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Punctuated Equilibrium and Radical Contingency

Darwin supposed that variation would involve very small changes that might be difficult to detect and would initially appear to have little significance for natural selection. The idea that evolution proceeds by such small steps and never makes jumps, is a key ‘dogma’ in neo-Darwinism. It is called gradualism. There have been some challenges to this belief but the most significant have been by Eldredge and Gould, stemming from a paper in 1972. They stated that there was strong evidence in the fossil record for long periods of stasis, during which virtually no evolution occurred. These long periods of several million years were punctuated by relatively short periods of rapid evolution, over periods of 5,000 to 50,000 years, which is very brief in geological time. This view has more or less been integrated into neo-Darwinism.

The work of Stephen Jay Gould in particular remains important, through his resolute resistance to Dawkins’ genetic reductionism, his insistence that evolution cannot be equated with progress, and his emphasis on historical contingency. In his beautiful book Wonderful Life, on the fossil evidence of the Burgess Shale, a sediment in the Canadian Rockies, Gould emphasises that it would have been impossible, inspecting the range of organisms of 500 million years ago, to say which would survive into later eras, yet all the vertebrates we know are thought to be descended from a single, insignificant-seeming type of worm called Pikaia. So running the tape of life again would be very unlikely to give rise to creatures like ourselves.Gould, SJ, Wonderful Life: The Burgess Shale and the Nature of History, especially Chapter V.

The status of Gould’s conclusions in Wonderful Life has recently been challenged by Simon Conway Morris in his The Crucible of Creation (1998).Conway Morris, S, The Crucible of Creation (Oxford: Oxford University Press, 1998). For other rebuttals of Gould see Dennett, DC, Darwin’s Dangerous Idea (Harmondsworth: Penguin, 1995) pp300-08 and...Conway Morris, one of the principal investigators of the Burgess Shale, takes issue in particular with one of Gould’s main points - that the last 500 million years have been characterised much more by the ‘grim reaper’ of extinction than by the continual branching of the tree of life. Different analyses of the data can give a very different conclusion - that evolutionary innovation has persisted, and shown continual evidence of convergence (the same characteristics arising by different evolutionary paths). Conway Morris infers from this that it was extremely likely that some form of complex life, such as humanity, would have evolved.Conway Morris, 1998, 13-14, 199-205. See God, Humanity and the Cosmos pp276-79.

Email link | Feedback | Contributed by: Dr. Christopher Southgate and Dr. Michael Robert Negus
Source: God, Humanity and the Cosmos  (T&T Clark, 1999)

Evolutionary Biology and Theology

Index - God, Humanity and the Cosmos, 1999 T&T Clark

Punctuated Equilibrium and Radical Contingency

Related Book Topics:

Important Evolutionists Before Darwin
Influences on Darwin
Darwin’s Evolutionary Scheme
Darwin and the Term ‘Evolution’
Darwin’s Challenge to Theological Positions
Some Recent Debates About Evolution
From Darwinism to Neo-Darwinism
Self-Organisation and the Development of Complexity
The Rhetoric of Darwinism
Evolution as a Science of the Unrepeatable Past
The Evolution of Hominids
The Neanderthals
The Paradox of the Development of Modern Humans
Religious Responses to the Science of Human Evolution
Humans as Made in the Image of God
The Doctrine of the Fall
The Science of Sociobiology Critiques the Truth-Claims of Religion
Evolution and Theology

Source:

Dr. Michael Robert Negus and Dr. Christopher Southgate in God, Humanity and the Cosmos. Published by T&T Clark.

See also:

Charles Darwin
Chromosome
DNA Double-Helix
Evolution
Purpose and Design
Does God Act?
Where did we Come From?
Opinions
Books on Biology, Genetics and Theology