Lynn Margulis portrait photograph

Lynn Margulis (1938-2011) was an American evolutionary biologist whose endosymbiotic theory proposed that complex cells arose through symbiotic mergers of simpler organisms. Her work emphasized cooperation and symbiosis as drivers of evolutionary innovation alongside competition.

Margulis proposed her theory in 1967, suggesting that complex cells with nuclei (eukaryotes) arose through symbiotic mergers of simpler bacterial cells. Her hypothesis that mitochondria and chloroplasts were once independent bacteria that became incorporated into larger cells faced initial resistance. Her paper “On the Origin of Mitosing Cells” was rejected by fifteen journals before publication. One grant application received the response: “Your research is crap.”

The theory gained acceptance by the 1980s after genetic evidence supported her claims. Ernst Mayr described the evolution of nucleated cells as “perhaps the most important and dramatic event in the history of life.” Margulis’s work suggested that this development resulted from cooperative mergers rather than solely competitive selection, reframing evolutionary biology’s emphasis on competition.

Margulis collaborated with James Lovelock throughout the 1970s to develop the Gaia hypothesis, which proposes that Earth functions as a self-regulating system through interactions between living organisms and their environment. She contributed biological expertise to Lovelock’s geochemical insights, examining how microbial processes influence planetary conditions.

She advocated for Robert Whittaker’s five kingdom classification of life, promoting recognition of microbial diversity. Her research emphasized that bacteria cooperate and exchange genetic material, challenging views of microorganisms as isolated competitors.

Margulis received election to the US National Academy of Sciences (1983), the National Medal of Science (1999), and the Darwin-Wallace Medal from the Linnean Society (2008). She published extensively with her son, science writer Dorion Sagan, making her research accessible to wider audiences.

Key Concepts

Essential Works

  1. “Origin of Eukaryotic Cells” (Yale University Press, 1970) - ISBN 0-300-01353-1
  2. “Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors” (HarperCollins, 1987) - ISBN 0-04-570015-X - With Dorion Sagan
  3. “Symbiosis as a Source of Evolutionary Innovation” (MIT Press, 1991) - ISBN 0-262-13269-9 - Editor
  4. “Symbiotic Planet: A New Look at Evolution” (Basic Books, 1998) - ISBN 978-0-465-07272-1
  5. “Acquiring Genomes: A Theory of the Origin of Species” (Basic Books, 2002) - ISBN 978-0-465-04391-6 - With Dorion Sagan

Selected Quotes

Life did not take over the globe by combat, but by networking. — Microcosmos (1987)

The view of evolution as chronic bloody competition among individuals and species, a popular distortion of Darwin’s notion of ‘survival of the fittest,’ dissolves before a new view of continual cooperation. — Microcosmos (1987)

All of us are walking communities of bacteria. The world shimmers, a pointillist landscape made of tiny living beings. — Microcosmos (1987)

Independence is a political, not a scientific term. — On symbiosis and cooperation

We abide in a symbiotic world. — Symbiotic Planet (1998)

Life on Earth is an elaborate and intricate symbiotic phenomenon. — Symbiosis in Cell Evolution (1981)

The romantic vision of biotic nature as a cooperative venture is far more scientifically accurate than the view of nature as violent and competitive. — Acquiring Genomes (2002)

I think the concept of symbiosis, of living together in physical contact, is a very important concept in evolution that has been neglected. — Interview

Further Reading

Biographical Sources

Key Books

Scientific Papers

Related Resources