600 miles off the coast of ecuador, the galapagos Islands offer one of the most startling and vibrant examples of biological diversity on the planet. Yet darwin’s archimedes moment – like the island’s improbable colonisation – almost didn’t happen at all.

The islands took just one month of a five year journey and Darwin narrowly avoided being rejected for the position of Naturalist on board the HMS Beagle on account of his nose, which Captain Robert Fitzroy felt belied a distinct lack of determination and energy. Happily, however, the 22 year old did set sail in late 1831 and the rest, as they say, is history.

The expedition took in Cape Verde, Brazil, the Falklands, Patagonia, the Galapagos, Tahiti, New Zealand, Australia, Cocos Islands, Mauritius, Cape Town and Tenerife - but of all these places it was the tiny Galapagos Islands that made the greatest impression on him. The question is why?

The answer is that this is where Darwin observed what we now refer to as speciation - the evolutionary process by which biological populations evolve to become distinct species.

The ideal hothouse for speciation is an island far enough from the nearest continent to become populated only by freak dispersals. Separated from South America by 600 miles of open water, the Galapagos are beyond ideal. Being volcanic and young by geological standards, never having been connected to any mainland. The entire fauna and flora of the islands must have travelled there, presumably from South America. 600 miles is enough to make crossing by songbirds a rare event - but not so rare that it will never happen. In other words, a blank canvas to be colonized only occasionally.

Even better than a remote island is a group of remote islands - exactly what the Galapagos are - 21 islands hundreds of miles from the mainland but only tens of miles from each other. This provides the ultimate recipe for speciation, where the different islands house species that are fairly similar to each other, but more different from their counterpartson the distant mainland. The animals and plants of each island of Galapagos are largely endemic to the archipelago, but they are also for the most part unique, in detail, from island to island. 

This is still clearly perceivable today (take a look at our Galapagos experiences); sailing from island to island to see the similar but unique species, making the Galapagos the ultimate evolution observatory. While the Galapagos provided outstanding insights into evolution in the 1830’s, why was it that none of the other islands that Darwin spent time on were as illuminating?

One of the common characteristic of isolated islands is that there are few, or no, predators. Under these circumstances species evolve with no defenses against organisms from the large continents – as a result, islands colonized by people have always lost many of the endemic species that evolved there. By the time that the Beagle docked in Mauritius for example, the Dodo had been extinct for at least 170 years and the island was already more sugarcane than forest,  fat with rats, mice and other pests which (along with a host of other species) had been introduced by man. This scenario would have been true of many of the places that Darwin visited.

In the Galapagis however, their remoteness, poor soil and low rainfall made an unattractive proposition for human settlement. And as a result they suffered less from the heavy hand of man than almost anywhere on the planet. So here 'the greatest show on earth' rolls on unabated and exactly the same cornucopia of exotic, endemic and curious creatures that fascinated Darwin are blithely thriving.

The Galapagos are overflowing with wildlife - most of which is fearless and unique - allowing for more up-close-and-personal wildlife experiences than anywhere else on earth. Snorkeling with curious Sea Lions in the warm predator-free water while not exploring on-shore is another draw. To get the most out of the Galapagos - and understand what Darwin saw 180 odd years ago - you need to spend time on several of the islands - because each has its own unique wildlife, landscape and character - and the best way to achieve that is on a live-aboard boat, which carries you between islands overnight, arriving at a new one each morning. Catherine and Vanessa have been organising outstanding holidays to the Galapagos for years - drop them a line to start planning your trip (whatever your nose shape).