Williams' 1957 paper Pleiotropy, Natural Selection, and the Evolution of Senescence is one of the most influential in 20th century evolutionary biology, and contains at least 3 foundational ideas. The central hypothesis of antagonistic pleiotropy remains the prevailing evolutionary explanation of senescence. In this paper Williams was also the first to propose that senescence should be generally synchronized by natural selection. According to this original formulation
if the adverse genic effects appeared earlier in one system than any other, they would be removed by selection from that system more readily than from any other. In other words, natural selection will always be in greatest opposition to the decline of the most senescence-prone system.
This important concept of synchrony of senescence was taken up a short time later by John Maynard Smith, and the origin of the idea is often misattributed to him, including in his obituary in the journal Nature. Finally, Williams' 1957 paper was the first to outline the "grandmother hypothesis". William's formulation stated that natural selection might select for menopause and post-reproductive life in females. In his first book, Adaptation and Natural Selection, Williams advocated a "ground rule - or perhaps doctrine would be a better term -... that adaptation is a special and onerous concept that should only be used where it is really necessary", and, that, when it is necessary, selection among genes or individuals would in general be the preferable explanation for it. He elaborated this view in later books and papers, which contributed to the development of a gene-centered view of evolution; Richard Dawkins built on Williams' ideas in this area in the book The Selfish Gene. Williams was also well known for his work on the evolution of sex, and was an advocate of evolutionary medicine. In later books, including Natural Selection: Domains, Levels and Challenges, Williams softened his views on group selection, recognizing that clade selection, trait group selection and multilevel selection did sometimes occur in nature, something he had earlier thought to be so unlikely it could be safely ignored.
Williams became convinced that the genic neo-Darwinism of his earlier years, while essentially correct as a theory of microevolutionary change, could not account for evolutionary phenomena over longer time scales, and was thus an "utterly inadequate account of the evolution of the Earth's biota". In particular, he became a staunch advocate of clade selection – a generalisation of species selection to monophyletic clades of any rank – which could potentially explain phenomena such as adaptive radiations, long-term phylogenetic trends, and biases in rates of speciation/extinction. In Natural Selection, Williams argued that these phenomena cannot be explained by selectively-driven allele substitutions within populations, the evolutionary mechanism he had originally championed over all others. This book thus represents a substantial departure from the position of Adaptation and Natural Selection.
Williams, G.C., ed. 1971. Group Selection. Aldine-Atherton, Chicago.
Williams, G.C. 1975. Sex and Evolution. Princeton University Press, Princeton, N.J.
Paradis, J. and G.C. Williams. 1989. T.H. Huxley's Evolution and Ethics : with New Essays on its Victorian and Sociobiological Context. Princeton University Press, Princeton, N.J.
