The reality of ecological assemblages: A palaeo-ecological puzzle

Ecological communities, I argue, are objective units of nature if they have structure that regulates their membership. Evidence of such structure in c ontemporary ecology is scant, but the palaeoecological phenomenon of co-ord inated stasis is a prima facie example of internal regulation. I argue that no individualist attempts to explain away the appearance of internal regul ation succeeds. But no internalist model is fully satisfactory, either, in explaining the contrast between pre and post Pleistocene ecology.