Many developmental studies rely heavily on modifying a fea-ture of a model organism and looking at the phenotypic effects of a genetic mutation. However, just because a mutation may be pos-sible, in terms of evolutionary adaptation and selection, geneticmutations do not tell us anything without some knowledge onhow the modifications to morphology affect function and perfor-mance. Using the zebrafish model to combine molecular studies,developmental physiology, and functional morphology will offera wealth of opportunities to experimentally examine evolutionaryprocesses