How the Galapagos Islands Work

Giant tortoises rest in a pond in Puerto Ayora, Galapagos. The islands got their name from the massive animals.
­AP Photo/Kirsten Johnson

­Many of us recognize the Galapagos Islands as the place that inspired Charles Darwin's theory of evolution. Although Darwin made them famous, he can't take credit for their discovery. That distinction goes to Tomas de Berlanga, the Bishop of Panama, and his crew when their ship drifted there in calm ocean currents in 1535, 300 years before Darwin arrived on the HMS Beagle. De Berlanga and his men reported finding islands with tame wildlife, giant tortoise in abundance and little-to-no freshwater. While they didn't stick around, their nickname for the islands did: Galapagos, which means "tortoise" in Spanish.

The Galapagos Islands are a remote tropical archipelago made up primarily of 13 big islands: the Baltra, Espanola, Fernandina, Floreana, Genovesa, Isabela, Marchena, Pinta, Pinzon, San Cristobal, Santa Cruz, Santa Fe and Santiago. In addition to the 13 large islands, there are many more small islands and islets, all together about 3,000 square miles (8,000 square kilometers) of land total. They are spread out over 36,000 square miles (about 93,200 square kilometers) in the Pacific Ocean, a little more than 600 miles (1,000 kilometers) off the west coast of Ecuador [source: Galapagos Conservation Trust].


­Although politically, Galapagos is a province of the Republic of Ecuador, most scientists believe the islands were never geologically part of the mainland, and were instead formed by volcanic activity about 5 million years ago on the Nazca Plate, a hot zone that's one of the most active volcanic places in the world. Some of the volcanoes on the western side of the archipelago are still active today, with more than 50 eruptions in the last 200 years, creating new land in this evolving region.

­The enchantment of the Galapagos Islands, or as they're officially named, the Archipiélago de Colón, is that because of their remote location, they are home to plants and wildlife found nowhere else in the world.


Fauna and Flora on the Galapagos Islands

The blue-footed booby is so secure in its safety that it lays its eggs on the ground.


­Due to the islands' isolation, and depending on their wind and elevation, there are four main ecosystems across the archipelago:


  1. Arid lowlands and forests of cacti
  2. Forests
  3. Dense forests at high elevations
  4. Treeless areas with ferns and grass

Solid bare lava forms cliffs and coastlines.

There are more than 500 plant species found on the Galapagos, about one-third of which are endemic, meaning they're native to the islands and found nowhere else in the world. Exclusive species of cotton, guava, passion flower, pepper and tomatoes all grow here.

While explorers and sailors left behind some animal inhabitants, such as goats and pigs, much of the wildlife on the islands are endemic species, some exclusive to certain islands in the archipelago. Many are fearless from living without predators. The blue footed booby booby is one example: These birds have stopped nest building in their isolated habitat and lay eggs directly on the ground.

The Galapagos Islands are important because of these endemic species -- there are roughly 9,000 species living on the islands and in surrounding waters. Fourteen distinct subspecies of giant tortoise live on the islands, for example, as well as the only tropical-dwelling penguins. There are several reptile species including land and marine iguanas (marine iguanas are the only lizard known to swim in the ocean), lava lizards, geckos and snakes, 1,600 species of insects and 400 species of fish.

­Competing with the giant tortoises for most famous species on the islands are the 13 species of finches, known as Darwin's finches because they provided evidence for his theory of evolution by natural selection. These finches are an example of what's called adaptive radiation, the process of rapid speciation of a single species. Darwin's finches began as a single species of finch when they arrived on the islands, but through mutation and natural selection, they evolved into different species with different beak shapes -- giving each an advantage in the specific island habitats.


Galapagos Islands Conservation Issues

Tourism brings in a lot of money for Ecuador but could threaten the islands' resources.

­The islands are also home to a small population of people. There are no known aboriginal tribes of the Galapagos. When people from the Ecuadorian mainland began moving to the Galapagos Islands, it was at a very slow rate. While the human population on the archipelago numbered as few as 1,500 in 1955, the modern-day population has swelled more than 19,000 residents as of 2006 [source: Galapagos Conservation Trust].

Tourism is big business on the islands, and the 160,000 tourists who visit the Galapagos to see its natural wonders produce $100 million in annual revenue for Ecuador [source: Telegraph and Inter-American Development Bank]. Coffee and cattle are the area's biggest exports. Work on the islands offers high salaries, up to 50 percent higher than those on the mainland. Although the Ecuadorian government tries to contain the islands' population growth, jobs are hard to resist in a country with a 40 percent unemployment rate [source: Galapagos Online].


The human impact -- both the growing rate of permanent residency and tourism -- poses a threat to the islands' ecosystems and availability of resources and services. Additionally, overfishing and the introduction of non-native species are causing environmental problems on the islands. An unsustainable rise in legal and illegal commercial fishing of sea cucumbers, shark fins and lobsters threatens marine ecosystems.

Non-native species introduced to the islands -- whether today when a plane touches down or hundreds of years ago when explorers landed -- have compete with endemic wildlife for food. Take goats, for instance. A handful of goats were brought to Santiago Island in the 1800s and were once estimated to number close to 100,000. The Galapagos goat population fed on native vegetation and competed with the giant tortoises for food, literally eating some species into extinction. That's why the Galapagos National Park Service pursued a dogged campaign to eradicate goats from several of the islands, including Pinta, Santiago and northern Isabela.

Since tourism began on the Galapagos in the 1960s, conservation efforts have been established on the islands. The Charles Darwin Foundation, a nonprofit organization focused on scientific research and conservation, is an active presence. Additionally, the Ecuadorian government established 90 percent of the archipelago as a wildlife preserve, the Galapagos National Park and Galapagos Marine Reserve.

­Under a new law, the Special Regime for the Galapagos, the government is attempting to limit migration, control development and protect native species and ecosystems. Yet despite conservation efforts, the World Heritage Committee added Galapagos to UNESCO's List of World Heritage Sites in Danger in 2007.


Lots More Information

Related HowStuffWorks Articles

More Great Links

  • "Adaptive Radiation." Bio-Medicine.
  • "Charles Darwin and the Galapagos Islands Fact Sheet." Galapagos Conservation Trust.
  • "Conservation and Preservation of the Galapagos National Park." Galapagos Online.
  • "Destination: Galapagos Islands." Scientific American Frontiers. PBS. 1990-2000.
  • "Ecuadorian plan to protect Galapagos Islands' ecosystems receives IDB loan for $10.4 million." Inter-American Development Bank. 2000.
  • "Galapagos Islands." World Wildlife Fund. 2006.
  • Galapaguide.
  • Gray, Louise. "Darwin's Galapagos islands under threat from tourism, warns Andrew Marr." Telegraph. 2009. ­islands-under-threat-from-tourism-warns-Andrew-Marr.html
  • "History of the Galapagos Islands." Galapagos Conservation Trust.
  • Shukman, David. "Galapagos damage 'must be curbed.'" BBC. 2009.
  • "The Galapagos - Threats." World Wildlife Fund.