[feoren]

> you change what your species used to eat, you evolve into something else

That is definitely not how evolution works. First of all, evolution doesn't happen noticeably over one or two generations, which is the timeline we're talking about here. Secondly, show me how something affects fecundity or survival before we can even begin talking about its affect on evolution.

[aaaaaaaaata]

Survival is not a requirement. Random chance is fine.

[feoren]

You seem confused. Random chance for what? Affecting what? If not survival or fecundity, what is it affecting? If an effect is completely random, it cannot drive evolution, because it is not a force for selection of particular traits over other traits. What are you talking about?

[aaaaaaaaata]

Improved* survival is not required