Linking global patterns in biodiversity to evolutionary dynamics using metabolic theory.

Starting in 2002, with a paper entitled ‘‘Global biodiversity, biochemical kinetics and the energeticequivalence rule,’’ we have been developing a theoretical framework to understand the mechanisms underlying broadscale biodiversity gradients, particularly the latitudinal gradient. This work is part of a broader Metabolic Theory of Ecology (MTE) being developed to predict various aspects of the structure and function of ecological systems (Brown et al. 2004). Although MTE has been criticized (see Hawkins et al. 2007), support for its predictions continues to grow (Anderson et al. 2006, Anfodillo et al. 2006, Lopez-Urrutia et al. 2006, Meehan 2006,Robinson 2006). In the preceding paper,Hawkins et al. (2007) criticize the original work of Allen et al. (2002) based on their analyses of a large number of empirical data sets. Here we respond to their major criticisms and discuss important issues raised by their paper.