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Ontogeny and the explanation of form: an allometric analysis

Published online by Cambridge University Press:  20 December 2017

Stephen Jay Gould*
Affiliation:
Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts

Abstract

Significant allometry occurs during the ontogeny of every variable in Poecilozonites bermudensis, a Pleistocene-Recent land snail from Bermuda. The adaptive significance of shell allometry may lie in the necessity for preserving a high value of the foot surface/body volume ratio. In the absence of allometry, this ratio must decline as size increases. Three strategies could be used to keep this ratio sufficiently high: positive allometry of foot growth, structural strengthening of the foot, and the development of a foot initially large enough to withstand decline in the ratio during growth. As indicated by ontogenetic changes in apertural shape, a small amount of positive allometry occurs during ontogeny of the foot in P. bermudensis. This is not sufficient to prevent decline of the foot surface/body weight ratio, and I conclude that the strategy of possessing an initially large foot is also used. A simple model of doming, reflecting this latter strategy, is constructed (doming is a major allometric feature of P. bermudensis). In this model, the foot volume/body volume ratio is constant throughout ontogeny in each of two shells, but this value is higher in the more strongly domed shell.

Knowledge of ontogenetic allometry is a prerequisite for understanding the phylogeny of P. bermudensis, for paedomorphosis has been the primary evolutionary event in this taxon. Paedomorphic samples are scaled-up replicas of juvenile shells of the central stock, P. bermudensis zonatus. The degree of ontogenetic retardation in development is the same for all variables (color, thickness, and external shape). Paedomorphosis has occurred several times during the Pleistocene, providing an example of iterative evolution at the infraspecific level. Four paedomorphic taxa are known: P. b. fasolti, P. b. siegmundi, P. b. sieglindae, all new; and P. b. bermudensis (Pfeiffer). They have the geographic distribution (small, peripheral isolates) expected of diverging populations and seem to be genetically distinct entities, not mere phenotypic variants. The most paedomorphic subspecies originated in red soils; paedomorphs did not evolve in times of carbonate-dune deposition. The thin shells of paedomorphs might have been adaptive in the low-calcium environment of red soils. The general significance of iterative evolution at the infraspecific level does not provide an adequate model for corresponding events at higher levels.

Type
Research Article
Copyright
Copyright © 1968 Paleontological Society 

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References

Barker, R. M., 1964, Microtextural variation in pelecypod shells: Malacologia, v. 2, p. 6986.Google Scholar
, A. W. H., & Lott, Leroy, 1964, Shell growth and structure of planktonic forams: Science, v. 145, p. 823824.CrossRefGoogle Scholar
Boettger, C. R., 1952, Grössenwachstum und Geschlechtsreife bei Schnecken und pathologischer Riesenwuchs als Folge einer gestörten Wechselwirkung beider Faktoren: Zool. Anz., v. 17, suppl., p. 468487.Google Scholar
Bretz, J H., 1960, Bermuda: a partially drowned, late mature, Pleistocene karst: Geol. Soc. America, Bull., v. 71, p. 17291754.CrossRefGoogle Scholar
Carlquist, Sherwin, 1966, The biota of long distance dispersal: I. Principles of dispersal and evolution: Quart. Rev. Biol., v. 41, p. 247270.CrossRefGoogle ScholarPubMed
Clarke, Bryan, 1966, The evolution of morph-ratio clines: Amer. Naturalist, v. 100, p. 389402.CrossRefGoogle Scholar
Cock, A. G., 1966, Genetical aspects of metrical growth and form in animals: Quart. Rev. Biol., v. 41, p. 131190.CrossRefGoogle ScholarPubMed
Comfort, A., 1951. The pigmentation of molluscan shells: Biol. Rev., v. 26, p. 285301.CrossRefGoogle Scholar
Davis, D. D., 1962, Allometric relations in lions vs. domestic cats: Evolution, v. 16, p. 505514.CrossRefGoogle Scholar
De Beer, G. R., 1958, Embryos and ancestors: Oxford, Oxford Univ. Press, 197 p.Google Scholar
Gould, S. J., 1966a, Notes on shell morphology and classification of the Siliquariidae; the protoconch and slit of Siliquaria squamata Blainville: Amer. Mus. Nat. History, Novitates, no. 2263, 13 p.Google Scholar
Gould, S. J., 1966b, Allometry and size in ontogeny and phylogeny: Biol. Rev., v. 41, p. 587640.CrossRefGoogle ScholarPubMed
Gould, S. J., 1966c, Allometry in Pleistocene land snails from Bermuda: the influence of size upon shape: Jour. Paleontology, v. 40, p. 11311141.Google Scholar
Gould, S. J., 1967, Evolutionary patterns in pelycosaurian reptiles: a factor-analytic study: Evolution, v. 21, p. 385401.CrossRefGoogle ScholarPubMed
Gould, S. J., in press, An evolutionary microcosm: Pleistocene and Recent history of the land snail P. (Poecilozonites) in Bermuda: Harvard Univ., Mus. Comp. Zoology, Bull. Google Scholar
Haldane, J. B. S., 1965, On being the right size, in Shapley, Harlow, Rapport, Samuel, & Wright, Helen, (eds.), The new treasury of science: New York, Harper & Row, p. 474478.Google Scholar
Hecht, M. K., 1965, The role of natural selection and evolutionary rates in the origin of higher levels of organization: Syst. Zool., v. 14, p. 301317.CrossRefGoogle ScholarPubMed
Huxley, J. S., 1958, Evolutionary processes and taxonomy with special reference to grades: Uppsala Univ., Arsskr., p. 2138.Google Scholar
Imbrie, John, & van Andel, T. H., 1964, Vector analysis of heavy-mineral data: Geol. Soc. America, Bull., v. 75, p. 11311156.CrossRefGoogle Scholar
Land, L. S., Mackenzie, F. T., & Gould, S. J., 1967, The Pleistocene history of Bermuda: Geol. Soc. America, Bull, v. 78, p. 9931006.CrossRefGoogle Scholar
Lozek, Vojen, 1962, Soil conditions and their influence on terrestrial Gastropoda in central Europe, in Murphy, P. W., (ed.), Progress in soil zoology: London, Butterworths, p. 334342.Google Scholar
Manson, Vincent, & Imbrie, John, 1964, FORTRAN program for factor and vector analysis of geologic data using an IBM 7090 or 7094/1401 computer system: Kansas Geol. Survey, Spec. Distr. Pub. 13, 46 p.Google Scholar
Mayr, Ernst, 1963, Animal species and evolution: Cambridge, Mass., Harvard Univ. Press, 797 p.CrossRefGoogle Scholar
Moore, G. P., 1966, The use of trabecular bands as growth indicators in spines of the sea urchin Heliocidaris erythrogramma : Aust. Jour. Science, v. 29, p. 5254.Google Scholar
Morton, J. E., 1964, Locomotion, in Wilbur, K. M., & Yonge, C. M., (eds.), Physiology of Mollusca: New York, Academic Press, p. 383423.CrossRefGoogle Scholar
Mosimann, J. E., 1958, An analysis of allometry in the chelonian shell: Rev. Can. Biol., v. 17, p. 137228.Google ScholarPubMed
Nyholm, Karl-Georg, 1961, Morphogenesis and biology of the foraminifer Cibicides lobatulus : Zool. Bidrag Uppsala, v. 33, p. 158196.Google Scholar
Oldham, C., 1934, Further observations on the influence of lime on the shells of snails: Malac. Soc. London, Proc., v. 21, p. 131138.Google Scholar
Powell, A. W. B., 1966, The molluscan families Speightiidae and Turridae: Aukland Inst. Mus., Bull. 5, 184 p.Google Scholar
Raup, D. M., 1966, Geometric analysis of shell coiling: general problems: Jour. Paleontology, v. 40, p. 11781190.Google Scholar
Rensch, Bernhard, 1932, Über die Abhängigkeit der Grösse, des relativen Gewichtes und der Oberflächenstruktur der Landschneckenschalen von den Umweltsfaktoren: Zeits. Morph. Okol. Tiere, v. 25, p. 757807.CrossRefGoogle Scholar
Rohlf, F. J., 1963, Congruence of larval and adult classifications in Aedes (Diptera: Culicidae): Syst. Zool., v. 12, p. 97117.CrossRefGoogle Scholar
Romer, A. S., 1939, Notes on branchiosaurs: Amer. Jour. Science, v. 237, p. 748761.CrossRefGoogle Scholar
Rothschild, Anne, & Rothschild, Miriam, 1939, Some observations on the growth of Peringia ulvae (Pennant) 1777 in the laboratory: Novitates Zool., v. 41, p. 240247.Google Scholar
Ruhe, R. V., Cady, J. G., & Gomez, R. S., 1961, Paleosols of Bermuda: Geol Soc. America, Bull., v. 72, p. 11211142.CrossRefGoogle Scholar
Runcorn, S. K., 1966, Corals as paleontological clocks: Sci. American, v. 215, no. 4, p. 2633.CrossRefGoogle Scholar
Schaeffer, Bobb, 1965, The role of experimentation in the origin of higher levels of organization: Syst. Zool., v. 14, p. 318336.CrossRefGoogle ScholarPubMed
Schaeffer, Bobb, & Hecht, M. K., 1965, The origin of higher levels of organization: introduction and historical resume: Syst. Zool., v. 14, p. 245248.CrossRefGoogle ScholarPubMed
Schaeffer, Bobb, & Rosen, D. E., 1961, Major adaptive levels in the evolution of the actinopterygian feeding mechanism: Amer. Zoologist, v. 1, p. 187204.CrossRefGoogle Scholar
Scrutton, C. T., 1964 [1965], Periodicity in Devonian coral growth: Palaeontology, v. 7, p. 552558.Google Scholar
Smith, R. E., & Saville, P. D., 1966, Bone breaking stress as a function of weight bearing in bipedal rats: Amer. Jour. Phys. Anthropology, v. 25, p. 159164.CrossRefGoogle ScholarPubMed
Thompson, D'A. W., 1942, On growth and form: Cambridge, Cambridge Univ. Press, 1116 p.Google Scholar
Tihen, J. A., 1955, A new Pliocene species of Ambystoma, with remarks on other fossil ambystomids: Michigan, Univ., Mus. Paleontology, Contr., v. 12, p. 229244 Google Scholar
Waller, T. R., 1968, Two FORTRAN II programs for the univariate and bivariate analysis of morphometric data: U. S. Natl. Mus., Bull. (in press).CrossRefGoogle Scholar
Warburton, F. E., 1955, Feedback in development and its evolutionary significance: Amer. Naturalist, v. 89, p. 129140.CrossRefGoogle Scholar
Wells, J. W., 1963, Coral growth and geochronometry: Nature, v. 197, p. 948950.CrossRefGoogle Scholar
Wood, A. E., 1965, Grades and clades among rodents: Evolution, v. 19, p. 115130.CrossRefGoogle Scholar