Andrew Knoll is a paleontologist and Fisher Professor of Natural History at Harvard University. He studies the relationship of geological and biological perspectives on early life, and specializes in Archean and Proterozoic paleontology and biogeochemistry. In 2001, he co-wrote (with biologist Norman Myers) a paper about the evolutionary crisis he believes Earth is undergoing today. In 2009, he contributed to a New Yorker article on today’s biotic crisis, “The Sixth Extinction”.