Hostname: page-component-6bb9c88b65-dwch4 Total loading time: 0 Render date: 2025-07-27T00:27:19.022Z Has data issue: false hasContentIssue false
  • English
  • Français

Punctuated equilibrium and evolutionary stasis

Published online by Cambridge University Press:  08 February 2016

Thomas J. M. Schopf
Thomas J. M. Schopf*
Affiliation:
Dept. Geophysical Sciences, University of Chicago, Chicago, IL 60637
Get access Rights & Permissions [Opens in a new window]

Extract

Writers as disparate in professional interest as those describing speciation in Drosophila, predicting weather, or supporting creationism have all recently focused on the “sudden” appearance of taxa in the geologic record. In the process, each has cited the punctuated equilibrium argument. Owing to the enormously wide attention which this issue has received since its introduction almost a decade ago, it seems worthwhile to try to place the paleontological and biological evidence in a 1981 perspective. The focus I have chosen is to try to analyze the issue, much as in recent columns in Current Happenings on competitive exclusion, and on larval dispersal and biogeography, in which are put forth alternative explanations for a set of data on a general problem.

Information

Type
Current Happenings
Information
Paleobiology , Volume 7 , Issue 2 , Spring 1981 , pp. 156 - 166
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

1Jones, J. S. 1981. Models of speciation—the evidence from Drosophila. Nature. 289:743–744.CrossRefGoogle ScholarPubMed
2Ramage, C. S. 1980. Sudden events. Futures. August, 1980. Pp. 268–274.Google Scholar
3 See the discussion in Gurin, J. 1981. Is it serious science, or just monkey business? The Sciences. 23:16–19, 34. [April, 1981.] And in Godfrey, L. R. 1981. The flood of antievolutionism. Natural History. 90: 4–10.CrossRefGoogle Scholar
4Gould, S. J. 1981. Creationists vs. Evolutionists. Discover. 32–37. [May, 1981.]Google Scholar
5Eldredge, 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 & Co.; San Francisco. The history of the article is as follows. On March 9, 1970, I wrote Steve in my capacity as the organizer of a Paleontological Society symposium titled Models in Paleontology, and invited him to participate with a paper directed along the theme of ‘Models of Speciation’. On March 13, he replied, “A damned good idea, your symposium. I'm flattered by your invitation and will gladly accept. My only hesitation is that you have given me a topic that ranks only third on your list in terms of my competence. I could handle either morphology or phylogeny with much greater ease and would request, if either Dave Raup or Mike Ghiselin can't participate, that you allow me to cover one of their topics. In that case, I would suggest that you invite Niles Eldredge (Invertebrate Fossils, American Museum of Natural History) to speak on speciation. He's our best new thinker (isn't it ridiculous that we are already a generation older than someone else), and worries constantly about speciation in paleontology. Otherwise, of course, I will accept the topic you suggest. I hope you would then allow me to expand it somewhat to speciation and the origin of new taxa in general. This would not transgress the domain of any other speaker (not even phylogeny I assure you) and would, in any case, be based in speciation theory. Let me know as soon as possible; I may even start work early.” Both Raup and Ghiselin did participate, and so the talk at the symposium was authored by Gould and Eldredge, and the manuscript was by Eldredge and Gould. The editorial introduction which I supplied for the article focused on placing punctuated equilibria in historical perspective, as a continuation of modern thought of the day. In my initial letter to Steve, I had written, “What I would like the papers of this Symposium (and published volume) to accomplish is to identify and evaluate the theoretical models which are guiding (by accident or design) the development of various parts of our science. We now have both an extensive and a modern documentation of life of the past in the Treatise, in discussions about specific groups in the Journal, and elsewhere. The theoretical framework, however, dictates where one looks and how one goes about the descriptive process.” Eldredge and Gould succeeded enormously in this task, and their paper has provided for more than a decade the conceptual foundation for paleontological research in evolution. Few if any among us realized at the time the enormous impact and attention which that article would come to have.Google Scholar
6 See also: Gould, S. J. and Eldredge, N. 1977. Punctuated equilibria: the tempo and mode of evolution reconsidered. Paleobiology. 3:115–151. Levinton, J. S. and C. M. Simon. 1980. A critique of the punctuated equilibria model and implications for the detection of speciation in the fossil record. Systematic Zoology. 29:130–142.CrossRefGoogle Scholar
7Heck, K. L. Jr. 1980. Competitive exclusion or competitive delusion? Paleobiology. 6:241–242.Google Scholar
8Strathman, R. R. 1980. Why does a larva swim so long? Paleobiology. 6:373–376.CrossRefGoogle Scholar
9Gordon, R. J. 1981. Macroeconomics. Second Edition. Little, Brown and Co.; Boston. 610 pp.Google Scholar
10Schopf, T. J. M. 1979. Evolving paleontological views on deterministic and stochastic approaches. Paleobiology. 5:337–352.CrossRefGoogle Scholar
11Muller, H. J. 1949. Redintegration of the symposium on genetics, paleontology, and evolution. pp. 421–445. In: Genetics, Paleontology, and Evolution. Ed. by Jepsen, G. L., Mayr, E. and Simpson, G. G.Princeton University Press. (Reprinted 1963 as an Atheneum paperback.)Google Scholar
12Janzen, D. H. 1976. Why are there so many species of insects? Proceedings of the 15th International Congress of Entomology. pp. 84–94.Google Scholar
13Raup, D. M. 1981. Extinction: bad genes or bad luck? Acta Geològica Hispànica. 16:25–33.Google Scholar
14White, M. J. D. 1978. Modes of Speciation. W. H. Freeman and Co.; San Francisco. 455 pp.Google Scholar
15Mayr, E. 1963. Animal Species and Evolution. Belknap Press; Cambridge, Mass. 797 pp. (see pp. 578–580). Schopf, T. J. M. and L. S. Murphy. 1973. Protein polymorphism of the hybridizing seastars Asterias forbesi and Asterias vulgaris and implications for their evolution. Biol. Bull. 5:589–597. Other examples of rapid diversification are the various cases of species swarms in rift lake valleys, or Lake Baikal, or the Pontian (Caspian) cockles, the latter as recounted by S. M. Stanley. 1975. A theory of evolution above the species level. Proc. Nat. Acad. Sci. 72:646–650.CrossRefGoogle Scholar
16Bernard, F. 1895. Éléments de Paléontologie. J.-B. Baillière et Fils. Paris. 1168 pp. (Reprinted 1980 by Arno Press, New York. Partly reprinted 1895 in pamphlet form, and translated into English; 91 pp.; also reported to be in the Annual Report of the New York State Geological Survey. 14: 127–217. The critical passage on absence of finding intermediates is quoted in the editorial introduction to Eldredge and Gould, 1972; see ref. 5.)Google Scholar
17Lande, R. 1980. Genetic variation and phenotypic evolution during allopatric speciation. American Naturalist. 116:463–479. And literature cited therein.CrossRefGoogle Scholar
18 There is a lot of literature on this, and one easily accessible reference to a common marine taxon is: Schopf, T. J. M. and Dutton, A. R. 1976. Parallel clines in morphologic and genetic differentiation in a coastal zone marine invertebrate: the bryozoan Schizoporella errata. Paleobiology. 2:255–264.CrossRefGoogle Scholar
19Schopf, T. J. M. 1981. Evidence from molecular biology with regard to the rapidity of genomic change and species durations. In: Niklas, K. J., ed. Paleobotany, Paleoecology and Evolution: Festschrift for Harlan P. Banks. Praeger Pubs.; New York. Vol. 1, pp. 91–142.Google Scholar
20Dover, G. 1978. DNA conservation and speciation: adaptive or accidental? Nature. 272:123–124.CrossRefGoogle Scholar
21Bush, G. L. 1975. Modes of animal speciation. Ann. Rev. Ecology and Systematics. 6:339–364. Templeton, A. R. 1980. Modes of speciation and inferences based on genetic distances. Evolution 34: 719–729.CrossRefGoogle Scholar
22Schindel, D. E. 1980. Microstratigraphic sampling and the limits of paléontologic resolution. Paleobiology. 6:408–426.CrossRefGoogle Scholar
23 The diagram follows from a view expressed in 1976 that “On balance, it appears at least to Schopf that the data of this paper are most easily accepted into a model of dynamic, changing phyletic gradualism instead of a static, unchanging punctuated equilibrium.” (P. 263 in ref. 18.)Google Scholar
24Stanley, S. M. 1977. Animal evolution. pp. 136–138. In: McGraw-Hill Yearbook of Science and Technology. McGraw-Hill Co.; New York.Google Scholar
25Schopf, T. J. M. 1966. Conodonts of the Trenton Group (Ordovician) in New York, Southern Ontario, and Quebec. New York State Museum and Science Service. Bull. 405. 105 pp.Google Scholar
26Stitt, J. H. 1977. Late Cambrian and earliest Ordovician trilobites; Wichita Mountains area, Oklahoma. Oklahoma Geological Survey. Bull. 124:1–79.Google Scholar
27 For example, Table 1 of Thierstein, H. R. and Okada, H. 1979. The Cretaceous-Tertiary boundary event in the North Atlantic. Initial Reports of the Deep Sea Drilling Project. 43:601–616.Google Scholar
28Bolli, H. M. 1980. The ages of sediments recovered from DSDP Legs 1–4, 10–15, and 36–53 (Atlantic, Gulf of Mexico, Caribbean, Mediterranean, and Black Sea). Initial Reports of the Deep Sea Drilling Project. 51, 52, 53:1525–1534.Google Scholar
29 Reviewed in Schopf, T. J. M. 1980. Paleoceanography. Harvard Univ. Press; Cambridge, Mass.CrossRefGoogle Scholar
30 Note for example that two-thirds or more of the width of present continental shelves of the world have had no sediment deposited for the past 10,000 or more years. The sediment on the present shelf chiefly is relict from earlier stands of sea level. Thus one dredges mastodon and mammoth teeth, for example, which date from several thousand years ago when sea level was 150 m lower. See p. 360 et seq. in Emery, K. O. and E. Uchupi. 1972. Western North Atlantic Ocean: topography, rocks, structure, water, life and sediments. American Association of Petroleum Geologists. Memoir 17. 532 pp.Google Scholar
31Kielan-Jaworowska, Z. 1974. Migrations of the Multituberculata and the late Cretaceous connections between Asia and North America. Annals of the South African Museum. 64:231–243.Google Scholar
32Sepkoski, J. J. Jr. 1981. A factor analytic description of the Phanerozoic marine fossil record. Paleobiology. 7:35–63. The fossil deposits are the Burgess Shale (Cambrian), Hünsruck Shale (Devonian), and Mazon Creek concretions (Pennsylvanian).CrossRefGoogle Scholar
33 There is a large and technical literature in paleontology and in sedimentology on evaluating the preservational potential of different taxa, of different types of sediments, and of different environments.Google Scholar
34 The reasons why taxa usually appear “suddenly” is poorly understood by those who support creationism and who usually have not had the opportunity for requisite advanced training in sedimentary geology, in chemical and physical diagenesis, and in paleontology. Perhaps an analogy with archeology would help. The fragmentary nature of human civilization is legion. Yet no one doubts that there were ancient cities of tens to hundreds of thousands of people. The disintegration of this record over a time scale of only a few thousand years must give one pause in trying to evaluate what ought to be the record for species, many of which were rare to begin with, which died out millions of years ago.Google Scholar
35Raup, D. M. 1979. Biases in the fossil record of species and genera. Bulletin Carnegie Museum of Natural History. 13:85–91.Google Scholar
36 Pp. 334 et seq. in Mayr, 1963, in ref. 15.Google Scholar
37 For example, Vorontsov, N. N., Frisman, L. V., Lyapunova, E. A., Mezhova, O. N., Serdyuk, V. A., and Fomicheva, I. I. 1980. The effect of isolation on the morphological and genetic divergence of populations. Genetica 52/53:339–359.CrossRefGoogle Scholar
38Cheetham, A. H. 1968. Morphology and systematics of the bryozoan genus Metrarabdotos. Smithsonian Mis. Coll. 153:1–121. Malmgren, B. A. and J. P. Kennett. 1981. Phyletic gradualism in a late Cenozoic planktonic foraminiferal lineage; DSDP site 284 southwest Pacific. Paleobiology. 7:230–240.Google Scholar
39Raup, D. M. and Crick, R. E. 1981. Evolution of single characters in the Jurassic Ammonite Kosmoceras. Paleobiology. 7:200–215.CrossRefGoogle Scholar
40 Some authors have sought to take into account the fact that (on a probabilistic basis) a taxon will not occur throughout the full subdivision of geologic time to which it belongs. However these corrections are never based on actual detailed records of taxa, and the number to be corrected is always the longer time interval to which the fossil was initially assigned.Google Scholar
41 This has been analyzed with respect to taxonomic survivorship curves by Sepkoski, J. J. Jr. 1975. Stratigraphic biases in the analysis of taxonomic survivorship. Paleobiology. 1:343–355.CrossRefGoogle Scholar
42Hallam, A. 1976. Stratigraphic distribution and ecology of European Jurassic bivalves. Lethaia. 9:245–259. Hallam, A. 1978. How rare is phyletic gradualism and what is its evolutionary significance? Evidence from Jurassic bivalves. Paleobiology. 4:16–25. The 1976 paper includes the stratigraphic range of 323 species. In ascending order, the lower Jurassic includes stages inferred to be 3, 6, 5 and 6 m.y., the middle Jurassic 3, 7, 7 and 6 m.y. and the upper Jurassic 7, 5 and 7 m.y.CrossRefGoogle Scholar
43 The next couple of decades may see widespread assignment of marine taxa to subdivisions finer than a stage as the use of conodont zones becomes wide spread for Paleozoic and Triassic rocks, and as microfossils are increasingly used as the basis for zonal classification for the Jurassic and Cretaceous.Google Scholar
44 A cohort method of estimating durations was introduced by Raup, D. M. 1978. Cohort analysis of generic survivorship. Paleobiology. 4:1–15. However the first census point for each of the geologic system generic cohorts is after 90 percent of each cohort is no longer existing. (Unpublished series level data were reported to be “compatible” with system level data). Species durations were obtained in a backward calculation from inferred generic survivorship. This is not (nor was it represented to be) a direct measure of species durations.CrossRefGoogle Scholar
45 BEIR III Report. 1981. National Academy of Sciences—National Research Council, Advisory Committee on the Biological Effects of Ionizing Radiation. Selby, P. B. 1979. Radiation-induced dominant skeletal mutations in mice: Mutation rate, characteristics, and usefulness in estimating genetic hazard to humans from radiation. In: Radiation Research Proceedings of the 6th International Congress of Radiation Research, May 13–19, 1979. Tokyo. Edited by S. Okada, M. Imamura, T. Terashima, and H. Yamaguchi. Toppan Printing Co. Tokyo; pp. 537–544. Selby, P. B. and P. R. Selby. 1978. Gamma-ray induced dominant mutations that cause skeletal abnormalities in mice. Mutation Research. 51: 199–236.Google Scholar
46 Pp. 38 et seq. in Mayr, 1963, in ref. 13.Google Scholar
47 “Nearly every major group of organisms has been discovered to have extensive complexes of sibling species. One example is the Hydrobiidae, a family of freshwater snails of world wide distribution. Assignment of the 11 genera and 92 species resisted correct assignment owing to ‘convergence in shell, radula, penis, and operculum’ (Davis 1979). Only characters of the female reproductive system proved to be reliable and confirmed by electrophoretic analysis of various taxa (G. M. Davis, personal communication 1980) …. And in another recent study, this one on a fiddler crab, Salmon et al. (1979, p. 190) concluded that ‘available evidence suggests that speciation in most of the other North American fiddler crabs has proceeded without significant morphological divergence’. What one finds at the molecular level may provide for rapid adaptation, and what one finds at the gross morphological level may be much more constrained by a variety of factors (e.g., structural design).” Schopf in ref. 19. Davis, G. M. 1979. The origin and evolution of the gastropod family Pomatiopsidae, with emphasis on the Mekong River Triculinae. Acad. Natural Sci. of Philadelphia. Monograph 20. Salmon, M. S., Ferris, S. D., Johnston, D., Hyatt, G., and Whitt, G. S. 1979. Behavioral and biochemical evidence for species distinctiveness in the fiddler crabs. Evolution. 33:182–191.Google ScholarPubMed
48Emmons, S. W., Klass, M. R., and Hirsh, D. 1979. Analysis of the constancy of DNA sequences during development and evolution of the nematode Caenorhabditis elegans. Proceedings of the National Academy of Sciences. 76:1333–1337.CrossRefGoogle ScholarPubMed
49Dillon, R. T. Jr. and Davis, G. M. 1980. The Goniobasis of southern Virginia and northwestern North Carolina: genetic and shell morphometric relationships. Malacologia. 20:83–98.Google Scholar
50Schnell, G. D., Best, T. L., and Kennedy, M. L. 1978. Interspecific morphologic variation in kangaroo rats (Dipodomys): degree of concordance with genic variation. Systematic Zoology. 27:34–48.CrossRefGoogle Scholar
51Murray, J. and Clarke, B. 1980. The genus Partula on Moorea: speciation in progress. Proc. Royal Soc. London. Series B. 211:83–117. And references cited therein.Google Scholar
52Nevo, E. and Cleve, H. 1978. Genetic differentiation during speciation. Nature. 275:125–126.CrossRefGoogle ScholarPubMed
53Gottlieb, L. D. 1976. Biochemical consequences of speciation in plants. pp. 123–140. In: Molecular Evolution, Ayala, F. J., ed. Sinauer Pub.; Sunderland, Mass.Google Scholar
54Avise, J. C. 1976. Genetic differentiation during speciation. pp. 106–122. In: Molecular Evolution, Ayala, F. J., ed. Sinauer Pub.; Sunderland, Mass. Ayala, F. J. 1975. Genetic differentiation during the speciation process. Evolutionary Biology. 8: 1–78.Google Scholar
55Mizuno, S. and Macgregor, H. C. 1974. Chromosomes, DNA sequences, and evolution in salamanders of the genus Plethodon. Chromosoma. 48:239–296; see p. 292.CrossRefGoogle ScholarPubMed
56Avise, J. C. and Ayala, F. J. 1976. Genetic differentiation in speciose versus depauperate phylads: evidence from the California minnows. Evolution. 30:46–58. Avise, J. C. and J. R. Gold. 1977. Chromosomal divergence and speciation in two families of North American fishes. Evolution. 31:1–13.CrossRefGoogle ScholarPubMed
57 Use of the fossil record for studies of speciation is sometimes justified on the grounds that it is the only record we have. For example, “Whether the fossil ‘species’ should be renamed morphospecies or whatever, study of their patterns of change through time must remain an integral part of any comprehensive evolutionary discipline.” (Hallam, A. 1981. Macroevolution conference report. Palaeontological Association Circular 103. pp. 6–8.) However if the answer to the question of what is the dominant mode of evolution is invested in an assumption about what these “morphospecies” represent, then it becomes a tautology and one can get any answer one wants, an obviously unsatisfactory state of affairs.Google Scholar
58Schopf, 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. 1:63–70.CrossRefGoogle Scholar
59Ruedemann, R. 1917. The Paleontology of arrested evolution. New York State Museum Bulletin, No. 196. pp. 107–134. Reprinted in: Presidential Addresses of the Paleontological Society, T. J. M. Schopf, ed. 1980. Arno Press. And reanalyzed in, Schopf, T. J. M. 1980. The Paleontology of arrested evolution. Abstracts with programs. Geological Society of America. 12: 517.Google Scholar
60Van Valen, L. 1973. A new evolutionary law. Evolutionary Theory. 1:1–30. Raup, D. M. 1975. Taxonomic survivorship curves and Van Valen's Law. Paleobiology. 1:82–96.Google Scholar
61Gould, S. J. 1981. Evolution as fact and theory. Discover. P. 34–37. (May, 1981.)Google Scholar
62 In recognition of this fact, M. J. D. White wrote “We once again urgently need a new synthesis of two traditions—those of evolutionary and molecular biology.” White, M. J. D. 1981. Tales of long ago—the birth of evolutionary theory as a scientific discipline. Review of The Evolutionary Synthesis: Perspective on the Unification of Biology, E. Mayr and W. B. Provine, eds. Harvard Univ. Press. Paleobiology. 7:287–291.Google Scholar
63Shapiro, J. A. 1980. Changes in gene order and gene expression. Research Frontiers in Aging and Cancer. National Cancer Institute Monograph. pp. 1–95. Shapiro, J. A. 1981. Reflections on the information content of chromosome primary structure and how it changes. Submitted.Google Scholar
64 “One might argue that genetic changes occur in a lineage through time, and thus the main impact of the views presented here is on the ‘arbitrary’ phyletic subdivision of a gradual transitional lineage (i.e., anagenesis). In fact, evidence for rapid genomic change also implies that phyletic splitting (i.e., cladogenesis) often should occur—that is, lineages need be ‘separated’ only for short periods of time (a few thousand years) in order to achieve reproductive isolation …. Thus, both phyletic transformation and phyletic splitting may occur far more often than has been generally recognized.” From Schopf, ref. 19.Google Scholar
65 Those who believe that the fossil record harbors any support for special creation should take no consolation from any arguments concerning punctuated equilibrium. To do so is to incorrectly understand the issues, only one of which concerns preservation and the fossil record30,34.Google Scholar
Paleontology both benefits and suffers from an almost universal necessity to have its ideas conveyed in words instead of in chemical formulae or mathematics, and therefore it has the appearance of being readily accessible to the general reader who lacks training and experience in this field. This appearance of accessibility is both pleasant (it attracts interest to the field) and disconcerting (statements are wildly taken out of context). Of course one can believe that the fossil record supports creationism, just as one can believe that the earth is flat. But in either case the justification has no scientific basis whatsoever. The distortion of facts is as injurious to the understanding of science in general as it is disrespectful to religion in particular. Religion does not depend upon such distortions to justify its value in our society. Indeed religion can only lose respect in the long run if it is tied in the public mind to notions that are so patently false as the view that the fossil record in any way supports creationism.Google Scholar
It is ironic that the recent anti-evolution publicity should appear during the time that molecular biology and modern medical sciences are providing the most detailed account yet available of the evolutionary history of humans and other animals.Google Scholar
King, M.-C. and Wilson, A. C. 1975. Evolution at two levels in humans and chimpanzees. Science. 188:107–116. Deininger, P. L. and Schmid, C. W. 1976. Thermal stability of human DNA and chimpanzee DNA heteroduplexes. Science. 194:846–848. Wilson, A. C., Carlson, S. S., and White, T. J. 1977. Biochemical evolution. Annual Reviews of Biochemistry. 46:573–639. Efstratiadis, A. et al. 1980. The structure and evolution of the human β-globin gene family. Cell. 21:653–668. Perler, F. et al. 1980. The evolution of genes: the chicken preproinsulin gene. Cell. 20:555–566. Heilig, R. et al. 1980. The ovalbumin gene family: structure of the X gene and evolution of duplicated split genes. Cell. 20:625–637.CrossRefGoogle ScholarPubMed