Genesis: Final Point – Fernando Gonzalez-I. Sitges (2000)

Galapagos archipelago occupies a special place in our quest to understand nature. It sits right on the junction of the Pacific ocean current where warm and cold water shifts. The nutrient levels reaching the islands by cold Humboldt current show a drastic decline when warm surface waters engulf the archipelago. The Galapagos lies at the southeast trade winds. When the current shifts the rainfall pattern changes drastically.

The El Niño Southern Oscillation, phenomenon wreaks havoc on animal communities. These severe long term weather fluctuations impose a strong selective pressure and lead to speciation of the organisms.

The Galapagos is home to many iconic species that are each unique on their own and form a case study in evolutionary biology. Darwin’s finches and mocking birds with their striking beak morphology provided the first clues to Darwin in formulating the mechanism of evolution by natural selection. Similarly tortoises all around the Pacific region with their shell structures provided overwhelming evidence for how available food types led to distinct shell forms. The famous Lonesome George was the poster child of extinction in evolution. Marine iguanas also suprise everyone with their adaptations to underwater feeding habits and salt tolerance. These characters only evolved in Galapagos. Perhaps the least known secret in the archipelago is a very unusual group of plants species belonging to the daisy family (Asteraceae) that have evolved into woody form. Members of the daisy family have never evolved into tree form with the exception of Scalesia.

Biological evolution is tightly coupled to geology. Varying geological age of each island shows how landscapes evolve together with biological communities residing on them.

 

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