In contrast to the single species of finch on the mainland of Ecuador whose beak was adapted for crushing seeds, six major beak types(see Figure 4.8) were found on the Galapagos islands, each adapted for a particular method of feeding. Not all groups of finches are represented in all the islands. Even where one type of finch is present, it is differentiated into many subgroups, each subgroup differing in its ecological requirements.