HOW IS BIODIVERSITY PRODUCED? MOVING FROM BIODIVERSITY PATTERNS TO SPECIATION PROCESSES DURING THE GREAT ORDOVICIAN BIODIVERSIFICATION EVENT

The accumulation of diversity is dependent on the production (and subsequent continuation) of new species, thus it is important to contextualize the Great Biodiversification Event (GOBE) as the sum of a series of individual speciation events. Studies of speciation processes are only beginning to emerge for the GOBE, but early analyses of brachiopods and other taxa suggest that such research questions are tractable given appropriate data sets and analyses. In order to understand the GOBE it is important to move from correlating diversity trends with environmental changes to explicitly assessing how correlative Earth system processes can facilitate the process and mechanisms of speciation. Explicit consideration of the hierarchical structure and biogeography of evolutionary processes provides a dynamic perspective to analyze speciation. Biogeographic processes of dispersal and vicariance provide the link between local and global diversity levels, and oscillations between these two biogeographic modalities can generate an effective speciation dynamo. Geographic isolation due to paleogeography, numerous interoceanic islands, tectonism, glacial-interglacial cycles, and newly developed habitat heterogeneity were likely key factors in promoting speciation. Understanding the processes that produced the GOBE will require careful consideration of the oceanic, climatic and tectonic processes operating during the early Paleozoic as well as the speciation process itself.