Galapagos Species Arrival and Darwin's Theory of Evolution

Created from a volcanic hot spot located on the ocean floor, the Galapagos are oceanic islands which have never been connected to a continent. All of the organisms found in the Galapagos arrived in the islands by swimming, flying or floating. 

The majority of organisms present in the Galapagos originated from North, South or Central America the Caribbean or the Antarctic. The unique location of the archipelago in relation to Southern Humboldt Current and Northern Panama Current has played a large role in the unique mix of plants that made their way to the islands.  

The currents and the trade winds have transported plants and animals to these remote islands that have a distinctly different biological make-up than those species found on the neighboring continent. California Sea Lions, Pink Flamingos, Finches, and Warblers made their way south from North America and the Caribbean while Fur Seals and Penguins made their way north from Antarctica.

Species had 3 methods of arrival in the islands, marine life including whales, dolphins, fish, seals and penguins arrived by swimming along with the currents. Birds arrived by flying as did many seeds, mosses orchids and ferns, which arrived by air currents rather than actual flight. Other species like tortoises, iguanas, trees, insects, and some seeds arrived by floating either due to a built-in air chamber or by floating on trees and other plants.

Once these species arrived the islands became populated with an unbalanced collection of species; the presence of reptiles but no amphibians, numerous birds but few mammals, grasses and ferns but hardly any plants with large flowers or heavy seeds. 

The species that were able to make the journey across the ocean began to distribute themselves throughout the archipelago.  Since the landscape and resources of each island varied the plants and animals able to establish themselves on the islands varied too.  Many species found it necessary to adapt to the environment in order to survive. As the years progressed and adaptations occurred new species and subspecies began to populate the islands. The lack of natural predators allowed many species to flourish and eventually give the Galapagos their unique make up. 

Galapagos, Darwin and the Theory of Evolution

Charles Darwin arrived in the Galapagos aboard the Beagle he had spent years observing the various plants and animals around the world.  This voyage and the visit to the Galapagos helped him make formulate an astonishing theory.  He concluded that flora and fauna evolve over time in a process of natural selection.   The species to survive would alter based on environmental conditions.

The Galapagos Islands provided ample examples of adaptation for Charles.  One example is the 13 species of finch collectively known as Darwin's Finches.  Each originating from a common ancestral species developed its own traits over years in order to compete for survival within its environment.

In the case of Darwin's Finches the birds are similar in appearance yet the scarcity of food required that they adapt in order to survive.  Over thousands of years each species sought food from a different source and the finch's beaks evolved in order to efficiently cope with the variety of food sources. Ground Finch developed large beaks allowing them to crush seeds where the Warbler finch developed a pointed beak for eating insects.

The Charles Darwin Research Station in Puerto Ayora offers an interpretive display discussing the evolution of life in the Galapagos Islands.

In any population of animals, a relatively large number of young are produced. Since not all survive, a struggle for existence must occur.

Within a population there is much variability. Some differences may confer an advantage in the struggle for existence. Those organisms, which are best adapted to their environment, will survive.

Due to heredity, offspring tend to resemble their parents. Well-adapted organisms tend to have well-adapted offspring. Thus, certain traits become established in the population.

If environmental conditions change, there may be selection for different traits. The variability within a population determines whether it will be able to survive these changes.

Darwin's theory set the world on edge when his book The Origin of Species by Natural Selection was published.  His ideas still create conflict with those who believe in Creation rather than Evolution.  While traveling through Darwin's Islands visitors have the opportunity to observe the same animals that he did in order to make their own conclusions.  The most obvious conclusion is the creatures of the Galapagos having lived years without the threat of predators do not have the natural fear of human that most animals posses.  Viewing the wildlife is an easy and fun experience.