Inferring patterns of diversification

Article By:

Moore, Brian R. Department of Ecology and Evolutionary Biology, Environmental Science Center, Yale University, New Haven, Connecticut.

Last reviewed:2008

DOI:https://doi.org/10.1036/1097-8542.YB081830

Episodes of prolific cladogenesis (branching of new species from common ancestral lineages), adaptive radiation (rapid speciation of an ancestral lineage to fill diverse ecological niches), species selection (differential success of lineages owing to species-intrinsic properties), key innovations, and mass extinctions are a few examples of evolutionary phenomena involving differential rates of diversification (speciation minus extinction rate). Although traditionally based on patterns of fossil diversity chronicled in the paleontological record, the study of diversification increasingly relies upon information from phylogenetic analyses of extant species (estimates of evolutionary relationships that collectively comprise the Tree of Life). Tremendous technical progress in the generation of molecular sequence data and parallel theoretical, methodological, and computational advances in the analysis of those data have wrought an exponential increase of ever more reliable phylogenetic trees. Depending on the nature of the data and methods of analysis, phylogenetic trees can provide two sources of information relevant to the inference of diversification rates (Fig. 1): topological distribution of species diversity across branches of the tree and temporal distribution of branching events through time. These phylogenetic observations can be compared to expectations generated under various null models to explore numerous evolutionary phenomena.

The content above is only an excerpt.