Abstract Detail

Empirical Approaches to Phylogenetic Comparative Methods in Plant Science

Sanchez-Reyes , Luna Luisa [1], Morlon, Hélène [2], Magallón, Susana [3].

Multiple shifts in diversification and rate of origin of higher clades might explain species richness heterogeneity in flowering plants.

Underpinning the causes of species richness heterogeneity among clades is a long standing challenge in evolutionary biology. One of the main difficulties comes from the inability to disentangle effects between factors, establish correlations confidently and assigning causality. It has been recently pointed out that assuming a particular model of diversification might dramatically alter estimates of statistical correlations and thus the causal relationships inferred. Therefore, considering the true underlying model of diversification of a particular clade is crucial. Yet, this is not an easy task because it has been observed that within models of unlimited diversification, extinction is difficult to estimate in extant clades. Moreover, it has been suggested that models of limited diversification could better explain diversification dynamics. In this scenario, it is not diversification rate, but the macroevolutionary carrying capacity imposed by ecological factors, that determines the species richness of clades. There are numerous methods to evaluate models of limited and unlimited diversification based on model fitting approaches with maximum likelihood or Bayesian statistics. These methods are able to find the best model based on phylogenetic or taxonomic data. However, they can sometimes infer a best model that is not necessarily the true model. This can be evaluated with simulations and comparisons between statistical properties expected under simulations and the ones observed from empirical diversification processes. Using the simulation approach it has often been detected that best models not always behave as the empirical data, suggesting that the true underlying model might be very different from the best inferred one. An alternative hypothesis is that the simulation methods might not be optimal since they rarely take into account phylogenetic and taxonomic structure, two conditions whose magnitudes could impact the estimates of theoretical statistical properties of the evaluated diversification models. In this work we propose a simulation procedure that takes into account both phylogenetic and taxonomic structure to explore the correlation between age of clades and species richness under different diversification models in angiosperms. We found out that a model of diversification with multiple increases and decreases in diversification rates, heritability of these rates and a medium rate of origin of higher taxonomic clades accounts for the diversity patterns observed in extant flowering plants, evidencing the importance of taxonomic structure in the diversity patterns. We believe that this model is a small but important contribution to evaluation of diversification factors such as key attributes and ecological features.

1 - Instituto de Biología, UNAM, Departamento de Botánica, 3er Circuito de Ciudad Universitaria, Delegación Coyoacán, Mexico City, DF, 04510, Mexico
2 - IBENS, École Normale Supérieure, Umr 8197 Cnrs, 46 rue d'Ulm, Paris, 75005, France
3 - Instituto De Biologia, Universidad Nacional Autonoma De Mexico, 3er Circuito De Ciudad Universitaria, Del. Coyoacan, A.P. 70-233, Mexico City, Mexico D.F., N/A, 04510, Mexico

Keywords:
macroevolution
phylogenetic signal
taxonomic structure
angiosperms
simulations.

Presentation Type: Symposium or Colloquium Presentation
Session: C1
Location: Summit/Boise Centre
Date: Monday, July 28th, 2014
Time: 2:45 PM
Number: C1006
Abstract ID:380
Candidate for Awards:None