Dr. Andrew Knoll is the Fisher Professor of Natural History in Harvard University’s Department of Organismic and Evolutionary Biology, where he studies ancient life, its impacts on the environment, and how the environment, in turn, shaped the evolution of life. In recognition of the 200th anniversary of Charles’ Darwin’s birth and the 150th anniversary of the first printing of his book, “On the Origin of Species”, the American Society for Microbiology has invited Dr. Knoll to deliver the opening lecture, titled “Microbes and Earth History,” at the society’s general meeting in Philadelphia this year.

Before the dinosaurs, before trees and leaves, before trilobites, there were microbes. Vast, slimy layers of them covered the rocks and peppered the seas of the harsh, alien planet we now call Earth. Those slimy cells were our ancestors, and they played a defining role in changing that once-barren moonscape into the world we see today: a planet covered with diverse, striving life, topped by an oxygen-rich atmosphere. Dr. Knoll says he puts on his paleontologist’s hat and studies the fossil record to learn more about this ancient life, then he dons his geochemist’s hat to reconstruct Earth’s environmental history from the chemical signatures he finds in ancient sedimentary rocks. He weaves these two stories together to figure out how life has transformed the planet and how the planet has influenced the course of evolution.

In this interview, I talk with Dr. Knoll about what early earth must have looked like, his involvement with the Mars rover project, and how intelligent design concepts may well belong in high school curricula, but not in the context of science class.