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Lynn Margulis
Lynn Margulis.jpg
Born Lynn Petra Alexander
(1938-03-05)March 5, 1938
Chicago, Illinois, U.S.
Died November 22, 2011(2011-11-22) (aged 73)
Amherst, Massachusetts, U.S.
Nationality American
Fields Biology
Institutions Brandeis University
Boston University
University of Massachusetts Amherst
Alma mater University of Chicago
University of Wisconsin-Madison
UC Berkeley
Thesis An Unusual Pattern of Thymidine Incorporation in Euglena' (1965)
Doctoral advisor Max Alfert
Known for Symbiogenesis
Gaia hypothesis
Notable awards National Medal of Science (1999)
William Procter Prize for Scientific Achievement (1999)
Darwin-Wallace Medal (2008)
Spouse Carl Sagan
(m. 1957–1965, divorced)
Thomas Margulis
(m. 1967–1980, divorced)
Children Dorion Sagan (1959)
Jeremy Ethan Sagan (1960)
Zachary Margulis-Ohnuma
Jennifer Margulis di Properzio

Lynn Margulis (born Lynn Petra Alexander;[1][2] March 5, 1938 – November 22, 2011)[3] was an American biologist best known for her scientific theory on the origin of complex cells, called symbiogenesis. She obtained a bachelor degree from the University of Chicago at age 19, and married Carl Sagan, then a physics student. She graduated with master's degree in genetics and zoology from the University of Chicago at age 22. While working for a PhD at the University of California, Berkeley, she landed an appointment as lecturer at Brandeis University, where she worked during 1964-1966. She received her PhD in 1965. She joined the faculty of Boston University in 1966. In 1988 she became Distinguished Professor of Botany, and in 1997, Distinguished Professor of Geosciences at the University of Massachusetts at Amherst.[4]

Margulis conceived her theory on endosymbiosis when she was a junior faculty at Boston University. Her landmark publication, "On the Origin of Mitosing Cells" came out in 1967, after it was rejected by about fifteen journals. Ignored for a decade, her theory that cell organelles such as mitochondria and chloroplasts were once independent bacteria became widely accepted after it was substantiated by genetic evidences. She expanded her idea that symbiosis is one of the major driving forces of evolution. Her theory also made her a proponent of Gaia hypothesis, based on an idea developed by the English environmental scientist James Lovelock. She was also the principal defender of the five kingdom classification of Robert Whittaker.

Variously branded as "Science's Unruly Earth Mother",[5] a "vindicated heretic",[6] or a scientific "rebel",[7] Margulis was a strong critic of Charles Darwin's gradual selection theory and modern evolutionary theory. She explicitly stated that she was a Darwinist, but not a neo-Darwinist, a position that sparked a lifelong debate with leading Darwinian biologists, including Richard Dawkins, George C. Williams, and John Maynard Smith.[8][9]

Margulis was member of the US National Academy of Sciences from 1983. For her scientific innovations, President Bill Clinton presented her the National Medal of Science in 1999. The Linnean Society of London awarded her the Darwin-Wallace Medal in 2008.

Biography

Lynn Margulis was born in Chicago, to Morris Alexander and Leona Wise Alexander. She was the eldest of four daughters. Her father was an attorney and run a company that made road paints. Her mother operated a travel agency.[10] She entered the Hyde Park Academy High School in 1952,[11] describing herself as a bad student who frequently had to stand in the corner. She recalled that as early as the fourth grade to she was able to "tell bullshit from ... real authentic experience".[2] A precocious child, she was accepted at the University of Chicago Laboratory Schools[12] while on her second secondary year at the age of fifteen (she had applied a year earlier).[13][14] She recalled, "because I wanted to go and they let me in".[15] She entered the university after a year in 1954, and received her 12th grade certificate after being a college student in 1955.[16] In 1957, at age 19, she earned a BA in Liberal Arts. She joined the University of Wisconsin to study biology under Hans Ris and Walter Plaut, her supervisor, and graduated in 1960 with an MS in genetics and zoology. (Her first publication was with Plaut, on the genetics of Euglena, published in 1958 in the Journal of Protozoology.)[17] She then pursued research at the University of California, Berkeley, under the zoologist Max Alfert. Before she could complete her dissertation, she was offered research associateship, and then lecturership, at Brandeis University in Massachusetts in 1964. It was while working there that she obtained her PhD from the University of California, Berkeley in 1965. Her thesis was An Unusual Pattern of Thymidine Incorporation in Euglena.[16] In 1966 she moved to Boston University, where she taught biology for twenty-two years. She was initially an Adjunct Assistant Professor, and appointed to Assistant Professor in 1967. She was promoted to Associate Professor in 1971, to full Professor in 1977, and to University Professor in 1986. In 1988 she was appointed Distinguished Professor of Botany at the University of Massachusetts at Amherst. She was Distinguished Professor of Biology in 1993. In 1997 she transferred to the Department of Geosciences at Amherst to became Distinguished Professor of Geosciences "with great delight",[18] the post which she held until her death.[19]

Personal life

Margulis married astronomer Carl Sagan in 1957 soon after she got her bachelor degree. Sagan was then a graduate student in physics at the University of Chicago. Their marriage ended in 1964, just before she completed her PhD. They had two sons Dorion Sagan, who later became popular science writer and her collaborator, and Jeremy Sagan, software developer and founder of Sagan Technology.
In 1967, she married Thomas N. Margulis, a crystallographer. They had a son Zachary Margulis-Ohnuma, New York City criminal defense lawyer, and a daughter Jennifer Margulis, teacher and author .[20][21] They divorced in 1980. She commented, "I quit my job as a wife twice," and, "it’s not humanly possible to be a good wife, a good mother and a first-class scientist. No one can do it — something has to go."[22] In the 2000s she had a relationship with fellow biologist Ricardo Guerrero.[11]

She was an agnostic,[11] and a staunch evolutionist. But she totally rejected the modern evolutionary synthesis,[23] and said:
I remember waking up one day with an epiphanous revelation: I am not a neo-Darwinist! It recalled an earlier experience, when I realized that I wasn't a humanistic Jew.
Although I greatly admire Darwin's contributions and agree with most of his theoretical analysis and I am a Darwinist, I am not a neo-Darwinist.[9]
Her sister Joan Alexander married Nobel Laureate Sheldon Lee Glashow; another sister, Sharon, married mathematician Daniel Kleitman.

Death

Margulis died on November 22, 2011 at home in Amherst, Massachusetts, five days after suffering a hemorrhagic stroke.[1][2][22][24] As her wish, she was cremated and her ashes were scattered in her favorite research areas, near her home.[25]

Contributions

Endosymbiosis theory

In 1966, as a young faculty member at Boston University, Margulis wrote a theoretical paper titled "On the Origin of Mitosing Cells".[26] The paper however was "rejected by about fifteen scientific journals," she recalled.[27] It was finally accepted by Journal of Theoretical Biology and is considered today a landmark in modern endosymbiotic theory. Although it draws heavily on symbiosis ideas first put forward by mid-19th century scientists and by Merezhkovsky (1905) and Ivan Wallin (1920) in the early-20th century, her endosymbiotic theory formulation is the first to rely on direct microbiological observations (as opposed to paleontological or zoological observations which were previously the norm for new works in evolutionary biology). Weathering constant criticism of her ideas for decades, Margulis is famous for her tenacity in pushing her theory forward, despite the opposition she faced at the time. The fact that mitochondria descended from bacteria and chloroplasts from cyanobacteria was experimentally demonstrated in 1978 by Robert Schwartz and Margaret Dayhoff.[28] This became the first proof of her theory.[2]
The underlying theme of endosymbiosis theory, as formulated in 1966, was interdependence and cooperative existence of multiple prokaryotic organisms; one organism phagocytosed another, yet both survived and eventually evolved over millions of years into eukaryotic cells. Her 1970 book, Origin of Eukaryotic Cells, discusses her early work pertaining to this organelle genesis theory in detail. Currently, her endosymbiosis theory is recognized as the key method by which some organelles have arisen (see endosymbiotic theory for a discussion) and is widely accepted by mainstream scientists. The endosymbiosis theory of organogenesis gained strong support in the 1980s, when the genetic material of mitochondria and chloroplasts was found to be different from that of the symbiont's nuclear DNA.[29]

In 1995, English evolutionary biologist Richard Dawkins had this to say about Lynn Margulis and her work:

Symbiosis as evolutionary force

Margulis later formulated a theory to explain how symbiotic relationships between organisms of often different phyla or kingdoms are the driving force of evolution. Genetic variation is proposed to occur mainly as a result of transfer of nuclear information between bacterial cells or viruses and eukaryotic cells. While her organelle genesis ideas are widely accepted, symbiotic relationships as a current method of introducing genetic variation is something of a fringe idea.
She also held a negative view of certain interpretations of Neo-Darwinism that she felt were excessively focused on inter-organismic competition, as she believed that history will ultimately judge them as comprising "a minor twentieth-century religious sect within the sprawling religious persuasion of Anglo-Saxon Biology."[31] She also believed that proponents of the standard theory "wallow in their zoological, capitalistic, competitive, cost-benefit interpretation of Darwin – having mistaken him... Neo-Darwinism, which insists on [the slow accrual of mutations by gene-level natural selection], is in a complete funk."[31]

She opposed such competition-oriented views of evolution, stressing the importance of symbiotic or cooperative relationships between species.

Gaia hypothesis

Gaia hypothesis states that the Earth is a unit of organism, with all the different organisms in it merely its parts.[32][33] It was formulated as a scientific hypothesis by an English scientist James Lovelock in 1965, and publicized it in 1972. In a scientific perspective the hypothesis states that the Earth's environmental and geological conditions are maintained in stable and self-regulating process (homeostasis) by its living organisms.[34] Margulis joined forces with Lovelock, and strengthened the hypothesis with her expertise in microbiology. She described the Earth as "super organismic system" and its organisms interact and evolve through cooperation.[35][36] It was generally received with criticism, as it lacks testable evidence. But some scientists are of the opinion that it has a broader perspective and even might be tested in the future.[37][38] Margulis was not in favour of the strong Gaia hypothesis of Lovelock, which has elements of paganism.[39] Her arguments are entirely biological, and inherently anti-Darwinian that it is cooperation that creates species, but not natural selection.[9][35] But later supporters of the hypothesis embraced that the hypothesis is of Darwinian principle, and that the stabilizing effect (feedback mechanism) is promoted by natural selection on each organism.[40][41][42] In 1991, an evolutionary biologist John Maynard Smith had cautiously remarked:

AIDS/HIV theory

In 2009 Margulis co-authored with seven others a paper stating "Detailed research that correlates life histories of symbiotic spirochetes to changes in the immune system of associated vertebrates is sorely needed" and urging the "reinvestigation of the natural history of mammalian, tick-borne, and venereal transmission of spirochetes in relation to impairment of the human immune system."[43] Margulis later argued that "there's no evidence that HIV is an infectious virus" and that AIDS symptoms "overlap ... completely" with those of syphilis.[44] Seth Kalichman, HIV researcher and professor of psychology who spent a year infiltrating HIV denialist groups, cited her 2009 paper as an example of AIDS denialism "flourishing",[45] and argued that her "endorsement of HIV/AIDS denialism defies understanding."

Metamorphosis theory

In 2009, via a then-standard publication-process known as "communicated submission", she was instrumental in getting the Proceedings of the National Academy of Sciences (PNAS) to publish a paper by Donald I. Williamson rejecting "the Darwinian assumption that larvae and their adults evolved from a single common ancestor."[46][47] Williamson's paper provoked immediate response from the scientific community, including a countering paper in PNAS.[46] Conrad Labandeira of the Smithsonian National Museum of Natural History said, "If I was reviewing [Williamson's paper] I would probably opt to reject it," he says, "but I'm not saying it's a bad thing that this is published.
What it may do is broaden the discussion on how metamorphosis works and…[on]…the origin of these very radical life cycles." But Duke University insect developmental biologist Fred Nijhout said that the paper was better suited for the "National Enquirer than the National Academy."[48] In September it was announced that PNAS would eliminate communicated submissions in July 2010. PNAS stated that the decision had nothing to do with the Williamson controversy.[47]

Five kingdoms of life

The entire life on earth was traditionally classified into five kingdoms, as introduced by Robert Whittaker in 1969.[49] Margulis became the most important supporter, as well as critic.[50] Critic in the sense that she was the first to recognize the limitations of Whittaker's classification of microbes.[51] But later discoveries of new organisms, such as archaea, and emergence of molecular taxonomy challenged the concept.[52] By the mid-2000s, most scientists began to agree that there are more than five kingdoms.[53][54] Margulis became the most important defender of the five kingdom classification. She rejected the three-domain system introduced by Carl Woese in 1990, which gained wide acceptance. She introduced an improved classification by which all life forms, including the newly discovered, could be integrated into the classical five kingdoms. According to her the main problem, archaea, falls under the kingdom Prokaryotae alongside bacteria (in contrast to the three-domain system which treat archaea as a higher taxon than kingdom, or the six-kingdom system which holds that it is a separate kingdom).[52] Her concept is given in detail in her book Five Kingdoms, written with Karlene V. Schwartz.[55] It is mainly because of her that this five-kingdom system survives.[18]

Awards and recognitions

Select publications and bibliography

Books

  • Margulis, Lynn (2009). "Genome acquisition in horizontal gene transfer: symbiogenesis and macromolecular sequence analysis". In Gogarten, Maria Boekels; Gogarten, Johann Peter; Olendzenski, Lorraine C. Horizontal Gene Transfer:Genomes in Flux 532. Humana Press. pp. 181–191. doi:10.1007/978-1-60327-853-9_10. ISBN 978-1-60327-852-2. PMID 19271185. 
  • Margulis, Lynn, and Dorion Sagan (2007). Dazzle Gradually: Reflections on the Nature of Nature, Sciencewriters Books, ISBN 978-1-933392-31-8
  • Margulis, Lynn, and Eduardo Punset, eds. (2007). Mind, Life and Universe: Conversations with Great Scientists of Our Time, Sciencewriters Books, ISBN 978-1-933392-61-5
  • Margulis, Lynn (2007). Luminous Fish: Tales of Science and Love, Sciencewriters Books, ISBN 978-1-933392-33-2
  • Margulis, Lynn, and Dorion Sagan (2002). Acquiring Genomes: A Theory of the Origins of Species, Perseus Books Group, ISBN 0-465-04391-7
  • Margulis, Lynn, et al. (2002). The Ice Chronicles: The Quest to Understand Global Climate Change, University of New Hampshire, ISBN 1-58465-062-1
  • Margulis, Lynn (1998). Symbiotic Planet : A New Look at Evolution, Basic Books, ISBN 0-465-07271-2
  • Margulis, Lynn, and Karlene V. Schwartz (1997). Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, W.H. Freeman & Company, ISBN 0-613-92338-3
  • Margulis, Lynn, and Dorion Sagan (1997). What Is Sex?, Simon and Schuster, ISBN 0-684-82691-7
  • Margulis, Lynn, and Dorion Sagan (1997). Slanted Truths: Essays on Gaia, Symbiosis, and Evolution, Copernicus Books, ISBN 0-387-94927-5
  • Sagan, Dorion, and Margulis, Lynn (1993). The Garden of Microbial Delights: A Practical Guide to the Subvisible World, Kendall/Hunt, ISBN 0-8403-8529-3
  • Margulis, Lynn (1992). Symbiosis in Cell Evolution: Microbial Communities in the Archean and Proterozoic Eons, W.H. Freeman, ISBN 0-7167-7028-8
  • Margulis, Lynn (1991). "Symbiosis in Evolution: Origins of Cell Motility". In Osawa, Syozo; Honzo, Tasuku. Evolution of Life: Fossils, Molecules and Culture. Japan: Springer. pp. 305–324. doi:10.1007/978-4-431-68302-5_19. ISBN 978-4-431-68304-9. 
  • Margulis, Lynn, ed. (1991). Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis, The MIT Press, ISBN 0-262-13269-9
  • Margulis, Lynn, and Dorion Sagan (1991). Mystery Dance: On the Evolution of Human Sexuality, Summit Books, ISBN 0-671-63341-4
  • Margulis, Lynn, and Dorion Sagan (1987). Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors, HarperCollins, ISBN 0-04-570015-X
  • Margulis, Lynn, and Dorion Sagan (1986). Origins of Sex : Three Billion Years of Genetic Recombination, Yale University Press, ISBN 0-300-03340-0
  • Margulis, Lynn (1982). Early Life, Science Books International, ISBN 0-86720-005-7
  • Margulis, Lynn (1970). Origin of Eukaryotic Cells, Yale University Press, ISBN 0-300-01353-1

Journals