Evolution: Abrupt Changes

[Chas]

Yes. New environmental conditions will encourage speciation in two ways:  it opens up room for new adaptations better suited for the new environment to be selected, and it also ween old obsolete adaptations from the population.  So rate of selection for significant changes goes up. But overtime, if the environment remains stable, then as better adaptation accumulate, there is reduced room for further improvements to adaptation, so the rate of selection for significant changes goes down.

Thanks a bunch! That makes a lot more sense. Yeah, because I had always thought evolution was always nothing but gradual, but yeah, that makes more sense.

Evolution is always gradual when viewed in a human time frame.  "Abrupt" in evolutionary terms is something that occurs in centuries or millennia instead of hundreds or thousands of millennia.
Speciation requires many generations - never just one.