We propose a working group to assess the usefulness of algorithms and quantitative approaches to measuring biodiversity in terms of 'taxonomic distinctiveness' or 'independent evolutionary units'. We will critically evaluate whether and how phylogenetic information can be used to measure species value. Specifically, we will analyze the effects of sample size, topology, branch lengths and model of evolutionary change on various quantitative measures of phylogenetic diversity. Measures of phylogenetic diversity will then be applied to various conservation problems such rarity, species' conservation status, and extinction risk. The working group will provide a collaborative effort among ecologists, evolutionary biologists, paleontologists, systematists (both molecular and morphological) and conservation biologists, all of whom deal with synthetic comparative data in their respective fields. The end product will be a series of papers and an edited volume, Phylogeny and Conservation. collapse