Often this type of speciation occurs in three steps ... But gene flow is interrupted if the population becomes divided into two groups. One way this happens is by "vicariance," geographical ...

but changes to strong or complete in later stages of speciation (Figure 2). One or more of the many types of isolating mechanisms may play a role in the evolution of species along a continuum ...

What is unknown is whether such local ‘adaptations' are correlated with genetic differentiation, which is a necessary precursor to speciation. Future studies that incorporate ecological ...