Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

On the eve of the Cambrian animal radiation: the Ediacaran fossil record and its implications for the early evolution of complex life forms and ecosystems

Shuhai Xiao

Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA; xiao@vt.edu

Abstract

The phylogenetic diversity and ecological complexity of the biosphere before the Cambrian explosion are poorly understood. The Ediacaran Period documents an important evolutionary episode just before the Cambrian explosion and preserves critical information about the early evolution of complex life forms and ecosystems. Although the interpretation of Ediacaran fossils can be challenging, the fossil record offers the only direct window into the biosphere on the eve of the Cambrian explosion. I will examine several case studies to elucidate the phylogenetic diversity and ecological complexity of the Ediacaran marine ecosystems. The Ediacaran fossil record seems to show that the Ediacaran biosphere was phylogenetically diverse but ecologically simple. A wide range of organisms, including various algae, protists and stem-group animals with exotic bodyplans, are represented in the Ediacaran fossil record. But the Ediacaran marine ecosystems were relatively simple, dominated by epibenthic osmotrophs, shallow deposit feeders and grazers, but few if any predators. This ecological simplicity may, in part, accounts for the evolutionary patterns of Ediacaran organisms.

Shuhai Xiao

Professor of Geobiology, Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA

Biography

Prof. Shuhai Xiao received his BSc and MSc degrees from Peking University and PhD from Harvard University. He is currently Professor of Geobiology at Virginia Polytechnic Institute and State University (also known as Virginia Tech). His research focuses on the Precambrian evolutionary history of eukaryotic life, including early animals. He is also interested in the application of geochemical proxies to reconstruct the environmental context of critical evolutionary innovations. His current research involves field investigation in South China and Arctic Siberia. He is a fellow of the Paleontological Society and was the 2006 recipient of the Charles Schuchert Award.