Acclaimed biologist Lynn Margulis presented her once-divisive theories about evolutionary biology and gave her personal rendition of the history of primitive evolution at yesterday's Richard E. Synder Presidential Lecture.
Margulis, a professor at the University of Massachusetts (UMass) Amherst, has been criticized for promoting the theory of symbiogenesis, which contends that many early life forms took shape and developed not as independently evolving organisms, but as symbiotically interacting individuals. That is, bacteria and other Precambrian forms of life evolved to some degree as a result of the interactions they had with other organisms.
In yesterday's lecture, held in a tightly-packed Cabot Auditorium, the poetry-loving biologist sprinkled quips into her discourse and interacted with the audience by asking questions, portraying an interactive but professorial lecture style.
The goal of the Snyder Presidential Lecture Series, which began with a donation from Richard Snyder (A '55) in 2004, is to bring speakers to campus once a semester who challenge conventional wisdom in their fields.
University President Lawrence Bacow said in his introductory remarks that Margulis certainly met this criterion.
"Lynn Margulis fits this description, I think, extraordinarily well," he said. "Lynn is a scientist who was viewed skeptically for many years for the theory which she expounded."
Bacow explained that today, her theory of symbiogenesis has become more widely accepted, though it is still somewhat controversial. One reason for the controversy is that symbiogenesis challenges one of the fundamental tenets of neo-Darwinism, which states that natural selection is the primary mechanism of evolution.
"I am not a neo-Darwinist," Margulis clarified yesterday. "I am a Darwinist."
Bacow summed up the biologist's complex theory in his introduction.
"Margulis has proposed that an inherited variation of a species does not come mainly from random mutation, but instead evolves through the associations of members of different species, or - and I love this phrase - the 'long-lasting intimacy of strangers,'" he said.
Once at the podium, Margulis only gave a brief overview of this once-revolutionary theory.
Instead of expounding on it, she spent a great deal of time explaining the history of cellular evolution through a detailed PowerPoint presentation and stressing that symbiosis, the interaction between organisms living in close physical association, is essential to this process.
She emphasized that while many people believe that the Archean Eon - the time period that ended around 2.5 billion years ago - is too prehistoric and therefore ignore it, one must go back to this era to understand the birth of the building blocks of life.
"If you don't remember anything else I say, remember that everything important evolved during this first period," she said.
On the subject of natural selection, a topic she touched upon when describing the components of evolution, Margulis stressed that the process cannot be fully understood without taking environments into consideration. This point echoed her overarching emphasis on the importance of interaction between different forms of life.
"[We] cannot talk about [natural selection] unless we are talking about the conditions: when and where and the effect of the environment on members of the population," Margulis said.
She also explained scientist Jim Lovelock's Gaia hypothesis, which states that all aspects of the Earth's atmosphere and surface sediments are regulated by the activities of over 30 million types of living organisms.
"Neo-Darwinists believe this [regulation occurs] by chance alone," she said, explaining that she disagrees and instead illustrated the way in which organisms and the greater environment live symbiotically.
"Organisms are actively maintaining and regulating the environment to which they respond," she said. "It's a dialogue and it's not by chance alone. Earth has a physiology; from many different angles, one can see that the Earth is a living planet, unlike its dead neighbors, Mars and Venus."
Margulis showed various photographs, graphs, some comic illustrations and a few videos. At one point, she decided to interrupt the lecture for over five minutes, called over a technology assistant and fiddled with her computer in order to ensure that the audience could hear the background music for a video demonstrating marine biology research.
Margulis' famous claim that symbiogenesis has played a central role in evolution can be seen as a type of extension of her theory of endosymbiosis.
The theory of endosymbiosis, for which Margulis came under fire, states that mitochondria, the power plants that generate most of a cell's chemical energy, once existed as freely living organisms. It was only when these mitochondria came into contact with other species that they combined to form the cells that are now the building blocks of life.
Endosymbiosis is now accepted as fundamental truth.
Audience members felt that Margulis' speech was broader than standard scientific research presentations.
"Margulis painted a big picture of evolution," Assistant Professor of Philosophy Patrick Forber said. Forber teaches a course, "Biology and Society," that deals with the philosophy of evolutionary biology.
Senior biochemistry major Jordan Jastrab agreed with Forber. "If you were hoping to get a biochemistry background out of her speech, she didn't really go that in-depth," he said. "But she made some very interesting points about a less-traveled path in research that we don't have a lot of background in."
Sophomore Becky Baumwoll felt the speech was an attempt by Margulis to challenge and reframe our understanding of evolution.
"She was telling us what the conventionalists have done wrong," Baumwoll said.Overall, audience members seemed satisfied with the speech.
"She made a clear presentation of her heterodox and challenging views, though they are a departure from the mainstream," Forber said.
Giovanni Russonello contributed reporting to this article.
