The Galápagos Islands

In 1831, the British ship HMS Beagle set out on a trip around the globe, sailing around the tip of South America and eventually up to a little-explored cluster of islands called the Galápagos. 

The Galápagos Islands in Ecuador are a volcanic group of islands about 1,000 kilometers off South America’s Pacific coast. The Charles Darwin Research Station in Puerto Ayora town is the main scientific facility and laboratory on the islands.

The Beagle voyage was intended to last 2 years but stretched to 5 years. From Tierra del Fuego to Tahiti, Darwin wrote vivid observations about the rocks, plants, animals, and people he saw and collected important fossils and specimens. 

Darwin’s scientific passion led to his being introduced to Robert FitzRoy, another scientific hobbyist and commander of an upcoming expedition to explore the world’s tropics. That expedition, the HMS Beagle, would eventually make Darwin, and his theory of evolution, famous.

In 1859, Darwin put forward a revolutionary idea in his book On the Origin of Species: the many different species of finches he observed on the Galápagos Islands had once been a single species that arrived on the archipelago and gradually began to split into different species as each population adapted to the particular conditions on its island over time.

On the Origin of Species was the first comprehensive description of what we know as the theory of evolution.

Is each of the Galápagos Islands’ tortoises a separate species, variations of a single species, or something in between? As scientists have analyzed tortoises’ DNA, they’ve come to realize groups of organisms are constantly changing in response to their environment.

The different Galápagos species are examples of dispersal, in which one original population spreads out across many locations and adapts to different environments. Over time, the shapes of finches’ beaks, their nesting times, and their need for water have changed.

The Galápagos Islands are relatively young. The islands’ animals are still quite similar to each other. They’re at the beginning of the evolution process, giving scientists a snapshot in time of how populations spread out, diversify, and eventually evolve.

Galápagos plants rarely get as much attention as animals, but they’re critically important to the island ecosystem. They’re also particularly vulnerable to destruction by invasive species. The Darwin Research Station studies the plants of the Galápagos and attempts to preserve or restore the native ecosystem.

The Galápagos lie in the Pacific Dry Belt, an area associated with dry weather and desert plants like cacti. Many visitors are surprised to find the islands covered in dry grasses and cacti. At the same time, the cold Humboldt Current of the Pacific Ocean keeps the island unusually cool and foggy. Some trees capture moisture from passing fog, creating lush “fog forests” on parts of the islands. 

One way of cataloging plants is by their pollen—tiny grains that carry the plants’ sperm cells. The pollen’s outer coating is often ornamented with extremely complex patterns. Each pollen grain is unique to the plant species, like a human fingerprint. 

Research Center scientists and volunteers try to restore areas on the islands where vegetation has been damaged by agriculture, development, or invasive species. The Herbarium also researches sustainable farming techniques that could be used on the Galápagos.

Plants arrived on the Galápagos much the way that animals did—mostly by accident, probably blown there by storms. Some plants, however, are adapted specifically to colonize remote islands. Coconuts are large, light seeds designed to germinate when they reach land.

Like many isolated islands, the Galápagos are a breeding colony for sea birds. The blue-footed booby is one of the most famous Galápagos residents. About half of the world’s blue-footed boobies breed on the Galápagos. 

They get their unusual name because of their obvious blue feet and their clumsiness and lack of fear when on land. At sea, however, the blue-footed booby sails effortlessly on a wide wingspan and makes plunging dives into the sea for their favorite food, sardines.

The blue-footed booby lays between 1 and 3 eggs and incubates the eggs so that they hatch at different times. Scientists have found that this spaced-out hatching leads to more or less surviving offspring depending on the food supply. 

The frigatebird’s bright throat pouch is a mating display. Males inflate their bright-red sack of skin and aim it skyward to attract females cruising overhead. Males also use the large skin sac to produce a bellowing call. 

Frigatebirds have the largest wingspan in relation to their body weight of any bird. They also have incredibly light bones. These adaptations make them superb gliders, with the ability to fly continuously for more than a week at a time. 

Frigatebird chicks have one of the longest childhoods of any bird, spending over a year dependent on their parents for food. Both parents help feed chicks for roughly the first 3 months, but females assume the remaining months of work. 

An invasive species is a plant or animal that’s been introduced into a new environment, where its population explodes. Invasive species have been incredibly destructive on the Galápagos, in part because they prey on native animals that have no defenses against them. Some were brought to the islands accidentally—think of rats brought in as stowaways on ships.

Others, like goats, were brought in as domesticated agricultural animals, some of which escaped and survived in a feral state in the wild. Feral goats are possibly the most destructive species on the Galápagos. Goats eat nearly every kind of vegetation and can destroy entire forests. Without trees and the shade they cast, parts of the Galápagos dried out and turned to semi-desert.

Invasive plants like blackberry engulf enormous areas of land, crowding out native plants and blocking animal habitats. Invasive plants are often more difficult to control than invasive animals. A tiny seed carried off by a visitor can start an invasion. 

Project Isabella, a campaign to remove feral goats from the islands, began in 1997. Hunters systematically shot thousands of goats, effectively eradicating them from the islands by 2006. This was considered necessary to save the forests and their native species.