Download Writing Assignment - Jackie`s SLCC education

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Jackie De Jesus
Biology 1010
Writing Assignment
The theory on the origin of eukaryotic organelles was founded by Lynn Margulis. Lynn is
best known for this and also her contributions to the endosymbiotic theory. The endosymbiotic
theory explains how certain organelles were formed. Lynn Margulis attended the University of
Chicago, received her master’s degree from the University of Wisconsin-Madison in 1960 and
received her Ph.D from UC Berkeley in 1963.
Lynn was also associated with the Gaia hypothesis, based on an idea developed by the
English environmental scientist James Lovelock. After having her theoretical paper rejected by
many journals, The Origin of Mitosing Eukaryotic Cells, it was finally accepted by The Journal
of the Theoretical Biology, and to this day is a landmark in modern endosymbiotic theory.
In the late 1960's, at the same time that the Gaia Hypothesis was first being stated,
Margulis first put forward her creative theory of endosymbiosis. When it was first formulated,
the concept was so new and required such a degree of leading edge specialized information, that
it was often completely misunderstood, not only by researchers in unrelated fields, but also by
her peers. Margulis’s endosymbiotic theory was formulated in 1966, was interdependence and
cooperative existence of multiple prokaryotic organisms.
In this theory one organism engulfed another, yet both survived and eventually evolved
over millions of years in to eukaryotic cells. This formulation is the first to rely on direct
microbiological observations. Effectively, Lynn Margulis contended that symbiosis, not chance
mutation, was the driving force behind evolution and that the cooperation between organisms
and the environment are the chief agents of natural selection.
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Endosymbiosis attempts to specify the relationship between organisms which live one
within another in a mutually beneficial relationship with one serving as a host cell (the boss cell)
and another the symbiont (the dependent organism) which resides within the host cell. Lynn
proposes that the ancestors of eukaryote cells were symbiotic consortiums of prokaryote cells
with one or more species (endosymbionts) involved. As they became more interdependent an
obligatory symbiosis evolved.
Eukaryotic cells originated in a symbiosis between several prokaryotes that continued to
live on as organelles within the new type of cell. The two kinds of organelles-mitochondria and
chloroplasts regulate the complementary respiration requirements of animals and plants. Lynn
Margulis is famous for her tenacity in pushing her theory forward, despite the opposition she
faced at the time.
After researching Lynn Margulis and the theory she concluded about evolution I
remember learning in class about the definitions of theory, fact, hypothesis, evolution, etc.
Margulis opposed of any competition on her view of evolution compared to others views and
focused on the importance of symbiotic theory to share relationships between species. This was
also around the time when we discussed the many theories discovered, like for example
Darwin’s and Lamacks.
Later Lynn formulated a theory to explain how symbiotic relationships between
organisms of often different phyla or kingdoms are the driving force of evolution. She then
proposed that genetic variation is to occur mainly as a result of transfer of nuclear information
between bacterial cells, viruses, and eukaryotic cell. Lynn Margulis has much personal and
professional recognition given to her for her knowledge, ambition, and great achievements of
evolutionary biology.
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Works Cited
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http://www.mountainman.com.au/gaia_lyn.html
Section 3: Dr Lynn Margulis
Microbiological Collaboration of the Gaia Hypothesis
Web Publication by Mountain Man Graphics, Australia in the Southern Autumn of 1996
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http://en.wikipedia.org/wiki/Lynn_Margulis#Professional_recognition
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http://en.wikipedia.org/wiki/Lynn_Margulis#Research
Lynn Sagan (1967). "On the origin of mitosing cells". J Theor Bio. 14 (3): 255–274.