Ambiguous edges: Steven Gould draws our attention. to an important distinction in natural ecologies between two kinds of edges: boundaries and borders. The boundary is an edge where things end; the border is an edge where different groups interact. At borders, organisms become more interactive, due to the meeting of different species or physical conditions; for instance, where the shoreline of a lake meets solid land is an active zone of exchange where organisms find and feed off other organisms. Not surprisingly, it is also at the borderline where the work of natural selection is the most intense. Whereas the boundary is a guarded territory, as established by pride of lions or packs of wolves. No transgression at the boundary: Keep Out! Which means the edge itself is dead.