122 Evolution and the Fossil Record
FIGURE 4.13. Although Darwin didn’t notice this while he was in the Galapagos, the majority of the birds are
finches, which have evolved from a generalized finch ancestor blown over from South America into birds
with a wide variety of bills for nutcracking, probing for insects, picking up tiny seeds, and many other tasks
performed by different families of birds on the mainland. (Modified from Lack 1947; used by permission)
ORIGINAL
ANCESTORhighly modified beaks and different color patterns. It was not until he got back to England
that ornithologist John Gould (recruited to study Darwin’s specimens) pointed this out to
him. In the twentieth century, David Lack did a much more detailed study published in 1947.
In recent years, Darwin’s finches have been the focus of research of Peter and Rosemary
Grant of Princeton University. The Grants visited the islands year after year, documenting
the changes in the finch populations. On one island (Daphne Major), the finch population
changed dramatically from year to year. During a 1977 drought, the finches with strong beaks