An ecological unit is a composite of an 'environment piece' and a 'behavior piece'. They are hybrid artifacts that exist as quasi-objective entities, much like Searle’s "observer-relative features of the world" (Searle, 1995). An example that Barker (1968) uses (p.11) is a road—a road is a track (physical feature) used for travelling or carrying goods (expression of 'molar behavior'). The coupling of a molar behavior to an environmental feature (affordance) is the mechanism through which the reciprocal relations between different levels of nested or related phenomena occur. The ecological unit is the foundation for the concept of a 'behavior setting' which was defined above. More generally, it seems that this notion captures the relationship of any organism to its niche and is captured by Reed (1996) in his discussion of the 'affordance'.