Lynn Margulis (bornLynn Petra Alexander; March 5, 1938 – November 22, 2011) was an Americanevolutionary biologist, and was the primary modern proponent for the significance ofsymbiosis in evolution. In particular, Margulis transformed and fundamentally framed current understanding of theevolution ofcells with nuclei by proposing it to have been the result of symbiotic mergers of bacteria. Margulis was also the co-developer of theGaia hypothesis with the British chemistJames Lovelock, proposing that the Earth functions as a single self-regulating system, and was the principal defender and promulgator of thefive kingdom classification ofRobert Whittaker.
Throughout her career, Margulis' work could arouse intense objections,[1][2] and her formative paper, "On the Origin of Mitosing Cells", appeared in 1967 after being rejected by about fifteen journals.[3] Still a junior faculty member at Boston University at the time, her theory thatcell organelles such asmitochondria andchloroplasts were once independentbacteria was largely ignored for another decade, becoming widely accepted only after it was powerfully substantiated through genetic evidence. Margulis was elected a member of the USNational Academy of Sciences in 1983. PresidentBill Clinton presented her theNational Medal of Science in 1999. TheLinnean Society of London awarded her theDarwin-Wallace Medal in 2008.
Margulis was a strong critic ofneo-Darwinism.[4] Her position sparked lifelong debate with leading neo-Darwinian biologists, includingRichard Dawkins,[5]George C. Williams, andJohn Maynard Smith.[1]: 30, 67, 74–78, 88–92 Margulis' work on symbiosis and herendosymbiotic theory had important predecessors, going back to the mid-19th century – notablyAndreas Franz Wilhelm Schimper,Konstantin Mereschkowski,Boris Kozo-Polyansky, andIvan Wallin – and Margulis not only promoted greater recognition for their contributions, but personally oversaw the first English translation of Kozo-Polyansky'sSymbiogenesis: A New Principle of Evolution, which appeared the year before her death. Many of her major works, particularly those intended for a general readership, were collaboratively written with her sonDorion Sagan.
In 2002,Discover magazine recognized Margulis as one of the 50 most important women in science.[6]
Lynn Petra Alexander[7][8] was born on March 5, 1938[9] inChicago, to aJewish family.[10] Her parents were Morris Alexander and Leona Wise Alexander. She was the eldest of four daughters. Her father was an attorney who also ran a company that made road paints. Her mother operated a travel agency.[11] She entered theHyde Park Academy High School in 1952,[12] describing herself as a bad student who frequently had to stand in the corner.[8]
A precocious child, she was accepted at theUniversity of Chicago Laboratory Schools[13] at the age of fifteen.[14][15][16] In 1957, at age 19, she earned a BA from the University of Chicago inLiberal Arts. She joined theUniversity of Wisconsin to study biology underHans Ris and Walter Plaut, her supervisor, and graduated in 1960 with anMS in genetics and zoology. (Her first publication, published with Plaut in 1958 in theJournal of Protozoology, was on the genetics ofEuglena,flagellates which have features of both animals and plants.)[17] She then pursued research at theUniversity of California, Berkeley, under the zoologist Max Alfert. Before she could complete her dissertation, she was offered research associateship and then lectureship atBrandeis 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 wasAn Unusual Pattern of Thymidine Incorporation inEuglena.[18]
In 1966 she moved toBoston University, where she taught biology for twenty-two years. She was initially an Adjunct Assistant Professor, then was 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 theUniversity of Massachusetts at Amherst. She was Distinguished Professor of Biology in 1993. In 1997 she transferred to the Department of Geosciences at UMass Amherst to become Distinguished Professor of Geosciences "with great delight",[19] the post which she held until her death.[20]
In 1966, as a young faculty member atBoston University, Margulis wrote a theoretical paper titled "On the Origin of Mitosing Cells".[22] The paper, however, was "rejected by about fifteen scientific journals," she recalled.[3] It was finally accepted byJournal of Theoretical Biology and is considered today a landmark in modernendosymbiotic theory. Weathering constant criticism of her ideas for decades, Margulis was famous for her tenacity in pushing her theory forward, despite the opposition she faced at the time.[8] The descent of mitochondria from bacteria and of chloroplasts from cyanobacteria was experimentally demonstrated in 1978 byRobert Schwartz andMargaret Dayhoff.[23] This formed the first experimental evidence for the symbiogenesis theory.[8] The endosymbiosis theory of organogenesis became widely accepted in the early 1980s, after the genetic material ofmitochondria andchloroplasts had been found to be significantly different from that of the symbiont'snuclear DNA.[24]
In 1995, English evolutionary biologistRichard 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.[3]
Margulis opposed competition-oriented views of evolution, stressing the importance of symbiotic or cooperative relationships between species.[25]
She later formulated a theory that proposed symbiotic relationships between organisms of different phyla, or kingdoms, as the driving force ofevolution, and explainedgenetic variation as occurring mainly through transfer of nuclear information betweenbacterial cells orviruses andeukaryotic cells.[25] Her organelle genesis ideas are now widely accepted, but the proposal that symbiotic relationships explain most genetic variation is still something of a fringe idea.[25]
Margulis also held a negative view of certain interpretations ofNeo-Darwinism that she felt were excessively focused on competition between organisms, 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."[25]She wrote 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."[25]
Margulis initially sought out the advice ofJames Lovelock for her own research: she explained that, "In the early seventies, I was trying to align bacteria by their metabolic pathways. I noticed that all kinds of bacteria produced gases. Oxygen, hydrogen sulfide, carbon dioxide, nitrogen, ammonia—more than thirty different gases are given off by the bacteria whose evolutionary history I was keen to reconstruct. Why did every scientist I asked believe that atmospheric oxygen was a biological product but the other atmospheric gases—nitrogen, methane, sulfur, and so on—were not? 'Go talk to Lovelock,' at least four different scientists suggested. Lovelock believed that the gases in the atmosphere were biological."[3]
Margulis met with Lovelock, who explained his Gaia hypothesis to her, and very soon they began an intense collaborative effort on the concept.[3] One of the earliest significant publications on Gaia was a 1974 paper co-authored by Lovelock and Margulis, which succinctly defined the hypothesis as follows: "The notion of the biosphere as an active adaptive control system able to maintain the Earth in homeostasis we are calling the 'Gaia hypothesis.'"[26]
Like other early presentations of Lovelock's idea, the Lovelock-Margulis 1974 paper seemed to give living organisms complete agency in creating planetary self-regulation, whereas later, as the idea matured, this planetary-scale self-regulation was recognized as anemergent property of theEarth system, life and its physical environment taken together.[27] When climatologist Stephen Schneider convened the 1989 American Geophysical Union Chapman Conference around the issue of Gaia, the idea of "strong Gaia" and "weak Gaia" was introduced by James Kirchner, after which Margulis was sometimes associated with the idea of "weak Gaia", incorrectly (her essay "Gaia is a Tough Bitch" dates from 1995 – and it stated her own distinction from Lovelock as she saw it, which was primarily that she did not like the metaphor of Earth as a single organism, because, she said, "No organism eats its own waste").[3] In her 1998 bookSymbiotic Planet, Margulis explored the relationship between Gaia and her work on symbiosis.[28]
In 1969, life on earth was classified intofive kingdoms, as introduced byRobert Whittaker.[29] Margulis became the most important supporter, as well as critic[30] – while supporting parts, she was the first to recognize the limitations of Whittaker's classification of microbes.[31] But later discoveries of new organisms, such asarchaea, and emergence of molecular taxonomy challenged the concept.[32] By the mid-2000s, most scientists began to agree that there are more than five kingdoms.[33][34] Margulis became the most important defender of the five kingdom classification. She rejected thethree-domain system introduced byCarl Woese in 1990, which gained wide acceptance. She introduced a modified classification by which all life forms, including the newly discovered, could be integrated into the classical five kingdoms. According to Margulis, the main problem, archaea, falls under the kingdom Prokaryotae alongside bacteria (in contrast to the three-domain system, which treats archaea as a higher taxon than kingdom, or the six-kingdom system, which holds that it is a separate kingdom).[32] Margulis' concept is given in detail in her bookFive Kingdoms, written with Karlene V. Schwartz.[35] It has been suggested that it is mainly because of Margulis that the five-kingdom system survives.[19]
In 2009, via a then-standard publication-process known as "communicated submission" (which bypassed traditionalpeer review), she was instrumental in getting theProceedings of the National Academy of Sciences (PNAS) to publish a paper byDonald I. Williamson rejecting "the Darwinian assumption that larvae and their adults evolved from a single common ancestor."[36][37] Williamson's paper provoked immediate response from thescientific community, including a countering paper inPNAS.[36] Conrad Labandeira of theSmithsonian 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." ButDuke University insect developmental biologistFred Nijhout said that the paper was better suited for the "National Enquirer than the National Academy."[38] In September it was announced thatPNAS would eliminate communicated submissions in July 2010.PNAS stated that the decision had nothing to do with the Williamson controversy.[37]
In 2009 Margulis and seven others authored a position paper concerning research on the viability of round body forms of some spirochetes, "Syphilis, Lyme disease, & AIDS: Resurgence of 'the great imitator'?"[39] which states that, "Detailed research that correlates life histories of symbioticspirochetes 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". The paper went on to suggest "that the possible direct causal involvement of spirochetes and their round bodies to symptoms of immune deficiency be carefully and vigorously investigated".[39]
In aDiscover Magazine interview, Margulis explained her reason for interest in the topic of the 2009 "AIDS" paper: "I'm interested in spirochetes only because of our ancestry. I'm not interested in the diseases", and stated that she had called them "symbionts" because both the spirochete which causes syphilis (Treponema) and the spirochete which causes Lyme disease (Borrelia) only retain about 20% of the genes they would need to live freely, outside of their human hosts.[4]
However, in theDiscover Magazine interview Margulis said that "the set of symptoms, or syndrome, presented by syphilitics overlaps completely with another syndrome: AIDS", and also noted thatKary Mullis[a] said that "he went looking for a reference substantiating that HIV causes AIDS and discovered, 'There is no such document' ".[4]
This provoked a widespread supposition that Margulis had been an "AIDS denialist". Jerry Coyne reacted on hisWhy Evolution is True blog against his interpretation that Margulis believed "that AIDS is really syphilis, not viral in origin at all."[40]Seth Kalichman, a social psychologist who studies behavioral and social aspects of AIDS, cited her [Margulis] 2009 paper as an example of AIDS denialism "flourishing",[41] and asserted that her [Margulis] "endorsement of HIV/AIDS denialism defies understanding".[42]
HistorianJan Sapp has said that "Lynn Margulis's name is as synonymous with symbiosis asCharles Darwin's is with evolution."[1] She has been called "science's unruly earth mother",[43] a "vindicated heretic",[44] or a scientific "rebel",[45] It has been suggested that initial rejection of Margulis' work on the endosymbiotic theory, and the controversial nature of it as well as Gaia theory, made her identify throughout her career with scientific mavericks, outsiders, and unaccepted theories generally.[1]
In the last decade of her life, while key components of her life's work began to be understood as fundamental to a modern scientific viewpoint – the widespread adoption of Earth System Science and the incorporation of key parts of endosymbiotic theory into biology curricula worldwide – Margulis if anything became more embroiled in controversy, not less. Journalist John Wilson explained this by saying that Lynn Margulis "defined herself by oppositional science,"[46] and in the commemorative collection of essaysLynn Margulis: The Life and Legacy of a Scientific Rebel, commentators again and again depict her as a modern embodiment of the "scientific rebel",[1] akin toFreeman Dyson's 1995 essayThe Scientist as Rebel, a tradition Dyson saw embodied inBenjamin Franklin, and which Dyson believed to be essential to good science.[47]
Margulis married astronomerCarl Sagan in 1957 soon after she got her bachelor's 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 a popular science writer and her collaborator, and Jeremy Sagan, software developer and founder of Sagan Technology.[citation needed]
In 1967 she married Thomas N. Margulis, acrystallographer. They had a son named Zachary Margulis-Ohnuma, a New York City criminal defense lawyer, and a daughter Jennifer Margulis, teacher and author.[64][65] They divorced in 1980.[citation needed]
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."[65]
In the 2000s she had a relationship with fellow biologist Ricardo Guerrero.[12]
Margulis argued that theSeptember 11 attacks were a "false-flag operation, which has been used to justify the wars in Afghanistan and Iraq as well as unprecedented assaults on [...] civil liberties." She wrote that there was "overwhelming evidence that the three buildings [of the World Trade Center] collapsed by controlled demolition."[1]
She was a religiousagnostic,[12] and a staunchevolutionist, but rejected themodern evolutionary synthesis,[4] and said: "I remember waking up one day with an epiphanous revelation: I am not a neo-Darwinist! I 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."[3] She argued that "Natural selection eliminates and maybe maintains, but it doesn't create", and maintained that symbiosis was the major driver of evolutionary change.[4]
Margulis died on November 22, 2011, at home inAmherst,Massachusetts, five days after suffering ahemorrhagic stroke.[9][7][8][65][66] As her wish, she was cremated and her ashes were scattered in her favorite research areas, near her home.[67]
Margulis, Lynn, and Dorion Sagan (1986).Origins of Sex: Three Billion Years of Genetic Recombination, Yale University Press,ISBN0-300-03340-0
Margulis, Lynn, and Dorion Sagan (1987).Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors, HarperCollins,ISBN0-04-570015-X
Margulis, Lynn, and Dorion Sagan (1991).Mystery Dance: On the Evolution of Human Sexuality, Summit Books,ISBN0-671-63341-4
Margulis, Lynn, ed. (1991).Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis, The MIT Press,ISBN0-262-13269-9
Margulis, Lynn (1991). "Symbiosis in Evolution: Origins of Cell Motility". In Osawa, Syozo; Honzo, Tasuku (eds.).Evolution of Life. Japan: Springer. pp. 305–324.doi:10.1007/978-4-431-68302-5_19.ISBN978-4-431-68304-9.
Margulis, Lynn (1992).Symbiosis in Cell Evolution: Microbial Communities in the Archean and Proterozoic Eons, W.H. Freeman,ISBN0-7167-7028-8
Sagan, Dorion, and Margulis, Lynn (1993).The Garden of Microbial Delights: A Practical Guide to the Subvisible World, Kendall/Hunt,ISBN0-8403-8529-3
Margulis, Lynn, and Dorion Sagan (1997).Slanted Truths: Essays on Gaia, Symbiosis, and Evolution, Copernicus Books,ISBN0-387-94927-5
Margulis, Lynn, and Dorion Sagan (1997).What Is Sex?, Simon and Schuster,ISBN0-684-82691-7
Margulis, Lynn, and Karlene V. Schwartz (1997).Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth, W.H. Freeman & Company,ISBN0-613-92338-3
Margulis, Lynn (1998).Symbiotic Planet: A New Look at Evolution, Basic Books,ISBN0-465-07271-2
Margulis, Lynn,et al. (2002).The Ice Chronicles: The Quest to Understand Global Climate Change, University of New Hampshire,ISBN1-58465-062-1
Margulis, Lynn, and Dorion Sagan (2002).Acquiring Genomes: A Theory of the Origins of Species, Perseus Books Group,ISBN0-465-04391-7
Margulis, Lynn (2007).Luminous Fish: Tales of Science and Love, Sciencewriters Books,ISBN978-1-933392-33-2
Margulis, Lynn, andEduardo Punset, eds. (2007).Mind, Life and Universe: Conversations with Great Scientists of Our Time, Sciencewriters Books,ISBN978-1-933392-61-5
Margulis, Lynn, and Dorion Sagan (2007).Dazzle Gradually: Reflections on the Nature of Nature, Sciencewriters Books,ISBN978-1-933392-31-8
Margulis, L (2005). "Hans Ris (1914–2004). Genophore, chromosomes and the bacterial origin of chloroplasts".International Microbiology.8 (2):145–8.PMID16052465.
^abcMargulis, Lynn (2002).Una revolución en la evolución: Escritos seleccionados (in Spanish). Valencia: Universitat de Valencia. pp. 45–48.ISBN978-8-437-05494-0.
^Margulis, Lynn (1971). "Whittaker's Five Kingdoms of Organisms: Minor Revisions Suggested by Considerations of the Origin of Mitosis".Evolution.25 (1):242–245.doi:10.2307/2406516.JSTOR2406516.PMID28562945.
Lynn Margulis (March 10, 2005)."Acquiring Genomes". San Jose Science, Technology and Society: 2005–2006 Linus Pauling Memorial Lectures. Institute for Science, Engineering, and Public Policy. Archived fromthe original on September 28, 2007. RetrievedMarch 12, 2005.
