Lynn Margulis (born March 5, 1938) is an American biologist and University Professor in the Department of Geosciences at the University of Massachusetts Amherst. She is best known for her theory on the origin of eukaryotic organelles, and her contributions to the endosymbiotic theory—which is now generally accepted for how certain organelles were formed.
Lynn Margulis attended the University of Chicago as an undergraduate, earned a master's degree from the University of Wisconsin-Madison in 1960, and received her Ph.D. in 1963 from UC Berkeley. In 1966, as a young faculty member at Boston University, she wrote a theoretical paper entitled The Origin of Mitosing Eukaryotic Cells. The paper however was "rejected by about fifteen scientific journals," Margulis recalled. It was finally accepted by The 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 Wallin (1920) in the early-20th century, Margulis's 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). The paper was initially heavily rejected, as symbiosis theories had been dismissed by mainstream biology at the time. 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 underlying theme of endosymbiotic theory, as formulated in 1966, was interdependence and cooperative existence of multiple prokaryotic organisms; one organism engulfed 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 endosymbiotic 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 endosymbiotic 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.
In 1995, prominent evolutionary biologist Richard Dawkins had this to say about Lynn Margulis and her work:
Theory of symbiotic relationships driving evolution
She 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. However, examination of the results from the Human Genome Project lends some credence to an endosymbiotic theory of evolution—or at the very least Margulis's endosymbiotic theory is the catalyst for current ideas about the composition of the human genome. Significant portions of the human genome are either bacterial or viral in origin—some clearly ancient insertions, while others are more recent in origin. This strongly supports the idea of symbiotic—and more likely parasitic—relationships being a driving force for genetic change in humans, and likely all organisms. It should be noted that while the endosymbiotic theory has historically been juxtaposed to Neo-Darwinism as a competitor, the two theories are not irreconcilable. An emerging synthesis holds that natural selection works on many levels (genetic up to the ecosystem) and variation is introduced both at the genetic and the cellular level.
She does, however, hold a negative view of certain interpretations of Neo-Darwinism, excessively focused on inter-organismic competition, as she believes that history will ultimately judge them as comprising "a minor twentieth-century religious sect within the sprawling religious persuasion of Anglo-Saxon Biology." She also believes 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 a complete funk."
She opposes such competition-oriented views of evolution, stressing the importance of symbiotic or cooperative relationships between species.
In addition to rejecting Neo-Darwinian evolution as an explanation for diversity (on the grounds that speciation due solely to random mutation and differential survival has yet to be proven), Margulis holds a number of opinions outside of mainstream science. In 2009 she co-authored a paper  arguing that the change in spirochete form, from more motile helical to more inactive cyst and back, may be a causal contributor to AIDS. In 2009 she also pushed the journal Proceedings of the National Academy of Sciences (PNAS) to publish a paper by Donald I. Williamson arguing that butterflies are the result of hybridization of a now extinct insect and velvet worms. As a member of the National Academy of Sciences, Margulis has the ability to "communicate" scientific papers, allowing them to be published with minimal review. Williamson's paper provoked immediate response from the scientific community, including a paper in PNAS . Developmental Biologist and Professor at Duke university Fred Nijhout was quoted as saying that the paper was better suited for "National Enquirer than the National Academy.". In September it was announced that PNAS will eliminate Communicated submissions in July 2010 but PNAS stated that the decision had nothing to do with the Williamson controversy.
* Margulis was elected to the National Academy of Sciences in 1983 and served as Chairman of the Academy’s Space Science Board Committee on Planetary Biology and Chemical Evolution.
She attended the University of Chicago at age 14 having entered 'because she wanted to go and they let me in' 
She married her first husband at age 19. She was the first wife of astronomer Carl Sagan, and is the mother of Dorion Sagan, popular science writer and co-author; Jeremy Sagan, software developer and founder of Sagan Technology; Zachary Margulis-Ohnuma, New York City criminal defense lawyer; and Jennifer Margulis, teacher and author.
* Margulis, Lynn and Dorion Sagan, 2007, Dazzle Gradually: Reflections on the Nature of Nature, Sciencewriters Books, ISBN 978-1-933392-31-8
1. ^ Lynn Margulis biography at U. Mass. (Accessed July 15, 2006)
* Interview and portrait of Lynn Margulis by Ariane Laroux in Portraits Parlés, éditions l'Age d'Homme (2006)
* UMass Bio Dept. (Accessed July 22, 2008)
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