Science Cafe Orlando

The Cambrian “Explosion” is a colorful name sometimes given to the adaptive radiation of animals with bilateral symmetry, seen in the early Cambrian period, approximately 540 to 510 million years ago. This critical span in life’s history has been a topic of keen interest for not only scientists but also many nonscientists ever since the publication of Wonderful Life by Stephen Jay Gould (1989). In that provocative work, Gould emphasized the bizarre morphology and problematic taxonomy of some of the invertebrate fossils of the Middle Cambrian Burgess Shale. In the twenty-plus years that have followed, new discoveries from the fossil record and the living world have been producing a better picture of early animal evolution, shedding light on the origins of some of the major branches on the animal tree of life (including arthropods, mollusks, and vertebrates). Furthermore, the explosiveness of this adaptive radiation has been defused by improvements in the record of Early Cambrian and Neoproterozoic (pre-Cambrian) fossils. Proposed causes of the Cambrian radiation are numerous and varied; in this talk we will explore the merits of the most prominent ideas.

John Werner has been a professor of Earth Sciences in the Physical Sciences Department at Seminole State College since 2003. He obtained a B.S. in geology from the California Institute of Technology and an M.S. and Ph.D. in geology (concentration in invertebrate paleontology) from the University of Illinois at Urbana-Champaign. While at UIUC, he earned that school’s highest award for undergraduate teaching. At Seminole State, he has originated three courses in geology, including Fossils and the History of Life.