Symbiotic Earth: How Lynn Margulis Rocked the Boat & Started a Scientific Revolution

review by Jack Kittredge

I have always wished that I had taken advantage of my proximity to Lynn Margulis during the many years she was a professor at UMass before her death in 2011. The time never seemed quite right to interview her on agricultural aspects of microbial behavior, and then, before history had a chance to recognize her Nobel-quality contribution to evolutionary biology, she was gone. This documentary is a tribute to her insights and her willingness to share them. It is composed of many photos and clips of Lynn throughout her life, explaining her work, and of her colleagues talking about her and the revolutionary impact she had on science.

lighter Lynn MargulisJohn had interviewed Lynn for a 2005 film, but after she saw the finished product she told him she was disappointed that her views were underrepresented in the film compared to “the neo-Darwinian party line.” John, unaware that there was even a viewpoint called neo-Darwinism, was fascinated and decided to explore Lynn’s ideas as they contrasted with it.

Neo-Darwinism, it turns out, is the view which posits that the variations from one individual to another that, when inherited, lead to evolutionary change are caused by differences in the genes of organisms, and that these differences are caused by mistakes (or mutations) which occur to the genes. This view has been taught for several generations as the synthesis of the work of Darwin on evolution and Gregor Mendel on the gene as the unit of heredity.

Lynn’s fundamental difference with neo-Darwinism challenges neither Darwin nor Mendel, however, just the later assertion that the primary source of variation is because of random mutations. She says, politely, that “there is very little evidence” for the theory that accumulation of such mutations is the way species evolve. For her, new species come primarily from organisms joining with one another.

That’s right, joining.

Lynn TheoryHer first insight into this development came when she encountered a speculation by Ivan Wallin a generation earlier that “mitochondria are symbiotic bacteria in the cytoplasm of the cells of all higher organisms”. Mitochondia are, of course, the “powerhouses of the cell”, organelles in cell nuclei that supply cell energy as well as numerous other vital functions. A mitochondrion has, however, independent of the cell’s DNA, its own genome — which is passed directly in the mother’s egg to the child, through the female line. This led Lynn to propose that nucleated cells evolved from the symbiotic merger of nonnucleated bacteria that had previously existed independently. She soon showed that chloroplasts and cilia were other examples of functional organelles in cell nuclei that had an independent origin, and spent her professional life finding other compelling evidence for her theory, termed, “endosymbiosis”.For many non-biologists, the most important difference between Lynn’s thinking about life and that of the neo-Darwinians is this: neo-Darwinism posited competition as the key mechanism selecting for evolutionary fitness, whereas Lynn posited that it was cooperation.

Of course such contrasting forces are easy to politicize. Competition suggested ideas like “masculine”, “capitalist”, and “domination” whereas cooperation suggested “feminine”, “socialist”, and “mutualism”.

As the environmental crisis has deepened, many are blaming our plight on anthropogenic thinking, and it’s resulting attitude that humans can exploit and control the earth. We need, they say, to listen to and work with nature, including finding ways to cooperate with other lifeforms. In agriculture the transformative recognition is spreading that tiny microbes are the crucial guarantors of soil health and crop quality — through their ability to symbiotically relate to plants and vastly improve a crop’s nutritional uptake.

This documentary is fascinating as the story of an independent and stubborn woman prevailing against a dominant intellectual brotherhood that initially mocked and belittled her. If you sit through the entire two and a half hours, as I did several times, transfixed, you will learn a great deal that is fascinating about how life surges and adapts, takes every possible pathway, and changes the world it finds until it is better suited for life.