Our goal in research is to understand the interaction between environmental change and biological evolution using fossils and the sedimentary rock record. How does environmental change influence evolutionary and ecological processes? And conversely, how do evolutionary and ecological changes affect the physical environment? Our group is focused primarily on finding answers to these questions on two timescales: 1) the timescale of catastrophic extinction events and their immediate aftermaths (up to a few million years); and 2) the timescale of geological periods and eras (tens to hundreds of millions of years). Our research combines macro-scale, field-based work on the stratigraphy and paleontology of carbonate platforms with micro-scale, laboratory-based work on the petrography and geochemistry of individual limestone samples and mineral phases. In addition to field and laboratory study, We also compile literature-based data and use theoretical models to help constrain interpretation of field-based data and to determine the extent to which local biotic patterns reflect global processes.
Causes and Consequences of Mass Extinction
One primary focus of current research in the Paleobiology Lab is field-based examination of biological evolution and environmental change associated with the end-Permian extinction and its aftermath. We have used a variety of approaches to attempt to better characterize the cause(s) of mass extinction, to quantify the pattern and timing of extinction and recovery, and to identify connections between biological and environmental change through this important interval of Earth history.
One of the most important unsolved questions in the fields of paleobiology, evolution, and conservation biology is why some species go extinct while others survive. Patterns of extinction selectivity in the fossil record can shed light on the causes of mass extinction events, reveal differences in process between background and mass extinction, quantify the importance of selection above the species level in driving evolutionary patterns, and help us to predict which living species are at greatest risk of extinction.
Evolutionary Paleoecology and Paleophysiology
Numerous paleontologists have suggested that the total abundance (or biomass) of animals has increased substantially over the course of the past 550 million years, perhaps driven by gradual or episodic increases in nutrient supply and food availability. We have been working to quantify short-term and long-term changes in animal abundance and food requirements.
Evolution of Body Size
Research on the evolution of body size in the lab has grown out of observed shifts in maximum and mean size in gastropods and other higher taxa across the end-Permian mass extinction. Our goal is to use time-series of sizes in gastropods and other higher taxa to identify environmental and biological controls on body size evolution.