Helz Lecture - Andrew H. Knoll from Harvard University - 4/4/24

George and Rosalind Helz Distinguished Lecture in Geology at the University of Maryland

with

Dr. Andrew H. Knoll
Fisher Professor of Natural History and Professor Emeritus of Earth and Planetary Sciences at Harvard University

"The Deep History of Life”

Fossils of shells, bones, tracks and trails record a history of animal evolution nearly 600 million years in duration. Earth, however, is 4 and a half billion years old. What kinds of organisms characterized our planet's youth and middle age? And how do we establish the nature of life and environments on the early Earth? The paleontological record shows that life has been present for most of our planet's history and that for most of that history, life was microbial. Animals are evolutionary late comers, radiating only during an interval of pronounced environmental change more than 3 billion years after the first microorganisms initiated Earth’s evolutionary odyssey.