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How rare is phyletic gradualism and what is its evolutionary significance? Evidence from Jurassic bivalves

Published online by Cambridge University Press:  08 April 2016

Anthony Hallam
Anthony Hallam*
Affiliation:
Department of Geological Sciences, University of Birmingham, Birmingham, B15 2TT, England
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Abstract

Both intensive analysis of Gryphaea and an extensive survey of Jurassic bivalves in Europe supports the punctuated equilibria model of speciation, with the exception of phyletic size increase, which appears within the limits of the data to be gradualistic and affects at least a significant minority of species. The size increase takes place both within species and between successive species in a lineage. In Liassic Gryphaea, a combination of allometry in the ontogenetic development of the ancestral species and paedomorphosis led also to changes of shape up the sequence. The production of evolutionary trends by species selection is not supported.

The favoured interpretation of phyletic size increase is a gradual delay in maturation time consequent upon a change in the organisms' adaptive strategy from the r-selected to the K-selected mode and is backed up by evidence on changing population numbers and distribution. An extinction/speciation model is proposed for neritic organisms based on fluctuating sea levels. Times of low sea level or regression correspond with times of high stress and hence high extinction among stenotopic organisms and increased rates of allopatric speciation, with r-selection as the dominant mode. Times of high sea level or transgression correspond with low extinction and speciation rates and increased freedom of migration. K-selection is the dominant mode and often leads to phyletic size increase provided the environment remains stable for a sufficiently long period.

Type
Research Article
Information
Paleobiology , Volume 4 , Issue 1 , Winter 1978 , pp. 16 - 25
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Cooper, M. R. 1977. Eustacy during the Cretaceous; its implications and importance. Palaeogeogr., Palaeoclimatol., Palaeoecol. 22:1–60.CrossRefGoogle Scholar
Dodson, M. M. and Hallam, A. 1977. Allopatric speciation and the fold catastrophe. Am. Nat. 111:415–433.Google Scholar
Eldredge, N. and Gould, S. J. 1972. Punctuated equilibria: an alternative to phyletic gradualism. Pp. 82–115. In: Schopf, T. J. M., ed. Models in Paleobiology. Freeman, Cooper and Co.; San Francisco, Calif.Google Scholar
Eldredge, N. and Gould, S. J. 1977. Punctuated equilibria: the tempo and mode of evolution reconsidered. Paleobiology. 3:115–151.Google Scholar
Gingerich, P. D. 1976. Paleontology and phylogeny: patterns of evolution at the species level in early Tertiary mammals. Am. J. Sci. 276:1–28.CrossRefGoogle Scholar
Gould, S. J. 1977. Ontogeny and Phylogeny. 501 pp. Harvard Univ. Press; Cambridge, Mass.Google Scholar
Gould, S. J., Raup, D. M., Sepkoski, J. J., Schopf, T. J. M. and Simberloff, D. S. 1977. The shape of evolution: a comparison of real and random clades. Paleobiology. 3:23–40.CrossRefGoogle Scholar
Hairston, N. G., Tinkle, D. W. and Wilbur, N. M. 1970. Natural selection and the parameters of population growth. J. Wildlife Manage. 34:681–690.Google Scholar
Hallam, A. 1960. A sedimentary and faunal study of the Blue Lias of Dorset and Glamorgan. Philos. Trans. Roy. Soc. London, B. 243:1–44.Google Scholar
Hallam, A. 1968. Morphology, palaeoecology and evolution of the genus Gryphaea in the British Lias. Philos. Trans. R. Soc. London, B. 254:91–128.Google Scholar
Hallam, A. 1972. Models involving population dynamics. Pp. 62–80. In: Schopf, T. J. M., ed. Models in Paleobiology. Freeman, Cooper and Co.; San Francisco, Calif.Google Scholar
Hallam, A. 1975a. Jurassic Environments. 269 pp. Cambridge Univ. Press; Cambridge, England.Google Scholar
Hallam, A. 1975b. Evolutionary size increase and longevity in Jurassic bivalves and ammonites. Nature. 258:439–496.Google Scholar
Hallam, A. 1976. Stratigraphic distribution and ecology of European Jurassic bivalves. Lethaia. 9:245–259.CrossRefGoogle Scholar
Hallam, A. 1977. Jurassic bivalve biogeography. Paleobiology. 3:58–73.Google Scholar
Hallam, A. 1978. Eustatic cycles in the Jurassic. Palaeogeogr., Palaeoclimatol., Palaeoecol. 23:1–32.CrossRefGoogle Scholar
Hallam, A. and Gould, S. J. 1975. The evolution of British and American Middle and Upper Jurassic Gryphaea. Proc. R. Soc. London, B. 189:511–542.Google Scholar
Kellogg, D. E. 1975. The role of phyletic change in the evolution of Pseudocubus verna (Radiolaria). Paleobiology. 1:359–370.CrossRefGoogle Scholar
Newell, N. D. 1949. Phyletic size increase—an important trend illustrated by fossil invertebrates. Evolution. 3:103–124.CrossRefGoogle Scholar
Newell, N. D. 1967. Revolutions in the history of life. Geol. Soc. Am. Spec. Pap. 89:63–91.Google Scholar
Ozawa, T. 1975. Evolution of Lepidolina multiseptata (Permian foraminifer) in East Asia. Mem. Fac. Sci. Kyushu Univ., Ser. D. Geol. 23:117–164.Google Scholar
Pianka, E. R. 1970. On r- and K-selection. Am. Nat. 104:592–597.Google Scholar
Raup, D. M. 1977. Stochastic models in evolutionary palaeontology. Pp. 59–78. In: Hallam, A., ed. Patterns of Evolution, as Illustrated by the Fossil Record. Elsevier; Amsterdam, Oxford and New York.Google Scholar
Raup, D. M. and Stanley, S. M. 1971. Principles of Paleontology. 388 pp. Freeman, Cooper and Co.; San Francisco, Calif.Google Scholar
Rensch, B. 1959. Evolution Above the Species Level. 419 pp. Columbia Univ. Press; New York.CrossRefGoogle Scholar
Schopf, T. J. M. 1974. Permo-Triassic extinctions: relation to sea floor spreading. J. Geol. 82:129–143.CrossRefGoogle Scholar
Schopf, T. J. M. 1977. Patterns and themes of evolution among Bryozoa. Pp. 159–207. In: Hallam, A., ed. Patterns of Evolution, as Illustrated by the Fossil Record. Elsevier; Amsterdam, Oxford and New York.Google Scholar
Southwood, T. R. E. 1976. Bionomic strategies and population parameters. Pp. 26–48. In: May, R. M., ed. Theoretical Ecology. Blackwell Scientific Publications; Oxford.Google Scholar
Stanley, S. M. 1973. An explanation for Cope's Rule. Evolution. 27:1–26.CrossRefGoogle ScholarPubMed
Stanley, S. M. 1975. A theory of evolution above the species level. Proc. Nat. Acad. Sci. (U.S.A.) 72:646–650.Google Scholar
Valentine, J. W. 1967. The influence of climatic fluctuations on species diversity within the Tethyan provincial system. Pp. 153–166. In: Adams, C. G. and Ager, D. V., eds. Aspects of Tethyan Biogeography. Systematics Assoc. Publ. No. 7.Google Scholar
Van Hinte, J. E. 1976. A Jurassic time scale. Bull. Am. Assoc. Pet. Geol. 60:489–497.Google Scholar