Lynn Margulis

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Lynn Margulis
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Lynn Margulis

Dr. Lynn Margulis (b. March 1938) is a biologist and University Professor in the Department of Geosciences at the University of Massachusetts Amherst.[1] 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.

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[edit] Research

Lynn Margulis 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.[2] The paper however was "rejected by about fifteen scientific journals," Margulis recalled.[3] 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 in the mid-19th century scientists as well as the early 20th century work of Merezhkovsky (1905) and Wallin (1920), 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 (single celled) 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 was actually proven in the 1980s, when the genetic material of mitochondria and chloroplasts was found to be different from that of the symbiont's nuclear DNA.[4]

She later formulated a theory to explain how symbiotic relationships that are taking place in modern day humans and animals are the driving force of evolution. Genetic variation is proposed to mainly occur 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 somewhat of a fringe idea. However, examination of the results from the Human Genome Project lead credence toward 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 with Neo-Darwinism, the two theories are not incompatible and the truth is likelier to be that natural selection works on many levels (genetic up to the ecosystem) and variation is introduced both at the genetic and the cellular level.

In 1995, prominent Neo-Darwinist evolutionary biologist Richard Dawkins had this to say about Lynn Margulis and her work:

I greatly admire Lynn Margulis's sheer courage and stamina in sticking by the endosymbiosis theory, and carrying it through from being an unorthodoxy to an orthodoxy. I'm referring to the theory that the eukaryotic cell is a symbiotic union of primitive prokaryotic cells. This is one of the great achievements of twentieth-century evolutionary biology, and I greatly admire her for it.[5]

Her present day efforts, in the form of books and lectures, strongly stress a symbiotic—and cooperative—relationship between all organisms and a strong leaning toward Gaia theory. Her advocacy outside the realm of biology and toward more sociopolitical ends has been criticized by more mainstream scientists—somewhat similar to criticisms aimed toward Carl Sagan's latter day ideas.

[edit] Other

  • She is also a proponent and co-developer of the modern version of Gaia hypothesis, based on an idea developed by the English atmospheric scientist James Lovelock.
  • She is to be profiled in a book scheduled to be published in 2006, called "100 Visionaries of the Twentieth Century," by Resurgence Magazine in the UK
  • In a book review on Amazon.com, Margulis has expressed deep skepticism regarding whether HIV causes AIDS: "We find the paucity of evidence published in standard peer-reviewed primary scientific journals that leads to the conclusion that "HIV causes AIDS" appalling. No amount of moralizing censorship, rhetorical tricks, consensus of opinion, pulling rank, obfuscation, ad hominem attacks or blustering newspaper editorials changes this fact. The conflation "HIV-AIDS" may be good marketing but is it science? No." [1]

[edit] Personal

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.

[edit] Publications and bibliography

  • Margulis, Lynn, 1970, Origin of Eukaryotic Cells, Yale University Press, ISBN 0-300-01353-1
  • Margulis, Lynn, 1982, Early Life, Science Books International, ISBN 0-86720-005-7
  • 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 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, 1991, Mystery Dance: On the Evolution of Human Sexuality, Summit Books, ISBN 0-671-63341-4
  • Margulis, Lynn, ed, 1991, Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis, The MIT Press, ISBN 0-262-13269-9
  • 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 and Dorion Sagan, 1997, Slanted Truths: Essays on Gaia, Symbiosis, and Evolution, Copernicus Books, ISBN 0-387-94927-5
  • 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, 1998, Symbiotic Planet : A New Look at Evolution, Basic Books, ISBN 0-465-07271-2
  • 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 and Dorian Sagan, 1997, What Is Sex?, Simon and Shuster, ISBN 0-684-82691-7

[edit] References

  1. ^ Lynn Margulis biography at U. Mass. (Accessed July 15, 2006)
  2. ^ Lynn Sagan (1967). On the origin of mitosing cells. J. Theoretical Biology 14(3), 255-274. PMID 11541392 DOI:10.1016/0022-5193(67)90079-3
  3. ^ John Brockman, The Third Culture, New York: Touchstone, 1995, 135.
  4. ^ Acceptance Doesn't Come Easy (Accessed July 15, 2006)
  5. ^ John Brockman, The Third Culture, New York: Touchstone, 1995, 144.

[edit] External links

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