microbial planet

Astrobiology | AM: This year marks the twentieth anniversary of the publication of Microcosmos, which you co-authored with your son Dorion Sagan. You expressed some ideas that at the time were considered pretty maverick. How much controversy did the book generate?

Lynn Margulis: Well it depends on which aspects. The idea that the Precambrian, that is from 4600 million years ago to 541 million years ago, 7/8ths of the entire fossil record, was empty, that nothing happened for all that time, that the fossils were so scarce that you couldn't trace lineages - that idea prevailed such that Stephen Jay Gould said it relatively recently before he died. It was overturned almost exclusively by the science supported by this guy Dick Young. He started as an embryologist, and he started funding non-human NASA biology.

Young had a great deal of insight. He funded people like Elso Barghorn, the professor at Harvard who in 1954 published a paper describing two billion year old plants from the Gunflint chert. They weren't plants, of course, they were bacteria, but at the time the world was divided into plants and animals and there wasn't any choice. Young funded the whole activity that started as exobiology - today it's more astrobiology than exobiology - that completely turned around that idea. And I was privileged to be involved with those people as these data were coming in on the evidence for early life.

Our book is very microbe-centric. The world is very anthropocentric. What we did was sort of turn it around, put the people on the bottom and the microbes on the top as far as their importance in running the ecological system of the Earth. We said people are totally late, typical animals, and are really very unimportant in the workings of the system, whereas the microbes are much earlier, they do all the major gas transformations, they created all the major things we think are important, like sex. Today we might say that this turnaround - people down and microbes up in a world that has always had people up and microbes down -is a strategic perceptual shift. As humans, you can't escape your human perspective. We have a more nuanced view than we had in Microcosmos. On the other hand, at the time it was absolutely necessary to make that shift toward microbial perception because of the skewed anthropocentrism that was driving everything.