Entities that reproduce with mutation will evolve under selection. I’m not so sure about the “natural” part. If AI takes over and starts breeding humans for long floppy ears, is that selection natural?
In some sense, all selection is natural, since everything is part of nature, but an AI that breeds humans for some trait can reasonably be called artificial selection (and mesa-optimization). If such a breeding program happened to allow the system to survive, nature selects for it. If not, it tautologically doesn’t. In any case, natural selection still applies.
But there won’t necessarily be more than one AI, at least not in the sense of multiple entities that may be pursuing different goals or reproducing independently. And even if there are, they won’t necessarily reproduce by copying with mutation, or at least not with mutation that’s not totally under their control with all the implications understood in advance. They may very well be able prevent evolution from taking hold among themselves. Evolution is optional for them. So you can’t be sure that they’ll expand to the limits of the available resources.
In a chaotic and unpredictable universe such as ours, survival is virtually impossible without differential adapation and not guaranteed even with it. (See my reply to lukedrago below.)
In some sense, all selection is natural, since everything is part of nature, but an AI that breeds humans for some trait can reasonably be called artificial selection (and mesa-optimization). If such a breeding program happened to allow the system to survive, nature selects for it. If not, it tautologically doesn’t. In any case, natural selection still applies.
In a chaotic and unpredictable universe such as ours, survival is virtually impossible without differential adapation and not guaranteed even with it. (See my reply to lukedrago below.)