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On the relationship between Phanerozoic diversity and changes in habitable area

Published online by Cambridge University Press:  08 April 2016

Karl W. Flessa
Affiliation:
Department of Geosciences, University of Arizona; Tucson, Arizona 85721
J. John Sepkoski Jr.
Affiliation:
Department of the Geophysical Sciences, University of Chicago; 5734 South Ellis Ave., Chicago, Illinois 60637

Abstract

Applications of the species-area equation to studies of fluctuations in Phanerozoic diversity have great promise but can involve questionable assumptions. Sepkoski's (1976) analysis of marine diversity throughout the Phanerozoic record assumes that total rock volume is a sufficient measure of sampling efficiency and that an isomorphous equation is appropriate for all of Phanerozoic time. The area of marine sedimentary rock and the area of continental seas are not independent variables. Residual variation in diversity (that which remains after subtracting the effects of rock volume) might be explained by either the species-area relationship or by another component of sampling efficiency. A species-area equation in which the slope (z) and intercept (k) are assumed constant receives mixed support from arguments based on Recent terrestrial and aquatic organisms. Observed z-values cluster near a value of 0.30 despite a wide taxonomic range, but are generally below those found for the Phanerozoic record. Temporal fluctuations in k values, in response to changes in the area of continental seas, may produce elevated estimates of z.

Information

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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