Recently, it has been shown that the power spectrum of extinction intensity during the Phanerozoic takes a power-law form, which, it is suggested, may indicate the presence of critical phenomena in the dynamics underlying the extinction process. In this paper we reproduce these results using the...

Recent Fourier analyses of fossil extinction data have indicated that the power spectrum of extinction during the Phanerozoic may take the form of 1/f noise, a result which, it has been suggested, could be indicative of the presence of "critical dynamics" in the processes giving rise to...

We show that the decline in the extinction rate during the Phanerozoic can be accurately parameterized by a logarithmic fit to the cumulative total extinction. This implies that extinction intensity is falling off approximately as the reciprocal of time. We demonstrate that this observation...

The identification of randomness and nonrandomness is a perennial problem in evolutionary research. Stochastic thinking in evolutionary biology and paleobiology has solidified the use of a statistical notion of chance, but the idea of chance in evolutionary studies goes beyond statistics. A...

Development is the usual arena of evolutionary change in morphology, and much of evolution obviously depends on it. It is very common, however, for discussions of human evolution and developmental change to focus on individual characters (brain size, body weight, bipedalism, etc.). This...

The dynamics of origination in the fossil record of three marine groups (molluscs, echinoderms and fishes) and three terrestrial groups (mammals, insects and plants) is analyzed in this paper. Four hypotheses are tested: (1) secular decline in lineage origination; (2) secular decline in...

The general theme of temporal asymmetries in clade histories has often been studied with particular attention to the lower Paleozoic radiations. Post-Paleozoic patterns, however, are less well understood. In this paper, disparity and diversity changes in Mesozoic heart urchins were analyzed in...

How are biodiversity dynamics developmentally constrained at various hierarchical levels? Patterns of diversity and associated process theories have conventionally been treated in extrinsic, particularly ecological, terms, and development has not been sufficiently integrated into discussions of...

Morphospace studies are rich in pattern and process. Techniques for adequate description and mapping of morphologies have been increasingly refined and applied, the same being true of metrics for relevant parameters (like disparity). However, the testing of process hypotheses for specific...