When the drought ended and the rains returned, however, food was plentiful, and the average beak size returned to normal.
Neo-Darwinians breathed a sigh of relief when in the 1930s they found a way to incorporate Mendel’s laws of heredity. Now, that relief is unraveling.
The authors offer a selectionist explanation, which is nevertheless uncertain. Note the repeated use of the subjunctive.
This is by no means an all-or-nothing selection (as the impression is sometimes given). Rather, the alleles are retained.
Scientific data are followed by the myth: “Finch beak morphology observed on the Galápagos Islands was used by Darwin to formulate his theory of evolution.”