Origins of Major Clades
From the first multicellular life to the ecological diversification of Aves, our research group explores the early evolution of both extinct and extant lineages. We study the pace and timing of the origination of interesting groups of animals through reconstruction of their phylogenetic relationships, biogeographic histories, and ecologies. Not only is our group interested in the phylogenetic origin of major groups of organisms, we are also interested in the origin of unique characteristics (apomorphies) of these important groups (e.g., the bird wishbone). With our collaborators, we are all interested in the drivers of these great evolutionary events.
Reconstructing the relationships of organisms remains one of the fundamental steps before reconstructing an organism’s paleobiology, biogeographic history, and ecology. Our group uses the latest phylogenetic reconstruction techniques and cutting-edge methods. More importantly, we focus on primary data collection as the first step in larger phylogenetic reconstruction; we focus on a specimen-by-specimen level.
Biotic Response to Global Changes
The Earth’s biota has evolved in response to both tectonic and climatic changes throughout geologic time. Our research group investigates the evolutionary patterns that emerge from the fossil record with respect to major transitions, such as the relationships between changes in taxonomic diversity, morphological disparity, and biogeographic distributions. By examining those patterns within an evolutionary and phylogenetic framework, we are able to analyze other secondary inferences, including biochronologic correlations, in a modern light.
The geologic timescale was built using discontinuities of faunas in the fossil record. We now know that five of these discontinuities correspond to the ‘Big Five’ mass extinctions in the Phanerozoic. Although the end-Cretaceous perhaps has garnered the most attention, there are still many questions to ask about the tempo and pace of all of these major Earth transitions. Particularly, our research group integrates specimen-level identifications, phylogeny, and paleoecological studies into examining both terrestrial and aquatic extinctions.
We are interested in improving our understanding of the taphonomic processes leading to exceptional preservation of soft-bodied organisms. In particular, we investigate how soft-bodied organisms are preserved through the processes of phosphatization, silicification, pyritization, kerogenization, and aluminosilicification. We integrate paleobiological, geochemical, mineralogical, and nanostructural data to analyze exceptionally preserved fossils and their hosting rocks in order to infer the geological conditions and processes that facilitate soft-tissue preservation.
A 1600-million-year-old eukaryote fossil with an intracellular structure (arrow in upper left panel) that tantalizingly resembles a nucleus but could be condensed protoplast in preparation for dormancy (Pang et al., 2013, Geobiology).