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Tempo of evolution in a Neogene bryozoan: are trends in single morphologic characters misleading?

Published online by Cambridge University Press:  08 April 2016

Alan H. Cheetham
Alan H. Cheetham*
Affiliation:
Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560
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Abstract

The extent to which perceived patterns of evolution are affected by the use of single characters versus overall morphology or measured versus counted and coded characters is explored empirically, employing multiple-character data from closely spaced sequential populations of the Neogene bryozoan Metrarabdotos. In all nine species examined, the pattern of evolution in overall morphology revealed by discriminant analysis is so highly punctuated that changes within species do not vary significantly from zero. Among the 46 single characters in the nine species, a few statistically significant temporal trends do occur, as apparent departures from the static pattern in overall morphology. However, these exceptions are so poorly related to the morphology that distinguishes inferred ancestor and descendant species from each other, and are so few in number, that they can be interpreted as chance variation from a general condition of no change within species. There is no difference in behavior between measured characters and counted or coded ones, in part because the distinction between the two types of characters can be artificial in bryozoans and other modular organisms. The results suggest that interpretation of single-character changes, in isolation rather than as statistical samples of the change in overall morphology, should be made with caution.

Type
Articles
Information
Paleobiology , Volume 13 , Issue 3 , Summer 1987 , pp. 286 - 296
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Chaline, J. and Laurin, B. 1986. Phyletic gradualism in a European Plio-Pleistocene Mimomys lineage (Arvicolidae, Rodentia). Paleobiology. 12:203–216.Google Scholar
Cheetham, A. H. 1968. Morphology and systematics of the bryozoan genus Metrarabdotos. Smithsonian Misc. Coll. 153:1–121.Google Scholar
Cheetham, A. H. 1985. Patterns of morphologic change in late Tertiary cheilostome bryozoans from the Dominican Republic: Metrarabdotos revisited. [Extended Abstract] Pp. 65–66. In: Nielsen, C. and Larwood, G. P., eds. Bryozoa: Ordovician to Recent. Olsen and Olsen; Fredensborg, Denmark.Google Scholar
Cheetham, A. H. 1986. Tempo of evolution in a Neogene bryozoan: rates of morphologic change within and across species boundaries. Paleobiology. 12:190–202.CrossRefGoogle Scholar
Cheetham, A. H. and Cook, P. L. 1983. General features of the class Gymnolaemata. Pp. 138–207. In: Robison, R. A., ed. Treatise on Invertebrate Paleontology, Part G. Bryozoa, Revised. Vol. 1: Introduction, Order Cystoporata, Order Cryptostomata. Geological Society of America and University of Kansas; Boulder, Colorado, and Lawrence, Kansas.Google Scholar
Cheetham, A. H. and Hayek, L. C.Manuscript. Phylogeny reconstruction in the Neogene bryozoan Metrarabdotos: a paleontologic evaluation of methodology.Google Scholar
Dingus, L. and Sadler, P. M. 1982. The effects of stratigraphic completeness on evolutionary rates. Syst. Zool. 31:400–412.CrossRefGoogle Scholar
Foster, A. B. 1986. Neogene paleontology in the northern Dominican Republic. 3. The Family Poritidae (Anthozoa: Scleractinia). Bull. Am. Paleontol. 90:43–123.Google Scholar
Gould, S. J. and Eldredge, N. 1977. Punctuated equilibria: the tempo and mode of evolution reconsidered. Paleobiology. 3:115–151.Google Scholar
Harper, J. L., Rosen, B. R., and White, J., eds. 1986. The growth and form of modular organisms. Phil. Trans. Roy. Soc. London B. 313:1–250.Google Scholar
Johnson, A. L. A. 1985. Third International Congress of Systematic and Evolutionary Biology, with a symposium on Random and Directed Events in Evolution, convened by the Palaeontological Association and the Linnean Society. Palaeontol. Assoc. Circ. 122:5–7.Google Scholar
Kelley, P. H. 1983. Evolutionary patterns of eight Chesapeake Group molluscs: evidence for the model of punctuated equilibria. J. Paleont. 57:581–598.Google Scholar
Kelley, P. H. and Johnston, J. E. 1986. Within-species variation as a basis for interspecific evolution of four Coastal Plain Exogyra species. Geol. Soc. Am., Abstracts with Programs. 18:654.Google Scholar
Kidwell, S. M. 1986. Models for fossil concentrations: paleobiologic implications. Paleobiology. 12:6–24.CrossRefGoogle Scholar
LaBarbera, M. 1986. Review of Evolutionary Case Histories from the Fossil Record, edited by Cope, J. C. W. and Skelton, P. W.Science. 232:407–408.CrossRefGoogle Scholar
Lazarus, D. 1986. Tempo and mode of morphologic evolution near the origin of the radiolarian lineage Pterocanium prismatium. Paleobiology. 12:175–189.CrossRefGoogle Scholar
Reyment, R. A. 1982. Analysis of trans-specific evolution in Cretaceous ostracods. Paleobiology. 8:293–306.Google Scholar
Saunders, J. B., Jung, P., and Biju-Duval, B. 1986. Neogene paleontology in the northern Dominican Republic. 1. Field surveys, lithology, and age. Bull. Am. Paleontol. 89:1–79.Google Scholar
Schindel, D. E. 1980. Microstratigraphic sampling and the limits of paleontologic resolution. Paleobiology. 6:408–426.Google Scholar
Schindel, D. E. 1982. Resolution analysis: a new approach to gaps in the fossil record. Paleobiology. 8:340–353.Google Scholar
Schopf, T. J. M. 1984. Rates of evolution and the notion of “living fossils.” Ann. Rev. Earth Planet. Sci. 12:245–292.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. Paleobiology. 2:63–70.Google Scholar
Simpson, G. G. 1953. The Major Features of Evolution. Columbia Univ. Press; New York and London.Google Scholar