Beak Speak 2 of 2
Oct 22, 2018
Part 2 of 2
Last time: During a visit to the Galapagos Islands in the early 1800’s, naturalist Charles Darwin found an intriguing group of finches. Each had a different way of feeding, and, correspondingly, a different type of bill. Now thought to represent 14 different species, Darwin’s finches apparently descended from a songbird that had flown off-course during a flight to or from South America.
On the other hand, the remarkably similar bills of the Northern Shoveler , the Roseate Spoonbill and the Spoonbill Sandpiper are considered classic examples of convergent evolution.
Members of different Orders, these species are taxonomically unrelated. The Northern Shoveler is a duck, the Roseate Spoonbill is a wading bird and the Spoonbill Sandpiper is a shorebird. Yet they all survive on small marine life found in shallow water and have evolved similar bills – flattened at the end – that are ideal for filtering small organisms.
Natural selection has apparently enabled these species to independently develop similar bills, suited to their specialized diet. Other examples of convergent evolution are found among unrelated species living in South American and African habitats, long separated by the Atlantic Ocean.