Nineteen islands and many smaller rock outposts cast amidst 23,000 square miles of ocean comprise the Galapagos, which are volcanic in origin. Isabela, at 82 miles long, is the largest of the islands.
While the islands were first officially discovered in 1535 by an off-course Spanish ship, the most famous aspect of their history is likely Charles Darwin's visit 300 years later as part of the HMS Beagle crew. Darwin's observations on the islands greatly influenced his theory of natural selection, introduced in his 1859 treatise, "On the Origin of Species."
Darwin found much to ponder on the Galapagos because their plants and animals, most of which appear to have originated in Central and South America, have evolved in isolation from the mainland into highly unique types. Species found nowhere else in the world, as is the case for many in the Galapagos, are called "endemic." Examples include the marine iguana, the only modern-day seagoing lizard, and the flightless cormorant.
Lying along the Equator, the Galapagos are enveloped in a productive confluence of several ocean currents, most notably the cold Humboldt. The collision of cold and warm currents creates upwellings, where cooler waters rich in nutrients rise to the surface and help support the islands' intricate foodweb.
Climate and Vegetation
The oceanic volatility contributes to the climate of the Galapagos, typified by a hot season of high temperatures and rain and a drier, misty cool season. On many larger islands, cactus woodland of lower, arid elevations grade to moister forest higher up, and barren highlands in the loftiest elevations (the highest point in the Galapagos is Mount Azul on Isabela at 5,541 feet).
Ecology and Tourism
The Galapagos, which today support a mostly Ecuadorian population on several islands, are a hot tourist destination. Not least of the attractions is the unique and remarkable wildlife: from the giant tortoises (which can live well over a century) and marine iguanas to great seabird colonies and congregations of fur seals, sharks, penguins and other sea life.