G. Ledyard Stebbins; Evolution Botanist
G. Ledyard Stebbins, a longtime UC Davis botanist whose theories established the discipline of plant evolution and made him one of the leading figures of evolutionary biology, died of cancer Wednesday at his Davis home. He was 94.
Stebbins was one of the “nine old men” credited with modernizing Charles Darwin’s theory of evolution in the 20th century. Called the evolutionary synthesis, the modern theory is considered one of the half-dozen greatest scientific achievements of the past 100 years.
Stebbins pulled together findings from genetics and other fields and applied them to the plant world, showing similarities and differences in the evolutionary processes of plants and animals.
“He was an icon of American botany of the 20th century,” said Vassiliki Betty Smocovitis, a science historian at the University of Florida at Gainesville. “He is evolutionary botany. He founded it on his own.”
Stebbins was the author of an influential text, “Variation and Evolution in Plants,” published in 1950. In the book, he argued that plants are subject to the same evolutionary processes as animals.
He also wrote high school biology textbooks and was heavily involved in post-Sputnik efforts to improve science education in America. He was instrumental in making evolution part of the high school and university curriculum.
Stebbins’ passion for natural history and the outdoors was cultivated by his parents. Born in Lawrence, N.Y., he was the son of Edith and George Stebbins, who developed the exclusive community of Seal Harbor, Me., and later helped to establish Acadia National Park in Maine.
He was introduced to Darwin’s theory of evolution while a student at Harvard in 1925. After taking a zoology course there, he began to mull over evolutionary ideas during plant collecting expeditions to nearby woods. At Harvard, he decided to become a botanist.
During his college years, scientists were struggling with gaps in their understanding of Darwin’s theory. Some believed that new species developed suddenly through mutations, but others supported Darwin’s notion of gradual change influenced by natural selection.
During the 1930s and ‘40s, a small group of scientists who were considered among the best scientific minds of their generation began to merge findings from various fields, including genetics, paleontology, biology and taxonomy. The result was the new field of evolutionary biology. The chief architects of this modern theory of evolution included Sewall Wright, J.B.S. Haldane, Ronald Fisher, Theodosius Dobzhansky, Ernst Mayr, George Gaylord Simpson and Stebbins.
Stebbins’ contribution was to give botanists a framework for understanding the evolution of plants.
“I just modified things so that people could understand how things were in the plant world,” he said in a UC Davis magazine in 1989. “I pointed out, and still point out, certain differences among higher plants and higher animals that make it necessary to understand species in a different way.”
He published his groundbreaking findings in “Variation and Evolution in Plants,” which cemented his standing as one of the century’s leading evolutionists. Two years later, in 1952, Stebbins was elected to the National Academy of Sciences.
In 1950 he joined the faculty at UC Davis, where he became known as a charismatic teacher. He founded Davis’ genetics department.
Colleagues also knew him as an avid naturalist with an encyclopedic knowledge of California flora.
“You could go on hikes with him and he could tell you what elevation you were at just by looking at the plants around him,” said Smocovitis, who is completing a biography on Stebbins.
Stebbins retired in 1973 but continued to write and do research. In 1979, he was awarded the National Medal of Science by President Jimmy Carter. In 1980, the UC regents named a UC natural reserve in his honor--the 577-acre Stebbins Cold Canyon Reserve, about 20 miles from the Davis campus.
He is survived by three children, seven grandchildren and nine great-grandchildren.
