In lecture we discussed the observed shift in beak depth of two finch species on the Galapagos islands when they live sympatrically (see below). What is this shift in beak depth an example of? Choose the most specific and relevant answer.

G. fuliginosa G. fortis Beak depth 60 Los Hermanos 40 G. fuliginosa, 20 allopatric O 60 Daphne 40 Percentage of individuals in each size class G. fortis, 20 allopatric 0 60 Floreana, San Cristobal Sympatric 40 populations 20 O 8 10 12 14 16 Beak depth (mm)