Abzhanov et al. 2006. The calmodulin pathway and the evolution of elongated beak morphology in Darwin’s finches.  Nature 442:563-567



1.      What is the underlying cause of elongated beaks in cactus finches?


2.      Looking at Figure 1d, what do you think is the evolutionary significance of the variance shown within species?


3.      What evidence suggests that the beak of the finch has enhanced evolvability?