Lynn Margulis illustrated the importance of bacteria to the study of life using slides, her video "Gaia to Microcosm" and excerpts from her book "What is Life" to a packed crowd in 3 Rockefeller Center yesterday afternoon.
Margulis rejected the idea of a possible answer to the question "What is life?"
But she did explain the minimum ingredients which would make a material living -- a simple system of genetic materials and minerals.
Her pursuit of an answer to the question: "What is life?," has been complicated because so few books address the issue, she said..
"Apparently, biologists take life for granted," she said. She said most biologists fail to recognize the interdependence between philosophy and the sciences.
But Margulis was able to offer a brief history of life.
Life began in the Archean period, three billion years ago with the formation of bacteria, she said.
Margulis said the root of life is symbiosis or "the long-term physical association between members of different species."
New organisms evolve from prior symbiotic relationships, she said. "Symbiosis is the author of the book of life, while [Darwin's] natural selection is the editor."
After establishing the roots of life, Margulis showed life in action.
Her video showed different kinds of bacteria, all set to music. She explained the life processes demonstrated in each frame.
Margulis showed the awakening of oxygen-producing bacteria. When sprinkled with water, the string-like parts of the bacteria expanded and extended.
Margulis said the behavior of bacteria is similar to that of all living organisms. Like a bear or a vulture, one type of bacteria in a video preyed on a lower form, devouring it from the outside in, and then growing within its remains .
In another part of the video, Margulis showed the bacteria's acts of survival. When threatened, a group of bacteria gathered together to form a large tower.
She said those that do not join the others will not survive, and likened this to how humans form committees.
Margulis also showed bacteria whose motions can be associated with those of animals. The audience laughed in response to the behavior of the "dancing plasmotea," whose name comes from the bacteria's dance-like motion.
Margulis also broadened her discussion of life from bacteria to the planet earth. The planet is a constantly changing biosphere, she said.
One of her slides showed "the rising earth" as viewed from space. She said the picture allows people to understand the planet itself as a living organism.
Although she did not answer the question: "What is life?" in her speech, she offered what she called a "quippy answer" when asked by an audience member in the question and answer session.
"Life is a material system that ... is capable of choice," she said.
