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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.〔Yoon C. K. January 21, 2000. Ledyard Stebbins, 94, Dies; Applied Evolution to Plants. ''New York Times'', Section B, Page 9〕 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."〔Mayr, Ernst. "Botany: Introduction" in ''The Evolutionary Synthesis: Perspectives on the Unification of Biology'', Ernst Mayr and William Provine, editors. Cambridge, Massachusetts: Harvard University Press, 1998. p. 138. Regarding the synthesis: "More than anything else, it was Stebbins' book, ''Variation and Evolution in Plants'' (1950), that brought botany into the synthesis. It had the same impact in botany as Dobzhansky's book in population genetics, integrating the widely scattered literature of plant evolution and providing abundant suggestions for further research."〕 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. ==Early life and education== Stebbins was born in Lawrence, New York, the youngest of three children. His parents were George Ledyard Stebbins, a wealthy real estate financier who developed Seal Harbor, Maine and helped to establish Acadia National Park, and Edith Alden Candler Stebbins; both parents were native New Yorkers and Episcopalians. Stebbins was known throughout his life as Ledyard, to distinguish himself from his father. The family encouraged their sons' interest in natural history during their periodic journeys to Seal Harbor. In 1914, Edith contracted tuberculosis and the Stebbins moved to Santa Barbara, California to improve her health. In California, Stebbins was enrolled at the Cate School in Carpinteria where he became influenced by Ralph Hoffmann, an American natural history instructor and amateur ornithologist and botanist.〔Colloquium on Variation and Evolution in Plants and Microorganisms – Toward a New Synthesis : 50 Years After Stebbins -By Michael I. Chegg〕 After graduating from high school, he embarked on a major in political studies at Harvard. By the third year of his undergraduate study, he had decided to major in botany.〔Raven, P. H. 2000. (G. Ledyard Stebbins (1906–2000): An appreciation ). ''Proceedings of the National Academy of Sciences'' 97:6945–6946〕 Stebbins started graduate studies at Harvard in 1928, initially working on flowering plant taxonomy and biogeography—particularly that of the flora of New England—with Merritt Lyndon Fernald. He completed his MA in 1929 and continued to work toward his Ph.D. He became interested in using chromosomes for taxonomic studies, a method that Fernald did not support. Stebbins chose to concentrate his doctoral work on the cytology of plant reproductive processes in the genus ''Antennaria'', with cytologist E. C. Jeffrey as his supervisor and Fernald on his supervisory panel. During his Ph.D. candidature, Stebbins sought advice and supervision from geneticist Karl Sax. Sax identified several errors in Stebbins's work and disapproved of his interpretation of results that, while in accordance with Jeffrey's views, were inconsistent with the work of contemporary geneticists. Jeffrey and Sax argued over Stebbins's dissertation, and the thesis was revised numerous times to accommodate their differing views.〔Smocovitis, V. B. 1997. G. (Ledyard Stebbins, Jr. and the evolutionary synthesis (1924–1950) ). ''American Journal of Botany'' 84:1625–1637〕 Stebbins's Ph.D. was granted by Harvard in 1931. In March that year, he married Margaret Chamberlin, with whom he had three children. In 1932, he took a teaching position in biology at Colgate University. While at Colgate, he continued his work in cytogenetics; in particular, he continued to study the genetics of ''Antennaria'' and began to study the behaviour of chromosomes in hybrid peonies bred by biologist Percy Saunders. Saunders and Stebbins attended the 1932 International Congress of Genetics in Ithaca, New York. Here, Stebbins's interest was captured by talks given by Thomas Hunt Morgan and Barbara McClintock, who spoke about chromosomal crossover. Stebbins reproduced McClintock's crossover experiments in the peony, and published several papers on the cytogenetics of ''Paeonia'', which established his reputation as a geneticist.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「G. Ledyard Stebbins」の詳細全文を読む スポンサード リンク
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