Inferring the Dynamics of Diversification: A Coalescent Approach
Each bar represents the probability—measured as the Akaike weight—that the phylogeny arises from the corresponding model, among the set of nine models considered. The phylogeny of the genus Bursera, comprising 73% of known species in that genus, overwhelmingly supports Model 2. Thus, the Bursera phylogeny is consistent with the hypotheses that diversity is saturated and that the turnover rate varies over time. The phylogeny of the genus Bicyclus, comprising 68% of known species, is consistent with the hypotheses that diversity is expanding and that speciation rates vary. The phylogeny of the genus Cicindela, comprising 84% of recognized species, is also largely consistent with the hypotheses that diversity expands and rates vary. However, the dynamics of diversification are less clear-cut in the Cicindela phylogeny, because models with saturated diversity and constant rates also have positive probabilities. Although there is high confidence for the presence of extinction in the phylogeny of Bursera, models with or without extinction are about equally likely in the phylogenies of Bicyclus and Cicindela. Models with time-varying diversification rates are written in blue text.