Galapagos Islands: Muse of Darwin's Theory of Evolution

Charles Darwin and his book 'The Origin of Species' will forever be linked with the Galapagos Islands.
Susan Fourtané
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The Galapagos Islands make up an archipelago of 13 major islands and more than a hundred smaller islands that straddle the equator off the Ecuadorian coast. Galapago is an old Spanish word for tortoise. So the meaning of Galapagos Islands is island of the tortoises

Galapagos islands
Source: M.Minderhoud/Wikimedia Commons

The Galapagos Islands are home to unique and extraordinary animal species such as giant tortoises, iguanas, fur seals, sea lions, sharks, and rays. In addition, there are 26 species of incredibly beautiful native birds, 14 of which make up the group known as Darwin’s finches.

Darwin's finches are considered to be the world’s fastest-evolving vertebrates. This is because their appearance and behavior quickly adapted to the closed and rapidly changing environment on the Galapagos Islands.

In addition to the unique fauna, the plants are just as interesting. In the highlands, there are trees that have evolved from daisies, covered in colorful mosses and lichens. In the lowlands there are many cacti that have adapted to the islands' climate that is hot during the day and cooler at night. 

The Galapagos Islands accidental discovery: How did it affect Darwin's thoughts 

During Charles Darwin's nearly five-year circumnavigation of the globe aboard HMS Beagle, he spent only five weeks on the Galapagos Islands. The year was 1835 and Darwin was 26 years old. His discoveries on the islands were paramount to the development of his Theory of Evolution by Natural Selection.

On the islands, Charles Darwin discovered several species of finches. Thanks to his close observations, he discovered that the different species of finches varied from island to island. Besides elaborating his thoughts on natural selection, this also helped him in his investigation on the evolutionary changes of the finches. 

Isabela Island formation by 6 volcanic explosions

wolf volcano Isabela island Galapagos
Wolf volcano, Isabela Island Source: NASA/Wikimedia Commons

Isabela, which is located on the western edge of the archipelago near the Galapagos hotspot, is one of the youngest islands. The one million year-old island was formed by the merger of 6 shield volcanoes: Alcedo, Cerro Azul, Darwin, Ecuador, Sierra Negra, and Wolf.

With the exception of Ecuador, these volcanoes are still active. This makes the Galapagos Islands one of the most volcanically active places on planet Earth. Volcan Ecuador and Volcan Wolf (the island's highest point with an elevation of 1,707 meters (5,600 feet), lie directly on the Equator.

The Isabela island provides excellent examples of a geologic occurrence that created the Galapagos Islands, including uplifts at Urvina Bay and the Bolivar Channel, tuff cones at Tagus Cove, and Pulmace on Alcedo and Sierra Negra, one of the most active volcanoes in the world.

Galapagos Islands: UNESCO World Heritage 

Galapagos islands unesco
 Galapagos Islands (Ecuador) Source: Francesco Bandarin, UNESCO

The Galapagos Islands are situated in the Pacific Ocean about 1,000 km from the Ecuador. The archipelago and its immense marine reserve is known as the unique living museum and showcase of evolution.

For this, the Galapagos Islands are part of the UNESCO's World Cultural and Natural Heritagetherefore, the islands and their species are actively protected from any threat, including human threat. 

Charles Darwin Research Station 

Charles Darwin research station
Charles Darwin Research Station Source: Waltermera182/Wikimedia Commons

A trip to the Galapagos Islands is not complete without a stop at the Charles Darwin Research Station. Located in Puerto Ayora, Santa Cruz Island, the research facility is the operative branch of the Charles Darwin Foundation (CDF). It houses an extensive collection of preserved specimens of the Galapagos Islands' plant life. 

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Fernandina Island: Home of first living marine iguana

Charles Darwin was amazed by the number of marine iguanas that foraged underwater. He thought that the iguana fed of fish and little animals. However, a dissection of a marine iguana led to the discovery that they feed off algae.

Fernandina Island - Galapagos
Fernandina Island Source: putneymark/Wikimedia Commons

Galapagos marine iguanas are pretty unique. They are the only modern lizards that can forage in the sea. They adapted to survive the scarce food on the Galapagos Islands. The marine iguanas scrape algae off rocks in the intertidal zone. Their flat faces help them gobble up more algae with each bite. 


Using their large sharp claws, the marine iguanas grip the rocky seafloor, so that the waves do not thrash them about. They are quite colorful animals. Although they are mostly black, on some islands they can also be spotted with a bit of red or blue. 

Galapagos land iguanas: threatened 

Relatives to the marine iguanas, the land iguanas on the Galapagos Islands are threatened to be extinct. By 1976, there were fewer than 100 left. The two endemic species of iguanas are among the largest in the world and unique to the Galapagos: they don't exist anywhere else on planet Earth. They are extremely vulnerable to human activity, which can cause their extinction. 

Charles Darwin research station iguanas
Charles Darwin Research Station Source: David Adam Kess/Wikimedia Commons

Charles Darwin & the Galapagos Islands 

Charles Darwin realized that the different islands that make up the archipelago were home to similar but different species. However, the unique creatures were perfectly adapted to their environments. This led him to ponder the origin of the inhabitants of these islands. 

When setting off from England in 1831, Charles Darwin was ready for a five-year voyage around the world with little ambitions for groundbreaking scientific research. However, after surveying the coasts of South America, the ship stopped over in the Galapagos Islands. This changed everything forever. 

Among those species that struck Charles Darwin so greatly were the finches, birds which are now named in his honor. Charles Darwin first supposed that these finches were all descendants of the same lineage.

But years later in 1859, Darwin finally consolidated all of his observations into his famous book On The Origin of Species. His book controversially altered the scientific view on the biological origins of life.

Charles Darwin and the HMS Beagle were on the Galapagos Islands during September and October of 1835. During five weeks, he had the opportunity to explore the islands and collect several Galapagos species which he used in his own research and that of his friends back in England.

Charles Darwin
Source: HombreDHojalata/Wikimedia Commons

Charles Darwin was born on February 12, 1809, in Shrewsbury, Shropshire, England. He died on April 19, 1882, in Downe, Kent, England. He was a celebrated and brilliant English naturalist whose scientific theory of evolution by natural selection became the foundation of all modern evolutionary studies.

Interestingly, the theory of evolution seems to go some 600 years before Charles Darwin was born. This also means that different scientists who lived in different times shared the same curiosity, observations, and arrived at the same conclusions despite living in different parts of the world.   

Species found by Darwin: Darwin finches 

The mystery of evolution became clear to Charles Darwin after his observation and study of birds rather than from the reptiles. Such birds, now better known as Darwin’s Finches, would help him crack the case more than anything else.

Charles Darwin collected finches from the different islands. He then noted that they were similarities to one species he had previously found in South America. However, it was the difference between their beaks as well as their behavior what he found so inspiring and thought-provoking.

Darwin's finches
Source: John Gould/Wikimedia Commons

It was not before leaving the Galapagos Islands that Charles Darwin concluded that one type of finch from South America had arrived on the recently-risen islands and, like it had happened with the tortoises, the finches had adapted to the different opportunities found on each island.

Later on, when Darwin was writing On the Origin of Species, he drew heavily on the animals he saw and observed on the Galapagos Islands. With his drawings, Darwin advanced his radical notion that the creation of the different species on the planet was not a single event but rather a process of change from one form into many different ones.

Lonesome George

On June 24, 2012, Lonesome George was found dead by members of the Galapagos National Park Service. He was the sole remaining Pinta Island tortoise and a Galapagos conservation icon. The death of Lonesome George marked the extinction of the Pinta species of tortoise.

 “Whatever happens to this single animal, let him always remind us that the fate of all living things on Earth is in human hands.” — These words are inscribed on the information panel outside the enclosure of Lonesome George at CDRS/GNP.

lonesome George
Source: Lonesome George/Wikimedia Commons

In 1959, fishermen released three goats on Pinta Island. The fishermen wanted fresh meat on their fishing voyages. However, the tiny goat population exploded. By 1970, it was estimated to be around 40,000.

The goats devastated the vegetation, food for most local species. The goats had essentially eliminated any good tortoise habitat left and with it, all the remaining Pinta tortoises.

Lonesome George was the last of its species. 

Darwin’s tortoise - Harriet

Darwin's Giant tortoise Harriet
Darwin's Tortoise Harriet Source: Thuresson/Wikimedia Commons 

Harriet was a Galapagos tortoise who had an estimated age of 175 years. She was born approximately in 1830 on the Galapagos Islands and was collected by Charles Darwin.

At the time of her death on June 23, 2006, she was a resident in Beerwah, Australia. She belonged to the Chelonoidis nigra species.

Harriet died of heart failure following a short illness. Harriet was the third oldest tortoise.

Tu'i Malila died in 1965 at the age of 188, and Adwaita died in 2006 at the estimated age of 255.

Galapagos penguin: endangered

The Galapagos penguin is on the endangered species list. It's a penguin endemic to the Galápagos Islands and the only penguin that lives north of the Equator.


The Galapagos penguin can survive due to the cool temperatures resulting from the Humboldt Current and cool waters from great depths brought up by the Cromwell Current. Climate change is currently threatening the Galapagos penguin. 

Penguins are also threatened by pollution, bycatch, and by species introduced by humans that carry diseases that can spread to penguins as well. Cats pose a threat as predators.

Past strong storms such as El Niño have caused mortalities of up to 77 percent of the population of penguins, with dramatic declines of prey species and reduced breeding success.

Sea lions are leaving the Galapagos Islands due to climate change

Both tourism and climate change represent major threats for species found on the Galapagos Islands that don't exist anywhere else on the planet. According to WWF, sea lions are endangered

Species that have been introduced by humans such as dogs, carry diseases that can spread to sea lions. Sea lions on the Galapagos Islands are vulnerable to the effects of climate change on ocean currents, which impacts their fish prey abundance. They are also victims of bycatch in fisheries.

Galapagos baby sea lion
Galapagos baby sea lion Source: CharlesJSharp/Wikimedia Commons

Sea lions are leaving the Galapagos Islands to go to better suited waters for them close to Peru in a move adapting to climate change. The conditions of the sea around Piura are now similar to the Galapagos.

The sea lions are moving to Peru's Foca Island, where the waters have risen in temperature over the past years from an average of 17C to 23C, which is similar to the waters of Galapagos, which have become a favorite destination of tourists and botanists who look for their unique ecosystem and reputation as a living laboratory of evolution. However, they are forcing sea lions to search for a new home. 

Galapagos Islands: Land of extinct species 

Charles Darwin used to record his journeys in his journal. He wrote about the places, species he encountered, and his observations and thoughts about them. In occasions, he remarked that the convicts regularly ate tortoises.

He also noted that whaling ships and pirates often took them: one such ship carried off 700 Floreana tortoises to eat while at sea. By 1846 the whole race was extinct.

The world needs to be conscious about the damage humans can cause to the environment and to precious species that are currently endangered before it's too late.