Kind of obvious isn't it? Under the premise of course that the resources required to replicate are too scarce to support an entire generation. Only then can you get a selection, be it natural or not.
That's not entirely correct though is it? (Which is actually detailed in the article). It's a common misunderstanding that evolution requires natural selection - it doesn't. If mutation is occurring, and even if there are no resource pressures, then if the mutant can survive and reproduce, it WILL (because, well, there's no pressure against it), forming sub-species.
Kind of obvious isn't it? Under the premise of course that the resources required to replicate are too scarce to support an entire generation. Only then can you get a selection, be it natural or not.
Very obvious. When you think about it, there's really no way evolution can't happen in a self-replicating system subject to random mutation and external pressures.
Obvious for us fortunately, but many science lay people should find this interesting.