1. What mechanism of allopatric speciation (dispersal or vicariance) is primarily acting on these studied populations of Centaurea? Justify your answer. 

2. How did the authors measure the degree of reproductive isolation among the three species examined?  

Examine figure 1, and answer the following three questions:

3. What is the relevance of the intracontinental crosses (that is, what piece of information did the authors get from these crosses)? 

4. What is the importance of the intercontinental crosses in determining the degree of allopatry? 

5. Are all three species displaying the same pattern of neo-allopatry? Briefly explain your answer. 

Attachment:- Montesinos et al 2012.pdf