Cladistic Analysis and Synthesis: Principles and Definitions, with a Historical Note on Adanson's Familles Des Plantes (1763-1764)

Cladistic analysis is the analysis of hierarchically branching diagrams (cladograms), which estimate, with more or less informativeness and efficiency, one or more cladistic parameters. Branch points (components) comprise part of the information of a cladogram (the component information); and branch tips (terminal taxa) comprise the other part (the term information). In an analysis of five cladograms published on allodapine bees, components were segregated into four categories: (1) replicates; (2) components non-combinable with replicates; (3) components combinable with replicates and with each other; (4) components individually combinable with replicates but not with each other. Components replicated in cladograms based on independent data sets have low, but specifiable, probabilities of occurrence. For the five cladograms of bees, the replicates were found to be non-random (P = 10−17%). Through cladistic synthesis, categories (1) and (3) were combined in a general cladogram—the best estimate of the only apparent cladistic parameter. In a comparison of the five cladograms of bees, phyletic procedures proved more efficient and more informative than phenetic procedures in estimating the cladistic parameter, as represented by the general cladogram. The number of characters on which each of the five cladograms is based seems either uncorrelated, or inversely correlated, with the cladogram's efficiency in estimating the cladistic parameter.