Why Are the Galapagos Islands Important for Evolution?
The Galapagos Islands have played a pivotal role in today’s understanding of evolution due to their geographic isolation, volcanic origin and unusually high rate of endemism. These three factors have come together to form a living laboratory for the scientific world where evolution literally occurs right before your eyes. However, perhaps more importantly, this laboratory is open to the public as well. The Galapagos Islands have helped humankind reimagine their role on this planet and, indeed, the origin of life itself.
Charles Darwin and Natural Selection
The name of Charles Darwin has become synonymous across the globe with the term “evolution.” Darwin played an essential role in developing society’s understanding of evolution and natural selection, and it is widely accepted that it was the Galapagos Islands that enabled him to finally bring the pieces of his theory together.
The idea that today’s species developed from less complex ones was not new at the time that Darwin set sail (though it was certainly not accepted), but the tool that led to evolution was still unknown – and that is where the Galapagos Islands came into play. During the few weeks that Darwin spent in the Galapagos Islands, he collected and observed several different plants, animals, and bird species, including the Galapagos mockingbirds and Galapagos giant tortoises. His keen observations led him to see slight differences between each closely-related species, as if they had evolved perfectly for the niche that they lived in. Upon returning home and further investigating the matter, he discovered that many of the species he had collected in the Galapagos were found nowhere else on earth. Considering that the Galapagos Islands had not existed at the time of the Earth’s creation (as they are of volcanic origin), this meant that these species had to have evolved from other species over time in order to adapt to their environment, providing an excellent argument for his theory of evolution by natural selection.
Not only did the Galapagos Islands play a fundamental role in Darwin’s theory of evolution, but they have continued to teach us just how fascinating and efficient evolution is. Rosemary and Peter Grant have been studying Galapagos finches in the Galapagos Islands for over 25 years and have witnessed evolution before their very eyes. The Galapagos Islands are an evolutionary hotspot due to the lack of competition and predators in the islands, as well as their isolated location. This means that animals are able to evolve almost unhindered in order to adapt to their surrounding environment.
The Grants saw this process occur from generation to generation of finches in the span of just two years. In 1977, the Galapagos Islands experienced a severe drought in which many of the plants shriveled up and died. Medium ground finches, which generally eat smaller seeds, were forced to consume larger seeds. The finches with larger beaks were able to do this, but those with smaller beaks starved to death and the population was forced to evolve. In 1978 when the Grants returned, the population’s beaks were 3-4% larger. Today, it is believed that a single species of finch evolved into at least 13 different species of Finches.
The Galapagos Islands have been undeniably critical in our understanding of evolution because of how clearly, they demonstrate its processes. Despite the well-cemented societal belief that all living creatures had existed since Earth’s creation, thanks to his observations in the Galapagos Islands, Darwin was able to reasonably support that they had instead evolved and adapted. These islands tell the stories of just a few remarkable creatures that found their way to the archipelago, reproduced and evolved; approximately 85% of all Galapagos birds and 97% of the reptiles found in the archipelago are entirely endemic to the islands. And that is no small feat.