Evolution: Abrupt Changes

[RiddledWithFear]

So you're saying that a large amount of enviroment change will change a species significantly, but slow changes will happen afterwards?

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.

[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.

[The Grand Nudger]

Not always.  Brassicaraph is a divergent hybrid -genera- that only took two generations to produce.

[Gawdzilla Sama]

Not always.  Brassicaraph is a divergent hybrid -genera- that only took two generations to produce.

Google fails me.

[Chas]

Not always.  Brassicaraph is a divergent hybrid -genera- that only took two generations to produce.

If you mean Brassicoraphanus, it is an artificially hybridized organism so it hardly qualifies as an example of rapid speciation.

[Gawdzilla Sama]

Aren't we all Agents of Darwin?

[Tonus]

"Something like that."

[Gawdzilla Sama]

"Something like that."

[The Grand Nudger]

Not always.  Brassicaraph is a divergent hybrid -genera- that only took two generations to produce.

If you mean Brassicoraphanus, it is an artificially hybridized organism so it hardly qualifies as an example of rapid speciation.

Artificial selection is still selection.  Speciation is speciation.  They didn't have fancy gene editing schemes pre-war.... it simply shows what the underlying biology is capable of, given the right conditions.   The question of whether or not rapid or abrupt speciation can occur, either on human timescales or the more common geological timescales is a resounding and well evidence yes.  The prospects of survival for those novel new species, however, looks grim. We have no idea how many hybrids may have happened out in the field. We do know that nearly all of them will fail to establish a population due to a variety of factors.

@Agents of Darwin
LOL, I know I took my secret oath, lol.  People sometimes get hung up on the "artifical" bit, I think.  It's linguistic, we take it to make fake.  That's not what it refers to in the context of evolutionary theory, even if that's how the words usage has evolved over time. Helps to remember artificial as in artificier.

[LastPoet]

Portuguese is also treacherous. When people ask me if I ever been 'soldado', that means soldier, the lowest rank, I tell them I was made of a single piece (soldado also means something welded together).