Is a New Evolutionary Synthesis Necessary?

Stebbins, G. Ledyard; Ayala, Francisco J.

doi:10.1126/science.213.4511.967

Cited by 212 publications

(52 citation statements)

References 32 publications

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“…Although sometimes interpreted as contradicting the gradualist theory of evolution (8,82), punctuated patterns of evolutionary change, especially in morphology, are expected under the (gradualist) alternative-adaptation hypothesis. This represents a further step in reconciling these two perhaps only superficially contradictory points of view.…”

Section: Discussionmentioning

confidence: 93%

Alternative adaptations, speciation, and phylogeny (A Review)

West‐Eberhard

1986

Proc. Natl. Acad. Sci. U.S.A.

319

259

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Alternative adaptations-different adaptive phenotypes maintained in the same life stage and the same population but not necessarily simultaneously expressed in the same individual-represent contrasting character sets produced by the same genome, in effect allowing a single species to occupy more than one sympatric niche. Such alternatives are particularly likely to give rise to novel adaptations because of selection for extreme dissimilarity between them and because established traits buffer populations against extinction while independently expressed alternatives evolve in new directions. Particular alternatives can be suddenly fixed in populations with little or no genetic change, leading to a period of rapid evolution (especially, of morphology) exaggerating the characteristics of the newly fixed form. This burst of change would facilitate rapid speciation and could produce "punctuated" patterns of evolution. Evidence from a wide variety of organisms shows that alternative phenotypes are exceedingly common in nature and that they are probably important in speciation and macroevolution. Although many of these ideas and observations have been noted piecemeal by previous authors, bringing them together demonstrates the probable importance of alternative adaptations in the origin of major evolutionary novelties and calls for a revision of current and traditional ideas about the role of behavior and ontogeny in the genesis of organic diversity.The Alternative-Adaptation HypothesisThe purpose of this paper is to suggest a change in the way biologists think about the origins of organic diversity: character divergence, speciation, and macroevolution or the invasion of major new adaptive zones.The usual way to visualize phylogenetically important divergence begins with reproductive isolation, or speciation: a branching point of a phylogenetic tree marks both the beginning of a new lineage and the beginning of character divergence. New characters may conceivably arise without reproductive isolation via gradual evolution over time, with the eventual formation of a new "chronospecies". But increased diversity and major innovation begin with speciation, and macroevolution leading to the origin of a new higher taxon requires a series of such events. On this evolutionists have generally agreed, even when holding otherwise disparate opinions (e.g., see p. 524 of ref.

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Section: Discussionmentioning

confidence: 93%

Alternative adaptations, speciation, and phylogeny (A Review)

West‐Eberhard

1986

Proc. Natl. Acad. Sci. U.S.A.

319

259

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show abstract

“…Nevertheless, a general feeling was that the accumulation of molecular data would lead to an evolution of Modern Synthesis more than to a revolution (Fitch 1982;Stebbins and Ayala 1981). It was also admitted that molecular observations made so far were peripheral to the mechanisms of evolution: only a precise description of the mechanisms of development could open the door to a description of the mechanisms of evolution.…”

Section: The Article In Its Scientific Contextmentioning

confidence: 96%

The genetic distance between humans and chimpanzees: What did Mary-Claire king and Allan Wilson really say in 1975?

Morange

2011

J Biosci

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“…Unfortunately, neither Gould nor any of the other critics have been able to provide an adequate alternative theory of heredity to explain something like punctuated equilibrium. Mendelism (including its molecular successor) has no place for such jumps or starts (Stebbins and Ayala 1981). Recently, it is the students of embryology, now known as evolutionary development, or evo-devo, who have been trying to break the Darwinian ties.…”

mentioning

confidence: 98%

Charles Darwin’s On the Origin of Species

Ruse

2007

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Is a New Evolutionary Synthesis Necessary?

Cited by 212 publications

References 32 publications

Alternative adaptations, speciation, and phylogeny (A Review)

Alternative adaptations, speciation, and phylogeny (A Review)

The genetic distance between humans and chimpanzees: What did Mary-Claire king and Allan Wilson really say in 1975?

Charles Darwin’s On the Origin of Species

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