This seminar will look through the lens of earth history to explore drivers of change in the biosphere and the impacts of these changes. We will focus on episodes of mass extinction, and the spectacular landscape changes and speciation events which often followed. Abrupt or gradual climatic changes, massive volcanism, asteroid impacts, catastrophic carbon releases, and human activity will be evaluated as the causes of major extinction events in Earth history. The course will involve reading of scientific literature, student-led discussions, oral presentations and research projects, as well as potential field trips to sites in Southern Ontario. Restricted to first-year students. Not eligible for CR/NCR option.