Darwin’s finches have different beaks in terms of size and shape to be able to eat different food sources like insects, nectar, and seeds. Cactus finches have longer, more pointed beaks to probe cactus flowers compared to their relatives, the ground finches.

If a plant disease killed a large portion of the cacti on the Galapagos islands, what would the future populations of finches look like in terms of beak size and shape? Use your knowledge of natural selection to determine which option is most likely.

A. Cactus finches would compete for food with ground finches and exhibit competitive exclusion, so the beaks of future generations would be similar to whichever finch outcompetes the other.

B. Ground finches would survive and pass on their shorter and wider beaks, so there would be a higher proportion of finches in future generations that have short and wide beaks.

C. Ground finches would survive and pass on their beaks, but they would mate with the remaining cactus finches, creating a new hybrid that is somewhere between short versus long and narrow versus wide.

D. Cactus finches would compete for food with ground finches and exhibit resource partitioning, so the beaks of future generations would not change.