This new thread topic arose from
Message 65:
Quetzal wrote:
I DO understand that selection must, by definition, operate at the level of the individual organism. After all, it's the organism that reproduces (or not). Evolution, on the other hand, operates at the level of a population. I would have thought that would be obvious (and no, this is REALLY not the thread to get into the pros and cons of group selection theory).
”HM replied:
Yes, perhaps a new thread is more appropriate, because “group selection” and “individual selection” need to be differentiated from “gene selection” and “kin selection.” It must be confusing to MartinV and his ilk that Darwinian biologists can’t agree on exactly what natural selection is and where it occurs. And, unless you invoke the selfish-gene theory, the same quandaries can be raised about evolution itself.
By definition, natural selection is the possible consequence of uneven reproductive success of individuals in a population. But this does not mean that natural selection necessarily operates on the individual or its population, even though the results may occasionally point in that direction. Looking closer, as did G. C. Williams, Wm. Hamilton, R. Dawkins, et al., the actual site of natural selection can often be seen at the level of genes and their alleles (i.e., genetic evidence of strategic altruism for kin survival). “Group selection” and “species selection” (i.e., 'for the good of the group or the species') are no longer regarded as credible by most biologists, although some still claim them to be true. Furthermore, natural selection is not the only cause of evolution. Non-selective agencies like genetic drift, gene flow, and preferential mating may also cause evolution to occur.
But who knows for sure exactly where natural selection occurs? And the same question can be raised about evolution. Any thoughts?
”HM