 The second way in which we might augment species richness is through disparity, morphological diversity, or more simply, phenotypic variation (Maclaurin &amp; Sterelny 2008: Ch. 3, 4; see Gould 1989 for a discussion of disparity in the history of life). Disparity, morphological diversity, or phenotypic vacation in general, concern the variation in phenotypic traits exhibited in and between species. Suppose we have one suite of species that are very similar phenotypically; however, we might have another suite of species that vary a great deal phenotypically. A measure of such variation would weight species richness with some parameter(s) representing the variation in phenotypic traits. Unfortunately, if we include such phenotypic variation per se we find ourselves exactly with the problems that dogged phenetic taxonomy and the attempt to capture some notion of overall similarity. Additionally, if we focus on disparity per se as opposed to mere phenotypic variation, we must try to capture some notion of basic “body plan” (Arthur 2000).