October 27 2015

12:00 1100 Terasaki LSB

Daniele Silvestro
University of Laussane, Switzerland and University of Gothenburg, Sweden

Comparative methods without phylogeny: Estimation of macroevolutionary rates from the fossil record.


Phylogenetic comparative methods have progressed very rapidly in recent years and substantially improved our understanding of macroevolutionary processes, such as the tempo and mode of speciation, extinction, migration, and phenotypic diversification. These methods rely on dated phylogenies, which are mostly restricted to extant species. Since present biodiversity only represents a very small fraction of the organisms that have ever lived, inferring evolutionary dynamics exclusively from extant taxa, despite the methodological advancements, may have limited power or provide biased results. Here, I present PyRate, a suite of quantitative methods that allow us to analyze fossil occurrences and infer macroevolutionary processes, even in the absence of an explicit phylogenetic hypothesis. Paleontological data, despite their inevitable incompleteness, can be analyzed in this framework to reliably infer speciation and extinction rates and their temporal trends. Using case studies from plant and animal clades I demonstrate the power of the method to detect trait correlated diversification, selectivity in mass extinction events, and clade competition through diversity dependence. Building upon the PyRate framework, a new dispersal-extinction-sampling model is developed to tackle other key aspects in macroevolution, namely the spatial dynamics and historical biogeography of taxa. This approach uses fossils to infer \(a\)symmetric dispersal rates and area-specific extinction rates and their variations through time, while accounting for sampling biases. Analyses of simulated and empirical data show that fossil-based estimates outperform those obtained from phylogenies of extant taxa. In conclusion, quantitative analyses of fossil data, even when lacking a reliable underlying phylogeny, can provide important insights into macroevolutionary processes.











































































































































































































































































































































































































































































































































































































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