Why is speciation most common when sub-populations are separated spatially?

Can speciation occur when a species has a large, yet continuous, geographic range?

Can speciation occur when a population is not separated geographically?

Does reproductive timing contribute to speciation?

Why is speciation most common when sub-populations are separated spatially?

Can speciation occur when a species has a large, yet continuous, geographic range?

Can speciation occur when a population is not separated geographically?

Does reproductive timing contribute to speciation?