Lynn Margulis (born 1938) is a biologist and a professor at the University of Massachusetts Amherst. In 1967 she proposed a contentious new hypothesis which became her most important scientific contribution as the endosymbiotic theory of the origin of mitochondria as separate organisms that long ago entered a symbiotic relationship with eukaryotic cells through endosymbiosis.
- "She is best known for her theory of symbiogenesis, which challenges a central tenet of neodarwinism. She argues that inherited variation, significant in evolution, does not come mainly from random mutations. Rather new tissues, organs, and even new species evolve primarily through the long-lasting intimacy of strangers. The fusion of genomes in symbioses followed by natural selection, she suggests, leads to increasingly complex levels of individuality." 
- " After the proposal of the endosymbiotic theory, Margulis predicted that if organelles were prokaryotic symbionts, then the organelles will have their own DNA that would be different from the DNA of the cell. This prediction was actually proven in the 1980's in mitochondria, centrioles, and chloroplasts." 
She was criticized as a radical and her scientific work was rejected by mainstream biology for many years. Her work has more recently received widespread support and acclaim. Margulis was inducted into the World Academy of Art and Science, the Russian Academy of Natural Sciences, and the American Academy of Arts and Sciences between 1995 and 1998.
She is also a proponent and co-developer of the modern version of Gaia theory, based on an idea developed by the English atmospheric scientist James Lovelock.
She was the first wife of astronomer Carl Sagan, and mother of popular science writer and co-author Dorion Sagan .
Publications - books
- Margulis, Lynn, 1970, Origin of Eukaryotic Cells, Yale University Press, ISBN 0300013531
- Margulis, Lynn, 1982, Early Life, Science Books International, ISBN 0867200057
- Margulis, Lynn and Dorion Sagan, 1986, Origins of Sex : Three Billion Years of Genetic Recombination, Yale University Press, ISBN 0300033400
- Margulis, Lynn and Dorion Sagan, 1987, Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors, HarperCollins, ISBN 004570015X
- Margulis, Lynn and Dorion Sagan, 1991, Mystery Dance: On the Evolution of Human Sexuality, Summit Books, ISBN 0671633414
- Margulis, Lynn, ed, 1991, Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis, The MIT Press, ISBN 0262132699
- Margulis, Lynn, 1992, Symbiosis in Cell Evolution: Microbial Communities in the Archean and Proterozoic Eons, W.H. Freeman, ISBN 0716770288
- Margulis, Lynn and Dorion Sagan, 1997, Slanted Truths: Essays on Gaia, Symbiosis, and Evolution, Copernicus Books, ISBN 0387949275
- Lynn Margulis and Karlene V. Schwartz, 1997, Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, W.H. Freeman & Company, ISBN 0613923383
- Margulis, Lynn, 1998, Symbiotic Planet : A New Look at Evolution, Basic Books, ISBN 0465072712
- Margulis, Lynn and Dorion Sagan, 2002, Acquiring Genomes: A Theory of the Origins of Species, Perseus Books Group, ISBN 0465043917
- Margulis, Lynn, et. al., 2002, The Ice Chronicles: The Quest to Understand Global Climate Change, University of New Hampshire, ISBN 1584650621