 Suppose, for example, that the units of interest are features of species (a feature might be some morphological characteristic). These features in general have unknown future benefits; feature diversity provides another example of biodiversity option value. If we apply the rationale that all these features should be treated as units of equal value, then some species (those that are phylogenetically distinctive; see below) will make larger contributions to the overall feature diversity represented by a set of species. Thus, equal value at the fine scale among features leads to differential values at the coarse scale among species.