Robert W. Scotland, Department of Plant Sciences, University of Oxford

Wednesday 9 July 11:00

Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)

The collective efforts of taxonomists over time has played a pivotal role in identifying many natural groups of monophyletic taxa.  How this task has been achieved is by no means clear given that for much of the history of taxonomy there has been no universally agreed method for discovering taxa. Nevertheless, many monophyletic taxa were discovered through the identification of shared characters (novelties, special similarities, synapomorphies, taxic homologues, good characters, conserved characters).  It seems the history of taxonomy is the history of ‘character weighting’ in favour of some characters being useful and others not. In more recent times all characters have been considered phylogenetically useful but only at the appropriate hierarchical level. Thus phylogenetic analysis of morphological data has become akin to the study of character evolution. 

In this talk I will show that morphological traits are poorly correlated with phylogeny and that measures ofphylogenetic diversity in conservation may not maximize feature diversity. Furthermore, because the probability of two random binary characters being compatible with each other converges to zero exponentially quickly as the number of taxa grows, then compatibility is best able to accurately discover and distinguish evolutionary novelty.

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