Structural equations for the most representative theoretical models.

*For each equation all of the variables included and causally connected with other variables present in the model are shown. The number in front of the variable’s name indicates the path’s parameter and the p value for the path, estimated using ML, is shown in parenthesis. mb = body mass, BMR = basal metabolic rate, MMR = maximum metabolic rate, Rmax = intrinsic population growth rate, Tb = body temperature.