Evolutionary models of extended phenotypes.

A variety of theoretical models incorporate phenotypes expressed in the external environment, but a core question is whether such traits generate dynamics that alter evolution. This has proven to be a challenging and controversial proposition. However, several recent modelling frameworks provide insight: indirect genetic effect (IGE) models, niche construction models, and evolutionary feedback models. These distinct approaches converge upon the observation that gene action at a distance generates feedback that expands the range of trait values and evolutionary rates that we should expect to observe in empirical studies. Such conceptual replication provides solid evidence that traits with extended effects have important evolutionary consequences, but more empirical work is needed to evaluate the predictive power of different modelling approaches.