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Survivorship analysis of Cambrian and Ordovician trilobites

  • Mike Foote (a1)

Abstract

Cohort analysis is used to investigate survivorship of trilobites originating during the Cambrian and Ordovician. Using a time-homogeneous branching model, it is estimated that trilobite genera and species originating during the Ordovician survived three times longer than Cambrian genera and species. Monte Carlo simulation of survivorship is used to show that (1) Cambrian and Ordovician survivorship are significantly different, (2) Ordovician cohorts conform more closely to the time-homogeneous model than do Cambrian cohorts, and (3) deviations from temporal homogeneity are more often produced by extraordinary extinction than by unusually slow turnover.

When Early Ordovician cohorts are decomposed into genera within families that originated in the Cambrian versus the Ordovician, no evidence that Cambrian and Ordovician survivorship differences are clade-specific can be found. Ordovician genera of Cambrian affinity and of Ordovician affinity become extinct at similar rates.

Some of the ultimate causes of these differences in survivorship include (1) taxonomic inconsistency, (2) greater environmental stability in the Ordovician, and (3) more highly structured ecosystems in the Ordovician that may have led to the weeding out of extinction-prone taxa.

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Bambach, R. K. and Gilinsky, N. L. 1986. Perspectives on the distribution of origination and extinction during the Phanerozoic. Geological Society of America Abstracts with Programs 18:534.
Bassett, M. G. and Dean, W. T., eds. 1982. The Cambrian-Ordovician Boundary: sections, fossil distributions, and correlations. National Museum of Wales, Geological Series No. 3; Cardiff. 227 pp.
Epstein, B. 1960. Tests for the validity of the assumption that the underlying distribution of life is exponential. Part I. Technometrics 2:83101.
Fortey, R. A. 1980. Generic longevity in Lower Ordovician trilobites: relation to environment. Paleobiology 6:2431.
Fortey, R. A. 1983. Cambrian-Ordovician trilobites from the boundary beds in western Newfoundland and their phylogenetic significance. Special Papers in Palaeontology 30:179211.
Fortey, R. A. and Chatterton, B. D. E. 1988. Classification of the trilobite suborder Asaphina. Palaeontology 31:165222.
Harland, W. B., Cox, A. V., Llewellyn, P. G., Pickton, C. A. G., Smith, A. G., and Walters, R. 1982. A Geologic Time Scale. Cambridge University Press; Cambridge. 131 pp.
Hoffman, A. and Kitchell, J. A. 1984. Evolution in a pelagic planktic system: a paleobiologic test of models of multispecies evolution. Paleobiology 10:933.
Jaanusson, V. 1979. Ordovician. Pp.A136–A166. In Robison, R. A. and Teichert, C. (eds.), Treatise on Invertebrate Paleontology, Part A, Introduction. The Geological Society of America and the University of Kansas; Boulder, Colorado, and Lawrence, Kansas.
Jablonski, D. 1986. Mass and background extinctions: the alternation of macroevolutionary regimes. Science 231:129133.
Jones, D. S. and Nicol, D. 1986. Origination, survivorship, and extinction of rudist taxa. Journal of Paleontology 60:107115.
Levinton, J. S. 1974. Trophic group and evolution in bivalve molluscs. Palaeontology 17:579585.
McNamara, K. J. 1986. The role of heterochrony in the evolution of Cambrian trilobites. Biological Reviews 61:121156.
Palmer, A. R. 1979. Cambrian. Pp.A119–A135. In Robison, R. A. and Teichert, C. (eds.), Treatise on Invertebrate Paleontology, Part A, Introduction. The Geological Society of America and the University of Kansas; Boulder, Colorado, and Lawrence, Kansas.
Palmer, A. R. 1983. The Decade of North American Geology 1983 geologic time scale. Geology 11:503504.
Palmer, A. R. 1984. The biomere problem: evolution of an idea. Journal of Paleontology 58:599611.
Quinn, J. F. 1983. Mass extinction in the fossil record. Science 219:12391240.
Raup, D. M. 1978. Cohort analysis of generic survivorship. Paleobiology 4:115.
Raup, D. M. 1981. Extinction: bad genes of bad luck? Acta Geologica Hispanica 16:2533.
Raup, D. M. 1987. Mathematical models of cladogenesis. Paleobiology 11:4252.
Raup, D. M. 1987. Mass extinction: a commentary. Palaeontology 30:113.
Raup, D. M., Sepkoski, J. J. Jr., and Stigler, S. M. 1983. Mass extinction in the fossil record (reply to Quinn). Science 219:12401241.
Sepkoski, J. J. Jr. 1979. A kinetic model of Phanerozoic taxonomic diversity II. Early Phanerozoic families and multiple equilibria. Paleobiology 5:222251.
Sepkoski, J. J. Jr. 1981. The uniqueness of the Cambrian fauna. Pp. 203207. In Taylor, M. E. (ed.), Short Papers for the Second International Symposium on the Cambrian System. United States Geological Survey Open-File Report 81-743.
Sepkoski, J. J. Jr. 1982. A compendium of fossil marine families. Milwaukee Public Museum Contributions in Biology and Geology 51. 125 pp.
Sepkoski, J. J. Jr. 1986a. Phanerozoic overview of mass extinction. Pp. 277295. In Raup, D. M. and Jablonski, D. (eds.), Patterns and Processes in the History of Life (Dahlem Konferenzen 1986). Springer-Verlag; Berlin.
Sepkoski, J. J. Jr. 1986b. Global bioevents and the question of periodicity. Pp. 4761. In Walliser, O. (ed.), Global Bio-Events (Lecture Notes in Earth Sciences Vol. 8). Springer-Verlag; Berlin.
Sheehan, P. M. 1982. Brachiopod macroevolution at the Ordovician-Silurian boundary. Third North American Paleontological Convention, Proceedings 2:477481.
Simpson, G. G. 1953. The Major Features of Evolution. Columbia University Press; New York. 434 pp.
Stanley, S. M. 1973. Effects of competition on rates of evolution, with special reference to bivalve mollusks and mammals. Systematic Zoology 22:486506.
Stanley, S. M. 1979. Macroevolution: pattern and process. W. H. Freeman and Company; San Francisco. 332 pp.
Stubblefield, C. J. 1960. Evolution in trilobites. Quarterly Journal of the Geological Society of London 115:145162.
Valentine, J. W. 1969. Patterns of taxonomic and ecological structure of the shelf benthos during Phanerozoic time. Palaeontology 12:684709.
Van Valen, L. M. 1973. A new evolutionary law. Evolutionary Theory 1:130.
Whittington, H. B. 1954. Status of Invertebrate Paleontology, 1953, VI. Arthropoda: Trilobita. Bulletin of the Museum of Comparative Zoology, Harvard University 112:193200.
Whittington, H. B. 1966. Phylogeny and distribution of Ordovician trilobites. Journal of Paleontology 40:696737.

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