Many eukaryotes, pathogenic and free-living alike, encyst during their life cycle. How these various organisms sense their environment to determine when and where to differentiate is largely unknown. Our recent work on the intestinal parasite Giardia lamblia has demonstrated that intestinal bile and elevated pH deplete cholesterol rich lipid rafts from the parasite plasma membrane which upregulates cyclic adenosine monophosphate (cAMP) production and initiates encystation. I will present our recent work on the regulation of encystation in Giardia.

The study of systematics integrates diverse fields of biology including taxonomy, computational biology, genomics, and natural history collections. My research uses these approaches to address fundamental questions about the evolution of tropical plants. In this seminar, I will discuss two major research areas: (1) What processes govern the generation and distribution of tropical biodiversity and (2) are seemingly convergent morphologies produced through similar anatomical and molecular modifications and do they perform similar functions?

One of the most important innovations in land plant evolution was the development of a vascular system (the set of tubes that moves water and nutrients through the body). These conducting tissues amplified mass flow rates by orders of magnitude, allowing plants to increase their photosynthetic capacity, grow larger, and alter aspects of the terrestrial ecosystem including carbon dioxide sequestration and increased oxygenation, in turn, profoundly affecting the course of evolution for life on land.

Plants are amazing survival artists capable of enduring harsh environments and thriving in newly opened niches. My research seeks to broadly understand how environmental changes and biological interactions re-model the genealogical histories across the plant’s genome, with the aim of identifying key innovations responsible for adaptive changes. At the macroevolutionary scale, I will demonstrate how whole genome duplications buffered plants through a historical global warming, and how ancient gene flows created hyperdiverse clades in the neotropics and Chinese Hengduan Mountains.

How landscape change has shaped patterns of diversity on Earth is a central question in Biology. In Plant Systematics, a great volume of research on this problem has centered on how major geological events shaped the evolution of the Neotropical flora (the world’s richest flora). In this talk, I will show how I rely on natural history observations as a powerful tool for identifying plant groups whose biology make them ideal model systems for approaching long-standing questions from unexplored angles.