Tom,

A species that has the potential to evolve into humanlike beings doesn't have the same moral status as human beings.

I did not say that it does. The question was would they have *any* moral status at all?

Rather than murdering idea creators we simply 'kill' false ideas through criticism.

Sure, but that does not explain why the other alternative is *wrong*, as in

killing a human being is wrong, except as a necessary consequence of defending another human being.

To say any idea can prove to have merits that are not recognized does not really provide a justification. even in the most non-violent and fair traditions there is limits of efficiency, many ideas could be forgotten only to be discovered later when their time has come (so to speak). So one can argue if an idea has merit it will eventually come up and be accepted once the need for it arises. So- it coudl be argued- what's the big deal? Why spend so much time and energy to ensure non-violence and idea preservation?
Harsh natural selection in the most brutal fashion could still be viewed by some to be as efficient a tool as any other in getting the meritful ideas out and distinguishing them from the not-meritful ones by speeding up the need for them. I still think this approach can't really provide a *moral* basis

...can you give an example of a way of suffering which can't be avoided?

What do you mean by being avoded? I guess any particular event that causes suffering is in principle avoidable (even death I guess, once technology advances that far.)
But in practice how can every single one of them be avoided by pre-planning for every single individual at all times? Accidents happen and new forms of problems emerge by necessity and the unkown will always remain there. At any given time and for any given individual there are myriads of things that can and will cauise him/her suffering even if all of them were in principle avoidable by itself. (Not to say that an individual who is so shelterd never to be challenged enought to *risk* suffering won't produce any interesting ideas after a while either.)