Methods for the analysis of comparative data in evolutionary biology

Inferences regarding phylogenetic patterns and constraints on the evolution of characters often can be derived only from comparisons of extant species. If the phylogeny of these species is known, then the mean phenotypes of taxa can be partitioned into heritable phylogenetic effects and nonheritable residual components. Methods are presented for estimation of phylogeny-wide means of characters, the variance-covariance structure of the components of taxon-specific means, and the mean phenotypes of ancestral taxa. The covariance structure of phylogenetic effects provides a description of a macroevolutionary pattern, whereas that for the residual effects, when corrected for sampling error, is more closely related to a microevolutionary pattern. -from Author