Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-24T17:47:52.087Z Has data issue: false hasContentIssue false
  • English
  • Français

Trends as changes in variance: a new slant on progress and directionality in evolution

Published online by Cambridge University Press:  02 September 2016

Stephen Jay Gould
Stephen Jay Gould*
Affiliation:
Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138
Get access Rights & Permissions [Opens in a new window]

Abstract

Trends are the primary phenomenon of macroevolution, but they have often been misinterpreted because an old and deep conceptual error has induced us to misread, as anagenesis in abstracted entities, a pattern that actually records changes in variance by increase or decrease in diversity or disparity among species within clades. These patterns are actually produced by the “entity making and breaking machine” of differential species success, but we misread history as anagenesis because we focus on extreme values (though they may only represent tails in variance of a system), or on measures of central tendency that shift passively as species birth and death work in their differential way. I discuss several examples in two classes: “increase trends” mediated by growth in variance, and “decrease trends” produced by diminution of diversity or disparity. I present two examples in extenso based on original data: threefold occurrence of Cope's rule in planktonic foraminifers as a consequence of increasing species diversity from small founding lineages (increase trend), and disappearance of 400 hitting in baseball as a decrease trend recording symmetrical decline of variance with increasing excellence of play, not the gradual extinction of a valued “thing.” A proper appreciation of trends as changes in variance flows from and into the two most important revisionary themes in modern evolutionary theory: 1) constraint and structure as an antidote to overreliance upon adaptation (questions about why founding lineages tend to be small, and why size ranges are constrained, lie primarily in structural, not adaptational, domains); 2) hierarchy (increase and decrease trends are powered by differential species sorting, not by extrapolated anagenesis of competition among organisms within populations).

Type
Presidential Address
Information
Journal of Paleontology , Volume 62 , Issue 3 , May 1988 , pp. 319 - 329
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.)

References

Alvarez, L. W., Alvarez, W., Asaro, F., and Michel, H. 1980. Extraterrestrial cause for the Cretaceous–Tertiary extinction. Science, 208:1095–1108.CrossRefGoogle ScholarPubMed
Benton, M. J. 1987. Progress and competition in macroevolution. Biologial Reviews, 62:305–338.Google Scholar
Bown, T. M., and Rose, K. D. 1987. Patterns of dental evolution in Early Eocene anaptomorphine primates (Omomyidae) from the Bighorn Basin, Wyoming. Journal of Paleontology, 61 (supplement to No. 5, Memoir 23), 162 p.CrossRefGoogle Scholar
Briggs, D. E. G., and Conway Morris, S. 1986. Problematica from the Middle Cambrian Burgess Shale of British Columbia, p. 167–183. In Hoffman, A. and Nitecki, M. (eds.), Problematic Fossil Taxa. Oxford University Press, New York.Google Scholar
Brown, J. H., and Maurer, B. A. 1986. Body size, ecological dominance and Cope's rule. Nature, 324:248–250.Google Scholar
Conway Morris, S. 1986. The community structure of the Middle Cambrian Phyllopod Bed (Burgess Shale). Palaeontology, 29:423–467.Google Scholar
Eldredge, N. 1979. Alternative approaches to evolutionary theory. Bulletin of the Carnegie Museum of Natural History, 13:7–19.Google Scholar
Gould, S. J. 1983. Losing the edge: the extinction of the 400 hitter. Vanity Fair, March (1983), p. 120, 264–278.Google Scholar
Gould, S. J. 1986. Entropic homogeneity isn't why no one hits 400 any more. Discover, August (1986):60–66.Google Scholar
Gould, S. J. 1987. Life's little joke; the evolutionary histories of horses and humans share a dubious distinction. Natural History, 96, April (1987):16–25.Google Scholar
Gould, S. J. and Eldredge, N. 1977. Punctuated equlibria: the tempo and mode of evolution reconsidered. Paleobiology, 3:115–151.Google Scholar
Gould, S. J. and Eldredge, N. In press. On the proper empirical test of punctuated equilibrium.Google Scholar
Gould, S. J., Gilinsky, N. L., and German, Rebecca Z. 1987. Asymmetry of lineages and the direction of evolutionary time. Science, 236:1437–1441.Google Scholar
Jablonski, D. 1987. How pervasive is Cope's rule? A test using Late Cretaceous mollusks. Geological Society of America, Abstracts with Programs, 19(7):713–714.Google Scholar
Jablonski, D., and Bottjer, D. J. 1983. Soft-bodied epifaunal suspension-feeding assemblages in the Late Cretaceous: implications for the evolution of benthic paleocommunities, p. 747–812. In Tevesz, M. J. S. and McCall, P. L. (eds.), Biotic Interactions in Recent and Fossil Benthic Communities. Plenum Press, New York.Google Scholar
Jerison, H. J. 1973. The Evolution of the Brain and Intelligence. Academic Press, New York.Google Scholar
Jerison, H. J. 1985. Issues in brain evolution. Oxford Surveys in Evolutionary Biology, 2:102–134.Google Scholar
Malmgren, B. A., and Kennett, J. P. 1981. Phyletic gradualism in a late Cenozoic planktonic foraminiferal lineage; DSDP Site 284, southwest Pacific. Paleobiology, 7:230–240.Google Scholar
Myrdal, G. 1944. An American Dilemma. Harper and Row, New York.Google Scholar
Runnegar, B. 1987. Rates and modes of evolution in the Mollusca, p. 39–60. In Campbell, K. S. W. and Day, M. F. (eds.), Rates of Evolution. Allen and Unwin, London.Google Scholar
Sepkoski, J. J. Jr., and Miller, A. I. 1985. Evolutionary faunas and the distribution of Paleozoic marine communities in space and time, p. 153–190. In Valentine, J. W. (ed.), Phanerozoic Diversity Patterns, Profiles in Macroevolution. Princeton University Press, Princeton, New Jersey.Google Scholar
Sepkoski, J. J. Jr., and Sheehan, P. M. 1983. Diversification, faunal change, and community replacement during the Ordovician radiations, p. 673–717. In Tevesz, M. J. S. and McCall, P. L. (eds.), Biotic Interactions in Recent and Fossil Benthic Communities. Plenum Press, New York.Google Scholar
Sheldon, P. R. 1987. Parallel gradualistic evolution of Ordovician trilobites. Nature, 330:561–563.Google Scholar
Stanley, S. M. 1973. An explanation for Cope's rule. Evolution, 27:1–26.CrossRefGoogle ScholarPubMed
Vrba, E. S., and Gould, S. J. 1986. The hierarchical expansion of sorting and selection: sorting and selection cannot be equated. Paleobiology, 12:217–228.Google Scholar
Whittington, H. B. 1985. The Burgess Shale. Yale University Press, New Haven, Connecticut.Google Scholar