January 26 2015

11:00 158 Hershey Hall

Jeremy Beaulieu
National Institute for Mathematical and Biological Synthesis, University of Tennessee

Exploring heterogeneity in flowering plant evolution


Biologists now have the capability of building large phylogenetic trees consisting of tens of thousands of species, from which important comparative questions can be addressed. However, to the extent that these large trees have been applied to comparative data of large flowering plant clades, it is clear that current methods make unrealistic assumptions about how traits are modeled. For instance, as phylogenies increase both in size and taxonomic scope it is likely that the lability of a trait will differ significantly among lineages. Here, I will describe how a new generalized model, which I refer to as the "hidden rates model" (HRM), can be used to identify different rates of growth form evolution along different branches of a phylogeny. I will demonstrate how this model can also quantify hidden evolutionary "flexibility" of contemporary species, and I will show how this novel measure can provide new insights into the construction of the Hawaiian Island Flora. Finally, I will argue that at greater phylogenetic scales it is increasingly difficult to confidently view any particular character as the underlying cause of increased diversification rates. I will propose one way forward, using the evolution of fruit type as an example. On the whole, examining evolution at across larger, older, and widespread clades is invaluable for validating new approaches, assessing confidence in relationships, and identifying gaps in our knowledge.















































































































































































































































































































































































































































































































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