Abstract
Ecological communities, I argue, are objective units of nature if theyhave structure that regulates their membership. Evidence of suchstructure in contemporary ecology is scant, but the palaeoecologicalphenomenon of co-ordinated stasis is a prima facie example ofinternal regulation. I argue that no individualist attempts to explainaway the appearance of internal regulation succeeds. But no internalistmodel is fully satisfactory, either, in explaining the contrast betweenpre and post Pleistocene ecology.