G. Ledyard Stebbins - UC Davis and Later Life

UC Davis and Later Life

Stebbins took an appointment at the University of California, Davis in 1950, where he was a key figure in the establishment of the University's Department of Genetics; he was the Department's first chairman and held the position from 1958 to 1963. At Davis, the focus of his research changed to incorporate newer areas, such as developmental morphology and genetics in crop plants, including barley. He continued to publish widely and extensively on plant evolution, writing over 200 papers and several books after 1950.

Stebbins and Edgar Anderson wrote a paper in 1954 on the importance of hybridization in adapting to new environments. They proposed novel adaptations would facilitate the invasion of habitats not utilized previously by either parent and that novel adaptations may facilitate the formation of stabilized hybrid species. Following this paper, Stebbins developed the first model of adaptive radiation. He proposed that a high degree of genetic variability was necessary for major evolutionary advances, that because of slow mutation rates, genetic recombination was the most likely source of this variation, and that variation could be maximised though hybridization. As of 2006, research is ongoing regarding whether hybridization is an accidental consequence of evolution or if it is necessary for the creation and evolution of plant species; it has been argued that contemporary studies are part of an intellectual lineage that started with the work of Stebbins and Anderson.

Stebbins wrote several books during his time at UC Davis. These included his follow-up to Variation and Evolution, Flowering Plants: Evolution Above the Species Level, which was published in 1974, following his delivery of the Prather Lectures at Harvard. Stebbins discusses the origins, genetics and developmental biology of the angiosperms. He argues for the role of adaptive radiation in the diversification of the angiosperms and the usefulness of applying our current understanding of species' genetics and ecology to gain knowledge about the evolution of ancient species. He also wrote Processes of Organic Evolution, The Basis of Progressive Evolution, Chromosomal Evolution in Plants and the textbook Evolution with co-authors Dobzhansky, Francisco Ayala and James W. Valentine. His last book, Darwin to DNA, Molecules to Humanity was published in 1982.

Stebbins was passionate about teaching evolution, advocating during the 1960s and 70s the teaching of Darwinian evolution in public schools. He worked closely with the Biological Sciences Curriculum Study to develop high school curricula based on evolution as the central unifying principle in biology. He also opposed scientific creationism groups. Stebbins was active in numerous science organizations—including the International Union of Biological Sciences, the Western Society of Naturalists, the Botanical Society of America, and the Society for the Study of Evolution—and served as President of the American Society of Naturalists. He was elected to the National Academy of Sciences in 1952. Stebbins received numerous awards for his contributions to science: the National Medal of Science, the Gold Medal from the Linnean Society of London, the Addison Emery Verrill Medal from the Yale Peabody Museum of Natural History, and the John Frederick Lewis Award from the American Philosophical Society. He was elected a Fellow of the American Academy of Arts and Sciences in 1952.

Stebbins was active in conservation issues in California during his later life. He established a California Native Plant Society branch in Sacramento in the early 1960s. Through the society, he created an active field trip program to increase interest in the native flora of California and to document rare plants. Stebbins was the state President of the Society during 1966. The society was instrumental in preventing the destruction of a beach on the Monterey Peninsula that he referred to as "Evolution Hill"—the area is now known as the S.F.B. Morse Botanical Area and is managed by the Del Monte Forest Foundation. He was a major contributor to the Society's 1996 book California's Wild Gardens: A Living Legacy. Stebbins was instrumental in the establishment of the Inventory of Rare and Endangered Vascular Plants of California by the California Native Plant Society; it is still used by state and federal bodies in the United States for conservation policy-making. Stebbins was also a member of the Sierra Club.

During his tenure at UC Davis, he trained more than 30 graduate students in genetics, developmental biology and agricultural science. In 1973, Stebbins gave his last lectures at UC Davis and was made professor emeritus. Following his retirement, he travelled widely, taught, and visited colleagues for the next 20 years. His last paper, "A brief summary of my ideas on evolution", was published in the American Journal of Botany in 1999. The same year he was co-recipient with Ernst Mayr of the Distinguished Service award from the American Institute of Biological Sciences. A colloquium was held by the National Academies of Science in 2000 to commemorate the 50th anniversary of the publication of Variation and Evolution in Plants. Stebbins died in his home in Davis the same year from a cancer-related illness. Stebbins was honored at a Unitarian memorial service—he had been active in the church in his later years following his 1958 marriage to his second wife, Barbara Monaghan Stebbins. His ashes were scattered at Stebbins Cold Canyon Reserve.