February 28 2012

12:00 LSB 2320

Erika Edwards
Dept EE Bio, Brown University

A Clade’s Eye View of Plant Ecological Adaptation


We are interested in the origins of phenotypic diversity, and work at the intersection of phylogenetics, ecology, and organismal biology to reconstruct the natural history of adaptation. Questions that motivate us include: why have certain traits evolved multiple times in certain lineages but not in others? What are the initial steps in the evolution of a complex trait, and how do those initial steps influence subsequent evolutionary possibilities? How can we tease out the evolutionary history of adaptation from the broad ecological patterns that we see across the landscape? These are large, basic problems that are central to understanding all of life, though our focus is on flowering plants. In this talk I will focus on our recent work concerning two major plant adaptive syndromes: the evolution of extreme succulence, and the evolution of C4 photosynthesis. Both syndromes have evolved repeatedly and recently, making their global mark largely beginning in the Miocene and continuing to present day. A large-scale phylogenetic look at the distribution of these traits across all of flowering plants suggests that certain plant lineages have an increased propensity to evolve both syndromes, and it is likely that both succulent and C4 syndromes were selected for by a shared set of environmental drivers. A fine-scale phylogenetic look within one lineage allows us to more carefully consider the organismal details that would bias a plant toward one evolutionary outcome or the other. I’ll present our very preliminary work and outline our future directions in this area, focusing on the plant lineage Portulacineae (Caryophyllales). Preliminary data suggest that some very basic aspects of leaf anatomy could have acted as an evolutionary ‘tipping point’- leading to repeated convergence of classical succulent and C4 phenotypes from relatively similar evolutionary starting points.











































































































































































































































































































































































































































































































































































































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