A Romantic Reading of Lynn Margulis’ Theory of Symbiogenesis

Romanticism was born out of protest against modernity. It emerged in the eighteenth century as a reaction to the rationalist objectivism and the Enlightenment values of reason and order and manifested in the arts, sciences, politics, philosophy, ethics, and religion. While providing a single definition of Romanticism has proven difficult, the movement’s general approach can be characterized by a commitment to holism. Resisting the historical narratives that split subject and object, self and the world, Romanticism conceived of nature as an organic whole that is continually undergoing a process of metamorphosis. However, with the rise of the “neutral” empirical sciences in the nineteenth century, the tenets of Romanticism were increasingly viewed as obstacles to science and consequently vilified. Romanticism’s critique of modernity has endured, at times resurfacing in the work of scientists who are dissatisfied with modernity’s totalizing assumptions. The American evolutionary biologist Lynn Margulis (1938–2011) is a good example.  

Margulis made two major theoretical contributions to science: serial endosymbiotic theory, or symbiogenesis, and the Gaia hypothesis, the latter of which she developed with the British environmentalist James Lovelock. Of those, only the Gaia hypothesis––which posits that the Earth and all living things on it constitute a single self-regulating system, analogous to a living organism––has been analyzed for its resonances with Romanticism. “Besides the name [Gaia], the description of the earth as a living organism represents romantic vitalism,” the literary scholar Bruce Clark has written.¹ “The Gaia hypothesis draws on a long intellectual tradition of anima mundi, or ‘world-soul,’ a variant of Naturphilosophie with well-developed roots in the Romantic period,” Oregon-based environmentalist Jade Hagan adds.² While the Gaia hypothesis has been criticized for what has been construed as an overly sentimental approach to evolutionary science, in my analysis of Margulis’s symbiogenesis theory, I emphasize its significant contribution to environmental thought by drawing on Romanticism’s resistance to modern disenchantment. 

Dating back to the nineteenth century, symbiogenesis has historically been received as a radical idea. In 1910, the Russian biologist and botanist Konstantin Mereschkowski coined the term as “the evolution of more complex cells from symbiotic relationship between less complex ones.”³ From the Greek syn, meaning “together”; bios, meaning “life”; and genesis, “origin and birth,” symbiogenesis, Margulis writes, “refers to the origin of new tissues, organs, organisms [even species] by establishment of long-term or permanent symbiosis.”⁴ Symbionts “sense” and “recognize” each other, she writes; they fuse and establish integrating mechanisms for prolonged associations.

Margulis does not explicitly use the terms “romantic” or “Romanticism,” but her thinking on evolution, which was conceived alongside the rise of popular environmental awareness in the twentieth century United States, is inflected with Romanticism’s appeal to humans’ holistic identification with nature. The reverberations of this appeal reside in Margulis’s theory of symbiogenesis, opening opportunities for rethinking the relationship between humans and nature. Margulis’s earliest formulation of symbiogenesis appeared in her paper, “On the Origins of Mitosing Cells,” which was published under the name Lynn Sagan in the Journal of Theoretical Biology in 1967.⁵ Considered a leading evolutionary theory today, Margulis’s position was long neglected, rejected, even derided.⁶

Margulis advanced the theory of symbiogenesis through isolated experiments in cytology and biochemistry and research she conducted into paleontology and geology on the formation of associations between living organisms in deep time. From her synthesis of this literature, Margulis proposed that all eukaryotic cells (cells with nuclei) are “multi-genome systems” that evolved during millions of years of interactions among highly responsive ancestor organisms.⁷ Her argument was that cytoplasmic organelles––mitochondria, cilia, and plastids, which populate cellular bodies––are remnants of ancestral prokaryotic bacteria (bacteria without a nucleus) that came to live symbiotically within a single cell. These organelles resemble the general anatomical features, physiological behaviors, and metabolic characteristics of ancestral bacterial cells, which are still living or whose traces are found in fossils. 

For the first two billion years of life on Earth, Margulis postulated, bacteria were the planet’s only inhabitants. They transformed the Earth’s surface and atmosphere, creating all of life’s essential chemical processes through fermentation, photosynthesis, oxygen respiration, and the conversion of atmospheric nitrogen into proteins. The emergence of these chemical systems triggered global crises in bacterial populations, leading to their starvation and intoxication long before the emergence of alternative life forms.⁸ The incorporation of one type of bacterium by another—symbiogenesis—was an evolutionary response to surviving these crises.⁹ Bacterial organisms of distinct taxa, Margulis proposed, developed stable relationships over time, exchanging metabolic products and genetic materials.¹⁰ This ensured the survival of co-symbionts in a specific and stable relation.  

In Margulis’s theory, four once-independent and physically separate ancestor bacteria allied and merged in a particular order, as the word serial in Serial Endosymbiosis indicates. First, the swimming bacterium merged with the acid-and-heat-tolerant fermenting bacterium, and then the oxygen-breathing bacterium was incorporated. The composite resulted in the ancestral cell (or protist), an example of which is the blue-green algae. Plants, fungi, and animal cells descended from the protist. Evolutionary development could only occur, therefore, after a great struggle in which one bacterium was invaded by another but not destroyed. As Margulis explains, “survivors of thwarted aggression formed uneasy truces.”¹¹ Forging a “truce” was an innovative mechanism that resulted in the merging of formerly independent bacteria into new kinds of complex cells.¹² In her telling, evolution is not merely a contest of kill or be killed but a progress in relationality. Margulis explains that life did not take over the globe by combat, but by networking. Life forms multiplied and complexified by co-opting others, not just by killing them.¹³

Evolutionary and planetary developments created the conditions of biological cohabitation. Of course, “nonphotosynthetic protoctists [protozoans, algae, and slime molds],” Margulis explains, “whether or not they indulge in sex, always eat. Some will eat anything under stressed conditions. If desiccated, starved, irradiated, or otherwise in imminent danger of death, and attempting to save themselves by eating their fellows, they fuse rather than die alone.”¹⁴ In this process, genes from bacteria that were trapped or consumed by other bacteria survived within the host cell and transformed it. Over time, a stable, eventually permanent liaison between the co-symbionts evolved. Drawing attention to the organic bond between all life forms across space and time, Margulis writes, “life has been, since inception and with no discontinuity, chemically connected to its past.”¹⁵ This means that the conservation of life in chemical compounds allows for genetically tracing the incorporation of one kind of bacterium by a different kind.¹⁶

Once independent microbes “teamed up,” as she puts it, and merged, they lost their singularity. To Margulis, eukaryotic cells were not individual entities, but populations or communities of organisms that interact within the boundary of cell membrane. Every entity is a composite: a unity that is a product of coevolved microbial communities. “United, the symbionts formed a single individual”¹⁷ and generated myriad offspring of “multiunit symbiotic new individuals.”¹⁸ Such characterizations of organisms as indivisible wholes are not only reminiscent of Romanticism, where a whole––from the Greek holos––refers to that which is more than the sum of its parts, but they also achieve the Romantic philosophical ideal of forming unity in diversity.  

Unity does not necessarily connote harmony, however. According to Margulis, symbiosis functions as “an uneasy alliance of distinct life-forms [that] may underlie the origin of major evolutionary novelty.”¹⁹ She maintained that natural selection occurs not so much through the accumulation of chance mutations but through the new kinds of relational organisms that co-evolved through symbiogenesis. In bringing together divergent genomes, the process of symbiogensis made possible some of the major cellular innovations responsible for the origin of higher taxa. Margulis, however, does not suggest that greater complexity yields greater organisms. The greatness is in the system that is created between organisms, she thinks, where the system constantly changes due to the interactions and relations it contains. 

Margulis’s concept of relational holism, moreover, challenged the conception of cellular membranes as enclosing boundaries. A membrane is not a concrete wall but a constantly changing semi-permeable barrier. “Cells are environments,” Margulis writes, allowing for taxonomic boundary crossings.²⁰ Margulis marshaled research from the intracellular transfer of genetic material that supported her theories of symbiogenesis. The transfer of genes and metabolic products from the nodules of nitrogen-fixing bacteria to the tumorigenic traits of bacteria in wounded plants exemplified the mechanism of symbiogenesis, she argued.²¹ Margulis also drew on the gene flow between fungi and photosynthesizer algae or bacteria that communally form lichens.²² She rejected the notion of organisms as fixed entities with materially closed surfaces.

Throughout her work, Margulis invited readers to consider Earth’s biota not as an interdependent collective of discrete, membrane-bound organisms, but as a semicontinuous spectrum of interactive life forms. By extending the kindred ancestry of humanity back to primal forms of life, she undermined the idea of humans as isolated beings. As polygenomic entities, humans possess “selves of multiple origins,” Margulis writes.²³ The dating of humanity’s origins, she claims, is “biologically absurd, totally artificial.”²⁴ Human life began as all life did, at least 3.5 billion years ago, with the first bacteria. 

Margulis’s move to position the human self in relation to that which surrounds it maintains a certain romantic sensibility. Her attitude to resituate humanity as itself symbiotic likewise resisted structural hierarchies that persist in long-held assumptions in the natural sciences passed down from Enlightenment. Margulis writes: 

All beings alive today are equally evolved. All have survived over three thousand million years of evolution from common bacterial ancestors. There are no “higher” beings, no “lower animals,” no angels, and no gods. . . .  My claim is that, like all other apes, humans are not the work of God but of thousands of millions of years of interaction among highly responsive microbes.²⁵ 

This vision for the origins of life is consistent with Romanticism’s holistic conceptualization of nature. Margulis agrees with the modern scientific cosmology that “all life came not from the hand of almighty God . . . but ultimately from first life, and first life originated from nonliving solar system matter.”²⁶ Yet her unitive metaphysics suggest something like what the literary critic M. H. Abrams called Romanticism’s “natural supernaturalism,” which esteems values that fall both within and outside of the modern scientific purview.²⁷

The literary and visual aesthetics suffusing Margulis’s work carry the Romantic aesthetic impulse forward. As early as 1967, she integrated concepts such as “relationship” and “association” into her scientific analyses. In her more popular writings, Margulis employed the language of intimacy to describe interspecies relations.²⁸ For instance, she opens her 1998 book Symbiotic Planet by describing various species’ symbiosis as the “living together” of organisms in physical contact. She writes: “Partners in symbiosis, fellow symbionts abide in the same place at the same time, literally touching each other or even inside each other. . . . All organisms are touching because all are bathed in the same air and the same flowing water.”²⁹ She adds elsewhere: “[Serial endosymbiosis] is a theory of coming together, of merging of cells of different histories and abilities.”³⁰ In both her academic and popular writings, Margulis consistently described the process of establishing associations between distant organisms as “teaming up,” “co-mingling,” “alliance,” “cooperation,” and “cohabitation.” She refers to affiliated organisms as “fellows” and “partners.” These recurring terms indicate the holistic vision embedded in the aesthetic dimension of symbiogenesis theory.  

In Romanticism’s holistic conception of nature, which stood in sharp contrast to the mechanistic conception of Enlightenment, diverse parts are connected or coordinated in the larger whole. Margulis anthropomorphized the relations between organisms to emphasize their interconnectedness. Her metaphors are not merely ornamental; they are aesthetic forms facilitating the transmission of scientific concepts concerning interrelatedness. 

The visual aesthetics of Margulis’s work also amplify its resonance with the Romantic tradition. These include photographs, drawings, and diagrams produced by Margulis herself, as well as those she commissioned or borrowed from other scientists. Most notably, the stippling technique that Margulis frequently used evokes the Romantic concept of holism. Stippling is a technique of applying points or dots of single pigments, often without using linear borders or edges. The denser the dots, the more intense the shades. This technique relies on optical perception, especially how vision synthesizes a series of impressions registered on the retina. The points merge to create a single image. Although color is absent from the stippled drawings Margulis commissioned, the method is similar to pointillism, another artistic technique she references. Both techniques rely on optical synthesis and navigate the seer’s subjective experience and its relationship to the objective physical phenomena. 

In Symbiotic Planet, Margulis explicitly characterizes bacterial ancestors as “pointillist.” She writes: 

Human and other animal consciousness, as well as other types of biological beauty and complexity, are properties of our coevolving, pointillist bacterial ancestry. Cellular interliving, an infiltration, and assimilation . . . produced everything from spring-green blooms and warm, wet mammalian bodies, to the Earth’s global nexus.³¹

Margulis favored the stippling technique for the way it re-creates our perception of reality, thereby challenging the duality of subject and object. The dots are allegorically related to the philosophy undergirding symbiogenesis. They represent the microcosm, and the multiplicity of points coheres into an image, just as the multitude of bacteria come together in Margulis’s theorization.

While Romanticism’s persistence in the natural sciences has been criticized for undermining empirical studies, Margulis gives us reason to appreciate the Romantic legacy in relation to modern scientific inquiry. The scientific content of Margulis’s theory of symbiogenesis and the aesthetic forms in which it is presented are indicative of a romantic sort of synthesis. There is the “alienation from the world which the natural sciences study,” as Margulis claimed, yet her inquiry into evolution did not redound to that alienation.³² Rather, she upheld the humanistic dimensions of science. 

For Margulis, science was replete with philosophical significance. It was a liberal art, a way of knowing. Despite the material sciences’ opposition to engaging sentiments and extracting moral meaning from an empirical knowledge of nature, Margulis infused her own subjectivity into the object of her study. From field to laboratory, she integrated metaphysics, aesthetics, and scientific knowledge in the natural phenomena she explored. In doing so, she cultivated a moral identification with nature through science. Upholding subjective insight into what it means to practice theoretical and empirical science, she fostered a romantic sensibility for understanding the more-than-human world. 

Symbiogenesis challenges humans’ assumptions of individuality, uniqueness, and independence. To accept Margulis’s position is to acknowledge that we are comprised of multiplicities, aggregates of other life forms. It is also to humble ourselves. As Margulis writes, “to admit that our ancestors are bacteria is humbling.”³³ The romantic insight that humans indeed are not “discrete physical beings separate from the rest of nature” is the lasting moral significance of Margulis’s approach and continued influence.

¹ Bruce Clark, “Mediating Gaia: Literature, Space, and Cybernetics in the Dissemination of Gaia Discourse,” in Imagining Earth, eds. Solvejg Nitzke and Nicolas Pethes (Transcript Verlag, 2017), 61–90. [Return to Section]

² Jade Hagan, “New Age Romanticism and the Afterlives of William Blake” (PhD Dissertation, Rice University, 2019), 393. [Return to Section]

³ Klaus V Kowallik and William F Martin, “The Origin of Symbiogenesis: An Annotated English Translation of Mereschkowsky’s 1910 Paper on the Theory of Two Plasma Lineages,” BioSystems 199 (2021): 104281. [Return to Section]

⁴ Lynn Margulis, Symbiotic Planet: A New Look at Evolution (Basic Books, 1998), 6. [Return to Section]

⁵ Lynn Sagan, “On the Origin of Mitosing Cells,” Journal of Theoretical Biology, vol. 14, no. 3, 225. Margulis’s first husband was the astronomer Carl Sagan. [Return to Section]

⁶ See for example Charles Mann, “Lynn Margulis: Science’s Unruly Earth Mother” Science, vol. 252, no. 5004, 378–381. The article’s subhead reads, “Lynn Margulis’ partisanship of Gaia enrages her colleagues in evolutionary biology, but nobody dismisses her out of hand—because she's been right before.” [Return to Section]

⁷ Sagan, “Mitosing Cells.” Margulis notes that “although these ideas are not new . . . in this paper they have been synthesized in such a way as to be consistent with recent data on the biochemistry and cytology of subcellular organelles.” [Return to Section]

⁸ Lynn Margulis and Dorion Sagan, Dazzle Gradually: Reflections on the Nature of Nature (Chelsea Green Publishing, 2007), 31. [Return to Section]

⁹ Ibid. See also “Mitosing Cells. [Return to Section]

¹⁰ Lynn Margulis, “Genetic and Evolutionary Consequences of Symbiosis,” in Experimental Parasitology 39.2, 339. [Return to Section]

¹¹ Margulis, Symbiotic Planet, 82. [Return to Section]

¹² Ibid., 82. [Return to Section]

¹³ Dazzle Gradually, 32. [Return to Section]

¹⁴ Symbiotic Planet, 127. [Return to Section]

¹⁵ Ibid., 101. In an essay entitled “Descartes, Dualism, and Beyond,” in Dazzle Gradually, Lynn Margulis, Dorion Sagan, and Ricardo Guerrero posit that all life is connected through Darwinian time and Vernadskian space. Also, in On the Origin of Species, Darwin writes: “We see in these facts [referring to evidence for his theory] some deep organic bond, prevailing throughout space and time, over the same areas of land and water, and independent of their physical conditions. . . . This bond, on my theory, is simply inheritance” (Charles Darwin, On the Origin of Species: By Means of Natural Selection [D. Appleton and Company, 1883], 350). [Return to Section]

¹⁶ Symbiotic Planet, 44. [Return to Section]

¹⁷ Ibid., 47. [Return to Section]

¹⁸ Ibid., 12. [Return to Section]

¹⁹ Ibid., 26. [Return to Section]

²⁰ Margulis, “Symbiogenesis and Symbionticism,” in Symbiosis as a Source of Evolutionary Innovation: Speciation and Morphogenesis, eds. Lynn Margulis and René Fester (MIT Press, 1991). [Return to Section]

²¹ Margulis, “Genetic and Evolutionary Consequences of Symbiosis,” Experimental Parasitology 39.2 (1976): 321. [Return to Section]

²² Margulis, Origin of Eukaryotic Cells: Evidence and Research Implications for a Theory of the Origin and Evolution of Microbial, Plant, and Animal Cells on the Precambrian Earth (Yale University Press, 1970), 153. [Return to Section]

²³ Dazzle Gradually, 22. [Return to Section]

²⁴ Symbiotic Planet, 115. [Return to Section]

²⁵ Ibid., 5. [Return to Section]

²⁶ Ibid., 96. [Return to Section]

²⁷ M. H. Abrams, Natural Supernaturalism: Tradition and Revolution in Romantic Literature, (Norton, 1971). See also Akeel Bilgrami, “The Political Possibilities of the Long Romantic Period,” in Secularism, Identity, and Enchantment (Harvard University Press, 2014), 187–188. [Return to Section]

²⁸ Scholars have pointed out the use of Romantic literary aesthetics in Darwin’s writings as well. For example, he used the metaphor of “wedging” to describe how competition and natural selection drive species into new ecological niches, similar to how wedges are forced into a yielding surface. He also used “entangled bank” as a metaphor connoting peace and the beauty of natural phenomena. See Hajo Greif, “The Darwinian Tension: Romantic Science and the Causal Laws of Nature,” in Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 53: 53–61. See also On the Origin of Species, 67 and 489. [Return to Section]

²⁹ Symbiotic Planet, 2. [Return to Section]

³⁰ Ibid., 32. [Return to Section]

³¹ Ibid., 26. [Return to Section]

³² Ibid., 192. [Return to Section]

³³ Dazzle Gradually, 32. [Return to Section]

³⁴ Ibid. [Return to Section]

Daneshvar, Samira. "A Romantic Reading of Lynn Margulis’ Theory of Symbiogenesis" in Thinking with Plants and Fungi: Interdisciplinary Explorations of Ecology, Mind, and the More-than-Human World, edited by Rachael Petersen, Russell Powell, and Natalia Scott Schwein. Center for the Study of World Religions, Harvard Divinity School, 2026.  https://doi.org/10.70423/0003.02