eco subset ecologically related to confers advantage in An experimental relation currently used to connect a feature possessed by an organism (e.g. anatomical structure, biological process, phenotype or quality) to a habitat or environment in which that feature is well suited, adapted or provides a reproductive advantage for the organism. For example, fins to an aquatic environment. Usually this will mean that the structure is adapted for this environment, but we avoid saying this directly - primitive forms of the structure may not have evolved specifically for that environment (for example, early wings were not necessarily adapted for an aerial environment). Note also that this is a statement about the general class of structures - not every instance of a limb need confer an advantage for a terrestrial environment, e.g. if the limb is vestigial. adapted for environmental system Christopher J. Mungall