THE FAMED THEORIST INTEGRATES SYMBIOSIS WITH THE GAIA HYPOTHESIS
Lynn Margulis (1938-2011) was an American evolutionary theorist and biologist. (She was also married to Carl Sagan from 1957-1965.)
She wrote in the Prologue to this 1998 book, “‘Mom,’ what does the Gaia idea have to do with your symbolic theory?’ asked my son Zach… ‘Nothing,’ I immediately responded, ‘or at least nothing as far as I am aware.’ I have been pondering his question ever since. The book you hold in your hands attempts to provide the answer… This book is about planetary life, planetary evolution, and the ways our views of them are changing… it concerns exploration, specifically scientific exploration, and the many quirks and agenda that can nurture or block it… My claim is that, like all other apes, humans are not the work of God but of thousands of millions of years of interaction among highly responsive microbes. This view is unsettling to some. To some it is frightening news from science, a rejectable source of information. I find it fascinating: it spurs me to learn more.”
She explains, “Symbiogenesis, an evolutionary term, refers to the origin of new tissues, organs, organisms---even species---by establishment of long-term or permanent symbiosis… Symbiosis… is crucial to an understanding of evolutionary novelty and the origin of species. Indeed, I believe the idea of species itself requires symbiosis… No species existed before bacteria merged to form larger cells including ancestors to both plants and animals… In this book I will explain how long-standing symbiosis led first to the evolution of complex cells with nuclei and from there to other organisms…” (Pg. 6)
She recounts, “That animal and plant cells originated through symbiosis is no longer controversial. Molecular biology… has vindicated this aspect of my theory of cell symbiosis… But the full impact of the symbiotic view of evolution has yet to be felt. And the idea that new species arise from symbiotic mergers among members of old ones is still not even discussed in polite scientific society. Here is an example. I once asked… paleontologist Niles Eldredge whether he knew of any case in which the formation of a new species had been documented… He could muster only one good example: Dobzhansky’s experiments with Drosophila, the fruit fly. IN this fascinating experiment… fruit flies bred at progressively hotter temperatures, become genetically separated. After two years or so, the hot-bred ones could no longer produce fertile offspring with their cold-bred brethren… it was later discovered that the hot-breeding flies lacked an intracellular symbiotic bacterium found in the cold breeders Eldredge dismissed this case as an observation of speciation because it entailed a microbial symbiosis!... I could say… that symbiogenesis is a form of neo-Lamarckianism. Symbiogenesis is evolutionary change by the inheritance of acquired characteristics.” (Pg. 7-9)
She asserts, “I am fond of bragging that we, my students and colleagues, have won three of the four battles of serial endosymbiosis theory… One major, contentious issue remains: how did the swimming appendages, the cilia, originate? Here is where most scientists part company with me… The key idea… is that cilia, sperm tails, sensory protrusion, and many other appendages of nucleated cells arose in the original fusion of the archaebacterium with the swimming bacterium. I predict that within a decade we will win this argument: eventually we will be four for four!” (Pg. 38-39)
She acknowledges, “May Taylor is not unfair when he labels me a radical symbiogeneticist and dubs my version … ‘extreme.’ Why? In spite of slim evidence, I still believe swimmer organelles began by symbiogenesis.” (Pg. 41) Later she adds, “I still hope that the final … postulate will prevail. Many colleagues have told me to give up.” (Pg. 46)
She notes, “Sex, like symbiosis, is a matter of merging. But it is also a matter of periodic escape from the merger. Sex can be understood as a very special case of symbiosis: both sex … and symbiosis, merging of symbolic partners, produce new beings… But cell symbiosis is a deeper, more permanent and unique level of fusion. In the great cell symbiosis, those of evolutionary moment that led to organelles, the act of mating is, for all practical purposes, forever.” (Pg. 103)
She explains, “The term ‘Gaia’ was suggested to [James] Lovelock by the novelist William Golding… The ancient Greek word for ‘Mother Earth,’ GAIA provides an etymological root of many scientific terms, such as GEOlogy, GEOmetry, and PANgaea. The name caught on all too well. Environmentalists and religiously inclined people, attracted to the idea of a native goddess with power, latched on to it, giving Gaia a distinctly nonscientific connotation... Many scientists are still hostile to Gaia, both the word and the idea, perhaps because it is so resonant with anti-science and anti-intellectual folks. In popular culture… Gaia… will supposedly punish or reward us for our environmental insults or blessings to her body. I regret this personification.” (Pg. 118)
She concludes, “We people are just like our planetmates. We cannot put an end to nature; we can only pose a threat to ourselves. The notion that we can destroy all life… is ludicrous. I hear our nonhuman brethren snickering: ‘Got along without you before I met you, gonna get along without you now.’ … The tropical forest trees are … waiting for us to finish our arrogant logging so they can get back to their business of growth as usual. And they will continue their cacophonies and harmonies long after we are gone.” (Pg. 128)
This book will be of great interest to those interested in creative ideas in biology and evolution, as well as those interested in the GAIA hypothesis.