Punctuated equilibrium comes of age

  title={Punctuated equilibrium comes of age},
  author={Stephan jay Gould and Niles Eldredge},
The intense controversies that surrounded the youth of punctuated equilibrium have helped it mature to a useful extension of evolutionary theory. As a complement to phyletic gradualism, its most important implications remain the recognition of stasis as a meaningful and predominant pattern within the history of species, and in the recasting of macroevolution as the differential success of certain species (and their descendants) within clades. 

Punctuated Equilibrium and Phyletic Gradualism

In punctuated equilibrium, species tend to show morphological stasis between abrupt speciation events, whereas in phyletic gradualism species undergo more continuous change.


  • D. Futuyma
  • Biology
    Evolution; international journal of organic evolution
  • 2010
It is suggested that although constraints on individual characters or character complexes may often reside in the structure or paucity of genetic variation, organism‐wide stasis might better be explained by a hypothesis of ephemeral divergence, according to which the spatial or temporal divergence of populations is often short‐lived because of interbreeding with nondivergent populations.

The Race for Evolutionary Success

This paper balances a review of the forces threatening species survival with a comprehensive scan of factors that could act as counterweights that could individually or in combination avert massive species extinction.

Continuing the debate on the role of Quaternary environmental change for macroevolution.

  • K. Bennett
  • Environmental Science, Geography
    Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 2004
DNA characterization of modern populations in relation to their distributions nicely complements palaeoecological results by contributing ancestry and helps to understand how species originate and the causal factors of speciation.

Detection of punctuated equilibrium from molecular phylogenies

A method to detect punctuated evolution without reference to fossil data is presented, based on the phenotypes of extant species and on their relatedness as revealed by molecular phylogeny, describing morphological differentiation of two species over time.

Cryptic clues revealed

An analysis of mutant fruitflies now provides a mechanism for rapid morphological change, with implications for evolutionary theory.

Evolutionary uniformitarianism.

  • D. Erwin
  • Environmental Science
    Developmental biology
  • 2011


Analysis of cladogenesis at the specific level as an example shows that in order to correctly establish the possible merits of both concepts, the claims of each have to be verified against general evolutionary theory.

Punctuated Evolution Caused by Selection of Rare Beneficial Mutations

A clear and unambiguous case of punctuated evolution is presented for cell size in a population of Escherichia coli evolving for 3000 generations in a constant environment.

Evolution: Tempo and Mode

‘Tempo’ refers to the rate of evolution, the rate of phenotypic change either within lineages or expressed as averages within major taxonomic groups. ‘Mode’ refers to the pattern of evolution –



Punctuated equilibrium, morphological stasis and the palaeontological documentation of speciation: a reply to Fryer, Greenwood and Peake's critique of the Turkana Basin mollusc sequence

Critics of my analysis of morphological variation in a sequence of Plio-Pleistocene freshwater molluse faunas from the Turkana Basin in E Africa misunderstand the nature of the phenotypic variation in African freshwatermolluscs and its relevance to my study, and apparently misunderstand punctuated equilibrium theory.

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

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.

Punctuated equilibria: the tempo and mode of evolution reconsidered

It is argued that virtually none of the examples brought forward to refute the model of punctuated equilibria can stand as support for phyletic gradualism; many are so weak and ambiguous that they only reflect the persistent bias for gradualism still deeply embedded in paleontological thought.

Local extinction and ecological re-entry of early Eocene mammals

Phenacodus species are relatively static in size and morphology throughout the local section studied, and two of these show statistically significant discontinuities in temporal range, which points to ecological control of vertical events within a local section.

The genetics of stasis and punctuation.

This chapter discusses the theory and results of a large-scale study of variation in nature and the role that natural selection plays in this process.

A theory of evolution above the species level.

  • S. Stanley
  • Environmental Science, Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1975
Rates of speciation can be estimated for living taxa by means of the equation for exponential increase, and are clearly higher for mammals than for bivalve mollusks.

Punctuated morphological change in a Neogene diatom lineage: “Local” evolution or migration?

A biometric analysis of the morphology of a late Pliocene planktic diatom lineage, Rhizosolenia praebergonii Mukhina indicates that it appeared abruptly in the fossil record in the Indian Ocean at

Is evolution gradual or rectangular? Evidence from living fishes.

  • J. Avise
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1977
Electrophoretic analyses of genic composition in 69 species of North American Cyprinidae (minnows), and 19 species of Centrarchidae (sunfish) show results that are inconsistent with predictions of rectangular evolution, but are not demonstrably incongruent with phyletic gradualism.

Speciational Evolution: a Phylogenetic Test With Allozymes in Sceloporus (Reptilia)

A phylogenetic test in which amounts of discrete character change relative to an outgroup are compared between sister taxa is provided, which provides conceptual improvements regarding monophyly, equal age of taxa, and distribution of homoplasy.

Punctuated equilibria, morphological stasis and the palaeontological documentation of speciation: a biological appraisal of a case history in an African lake

The fossil molluscs complement information provided by the biology of extant fishes and invertebrates and emphasize the importance of these lakes in the study of evolution in living and extinct populations.