Grant: Discovery Grants Program - Individual

The Cambrian, Ordovician and Silurian periods (ca. 542-416 million years ago) were times of dramatically changing climate, sea level, and biodiversity. The second biggest mass extinction event in Earth history occurred near the end of the Ordovician Period and was responsible for the disappearance of approximately 85% of the species living at the time. The most important animals in the fossil record of marine plankton during these time periods was the graptolites, a group of extinct hemichordates. They were abundant, geographically widespread and evolved relatively rapidly, which means that they are excellent fossils for identifying short intervals of geologic time and correlation of those intervals over large areas of the globe. A thorough understanding of the classification, evolution, and paleobiology of these organisms, and their distribution within sedimentary strata maximizes our potential to use them to solve geological problems in areas such as tectonics and sedimentary basin history, as well as to help reconstruct the history of life. My research program has several major objectives: 1) to reconstruct the evolutionary history of graptolites and other hemichordates, using extraordinarily well-preserved fossils, such as those of the Burgess Shale (British Columbia) and the Cape Phillips Formation (Nunavut); 2) to understand the history of change of graptolite biodiversity as a result of changing rates of species origination and extinction, particularly through the cycles of climatic and oceanic changes that characterized the Ordovician and Silurian periods; 3) to study the physical and chemical record preserved in rock strata to better understand the paleoenvironmental cycles and their causes; 4) to use the study of graptolites and their occurrences in sedimentary strata to improve the resolution with which we can define and subdivide geological time. By improving our resolution of geological time we can gain clearer insights into the timing of events and rates of evolutionary and paleoenvironmental processes.