george ledyard stebbins

الإنجليزية - الإنجليزية

تعريف george ledyard stebbins في الإنجليزية الإنجليزية القاموس.: born Jan. 6, 1906, Lawrence, N.Y., U.S. died Jan. 19, 2000, Davis, Calif. U.S. botanist. He received his Ph.D. from Harvard University and later taught in the University of California system. In Variation and Evolution in Plants (1950) he became the first biologist to apply the modern synthetic theory of evolution a theory that distinguishes the basic processes of gene mutation and recombination, natural selection, changes in structure and number of chromosomes, and reproductive isolation to higher organisms. Working with polyploid plants (new species that originated by a spontaneous doubling of the chromosomes of an existing species), he employed a technique for doubling a plant's chromosomal number artificially to produce successful artificial polyploids from wild-grass species, becoming the first person to artificially hybridize a plant species that could thrive under natural conditions

george ledyard stebbins