Thanks Percy, that's what we've been saying.
Syamasu: The very first reply in the sci.bio.evolution thread says EXACTLY what we've been saying here. Worth quoting:
Natural selection would result in nothing if there were no genetic
variation to select on. You may be confused. Mutation (new variation) is not needed for natural selection to do its job. Natural selection can act on any population with existing genetic variation without the addition of new mutations. In your photosynthetic example if all plants had the same photosynthetic mechanism and they were all genetically identical. Shining light on them will not change the genetic composition of the next generation. If they were not genetically identical and some had different photosynthetic machinery than others shining light on them may select for the best genetic type under those conditions, and one variant may take over the population. Evolution is allele frequency change over time. No variant alleles, no evolution.
No evolution can occur, no future individuals of the population can become better adapted to their environment if there is no genetic variation to act on. You'd have to go to some form of Lamarkian changes to get evolutionary change without genetic variation. You could subject a bunch of clones to natural selection, but you wouldn't see any differences in the next generation. You could make the selection so severe that you killed off the population and all allele frequencies would go to zero, but that is about the only way a population will evolve with no genetic variation present. Ron Okimoto
And this is different how from what we've been telling you?
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