Lynn Margulis Dies – But Endosymbiosis Lives On.
In case you never heard of endosymbiosis, it is a controversial new theory by Dr. Lynn Margulis, which adds to our understanding of evolution. It simply states that the internal structures (organelles) of two separate organisms may combine and work in conjunction with each other.
Symbiogenisis is the creation of a totally new organism by the combining of two previous existing organisms. This can happen when one organism has another for lunch. Instead of digesting all of its lunch, the organism saves its meal and incorporates it into its own structure. The saved pieces eventually evolve into plant chloroplasts and animal mitochondria. The saved pieces of past lunches may also include the DNA of the ingested organism. Lichens, the green stuff on rocks and Alaskan tundra that reindeers love, is an example of two organisms, algae and fungus, that have decided in their nonexistent brains to join forces and live as one. Margulis and other investigators believed that in the past many single celled organisms have done just that. The combination of two previously distinct organisms is thought to be an example of evolution in fifth gear, rapid evolution. Could it be an explanation of Gould’s theory of “punctuated equilibrium” where evolution periodically speeds up after trudging along for ages? Some scientists suspect it is. The transition from Pre-Cambrian time to Cambrian time is often referred to as being a time of rapid change in the evolution of life. Endosymbiosis and symbiogenisis may have played a role in it.
Endosymbiosis is a theory once ridiculed but now accepted on the origin of organelles in some primitive single-celled organisms. I know this probably does not ring any bells for the average person, and you probably never heard of Margulis or her theory. Her theory was based on research from two obscure mid-19th century Russian scientists. Her scientific paper on the subject was initially rejected and ridiculed by journals and other scientists. She persisted and finally was successful in publishing the paper, which now is universally accepted by her peers. The paper added immensely to our knowledge of evolution and, for that, the scientific world is grateful.
The field of evolutionary biology traditionally depends heavily upon paleontological and biological observations. Margulis’s microbiological study of endosymbiosis added another supporting observation by which we can better understand how evolution works. When I first read about her research I was delighted. It was another great argument for believing in evolution.
Dr. Margulis believed endosymbiosis and symbiogenisis was more wide-spread in the animal and plant Kingdoms than other scientists believed. They accepted her thesis that endosymbiotic changes occurred in primitive single-celled organisms but she was lacking evidence that it also was prevalent in higher life forms. Margulis was ridiculed on her first breakthrough paper before it was accepted. Succeeding papers have also been ridiculed and she has been attacked for pushing her views too hard and disregarding conflicting information. Although I am not a scientist and cannot make a knowledgeable comment on these accusations, I can remind readers that Einstein, Galileo and others were totally wrong in some of their theories. Fortunately, some scientists live long enough to acknowledge and correct their mistakes. Unfortunately, some scientists do not. Perhaps Margulis’s greatest sin was that she died too soon.
Since Dr. Margulis’s break-though publication of her theory of endosymbiosis, her reputation has been tarnished by other opinions she had. I will not address them in this blog. She is currently the subject of heated debate in the scientific world due to these opinions and her “rough and tough” personality. She is the ex-wife of the noted astronomer Carl Sagan and mother of his son, scientific writer, Dorion Sagan. She was 73 years old.
I wonder what more she would have discovered had she lived longer?