SCALES OF CLIMATIC VARIABILITY AND TIME AVERAGING IN PLEISTOCENE BIOTAS - IMPLICATIONS FOR ECOLOGY AND EVOLUTION

Biotic responses to Pleistocene climatic fluctuations have traditional ly keen analyzed in the context of glacial-interglacial cycles on the scale of 10 000-100 000 years, However, emerging; evidence indicates t hat short-term, high-amplitude, climatic 'flickers', close to the limi ts of the resolving power of the fossil record, occurred within the gl acial and interglacial substages, Because species shift geographically in response to the climate flickers, community structures are fluid, with changes absorbed ecologically and not mediated macroevolutionaril y. The rapidity of these shifts may also explain anomalous fossil asse mblages.