Summary: Fossil diversity increased profoundly during the "Cambrian Explosion" with the evolution of complex life forms.  This diversity has waxed and waned since that time due to numerous factors but generally these factors are controlled by tectonic forces and the movements and locations of tectonic plates on the earth's surface.  Extinction driving forces include climate changes (both warming and cooling), volcanism, sea level changes, and large-scale impact events.  We will look briefly at the "Big Five" extinction events and what the fossil record tells us about which groups survived to produce the diversity we see on earth today.  

The lab will include a brief introduction and a chance to look at a collection (albeit somewhat limited) of mostly common fossils that represent which groups did or did not survive the big extinction events.  We'll do a quick review of how to identify common (primarily invertebrate) fossils and participants can explore fossil sets and try their hand at fossil identification.  There will also be the opportunity to identify a variety of Cretaceous microfossils from Montana using stereomicroscopes. 

Biography:  Jeff Thole is the Geology Laboratory Supervisor at Macalester College. He arrived at Macalester in 1996 after doing 5 years of environmental consulting. His work experience also includes spending a year as a geologist for the U.S. Geological Survey in Reston, Virginia. His primary duties include teaching introductory geology labs and maintaining, running, and user instruction for the instrumentation housed in the Macalester Science Division’s Keck Laboratory. Jeff received Master of Science in Geology from Washington State University in 1991 and Bachelor of Science in Geology from the University of Minnesota – Duluth in 1987.