Lecture 21: Impacts and Extinction

We end our exploration of life on the Earth with a look at death in the fossil record. This lecture looks at the role asteroidal impacts have played in the history of the Earth, and their possible role in mass extinction events in the fossil record. We will discuss near-earth asteroids, historical impacts, and the K-T event in which a massive asteroid impact caused a mass extinction of species that included all non-avian dinosaurs among its victims, opening up the biosphere to the dominance of mammals. We'll look at other mass extinctions during the past 500Myr, and talk about whether extinction-class impacts are in our future. Recorded live on 2009 Oct 22 in Room 1005 Smith Laboratory on the Columbus campus of The Ohio State University.