G. Ledyard Stebbins
George Ledyard Stebbins, Jr. (January 6, 1906 – January 19, 2000) was an American botanist and geneticist who is widely regarded as one of the leading evolutionary biologists of the 20th century. Stebbins received his Ph.D. in botany from Harvard University in 1931. He went on to the University of California, Berkeley, where his work with E. B. Babcock on the genetic evolution of plant species, and his association with a group of evolutionary biologists known as the Bay Area Biosystematists, led him to develop a comprehensive synthesis of plant evolution incorporating genetics.His most important publication was Variation and Evolution in Plants, which combined genetics and Darwin's theory of natural selection to describe plant speciation. It is regarded as one of the main publications which formed the core of the modern evolutionary synthesis and still provides the conceptual framework for research in plant evolutionary biology; according to Ernst Mayr, ""Few later works dealing with the evolutionary systematics of plants have not been very deeply affected by Stebbins' work."" He also researched and wrote widely on the role of hybridization and polyploidy in speciation and plant evolution; his work in this area has had a lasting influence on research in the field.From 1960, Stebbins was instrumental in the establishment of the Department of Genetics at the University of California, Davis, and was active in numerous organizations involved in the promotion of evolution, and of science in general. He was elected to the National Academy of Science, was awarded the National Medal of Science, and was involved in the development of evolution-based science programs for California high schools, as well as the conservation of rare plants in that state.