Written by Shaun Johnston Shaun Johnston
Published: April 9, 2011 April 9, 2011
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I'm embarked on a quest to come up with the briefest-possible account of why mutation plus natural selection can't be the primary mechanism of evolution. Here's my latest attempt:
- The great majority of mutations are harmful*. Without natural selection, in every generation harmful mutations predominate, and generation after generation will accumulate, leading to increased disorder and eventual extinction.
- Now introduce natural selection. An efficiency for natural selection of 1% may be assumed.* A 1% reduction in harmful mutations still leaves the great majority harmful (eg a reduction from 90% to 89%). For natural selection to drive evolution by favoring occasional beneficial mutations over harmful ones it would have to be close to 100% efficient, and for that by common consent you’d have to invoke the supernatural.
*from Evolution: The Modern Synthesis by Julian Huxley.
I'd welcome rebuttals.