When The Gaia Hypothesis melded with The Theory of Endosymbiosis
James Lovelock recently died July 22, 2022, at the age of 103 (1919–2022). This image from The EconomistSeptember 28, 2022: Brief update. Author Johanthan Watts, currenly writing an biography about Sir Lovelock, writes about his interviews: came from one of the many obituaries published around the world.
He was, I suppose, what many people might call a polymath. To say that his early life growing up in an English Quaker family was unconventional, and difficult, would be a huge understatement. He was recommended to the University of Manchester to study chemistry where he was then assigned to work at the Medical Research Council. In 1948 he received a PhD at the London School of Hygiene and Tropical Medicine. Lovelock was not only a scientist but an inventor much of his life; he alone funded much of his research. He was responsible for many of the instruments that NASA needed to explore the biospheres of other planets and later developed a detector that was capable of measuring the concentrations of CFCs (chlorofluorocarbons) that were responsible for destruction of the Earth’s ozone layer. For more on Lovelock’s biography please consult his Home Page.
Why does James Lovelock hold a special place in my scientific life and at a personal, philosophical level? In the late 1980’s I was late to read his book, the Gaia Hypothesis, “Named after the Greek goddess Gaia at the suggestion of novelist William Golding,[39] the hypothesis postulates that the biosphere has a regulatory effect on the Earth’s environment that acts to sustain life. “
Having grown up in a rural community I had everyday opportunities to observe plants, animals and insects during the changing seasons. I learned the hard way that wild animals were not suited for capture and handling by me. I quickly learned how easily a mourning dove could draw me away from her nest by feigning a broken wing, then fly away when I was less of a risk. I am still convinced that I saw one of the l ast den of the American red fox on the Southern High Plains that extended from the Western Canadian Prairies to the Texas Panhandle (my childhood home); extensive farming had reduced their habitats and that of the antelope except for a few local refugia. Plains Bison (buffalo) were gone many years earlier as were the people that depended upon them. Later living in Canada, I was fortunate to live near a national park reserve holding a herd of the northern subspecies, Wood Bison, colloquially called the Wood Buffalo. Native herds live protected in northern, boreal Alberta in Wood Buffalo National Park.
Embedded too was my maternal family lore that we carried the genes of indigenous peoples that were driven from their homes and onto reservations in Oklahoma. I gathered the history and photobooks of the Plains Indians. I did not cheer during movies when the US Calvary would rout and kill the Indians; DNA analyses leave this connection uncertain to this date, though I remain optimistic. While I was reared in a traditional conservative protestant home, I had this inexplicable sense that humans were only a part of a larger natural system which then I could not fathom, and still labour to do so. We were part of “Mother Earth”. For me, however, as put forth in Gaia, our system was not maintaining any sort of inherent homeostasis. Lovelock’s hypothesis was that humans were destroying the natural ebb and flow which had sustained our biosphere and we were destined to continue at our own peril; intensive research has demonstrated that since the mid-19th century industrialization has increased CO2 concentrations upward and continue to raise global temperatures that today are increasing atmospheric instability and greater frequency of extreme events.
Gaia, I believe, adopted as fact, and philosophically inviting, by many who were called “environmentalists”. Meanwhile prominent main stream scientists saw Lovelock as a person not to be taken seriously. Publications that were popular such as the The Last Whole Earth Catalog, which I had purchased in the early 1970s,possibly only diminished the scientific credibility of Gaia as a legitimate discipline by many scientists.
We now find out how Gaia and Endosymbiosis became mates in the science literature. Lynn Margulis (1938–2011) became interested in Lovelock’s “Gaia” and they began collaborating on a frequent basis. In 1973 Lovelock and Margulis published a paper entitled: “Atmospheric homeostasis by and for the biosphere: The Gaia hypothesis”. For that reason and their own unique individual research they are credited with the “Gaia hypothesis” as a model for the evolution of our biosphere. Here is a quote from their Abstract: “This paper offers an alternative explanation that, early after life began it acquired control of the planetary environment and that this homeostasis by and for the biosphere has persisted ever since.”.
At this point it is important to point out that near the same time Margullis’ Theory of Endosymbiosiswas put forward on the origins of modern eukaryotic organisms. My first introduction in the literature to those concepts by Lynn Margulis was welcomed because her hypothesis fit so well with what I then knew about higher plants. I was happy to find that she had early-on decided that in addition to the nuclear genome, plant cells contain chloroplasts and mitochondria and animal cells mitochondria. Thus both organelles were essential to the evolution of all organisms: consequently, higher plants possess three genomes and animals two. Eukaryotic cells were then able to evolve considerable autonomy after taking in those ancient single-celled, self-sustaining organisms, each containing copies of small DNA genomes. We can suppose possibly done so via a mechanism like Pinocytosis. This made perfect sense to me! It was in the 1980s when DNA analyses were being more widely used that her symbiosis theory became widely accepted; I was fortunate to participate in a peripheral way while attempting to study chloroplast DNA in the mid-1980s . Margulis’ ideas, much as Lovelock’s, were dismissed by many notable scientists at that time. Gaia and Endosymbiosis demonstrated the evolution of synergism and construction of biosystems at multiple levels in our biosphere. Therein was a kaleidoscope of genetic and phenotypic adaptation, encompassing molecular biology and systems ecology — earlier described by some scientists as holism and in German as, Ökologie.
“
https://www.open.edu/openlearn/science-maths-technology/biofuels/content-section-2.1
Chloroplasts are plant cell organelles “The
classic role of mitochondria”In 1967, Lynn Margulis (then Lynn Sagan) published an article entitled “On the Origin of Mitosing Cells” in the Journal of Theoretical Biology (Sagan, 1967 ). This publication did not have an auspicious beginning, reportedly having been rejected by more than a dozen journals before eventually finding a home (Archibald, 2014). Now, it is widely regarded as marking the modern renaissance of the endosymbiotic theory of organelle origins.” is oxidative phosphorylation, which generates ATP by utilizing the energy released during the oxidation of the food we eat. ATP is used in turn as the primary energy source for most biochemical and physiological processes, such as growth, movement and homeostasis.” How many of us recall in school the mitochondria being named the “cell’s power plant”? that convert light energy into relatively stable chemical energy via the photosynthetic process. By doing so, they sustain life on Earth. Chloroplasts also provide diverse metabolic activities for plant cells, including the synthesis of fatty acids, membrane lipids, isoprenoids, tetrapyrroles, starch, and …”.
Let’s close by having a brief look at the organelles that have been such essential and necessary ingredients to sustaining life on Earth.
Plant Chloroplast
Mitochondria
Finally, here is an excerpt of a 50th anniversary review of Lynn Sagan’s work (she was married to Carl Sagan at that time):
Thank you very much for taking your time to read my writing.
You can reach me at zackflorence2016@gmail.com. Here is a link to my profile: https://sites.google.com/view/zackflorencebiosketch/
Originally published at https://medium.com on September 28, 2022.
