| Abstract Detail
Deep Time: Integrating Paleobotany and Phylogenetics Soltis, Douglas E. [1], Soltis, Pamela S. [2], Herendeen, Patrick S. [3], Dilcher, David [4]. Deep Time: integrating paleobotany and phylogenetics. It is widely acknowledged that integrating fossils into data sets of extant taxa is imperative for proper placement of fossils, resolution of relationships, a better understanding of character evolution, and dating divergence times. However, the proper integration of fossils into data sets of extant taxa has been much debated. Fossils are to varying degrees incomplete and may have missing data relative to extant taxa. As a result, inclusion of fossils can lead to increased homoplasy, increased numbers of most parsimonious trees, and decreased resolution in phylogenetic analyses. Recent studies, such as those supported as part of Deep Time, have shown that despite concerns, fossil taxa may contain valuable phylogenetic information and unique combinations of plesiomorphic and derived character states. Furthermore, the inclusion of fossil taxa, even if fragmentary, can lead to a better understanding of character evolution and evolutionary relationships among extant taxa. Hence, the a priori exclusion of fossil data is unwarranted. Given that genes may evolve at heterogeneous rates in different lineages, simple clock-based approaches to estimating divergence times are likely to yield unreliable estimates. Recently, several approaches have been proposed that relax the assumption of a strict molecular clock: nonparametric rate smoothing, local clocks, penalized likelihood, Bayesian approaches, the Li-Tanimura method, and PATH. Recent research fostered as part of Deep Time have explored these methods and shown that these approaches often converge on what appear to be reliable age estimates for many clades. Case studies that (i) integrate fossil and modern taxa in phylogenetic analysis, (ii) estimate divergence times using fossil calibrations/constraints, or (iii) do both (i) and (ii) will be presented in this symposium.
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1 - University of Florida, Botany, PO Box 117800, Gainesville, FL, 32611, USA
2 - University of Florida, Florida Museum of Natural History, PO Box 117800, Gainesville, FL, 32611-7800, USA
3 - George Washington University, Biological Sciences, 2023 G St.NW, Washington, DC, 20052, USA
4 - University of Florida, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
Keywords:
paleobotany
phylogenetics
fossils
divergence time.
Presentation Type: Symposium or Colloquium Presentation
Session: SY08
Location: Stevens 4/Hilton
Date: Monday, July 9th, 2007
Time: 1:00 PM
Number: SY08SUM
Abstract ID:2037 |
