Lynn Margulis and Eukaryotic Cells

Charles Darwin’s idea of Natural Selection as the key driver of evolution has been demonstrated many times over. However, in the century and a half since his lifetime, scientists have added onto his theories as various scientific discoveries have been made. Perhaps no one has reframed the picture of Darwinian evolution as much as the scientist pictured here, Lynn Margulis.

The overall thrust of Darwinism for many decades emphasised the role of competition — after all, when there is a limit to resources, it makes sense that the creatures who can take advantage to gain the greatest amount will more likely propagate their genetic material. But Margulis developed another key concept in evolution with a very different take: the idea that symbiotic relationships among species can be a principle motivating force for species’ development.

Margulis wrote a paper as a young faculty biologist at Boston University in 1966 called “On the Origin of Mitosing Cells,” which was rejected by multiple journals. Too bad, because her ideas in that paper were both revolutionary and correct: she argued that complex cellular formation (cells with nuclei, which can perform many more complex operations and make life forms beyond simple bacteria and the like possible) happened when two types of organisms joined together to make one — these would be eukaryotic cells.

DNA exists to make more of itself, and in a eukaryotic cell, it turns out that there are two places where it exists — in the nucleus, and in the mitochondria. (See second image.) The nucleus of course is the directory of cell function, but the mitochondria is the powerhouse of the cell. Margulis argued that the differing genetic producers in eukaryotic cells came from separate bacteria-esque life forms that merged. For years, her ideas were considered outlier and rebellious, but by the early 1980s genetic evidence demonstrating that mitochondrial and nucleic DNA differed had proved her correct.

Margulis tended to embrace radical scientific theories, and was unafraid to live her life outside traditional norms. Her tenacity perhaps prevented our understanding of evolution from stagnating.

A Margulis quote: “Politicians need a better understanding of global ecology. We need to be freed from our species-specific arrogance. No evidence exists that we are chosen, the unique species for which all others were made. Nor are we the most important one because we are so numerous, powerful, and dangerous.”