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| Lynn Margulis |
By Bruce Weber, The New York Times, November 26, 2011
Lynn
Margulis, a biologist whose work on the origin of cells helped
transform the study of evolution, died on 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.
Dr. Margulis had the title of distinguished university professor of
geosciences at the University of Massachusetts, Amherst, since
1988. She 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 except mature red blood
cells, 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, Dr. 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.
“She talked a lot about the importance of micro-organisms,” said her
daughter, Jennifer Margulis. “She called herself a spokesperson for the
microcosm.”
The manuscript in which Dr. 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 Eukaryotic Cells.”
A revised version, “Symbiosis in Cell Evolution,” followed in 1981,
and though it challenged the presumptions of many prominent scientists, it has
since become accepted evolutionary doctrine.
“Evolutionists have been preoccupied with the history of animal
life in the last 500 million years,” Dr. Margulis wrote in 1995. “But we now
know that life itself evolved much earlier than that. The fossil record
begins nearly 4,000 million years ago! Until the 1960s, scientists ignored
fossil evidence for the evolution of life, because it was uninterpretable.
“I work in evolutionary biology, but with cells and micro-organisms.
Richard Dawkins, John Maynard Smith, George Williams, Richard Lewontin,
Niles Eldredge and Stephen Jay Gould all come out of the zoological tradition,
which suggests to me that, in the words of our colleague Simon Robson,
they deal with a data set some three billion years out of date.”
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 Dr. Sagan as they passed each other on a stairway.
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.
Dr. 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. In other words, it is something of a living organism in and of
itself.
Dr. Margulis’s marriage to Dr. Sagan ended in divorce, as did a
marriage to Thomas N. Margulis, a chemist. Dr. Sagan died in 1996.
In addition to her daughter and her son Dorion, a science writer with
whom she sometimes collaborated, she is survived by two other sons, Jeremy
Sagan and Zachary Margulis-Ohnuma; three sisters, Joan Glashow, Sharon Kleitman
and Diane Alexander; three half-brothers, Robert, Michael and Mark Alexander; a
half-sister, Sara Alexander; and nine grandchildren.
“More than 99.99 percent of the species that have ever existed have
become extinct,” Dr. Margulis and Dorion Sagan wrote in “Microcosmos,” a 1986
book that traced, in readable language, the history of evolution over four
billion years, “but the planetary patina, with its army of cells, has continued
for more than three billion years. And the basis of the patina, past, present
and future, is the microcosm — trillions of communicating, evolving microbes.”
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