are an archipelago of volcanic islands distributed on either side of the equator in the Pacific Ocean .surrounding the centre of the Western Hemisphere, 563 mi west of continental Ecuador.The islands are known for their large number of endemic species and were studied by Charles Darwin during the second voyage of HMS Beagle. His observations and collections contributed to the inception of Darwin's theory of evolution by means of natural selection.The first recorded visit to the islands happened by chance in 1535 when Fray Tomás de Berlanga, the Bishop of Panamá, was surprised with this undiscovered land during a voyage to Peru to arbitrate in a dispute between Francisco Pizarro and Diego de Almagro.