KEYNOTE: BIOLOGICAL IMPLICATIONS OF VARYING OXYGEN LEVELS DURING THE LATE PALEOZOIC THROUGH EARLY MESOZOIC

The consequences of varying Phanerozoic oxygen levels on the biology of the late Permian through Jurassic time interval have been inadequately assessed. Here I will propose that respiratory and metabolic adaptations are tied into the intervals in which varies groups originated. Because the Carboniferous-early Permian was a cool but high oxygen world, while the late Permian through early Jurassic was a warm, low oxygen world (based on the most recent GEOCARB III results obtained by R. Berner), groups orginating during these radically different environmental regimes can be expected to show quite different biologies. Here I will examine the time of origin of endothermy, ectothermy, live birth vs. egg laying, and the fates of various terrestrial and marine groups across the P/T and T/J mass extinctions in the context of varying oxygen levels.