Natural History of Galapagos

The Galápagos Islands were formed ages ago by what geologists call a “hot spot.” Basically, a hot spot is a place on the earth that is hotter than normal. As the earth’s crust moves over this spot, it burns holes in it which form volcanoes. If the hot spot is far out to sea, these volcanoes form islands. Hawaii was formed in a similar fashion.

Because the earth’s crust moves from west to east over the Galapagos hot spot, the oldest islands are the ones on the eastern side of the archipelago, such as Española and Genovesa. There were once other Galápagos islands to the east of Española, but they have been reclaimed by the sea.

The western islands of Isabela and Fernandina are the youngest islands, and they are also the ones that are still volcanically active, as they are still over the hot spot. These rocky, hot volcanic islands far out in the ocean are inhospitable to life, as fresh water is very scarce.

Nevertheless, life on earth is nothing if not rugged, and over time, plant and animal species found their way to the islands, colonizing them. Most if not all of the plants and animals in Galápagos came from the mainland. Sudden storms would wash a clump of vegetation out to the islands, perhaps with an iguana, tortoise or rat clinging to it; when it arrived, the plants and animals just might thrive and reproduce. Because the islands are so remote, island life has been dominated by birds and reptiles, which had a far better chance of getting there in the fi rst place.

Over time, these plants and animals evolved, filling availabilities in different ecological niches. Over the course of thousands of years, they became new species, endemic to the islands. Some of them died off naturally, but many of them are still there today.

The arrival of man to the islands had a disastrous effect, as they introduced new species into the mix, such as cats, dogs and goats, in addition to the even-harder-toeradicate plants. Scientists and park service staff are trying to reverse this damage with encouraging results.

Here are some related tips to help plan your trip to The Galápagos Islands: The Islanders Take Over, Human History of the Galapagos Islands and History of the Galapagos Islands.