Margulis in 2005
Lynn Petra Alexander
March 5, 1938
|Died||November 22, 2011 73) (aged|
Amherst, Massachusetts, U.S.
|Alma mater|| University of Chicago |
University of Wisconsin–Madison
University of California, Berkeley
|Known for|| Symbiogenesis |
(m. 1957;div. 1965)
(m. 1967;div. 1980)
|Children|| Dorion Sagan (1959) |
Jeremy Ethan Sagan (1960)
Jennifer Margulis di Properzio
|Awards|| National Medal of Science (1999) |
William Procter Prize for Scientific Achievement (1999)
Darwin-Wallace Medal (2008)
|Institutions|| Brandeis University |
University of Massachusetts Amherst
|Thesis||An Unusual Pattern of Thymidine Incorporation in Euglena' (1965)|
|Doctoral advisor||Max Alfert|
|Influences||Ivan Wallin, Konstantin Mereschkowski|
Lynn Margulis (born Lynn Petra Alexander;March 5, 1938 – November 22, 2011) was an American evolutionary theorist, biologist, science author, educator, and science popularizer, and was the primary modern proponent for the significance of symbiosis in evolution. Historian Jan Sapp has said that "Lynn Margulis's name is as synonymous with symbiosis as Charles Darwin's is with evolution." In particular, Margulis transformed and fundamentally framed current understanding of the evolution of cells with nuclei – an event Ernst Mayr called "perhaps the most important and dramatic event in the history of life" – by proposing it to have been the result of symbiotic mergers of bacteria. Margulis was also the co-developer of the Gaia hypothesis with the British chemist James Lovelock, proposing that the Earth functions as a single self-regulating system, and was the principal defender and promulgator of the five kingdom classification of Robert Whittaker.
Throughout her career, Margulis' work could arouse intense objection (one grant application elicited the response, "Your research is crap, do not bother to apply again" [ page needed ]), and her formative paper, "On the Origin of Mitosing Cells", appeared in 1967 after being rejected by about fifteen journals. Still a junior faculty member at Boston University at the time, her theory that cell organelles such as mitochondria and chloroplasts were once independent bacteria 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 US National Academy of Sciences in 1983. 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.
Called "Science's Unruly Earth Mother", pp30, 67, 74–78, 88–92) Margulis' work on symbiosis and her endosymbiotic theory had important predecessors, going back to the mid-19th century – notably Andreas Franz Wilhelm Schimper, Konstantin Mereschkowski, Boris Kozo-Polyansky (1890–1957), and Ivan Wallin – and Margulis not only promoted greater recognition for their contributions, but personally oversaw the first English translation of Kozo-Polyansky's Symbiogenesis: 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 son Dorion Sagan.a "vindicated heretic", or a scientific "rebel", Margulis was a strong critic of neo-Darwinism. Her position sparked lifelong debate with leading neo-Darwinian biologists, including Richard Dawkins, George C. Williams, and John Maynard Smith. (
In 2002, Discover magazine recognized Margulis as one of the 50 most important women in science.
Lynn Margulis was born in Chicago, to a Jewish, Zionist family.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. She entered the Hyde Park Academy High School in 1952, describing herself as a bad student who frequently had to stand in the corner.
A precocious child, she was accepted at the University of Chicago Laboratory Schoolsat the age of fifteen. In 1957, at age 19, she earned a BA from the University of Chicago 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.) 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 lectureship 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. In 1966 she moved to Boston 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 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 become Distinguished Professor of Geosciences "with great delight", the post which she held until her death.
Margulis married astronomer Carl 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. In 1967, she married Thomas N. Margulis, a crystallographer. They had a son named Zachary Margulis-Ohnuma, a New York City criminal defense lawyer, and a daughter Jennifer Margulis, teacher and author.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." In the 2000s she had a relationship with fellow biologist Ricardo Guerrero. Her sister Joan Alexander married Nobel Laureate Sheldon Lee Glashow; another sister, Sharon, married mathematician Daniel Kleitman.
She was a religious agnostic,and a staunch evolutionist. But she rejected the modern evolutionary synthesis, 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." 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.
In 2013, Margulis was listed as having been a member of the Advisory Council of the National Center for Science Education.
Margulis died on 22 November 2011 at home in Amherst, Massachusetts, five days after suffering a hemorrhagic stroke.As her wish, she was cremated and her ashes were scattered in her favorite research areas, near her home.
In 1966, as a young faculty member at Boston University, Margulis wrote a theoretical paper titled "On the Origin of Mitosing Cells".The paper, however, was "rejected by about fifteen scientific journals," she recalled. It was finally accepted by Journal of Theoretical Biology and is considered today a landmark in modern endosymbiotic 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. The descent of mitochondria from bacteria and of chloroplasts from cyanobacteria was experimentally demonstrated in 1978 by Robert Schwartz and Margaret Dayhoff. This formed the first experimental evidence for the symbiogenesis theory. The endosymbiosis theory of organogenesis became widely accepted in the early 1980s, after the genetic material of mitochondria and chloroplasts had been found to be significantly different from that of the symbiont's nuclear DNA.
In 1995, English 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.
Margulis opposed competition-oriented views of evolution, stressing the importance of symbiotic or cooperative relationships between species.
She later formulated a theory that proposed symbiotic relationships between organisms of different phyla or kingdoms as the driving force of evolution, and explained genetic variation as occurring mainly through transfer of nuclear information between bacterial cells or viruses and eukaryotic cells.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.
Margulis also held a negative view of certain interpretations of Neo-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."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."
Margulis initially sought out the advice of 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."
Margulis met with Lovelock, who explained his Gaia hypothesis to her, and very soon they began an intense collaborative effort on the concept.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.'"
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 an emergent property of the Earth system, life and its physical environment taken together.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" ). In her 1998 book Symbiotic Planet, Margulis explored the relationship between Gaia and her work on symbiosis.
Since 1969, life on earth was classified into five kingdoms, as introduced by Robert Whittaker.Margulis became the most important supporter, as well as critic – while supporting parts, she was the first to recognize the limitations of Whittaker's classification of microbes. But later discoveries of new organisms, such as archaea, and emergence of molecular taxonomy challenged the concept. By the mid-2000s, most scientists began to agree that there are more than five kingdoms. 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 a modified 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 treats archaea as a higher taxon than kingdom, or the six-kingdom system, which holds that it is a separate kingdom). Her concept is given in detail in her book Five Kingdoms, written with Karlene V. Schwartz. It has been suggested that it is mainly because of Margulis that the five-kingdom system survives.
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.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,” and in the commemorative collection of essays Lynn Margulis: The Life and Legacy of a Scientific Rebel, commentators again and again depict her as a modern embodiment of the "scientific rebel", akin to Freeman Dyson's 1995 essay, The Scientist as Rebel, a tradition Dyson saw embodied in Benjamin Franklin, and which he believed to be essential to good science. At times, Margulis could make highly provocative comments in interviews that appeared to support her most strident critics’ condemnation. The following describes three of these controversies.
In 2009, via a then-standard publication-process known as "communicated submission" (which bypassed traditional peer review), 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."Williamson's paper provoked immediate response from the scientific community, including a countering paper in PNAS. 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." 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.
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'?",which states that, "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." 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".
In a Discover Magazine interview which was published less than six months before her death, Margulis explained to writer Dick Teresi her reason for interest in the topic of 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.
However, in the Discover Magazine interview Margulis said that "the set of symptoms, or syndrome, presented by syphilitics overlaps completely with another syndrome: AIDS," and also noted that Kary Mullissaid that "he went looking for a reference substantiating that HIV causes AIDS and discovered, 'There is no such document.' "
This provoked a widespread supposition that Margulis had been an "AIDS denialist." Notably Jerry Coyne reacted on his Why Evolution is True blog against his interpretation that Margulis believed "that AIDS is really syphilis, not viral in origin at all."Seth Kalichman, a social psychologist who studies behavioral and social aspects of AIDS, cited her 2009 paper as an example of AIDS denialism "flourishing", and asserted that her "endorsement of HIV/AIDS denialism defies understanding."
Margulis argued that the September 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 claimed that there was "overwhelming evidence that the three buildings [of the World Trade Center] collapsed by controlled demolition."
An endosymbiont or endobiont is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον endon "within", σύν syn "together" and βίωσις biosis "living".) Examples are nitrogen-fixing bacteria, which live in the root nodules of legumes; single-cell algae inside reef-building corals, and bacterial endosymbionts that provide essential nutrients to about 10–15% of insects.
Symbiosis is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic. The organisms, each termed a symbiont, may be of the same or of different species. In 1879, Heinrich Anton de Bary defined it as "the living together of unlike organisms". The term was subject to a century-long debate about whether it should specifically denote mutualism, as in lichens. Biologists have now abandoned that restriction.
Symbiogenesis, or endosymbiotic theory, is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes taken one inside the other in endosymbiosis.
The evolution of flagella is of great interest to biologists because the three known varieties of flagella each represent a sophisticated cellular structure that requires the interaction of many different systems.
The Paleoproterozoic Era, spanning the time period from(2.5–1.6 Ga), is the first of the three sub-divisions (eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's geological history. It was during this era that the continents first stabilized.
The Gaia hypothesis, also known as the Gaia theory or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.
Multicellular organisms are organisms that consist of more than one cell, in contrast to unicellular organisms.
Microbial ecology is the ecology of microorganisms: their relationship with one another and with their environment. It concerns the three major domains of life—Eukaryota, Archaea, and Bacteria—as well as viruses.
Dorion Sagan is an American author, essayist, fiction writer, and theorist from Madison, Wisconsin. He has written and co-authored books on culture, evolution, and the history and philosophy of science, including Cosmic Apprentice,Cracking the Aging Code, and Lynn Margulis: The Life and Legacy of a Scientific Rebel. His book Into the Cool, co-authored with Eric D. Schneider, is about the relationship between non-equilibrium thermodynamics and life.
W. Ford Doolittle is an evolutionary and molecular biologist. He is a member of the US National Academy of Sciences and a Fellow of the Royal Society of Canada and the Norwegian Academy of Science and Letters. He is also the winner of the 2013 Herzberg Medal of the Natural Sciences and Engineering Research Council of Canada and the 2017 Killam Prize.
Mixotricha paradoxa is a species of protozoan that lives inside the gut of the Australian termite species Mastotermes darwiniensis.
Donald Irving Williamson was a British planktologist and carcinologist. He gained his first degree from the Durham University in 1942, his PhD from the same university in 1948, and a DSc from the Newcastle University in 1972. He worked at the Port Erin Marine Laboratory of the University of Liverpool from 1948 to 1997, and published on Irish Sea plankton, crustacean behaviour and taxonomy, and crustacean larvae.
Jan Anthony Sapp is a professor in the Department of Biology, York University, Canada. His writings focus especially on evolutionary biology beyond the classical neoDarwinian framework, and emphasize the fundamental importance of symbiosis and horizontal gene transfer in heredity and evolution.
Earth system science (ESS) is the application of systems science to the Earth. In particular, it considers interactions and 'feedbacks', through material and energy fluxes, between the Earth's sub-systems' cycles, processes and "spheres"—atmosphere, hydrosphere, cryosphere, geosphere, pedosphere, lithosphere, biosphere, and even the magnetosphere—as well as the impact of human societies on these components. At its broadest scale, Earth system science brings together researchers across both the natural and social sciences, from fields including ecology, economics, geography, geology, glaciology, meteorology, oceanography, climatology, paleontology, sociology, and space science. Like the broader subject of systems science, Earth system science assumes a holistic view of the dynamic interaction between the Earth's spheres and their many constituent subsystems fluxes and processes, the resulting spatial organization and time evolution of these systems, and their variability, stability and instability. Subsets of Earth System science include systems geology and systems ecology, and many aspects of Earth System science are fundamental to the subjects of physical geography and climate science.
Eukaryotes are organisms whose cells have a nucleus enclosed within a nuclear envelope. Eukaryotes belong to the domain Eukaryota or Eukarya; their name comes from the Greek εὖ and κάρυον. The domain Eukaryota makes up one of the domains of life in the three-domain system; the two other domains are Bacteria and Archaea. Eukaryotes represent a tiny minority of the number of living organisms; however, due to their generally much larger size, their collective worldwide biomass is estimated to be about equal to that of prokaryotes. Eukaryotes evolved approximately 1.6–2.1 billion years ago, during the Proterozoic eon.
Evolution of cells refers to the evolutionary origin and subsequent evolutionary development of cells. Cells first emerged at least 3.8 billion years ago. This was approximately 750 million years after the earth was formed.
Nancy A. Moran is an American evolutionary biologist and entomologist, University of Texas Leslie Surginer Endowed Professor, and co-founder of the Yale Microbial Diversity Institute. Since 2005, she has been a member of the United States National Academy of Sciences. Her seminal research has focused on the pea aphid, Acyrthosiphon pisum and its bacterial symbionts including Buchnera (bacterium). In 2013, she returned to the University of Texas at Austin, where she continues to conduct research on bacterial symbionts in aphids, bees, and other insect species. She has also expanded the scale of her research to bacterial evolution as a whole. She believes that a good understanding of genetic drift and random chance could prevent misunderstandings surrounding evolution. Her current research goal focuses on complexity in life-histories and symbiosis between hosts and microbes, including the microbiota of insects.
The hologenome theory of evolution recasts the individual animal or plant as a community or a "holobiont" – the host plus all of its symbiotic microbes. Consequently, the collective genomes of the holobiont form a "hologenome". Holobionts and hologenomes are structural entities that replace misnomers in the context of host-microbiota symbioses such as superorganism, organ, and metagenome. Variation in the hologenome may encode phenotypic plasticity of the holobiont and can be subject to evolutionary changes caused by selection and drift, if portions of the hologenome are transmitted between generations with reasonable fidelity. One of the important outcomes of recasting the individual as a holobiont subject to evolutionary forces is that genetic variation in the hologenome can be brought about by changes in the host genome and also by changes in the microbiome, including new acquisitions of microbes, horizontal gene transfers, and changes in microbial abundance within hosts. Although there is a rich literature on binary host–microbe symbioses, the hologenome concept distinguishes itself by including the vast symbiotic complexity inherent in many multicellular hosts. For recent literature on holobionts and hologenomes published in an open access platform, see the following reference.
Reticulate evolution, or network evolution, describes the origination of a lineage through the partial merging of two ancestor lineages, leading to relationships better described by a phylogenetic network than a bifurcating tree. Reticulate patterns can be found in the phylogenetic reconstructions of biodiversity lineages obtained by comparing the characteristics of organisms. Reticulation processes can potentially be convergent and divergent at the same time. Reticulate evolution indicates the lack of independence between two evolutionary lineages. Reticulation affects survival, fitness and speciation rates of species.
Endogenosymbiosis is an evolutionary process, proposed by the evolutionary and environmental biologist Roberto Cazzolla Gatti, in which "gene carriers" and symbiotic prokaryotic cells could share parts or all of their genomes in an endogenous symbiotic relationship with their hosts.
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