What happened to the Galapagos Islands to create the diversity found there?

It's not just their unique aesthetic and untouched charm that attract tourists to their shores. The islands are significant in the history of scientific thought, widely known as the place where Darwin developed his theory of evolution.

Despite what some disgruntled politicians in certain states might claim, the theory of evolution has as much evidence supporting it as the theory of gravity. In the realm of science, it is an indisputable fact, largely due to the unique biodiversity that flourishes on the islands.

But how did this small chain of landmasses, just off the coast of Ecuador, come to host so many interesting and unique species, each with subtle yet crucial differences from their counterparts?

Why are the Galapagos Islands famous?

 

The Galapagos Islands are a volcanic archipelago belonging to Ecuador, located in the Pacific Ocean about 1,000 km off the coast. These islands are renowned for their diverse and unique wildlife.

While some evidence suggests Polynesians may have reached the islands before European sailors discovered them in the 16th century, it is generally accepted that humans did not inhabit them for long periods. This makes sense, as the islands are primarily volcanic rock with little arable land.

Initially, the barren islands became a haven for pirates and were first mapped by the English buccaneer and occasional pirate William Ambrosia Cowley under John Cook. Until the 19th century, the islands served mainly as a base for whalers and other sailors, leading to the near-extinction of many native species, including the Galapagos Turtle, due to overhunting.

Ecuador gained independence from Spain in 1822, and a decade later, the islands were claimed as part of the country. The small communities on the islands comprised sailors and Ecuadorian criminals who settled there in exchange for commuted death sentences.

In 1835, Darwin visited the islands aboard the HMS Beagle. He made several notable observations, such as slight differences in mockingbirds depending on the island and unique shell patterns in tortoises from each island.

Upon returning to England, Darwin realized that some bird specimens he had collected, which he thought were different species, were actually various species of finch. These observations, along with others, formed the foundation for his theory of evolution by natural selection.

Although Darwin's theory was groundbreaking, it is important to acknowledge that he was not the first to propose ideas about evolution; several prominent thinkers, including his grandfather, had suggested similar concepts. However, Darwin's observations on the Galapagos Islands provided the crucial evidence needed to establish evolution by natural selection as an indisputable fact. Since then, the Galapagos Islands have become synonymous with evolution and scientific discovery.

What happened to the Galapagos Islands to create the diversity found there?

 

Despite being known for their diversity, the Galapagos Islands aren't teeming with wildlife. Compared to the South American mainland, especially the Amazon Basin, there are relatively few species. This is expected, given that they are a small chain of mostly rocky islands nearly a thousand miles from Ecuador.

However, it is this isolation that makes them special and accounts for the diverse range among the few species that do live there. The islands' harsh and remote environment has led the surviving animals to evolve specific traits for survival rather than diversifying widely. Essentially, the species that inhabit the islands have developed niche abilities and features suited to their specific environment, and because each island has slightly different conditions, they evolved uniquely.

Their remoteness also means they are relatively free from invasive species, providing a clearer view of natural selection. The animals and insects on the islands have adapted in unique ways to their specific conditions.

The lack of prolonged human contact is another reason for the interesting diversity. Humans have historically disrupted balanced ecosystems, and only recently has preserving nature become a priority. The wildlife on the Galapagos is so isolated that many animals are not even afraid of humans.

Darwin best commented on the uniqueness of the wildlife in 1845 when writing about his experiences aboard the Beagle:

“Considering the small size of these islands, we feel the more astonished at the number of their aboriginal beings, and at their confined range… Hence, both in space and time, we seem to be brought somewhere near to that great fact, that mystery of mysteries – the appearance of new beings on this earth.”

Due to the islands' remoteness, the first hints of life likely arrived in interesting ways: marine animals caught in currents, birds lost in storms, and seeds carried by strong winds are some theories of how life began to thrive on the islands.

In summary, the combination of their remoteness and long period of being untouched has made the Galapagos such a special place.