John Whittles Wildlife

The Galapagos Islands 2008

The Galapagos Islands 2008

The Galapagos archipelago straddles the equator, 600 miles west of Ecuador. It is on a volcanic hotspot being on the boundary of two tectonic plates. The westerly islands, Fernandina and Isabella, are the most volcanic and the most barren. The islands are drifting slowly to the east, away from the hotspot, and the further east one travels, the greener the islands become. The islands are also sinking as they move east, and will eventually be submerged. New islands, like Fernandina are formed in the West.

The Galapagos Islands are also at the convergence of four major ocean currents, driving up from Antarctica, down from Central America and from across the Pacific. The easterly, cold, deep water flow, the Cromwell current, is particularly important. When it reaches the Galapagos it is pushed up to the surface bringing a wealth of plankton which is the base of the food chain for many of the other creatures such as sea lions, penguins, sea birds, turtles, fish and whales. In El Nino years the warm water stops this up welling and the populations of some species crash.

Bartholome & Santiago

There are no land mammals on the islands, apart from imported species, and reptiles such as giant tortoises, have taken on the roles that are dominated by mammals elsewhere. This is particularly true of grazing.

Many of the animals on Galapagos are unique and those that are similar to species found in South America, from where they originated, have evolved into distinct species to cope with the particular conditions found on the islands. It was these differences which helped Charles Darwin to develop his theory of evolution through natural selection. One of the factors influencing natural selection is the isolation of species by physical features such as water, deserts, mountain ranges etc.

Darwin visited the islands in September 1835, and landed on five of them. We visited them in September 2008, five months before the bicentenary of Darwin’s birth. We . landed on eight islands, including four of those visited by Darwin. He only spent five weeks in Galapagos and it is staggering to consider how much he observed and deduced from so brief a time ashore. He commented on the fact that most of the animals showed no fear of humans. This is still the case as the photographs in the gallery testify.