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Postdoctoral Fellow

Evaluating effects of temporal distribution of fossil calibrations on divergence analyses

PI(s):	N. Adam Smith
Start Date:	1-Nov-2011
End Date:	14-Nov-2014
Keywords:	molecular biology, morphology, paleontology, phylogenetics, systematics

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Attempts to explain the causes of major evolutionary events, such as the radiation that led to the staggering diversity of living birds (~10,000 species), have historically been based on broad-scale correlations with the timing of geologic and paleoclimatic events. Although the timing of ancient evolutionary events was traditionally a topic restricted to paleontological studies, estimating when lineages diverged from one another using molecular sequence-based methods has become a common practice. Recently, paleontologists and molecular systematists have begun working together to combine knowledge of the fossil record with information gleaned from molecular sequence data. This interdisciplinary approach holds great potential to produce refined estimates of the timing of evolutionary events; however, these relatively new methods are in need of refinement. How fossils are chosen and applied to analyses that date evolutionary events has emerged as a central issue with respect to the accuracy of those analyses. Often, the groups of organisms that biologists are most interested in estimating species divergences for, are groups with poor fossil records, thus the choice of fossils available for analysis is limited. My research aims to evaluate how these limitations, specifically the different ages of fossils used in divergence time analyses, may affect resulting estimates of the timing of evolutionary events. Methodological refinements that provide more accurate divergence estimates will facilitate detailed comparisons between species diversity through time and paleoclimatic records, potentially providing valuable insights to biodiversity conservationists.