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Galapagos Islands Evolution Geology
To understand the uniqueness of the Galápagos Islands and their extraordinary wildlife you have to go way back in history…
The formation of the Galápagos archipelago is usually based on two theories:
Beneath the earth’s crust there are certain superheated areas that remain stationary (hot spot theory). From time to time their heat increases and results in a volcanic erruption. The hot spot that is the origin of the Galápagos lies obviously beneath the sea and the present-day islands are only the top part of huge undersea volcanoes.
The other theory states there are tectonic plates that slowly drift over the earth´s surface. The Galápagos rest on the Nazca plate that is gradually moving southeast.
That is why the oldest of the Galápagos Islands (about 9 million years old) are today deep under the ocean and lie about 700 km east of the archipielago. The oldest one of the contemporary islands is Española (about 3,3 million years old) and the youngest and today still the most active are Fernandina and Isabela (less than 750 000 years old).
As the islands were never connected to the mainland, they were totally bare in the beginning. The ancestors of all species that can be found on the islands today had to cross about 1000 km of open ocean. Obviously those species had the best chances to reach the islands that could either fly or swim long distances.
Almost excluded were insects and mammals.(Today there are some mammals that are the savaged offspring of the farm animals the settlers brought to the islands. They are a great danger for the original species.)
The migrating species produced offspring and always there were some who had subtle differences from their parents. The progeny that were fittet best the life on the islands (natural selection) or those who could occupy a certain ecological niche (adaptive radiation) survived and passed on their genes.
In our time some differ so much from their ancestors that they are considered another species altogether (Darwin´s theory of evolution). They are called endemic species because they only exist on the Galápagos, sometimes even only on one of the islands, and nowhere else in the world. This process took a long time and started on those islands that are now far away deep under the ocean.
To preserve this unique flora and fauna, please listen to the orders of the naturalist guide, do not touch the animals, do not throw litter and please do not leave the path. Future generations will thank you!
