How does genetic innovation translate into ecological innovation? Although evo-devo has successfully linked genes to morphology, the next stage is elucidating how genes predict resource use. This can be attained by broadening the focus of evo-devo from [genes→morphology], to [genes→morphology→functional ecology]. We suggest that the fields of evo-devo, functional morphology, and evolutionary ecology should be united under a common framework based on three predictions. The first is that morphological disparity should scale positively with functional complexity among different radiations. The second is that functional complexity should correlate negatively with the predictability of evolutionary divergence within lineages, and the third is that functional complexity should define the genetic architecture of adaptive radiations. These predictions could enable a broader understanding of how genetic variation is translated into variation in resource use.