1/10 Subway Stalinist
What's far-fetched with the idea of punctuated equilibrium? It's just the acknowledgement of the fact that ecosystems - and therefore evolutionary pressures - are part of a feedback system.Oh....sudden means gradual, then? No, it doesn't, but then you have 'punctuated equilibrium' to fall back on. There'll always be some far-fetched idea for you guys to cling to.
When a species is well-adapted to its environment, random mutations have a lower chance of being beneficial than when a species is less well-adapted (e.g. after a major change in the environment). The result is that species will tend to be more stable when the environment is stable, and less stable when the environment is less stable.
If you think this is far-fetched, please point out the part that's giving you trouble.