Allometric cascades

An allometric power-law relationship between metabolic rate and the mass of living organisms has been observed over many orders of magnitude in mass, indicating that (among other things) a characteristic mass scale is not applicable. Darveau et al. present a multiple-cause cascade model of metabolic allometry, which has been hailed as a new perspective on comparative integrative physiology and scaling relationships. Here we show that this cascade model is flawed and is therefore meaningless both for control of metabolic rate in an organism of a given size and for scaling of the metabolic rate.