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Taxonomic survivorship and morphologic complexity in Paleozoic bryozoan genera

Published online by Cambridge University Press:  08 April 2016

Robert L. Anstey
Robert L. Anstey*
Affiliation:
Department of Geology, Michigan State University, East Lansing, Michigan 48824
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Abstract

The shape of bryozoan taxonomic survivorship curves is strongly influenced both by grade of morphologic complexity and by mass extinction. Paleozoic bryozoan genera that are morphologically simple have linear taxonomic survivorship; morphologically intermediate taxa have slightly concave survivorship, and complex forms have very concave survivorship. Increasing morphologic complexity, and by inference, increasing specialization of adaptation appear to accompany a systematic departure from a stochastically constant extinction rate. However, the extinctions of the complex taxa are entirely concentrated during three mass extinction events, whereas the extinctions of the simple taxa are more uniformly distributed throughout the Paleozoic; the extinction pattern of the morphologically intermediate taxa is intermediate to those of the simple and complex groups. Exclusion of the genera affected by mass extinction increases the convexity of the survivorship curves, and reverses the apparent correlation of extinction rate with morphologic complexity. The macroevolutionary pattern of the complex genera resembles an r-strategy, whereas that of the simple taxa resembles a K-strategy.

Type
Research Article
Information
Paleobiology , Volume 4 , Issue 4 , Fall 1978 , pp. 407 - 418
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Anstey, R. L. and Chase, T. L. 1974. Geographic diversity of Late Ordovician corals and bryozoans in North America. J. Paleontol. 48:1141–1148.Google Scholar
Anstey, R. L. and Perry, T. G. 1970. Biometric procedures in taxonomic studies of Paleozoic bryozoans. J. Paleontol. 44:383–398.Google Scholar
Anstey, R. L. and Perry, T. G. 1973. Eden Shale bryozoans: a numerical study (Ordovician, Ohio Valley). Mich. State Univ., Pub. Mus., Paleontol. Ser. 1:1–80.Google Scholar
Astrova, G. G. 1960. Tip Bryozoa. Pp. 13–112. In: Sarycheva, T. G., ed. Osnovy Paleontologii, Mshanki, Brachipody. 343 pp.Akademiia Nauk S.S.S.R.; Moskva.Google Scholar
Borg, , 1926. Studies on recent cyclostomatous Bryozoa. Zoolog. Bid. Uppsala. 10:181–507.Google Scholar
Corneliussen, E. F. and Perry, T. G. 1973. Monotrypa, Hallopora, Amplexopora, and Hennigopora (Ectoprocta) from the Brownsport Formation (Niagaran), Western Tennessee. J. Paleontol. 47:151–220.Google Scholar
Cuffey, R. J. 1973. An improved classification, based upon numerical-taxonomic analyses, for the higher taxa of entoproct and ectoproct bryozoans. Pp. 549–564. In: Larwood, G. P., ed. Living and Fossil Bryozoa. 634 pp.Academic Press, London.Google Scholar
Eftaxiadis, T. 1973. Numerical taxonomy and phylogeny of Paleozoic bryozoans (ectoprocts). 103 pp. Unpubl. M.S. thesis, Mich. State Univ.Google Scholar
Larwood, G. P., Medd, A. W., Owen, D. W., and Tavener-Smith, R. 1967. Bryozoa. Pp. 379–395. In: Harland, W. B. et al., eds. The Fossil Record. 828 pp.Geol. Soc. London.Google Scholar
Levinton, J. S. 1974. Trophic group and evolution in bivalve molluscs. Palaeontology. 17:579–585.Google Scholar
Pachut, J. F. and Anstey, R. L. 1979. A developmental explanation of stability-diversity-variation hypotheses: morphogenetic regulation in Ordovician bryozoan colonies. In press.Google Scholar
Prezbindowski, D. R. and Anstey, R. L. 1978. A Fourier-numerical study of a bryozoan fauna from the Threeforks Formation (Lake Devonian) of Montana. J. Paleontol. 52:353–369.Google Scholar
Raup, D. M. 1975. Taxonomic survivorship curves and Van Valen's Law. Paleobiology. 1:82–96.Google Scholar
Raup, D. M. 1978. Cohort analysis of generic survivorship. Paleobiology. 4:1–15.CrossRefGoogle Scholar
Salthe, S. N.2975. Some comments on Van Valen's Law of extinction. Paleobiology. 1:356–358.Google Scholar
Schopf, T. J. M., Raup, D. M., Gould, S. J., and Simberloff, D. S. 1975. Genomic versus morphologic rates of evolution: influence of morphologic complexity. Palebiology. 1:63–70.Google Scholar
Sepkoski, J. J. 1975. Stratigraphic biases in the analysis of taxonomic survivorship. Paleobiology. 1:343–355.Google Scholar
Van Valen, L. 1973. A new evolutionary law. Evol. Theory. 1:1–30.Google Scholar
Younker, J. L. 1976. Analytical paleontology: patterns of taxonomic extinction. 114 pp. Unpubl. Ph.D. thesis, Mich. Stat Univ.Google Scholar
Younker, J. L. 1977. Taxonomic survivorship analysis and patterns of macroevolution in the fossil record. Geol. Soc. Am. Abstr. with Programs. 9:1238.Google Scholar
Younker, J. L. and Younker, L. W. 1977. Relationship between sediment survival and apparent patterns of taxonomic survivor ship. Geol. Soc. Am., Abstr. with Programs. 9:669–670.Google Scholar
Younker, J. L., Younker, L. W., and Anstey, R. L. 1976. Duration of taxa and probability of extinction. Geol. Soc. Am. Abstr. with Programs. 8:1179–1180.Google Scholar