  In models for the evolution of predation from initially purely competitive
species interactions, the propensity of predation is most often assumed to be a
direct consequence of the relative morphological and physiological traits of
interacting species. Here we explore a model in which predation ability is an
independently evolving phenotypic feature, so that even when the relative
morphological or physiological traits allow for predation, predation only
occurs if the predation ability of individuals has independently evolved to
high enough values. In addition to delineating the conditions for the
evolutionary emergence of predation, the model reproduces stationary and
non-stationary multilevel food webs with the top predators not necessarily
having size superiority.
