Dear Earthlings:
Michael Maranets:
A Book Report on Microcosmos: Four Billion Years of Microbial Evolution
by Lynn Margulis and Dorion Sagan
Microcosmos by
Lynn Margulis and Dorion Sagan, provides a fascinating look at the life of
microbes as they evolved over the course of the planet’s history. The
experience of reading the book in the context of an Ecosexuality class has been
informative in many ways. The book itself is very heavily based in the
microbiology of evolution and tracing the path of the planets development to be
suitable for life in the first place. In the context of an Ecosexuality class
this has particular relevance because of the heavy emphasis of symbiosis at
every point in the book’s description of the evolution of the planet and the
evolution of the microcosm.
Similarly, the themes of this book certainly fit within
the broader scientific themes discussed within the class, particularly with
regards to the aforementioned symbiosis, the unappreciated or unacknowledged
role that microorganisms play in planet wide symbiosis and the contributions of
both towards Gaia Theory. Like the other books written by Margulis that have
been read for this class, Microcosmos
deals heavily with microbial symbiosis and the origins of sex. It is closer to Symbiotic Planet than Mystery Dance in terms of its content
and how it approaches the idea of symbiosis. In terms of style it is also
closer to Symbiotic Planet because it
does not deal with as wide-ranging a field of academia as Mystery Dance did, focusing instead entirely on microbiology. While
it does discuss the sex lives of bacteria and how the molecular basis for the
genetic exchange involved in sex arose, its focus is on a much more basic level
biologically than the emphasis on larger zoological discussions of eukaryotes
in Mystery Dance. I would also say it
is aimed at a more biologically literate reader than Symbiotic Planet was but that it is still readily accessible to
anyone who has taken even high school biology.
The detail given to the idea of symbiotic evolution is
much more thorough than anything previously encountered in this course. An
example of this can be seen as Margulis traces a likely mechanism for evolution
of the various energy generating systems within the microcosm that lead
eventually to aerobic respiration that we carry out and its tremendous
efficiency. In her discussion of how fermentation or the breakdown of sugars in
the absence of oxygen arose, Margulis describes the tremendous inefficiency of
this mechanism and how the final products of fermentation like ethanol and
acetate can still be used to harvest additional energy. The truth of the former
can be seen by the fact that humans are now increasingly looking at microbial
produced ethanol as a source of alternative energy to replace oils. In the
bacterial world what happened instead was that other microbes arose that could
take these molecules of fermentation products, utilize it in their own
metabolic pathways, and subsequently create products which the original
fermenting bacteria could then feed on themselves. This cycle of food and waste
between these symbiotic organisms is one of the first examples of intra-species
cooperation she posits in the history of life on this planet and is one that
continues to this day in places low on oxygen and light.
Another example she provides to describe the tremendous
importance of symbiosis in evolution showcases that even bacteria that we may
think of as being pathogenic may actually be symbiotic in other organisms. She
describes the problem faced by a researcher of amoeba (one of the most basic
forms of eukaryotic life) that had been plagued by outbreak of pathogenic
bacteria, which seemed to kill all of the amoebic samples in his lab. While
safeguarding a sample of uninfected amoeba in another researcher’s lab, the
scientist began selecting for amoeba that could survive the pathogenic
bacteria. Eventually he had large quantities of these amoeba that could survive
being infected by 40,000 bacterial cells. He then retrieved one of the original
samples and transplanted nuclei of the now immune cells into the original
strain and put the nucleus of original amoeba into these immune amoeba. What
happened was quite surprising. The amoeba, which continued with bacterial
infection but had a new genome via its transplanted nucleus, was able to
survive indefinitely. The samples that lacked bacteria but had the genome of
the amoeba that survived infection, started dying off without bacteria, and
only after he incubated the growth medium with the appropriate strain of
bacteria did these amoeba start surviving.
Given the title of the book, a large amount of time is
spent describing the intricacies of the microcosm. I think her argument for the
idea of ‘super-organism’ she alludes to in Mystery
Dance is laid out in its clearest form in Microcosmos. She describes the work of researchers who have argued
for a degree of consciousness of bacteria as they interact with each other. In
describing these bacteria, Margulis personifies them to be a collective all
working on the same problem akin to how humans now dedicate billions at genetic
problems like cancer that threaten our existence. But, she also goes on to
describe how this microcosmic ‘super-organism’ is responsible for all other
life on Earth and how our symbiosis with them is the most crucial aspect of why
other life more complex than bacteria arose. The first example of this she
gives is that of nitrogen-fixation in organic molecules. Turning the inert gas
nitrogen into the molecule that can be used as the primary backbone of all DNA
and proteins in all living things is extremely energy intensive. Humanity has
learned how to achieve this process for the production of fertilizer but it is
extremely energy intensive and would not be possible without fossil fuels. And
yet, one of the earliest bacteria evolved the ability to fix nitrogen into
molecules, which can be used by all organic life. The process is energy intensive
in these organisms too, which is why so few other organisms adopted this
evolutionary niche subsequently. The symbiosis that occurs as a result of these
nitrogen-fixers is two-fold. First, their symbiotic relationship in the roots
of all living plants allows these plants to grow in the first place. All
organisms that consume these plants and each other subsequently rely on the
nitrogen from these bacteria. Without the evolution of these bacteria, no other
life could have evolved and if something were to happen to these bacteria in
the present, all life on Earth would quickly cease.
The other major example Margulis gives of the symbiosis
of the ‘super-organism’ and other life is that of the planet’s oxygen rich
environment, which was not present for the majority of Earth’s existence. The
pursuit of the ‘super-organism’ to find ever more efficient sources of
electrons eventually lead them to the energy readily locked up in water. The
oxygen that enabled the rise of life larger than microbes was only possible
because of the waste products generated by the ‘super-organism’.
These ideas certainly fit within the class’s discussion
of Gaia Theory. As mentioned in Symbiotic
Planet, Gaia Theory is purely the observation of our planetary symbiosis
from the macroscale of space. The plethora of examples Margulis provides as to
the altruistic cooperation evidenced by bacteria in their evolution and the
consequences of their evolution for all other life certainly provide a
compelling argument for the view of Gaia Theory we have been discussing.
The organization of this book is very similar to that
scene within Mystery Dance. Margulis
proceeds in a chronological manner starting from the competing ideas for the
origins of life on the planet and then into the possible mechanisms for how
life continued to evolve using a progression through the microbial fossil
record before getting into the intricate beauty of reproduction and the genetic
recombination of DNA that defines it. The topics are wide-ranging within the
study of bacteria and life, but for the purposes of the class limited purely to
the symbiotic basis for Gaia Theory, which we have been discussing. The book’s
insight is particularly keen given it was written in 1986 before there was as
much evidence for many of the theories that Margulis provides in this book.
Published with permission
WGSS 3998 - Ecosexuality and the Ecology of Love
Prof. Serena Anderlini-D'Onofrio
U Conn, Storrs, Spring 2013
Dear Earthlings:
Let "nature" be your teacher in the arts of love. Education is the heart of democracy, education to love. Come back for more wonders: Book Reports to appear every other Thursday. Book Reports scheduled every other Thursday. Check out our summer offerings: Ecosexuality in Portland, OR, July 17-21. Info and Registration here!
Namaste,
Serena Anderlini-D'Onofrio, PhD
Gilf Gaia Extraordinaire
University of Puerto Rico, Mayaguez
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