Abstract

Ecology is being introduced to Evolutionary Developmental Biology to enhance organism-, population-, species-, and higher-taxon-level studies. This exciting, bourgeoning troika will revolutionise how investigators consider relationships among environment, ontogeny, and phylogeny. Features are studied (and even defined) differently in ecology, development, and evolution. Form is central to development and evolution but peripheral to ecology. Congruence (i.e., homology) is applied at different hierarchical levels in the three disciplines. Function is central to ecology but peripheral to development. Herein, the supercategories form (‘isomorphic’ or ‘allomorphic’), congruence (‘homologous’ or ‘homoplastic’), and function (‘adaptive’ or ‘nonadaptive’) are combined with two developmental mode (i.e., growth) categories (‘conformational’ or ‘nonconformational’) to provide a 16-class system for analysing features in studies in which ecology, development, and evolution are integrated.