This is an interesting issue. At what point will our descendants feel that they are different enough from us through natural or guided (by science) evolution?
> At what point will our descendants feel that they are different enough from us through natural or guided (by science) evolution?
Easily answered: our species has existed for about 200,000 years. Based on that, and barring any speed-up in the rate of evolution by selection (natural or unnatural), we will have been replaced by another species in another 200,000 years. This will happen no matter what else happens -- assuming we're not subject to any global catastrophe, but simply evolve as a species into something we cannot presently imagine.
Easily answered: our species has existed for about 200,000 years. Based on that, and barring any speed-up in the rate of evolution by selection (natural or unnatural), we will have been replaced by another species in another 200,000 years. This will happen no matter what else happens -- assuming we're not subject to any global catastrophe, but simply evolve as a species into something we cannot presently imagine.