At the broadest level, I am interested in understanding the drivers of morphological diversification in organisms. I primarily approach this topic using seed plants as a study group, focusing on relationships between form and function in reproductive structures and asking how these interactions generate evolutionary patterns over million-year time scales. Properly answering these questions requires an understanding of the broader ecological, geological, and climatic contexts in which these changes are occurring, and I therefore use an integrative approach that incorporates techniques from paleontology, biogeography, and phylogenetics. My work particularly focuses on conifers because the group is diverse today but was also important in many ancient ecosystems, and the relationships between morphology and function can be directly tested in living as well as in extinct plants.
Andrew Leslie PI
aleslieb@stanford.edu
The evolution of different sexes and reproductive strategies is a complex topic in biology. This is especially true in plants, where the alternation of haploid and diploid generations has resulted in the evolution of a plethora of different sexual strategies among lineages. A critical evolutionary step in plant reproduction is the conversion of bisexual spores, which can function both as males and females, to sex-determined spores, which are either male or female. The evolution of this trait, in conjunction with differences in spore size called heterospory, has occurred many times in plant history, but the conditions favoring it remain largely unknown. By combining physical modeling with paleobotanical data and a molecular biology approach, I investigate the selective pressures acting on this transition and which genes might have been recruited to allow the evolution of difference sexes to take place.
Marco D'Ario postdoc
I am interested in the relationship between morphology and adaptation generally; how form changes to adapt to function, and what functions can be deduced from form. I use extant systems within botany, especially conifers, to explore relationships between morphology, disparity, function, and development in the context of reproductive biology. My current research at Stanford explores morphological disparity across ontogeny within conifer cones, specifically Cupressaceae, quantifying how disparity changes as seed cone functional roles shift from pollen capture to seed dispersal. This allows us to understand how developmental patterns and function may interact to generate morphological diversity.
Stepfan Huntsman graduate student
I am a palynologist, that is, I study fossilized pollen and spores! Previously I have worked on Permian-Triassic and Jurassic-Cretaceous palynology, but here at Stanford I'm excited to be exploring a new time interval and will be working on Silurian-Devonian palynology. My research will focus on how the evolution of terrestrial plants affected the marine redox record through palynology, paleobotany, and geochemistry (co-advised with Dr. Erik Sperling).
Emily Ellefson graduate student
I've worked with fossil plant material from the lower Miocene of New Caledonia, with the aim of understanding the diversity and paleoecology of ancient New Caledonian floras. In this process, I discovered exceptionally preserved epidermal cells and stomatal bands in a fossil conifer branch. My current project involves using light and SEM imaging of fossil and living Podocarpaceae cuticle to relate the fossil to extant conifer lineages in New Caledonia.
