Bridgett has a PhD in microbiology and immunology and teaches college biology.
The Life of Lynn Margulis
While Lynn Margulis may not be a household name, she led a life devoted to science. She developed endosymbiotic theory, which helped clarify complex evolutionary concepts and challenged long-held ideas.
Lynn Margulis was born Lynn Petra Alexander on March 5, 1938, in Chicago, Illinois. She attended the University of Chicago Laboratory Schools and graduated with her bachelor's degree at 18. One of her favorite courses was on genetics and heredity, which she took with James Watson, who later discovered the structure of DNA.
She met a physics student named Carl Sagan in Chicago and married him at age 19. They attended the University of Wisconsin-Madison, where Margulis got her Master's degree in zoology and genetics. They next attended the University of California-Berkeley, where Margulis began her PhD in genetics.
She completed her PhD in 1965 and began working at Boston University. She stayed at Boston University for 22 years before moving to the University of Massachusetts, Amherst. Her marriage to Sagan ended in 1963. She married Thomas Margulis in 1967, and they divorced in 1980.
Margulis received many honors for her work. She was a recipient of the 1999 National Medal of Science. She was also a member of the US National Academy of Sciences and received the Darwin-Wallace Medal of the Linnean Society of London. Lynn Margulis died of a stroke on November 22, 2011.
Margulis was an evolutionary biologist. She was most interested in the effect of symbiosis on evolution. 'Sym' means together, and 'biosis', of course, means living. So, symbiosis describes how two organisms live together. She was particularly interested in a part of the cell called the mitochondria, which helps make energy for the cell. Upon seeing a mitochondrion, she noted that it looked like a bacterium.
Margulis hypothesized that a free-living bacterium had 'moved in' with an ancestral eukaryote, and eventually became a part of it. The bacteria took over the job of energy production. In plant cells, bacteria also moved in and became chloroplasts, the organelle that performs photosynthesis. She published these ideas in her 1970 book Origin of Eukaryotic Cells.
This process was called endosymbiosis, which means one organism lives inside another. In this case, a free-living bacterium was living inside a larger eukaryotic cell. At first, this hypothesis was ridiculed by others. The long-standing ideas of scientists at the time thought that evolution only happened slowly, by random chance mutations. However, new genetic tools allowed scientists to compare the DNA found in mitochondria and in bacteria. They found a very close relationship, indicating that Margulis was probably correct. The concept of endosymbiosis is now widely accepted among evolutionary scientists.
Another idea that Margulis supported was symbiogenesis. Symbiogenesis is similar to endosymbiosis. It is an idea that says that complex eukaryotic cells evolved from smaller, simpler prokaryotic cells joining together. In addition to the mitochondria and chloroplasts, Margulis thought that the eukaryotic flagellum, a tail-like organelle that helps the cell swim around, was descended from a free-living bacterium.
Margulis was also a proponent of Gaia theory. This idea states that the entire Earth is alive and connected. All living things interact with the nonliving components and help keep a suitable balance.
Lynn Margulis was born Lynn Petra Alexander on March 5, 1938. She was an evolutionary biologist and the recipient of several prestigious scientific awards. She helped pioneer the theory of endosymbiosis, discussing how bacteria became the mitochondria and chloroplasts of eukaryotic cells. This challenged many previously held beliefs about evolution. Margulis went even further with the idea of symbiogenesis, saying that more complex cells evolved from combinations of smaller, less complex cells. She also supported Gaia theory, saying that every living thing on Earth interacts with nonliving things to help maintain a balance.
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