George Ledyard Stebbins, Jr. | Biography

Considered the founder of evolutionary botany, George Ledyard Stebbins, Jr., was the first scientist to apply modern synthetic evolutionary theory to the plant kingdom. Stebbins was one of the twentieth-century architects who developed the evolutionary synthesis by considering analysis of organic fossils and genetic information with respect to Darwinian theories, specifically natural selection. Stebbins' ideas established and advanced evolutionary biology techniques that examined the processes and mechanisms of genetic mutation, recombination, and chromosome structure and quantity in plants. By applying evolutionary concepts to plants, Stebbins became the first person to synthesize artificially a plant species that survived in a natural environment. His contributions to plant evolution guided other researchers who elaborated on his research, and his findings, especially concerning plant speciation, became accepted as a foundation for botanical investigations. Stebbins' familiarity with plants enhanced his theoretical insights which have been cited as some of the most significant twentieth-century scientific achievements.

Stebbins was born at Lawrence, New York, to affluent parents who encouraged him to explore and understand nature. Because his mother had tuberculosis, the family moved to California where Stebbins enjoyed examining regional plants. At the family's summer home near Seal Harbor, Maine, Stebbins learned about the flora and fauna of tide pools. Enrolling at Harvard University in 1924, Stebbins considered a career as an attorney or musician until Professor Merritt Lyndon Fernald, a botany expert, convinced him to earn botanical degrees. Stebbins completed a doctorate in 1931. While attending graduate school, Stebbins became interested in applying genetics to botanical research, but the use of innovative chromosomal analysis techniques divided botanists, and conflicts between professors delayed Stebbins's academic progress. Stebbins attended the International Botanical Congress at Cambridge, England, 1930, meeting eminent botanists who inspired him. He married Margaret G. Chamberlaine in 1931, and they had three children. They divorced in 1948, and Stebbins married Barbara Jean Brumley in 1958.

Conducting cytogenetic investigations, Stebbins taught at Colgate University in Hamilton, New York, from 1931 to 1935 when he accepted a position at the University of California at Berkeley where he intensified his evolution research. He became acquainted with Theodosius Dobzhansky, a California Institute of Technology geneticist who researched fruit flies. Both men were interested in studying the role of chromosomes in evolution, collected specimens together during horseback rides, and debated evolution research. Stebbins helped establish the Biosystematists, a group of scientists in the San Francisco Bay area committed to developing evolutionary methodology.

Working with Ernest B. Babcock, Stebbins experimented with flowering plant species. As early as the 1940s, Stebbins produced fertile hybrids by using artificially induced polyploidy to double the number of plants' chromosomes and form new species. He created wild grass polyploids, including Ehrharta erecta, a new species grown in a natural setting. Stebbins actively participated in the Society for the Study of Evolution, serving as that group's third president in 1948. Because most evolutionary researchers were zoologists, Stebbins voiced his concerns that the society's journal, Evolution, focused more on animals than plants, alienating botanists.

In 1947, Stebbins lectured at Columbia University, and his presentations were the basis of his 1950 book, Variation and Evolution in Plants, considered a classic text. Stebbins discussed his pioneering evolutionary botanical research and development of plant species, stressing that plants, like animals, undergo evolution but in unique ways because their cells differ. After his book was published, Stebbins moved to the University of California's campus at Davis to create a genetics department.

Stebbins wrote Processes of Organic Evolution (1966), The Basis of Progressive Evolution (1969), and Chromosomal Evolution in Higher Plants (1971) prior to retiring in 1973. He was a visiting professor at the University of Chile and several American universities. Stebbins later published Flowering Plants: Evolution Above the Species Level (1974) and Darwin to DNA, Molecules to Humanity (1982). He was a co-author of the textbook Evolution (1977) with Theodosius Dobzhansky, Francisco Ayala, and James Valentine. Stebbins promoted conservation and sought preservation of a Monterey Peninsula beach while he was president of the California Native Plant Society in 1967. He encouraged the protection of indigenous plants, especially rare species, and their habitats.

Elected a member of the National Academy of Sciences in 1952, Stebbins was also awarded a 1979 National Medal of Science in addition to receiving other significant medals, prizes, and fellowships presented by international scientific societies and honorary degrees from educational institutions. He was president of the Botanical Society of America and secretary general of the Union of Biological Sciences. In 1980, the University of California at Davis designated the Stebbins Cold Canyon Reserve to recognize his commitment to botany. National symposiums featured papers about Stebbins's theories and work. Stebbins died at Davis, California.