutionary and taphonomic mechanisms, but what mechanisms could create ongoing stasis? It becomes metaphysics to insist, the rhetoric writing checks the theory can't cash. Simpson also considers evolutionary and taphonomic contexts that could underly more slowly evolving taxa, but nowhere does he consider it reasonable to claim actual stasis is widespread. In fact he is very clear that the slow end of the distribution of evolutionary rates has a comparatively long tail, the opposite of stasis.
The more we know about molecular mechanisms the less we believe anything like "stasis" exists there; there are genes and genomic regions with slow evolutionary rates, yes, but these coexist with very rapid evolutionary rates within the same genome.
Simpson's treatment is masterful and generates much more insight, using creative figures and bold, comprehensive syntheses. It rewards a careful read.