I am broadly interested in the evolution of form in organisms. My work focuses on plants, particularly their reproductive structures, and combines techniques from the study of fossils, phylogeny, biomechanics, and the biology of living species in order to understand the processes that give rise to diverse morphologies. In this talk, I discuss several projects that illustrate these themes and focus on the evolution of reproductive cones in conifers, a group of plants with a global current distribution and an extensive fossil record stretching back 300 million years. I show how a unique pollination mechanism based on flotation links pollen shape with cone orientation over millions of years, resulting in correlated patterns of trait evolution. I also explore how the evolution of animal communities is likely responsible for the current range of conifer cone shapes and sizes. In particular, the fossil record suggests that changes in conifer cones over their history represent specializations for either increased seed protection from animals or more effective seed dispersal by animals. Both fossils and time-calibrated molecular phylogenies indicate that these shifts began in the Middle Jurassic (~170 million years ago) and accelerated with the diversification of small-bodied birds and mammals. The cones of living conifers can then be thought of as an unexpected record of major changes in terrestrial ecosystems over past 150 million years.
Dr. Andrew Leslie is an Assistant Professor in the Department of Earth and Planetary Sciences at Stanford University. After completing his undergraduate degree at Penn, he received a Ph.D. at the University of Chicago and conducted postdoctoral work at Yale University. Much of his work has focused on conifers, integrating phylogenetic analyses with data from the fossil record and insights from modern plants to better understand the drivers of morphological diversification. His research also includes field and specimen-based paleobotany, with projects focusing on the Jurassic of Argentina and the Cretaceous of Mongolia.
Location: Carolyn Hoff Lynch Lecture Hall