Species distance information

For the first set of measures (on the Taxdisc tab), the Taxonomy button gives a choice of whether the distances among species (or whatever the variables represent) are provided by a tree structure (•Taxonomy) or a direct distance matrix among species (•Resemblance). The latter then requires a Variable resemblance matrix to be specified (perhaps one calculated among species on the basis of their traits, if this is to be a functional rather than taxonomic-based distinctness index). The former requires a Variable information sheet – usually an aggregation file of the type seen near the start of Section 11 – which needs to be in the workspace before Analyse>DIVERSE is run (if only one such file has been read in, it will be the default). This is a look-up table which gives a taxonomic (or other) tree of all species, allowing the routine to calculate species distances internally (these are not actually output but could be so, if needed, by Analyse>Similarity when the active window is the aggregation worksheet, as seen in Section 5). For the second set of measures (the Phylogenetic tab in the DIVERSE dialog), the Taxonomy button offers only the option to input a Variable info. worksheet because the PD measures ($\Phi^+$ and $S \Phi^+$) can only be computed from a species tree and not from a triangular matrix of between-species distances.