Energetics in the global marinefauna: A connection between terrestrial diversification and change in the marine biosphere

Abstract The invasion of the land started in the Ordovician and continued into the Carboniferous. The peak ofdiversification rate and increase in biomass of terrestrial vegetation occurred during the Devonian. However, no permanent increase in marine diversity occurred at that time. Instead, a plateau of fluctuating but non-trending diversity extended for 200 million years from the later Ordovician to the beginning of the Late Permian. A second major increase in terrestrial productivity occurred with the diversification of the angiosperms. This began in the Cretaceous and continued into the Cenozoic. Although marine diversity also increased during the Mesozoic and Cenozoic, no permanent offset in diversification rate occurred during this interval. Instead, marine diversity increased nearly continuously through the Jurassic, Cretaceous, and Cenozoic at the same exponential rate of growth established early in the Mesozoic. Despite the lack of a clear signal of change in marine diversity associated with either interval of terrestrial plant diversification, patterns of turnover in the marine fauna during the Devonian and the Cretaceous suggest that these were times of increasing productivity in the oceans. In the Devonian, replacement in dominant orders of many taxa are consonant with the idea of increased food supplies and greater energetics in the fauna (energetics refers to the combination of biomass, general physical activity, metabolic rates, and the concomitant need for a level of food consumption sufficient for the suppor...