The Galapagos Islands may just inspire you to think differently about the world. The creatures that call the islands home, many found nowhere else in the world. This isolated group of volcanic islands and its fragile ecosystem has taken on almost mythological status as a showcase of biodiversity. Yet you don’t have to be an evolutionary biologist or an ornithologist to appreciate one of the few places left on the planet where the human footprint is kept to a minimum.
The Isles were formed around 4 or 5 millions years ago as a result of volcanic eruptions, emerging from the ocean surface. Today, the Galapagos are considered one of the most active volcanic island groups in the world. Many islands are only the tips of some volcanoes and show an advanced state of erosion, others are completely immersed. Recent eruptions as the Marchena in 1991 or Fernandina in 1995, are evidence that the other islands are constantly forming. Other islands like Baltra and North Seymour, have evidence of having been formed by tectonic movements, in which the bottom of the ocean was pushed towards the surface.
The Galapagos Islands have a low biodiversity (that is, few species), because the islands are 600 miles from the nearest land and this huge expanse of inhospitable ocean in-between makes it very difficult for new kinds of plants and animals to reach the islands. Marine organisms, such as green sea turtles and corals, probably came on their own, swimming, or as floating larvae. Sea birds are all strong flyers that frequently make long journeys across the open sea. But most of the Galapagos life forms reached the islands by accident, and all had a long sea voyage.
During that trip, both plants and animals were exposed to saltwater, drying winds, and intense sunlight. They had no fresh water or food. Galapagos reptiles are also more likely than land birds or mammals to be able to survive under these conditions. As a result, animals of the Galapagos Islands are species whose ancestors were already well suited for its harsh environments. Compared to elsewhere in the tropics there are few birds or Galapagos mammals, and many important groups are missing.