IGA/CGA KEYNOTE ADDRESS Friday 17th February 2012 The origin of animal ecosystems: integrating the Cambrian Explosion and Ordovician Radiation Professor Dave Harper (
[email protected]) Department of Earth Sciences, Durham University, Durham DH1 3LE, UK The Cambrian Explosion and the Great Ordovician Biodiversification Event (GOBE) marked two major turning points in the history of life. Although animals originated deep in the Neoproterozoic, some 13 animal phyla appeared for the first time during the early to mid Cambrian, many exceptionally preserved in Lagerstätten, for example Sirius Passet, and many representing some quite remarkable and bizarre body plans such as Anomalocaris, Hallucigenia and Opabinia. A modern-style marine ecosystem was already in place but that must wait some 30 million years before real biodiversity characterized community structures. During the GOBE, an interval of some 35 million years, accelerating inter-provincial (aided by dispersed continents), inter-community (migrations into deeper water) and intra-community (a narrowing of ecological niches) diversity generated a marked biodiversity spike in the later Ordovician. Traditionally both events have been viewed as discrete biotic radiations. New biodiversity trajectories for Late Precambrian - Palaeozoic biodiversity suggest that both can be placed in a sequence linking the soft-bodied ecosystems of the Neoproterozoic Ediacaran with the complex Devonian Nekton Revolution. Ecological factors, such as the escalation of predation, were major drivers of this biodiversity change. SHELL SPONSORED KEYNOTE ADDRESS Saturday 20th February 2012 On the link between climate and hominin evolution Professor Dick Kroon, University of Edinburgh, J.C.A. Joordens, University of Leiden, H.B. Vonhof, Vrije Universiteit, S.Jung, University of Edinburgh, D.