Obituary: Lynn Margulis / Trailblazing evolution theorist
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Lynn Margulis, a biologist whose work on the origin of cells helped transform the study of evolution, died Tuesday at her home in Amherst, Mass. She was 73. She died five days after suffering a hemorrhagic stroke, said Dorion Sagan, a son she had with her first husband, the cosmologist Carl Sagan.
Ms. Margulis, who had the title of distinguished university professor of geosciences at the University of Massachusetts Amherst since 1988, drew upon earlier, ridiculed ideas when she first promulgated her theory, in the late 1960s, that cells with nuclei, which are known as eukaryotes and include all the cells in the human body, evolved as a result of symbiotic relationships among bacteria.
The hypothesis was a direct challenge to the prevailing neo-Darwinist belief that the primary evolutionary mechanism was random mutation.
Rather, Ms. Margulis argued that a more important mechanism was symbiosis; that is, evolution is a function of organisms that are mutually beneficial growing together to become one and reproducing.
The theory undermined significant precepts of the study of evolution, underscoring the idea that evolution began at the level of micro-organisms long before it would be visible at the level of species.
The manuscript in which Ms. Margulis first presented her findings was rejected by 15 journals before being published in 1967 by the Journal of Theoretical Biology. An expanded version, with additional evidence to support the theory - which was known as the serial endosymbiotic theory - became her first book, "Origin of Eukarytic Cells."
Lynn Petra Alexander was born on March 5, 1938, in Chicago, where she grew up in a tough neighborhood on the South Side. Her father was a lawyer and a businessman. Precocious, she graduated at 18 from the University of Chicago, where she met Mr. Sagan.
She earned a master's degree in genetics and zoology from the University of Wisconsin and a Ph.D. in genetics from the University of California, Berkeley. Before joining the faculty at Massachusetts, she taught for 22 years at Boston University.
Ms. Margulis was also known, somewhat controversially, as a collaborator with and supporter of James E. Lovelock, whose Gaia theory states that Earth itself - its atmosphere, the geology and the organisms that inhabit it - is a self-regulating system, maintaining the conditions that allow its perpetuation.
Ms. Margulis' marriage to Mr. Sagan ended in divorce, as did a second marriage to Thomas N. Margulis, a chemist.
In addition to her daughter and her son Dorion, she is survived by two other sons, Jeremy Sagan and Zachary Margulis-Ohnuma; three sisters, Joan Glashow, Sharon Kleitman and Diane Alexander; two half-brothers, Robert and Mark Alexander; a half-sister, Sara Alexander; and nine grandchildren.
First Published November 25, 2011 12:31 am
