How does evolutionary variation in basal metabolic rates arise? A statistical assessment and a mechanistic model

Metabolic rates are related to the pace of life. Hence, research into their variability at global scales is of vital importance for several contemporary theories in physiology, ecology and evolution. Here we evaluated the effect of latitude, climate, primary productivity, habitat aridity, and species trophic habits, on mass-independent basal metabolic rates (BMR) for 195 rodent species. The aims of this paper were two-fold. First, we evaluated the predictive power of different statistical models (via a model selection approach), using a dimensional reduction technique on the exogenous factor matrix to achieve a clear interpretation of the selected models. Second, we evaluated three specific predictions derived from a recently proposed hypothesis, herein called the “obligatory heat” model (OHM), for the evolution of BMR. Obtained results indicate that mean / minimum environmental temperature, rainfall / primary productivity and, finally, species trophic habits are, in this order, the maj...