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Biology-Related Homework Help General Biology Topic started by: brandonq2015 on Feb 7, 2018



Title: This figure shows the geological history of North and South America and the closing of the Isthmus ...
Post by: brandonq2015 on Feb 7, 2018
This figure shows the geological history of North and South America and the closing of the Isthmus of Panama.
 
  If a single species were distributed throughout the region indicated by the arrow in the left-most panel, and today is found as two separate species, one in the Atlantic Ocean and one in the Pacific, would this be more likely to be an example of allopatric speciation by the dumbbell model or the peripheral isolate model? Why?
 
  What will be an ideal response?


Title: This figure shows the geological history of North and South America and the closing of the Isthmus ...
Post by: KaeKae on Feb 7, 2018
ANS:
This would more likely be an example of the dumbbell model, which splits a population roughly in two. With a widespread distribution originally, there is no reason to expect that the population on one side was smaller than the other side as found in the peripheral isolate model.