Question

I have to determine which kind of natural selection is most likely to begin speciation out of stabalizing, directional and disruptive. I would think Directional, since it favors one extreme which could eventually break away from the norm to the point a new species is formed. I think directional however could also create a new species. Which do you think is more likely to lead to speciation?

Answer 1

yes, directional can lead to speciation. See the Peripatric example here:
http://www.jiskha.com/display.cgi?id=1301694935

Yes, speciation can lead to new species, especially if cross mating is stopped.

But the bottom line, all can lead to specialition over time.