Posted: Jun 19, 2010 1:57 am
The whole business seems very resistant to a general model, IMHO. Clearly, good times favour gradualism, and mass extinctions appear punctuated. But the five major mass extinctions do not even form a pattern within themselves. By what criteria do we measure extinction and recovery? Species diversity or abundance? Trophic depth? Regional recoveries or global? Why do some clades appear more plastic than others? Background extinctions compared to pulse or press events? Stability vs flexibility of GRN's? Some clades make it through a big pulse event, only to die out shortly after! Recovery rates seem to vary greatly from a few hundred thousand years to 10 million or more. 
Gould and Eldridge tend to produce verbal theories rather than math models. They seemed to ignore the advances in Homeobox genes despite the fact that much information can be gained from Genes networks that are still extant.
The non-randomness of the fossil record, and fossil discovery is probably biasing all results and speculations. Any "rules" seem to demand exceptions. Nevertheless, both gradualism and PE seem to be operative, but I suspect genetic data [especially how Hox genes are both highly conserved, but somewhat plastic] rather than paleontological evidence will bring more light on the issue.
Gould and Eldridge tend to produce verbal theories rather than math models. They seemed to ignore the advances in Homeobox genes despite the fact that much information can be gained from Genes networks that are still extant.
The non-randomness of the fossil record, and fossil discovery is probably biasing all results and speculations. Any "rules" seem to demand exceptions. Nevertheless, both gradualism and PE seem to be operative, but I suspect genetic data [especially how Hox genes are both highly conserved, but somewhat plastic] rather than paleontological evidence will bring more light on the issue.