We have come to go on a week-long cruise around a small group of islands of the coast of Ecuador. On the map they look pretty insignificant but they are intimately associated with the name of one man and the development of one of the most important of all scientific theories. The islands are the Galapagos, the man is Darwin and the theory is of evolution by natural selection. Flying into the islands they look like unlikely candidates for such an important role. They are volcanic and from the air they look very barren, an impression that, for the most part, is confirmed as you walk around them. Whilst they are on the Equator they receive hardly any rain, there are few trees and the vegetation is generally pretty monotonous. The fauna, in terms of the number of species, is not especially impressive either. Birdwatching on the Galapagos is fairly easy. There are only 91 species listed in the most comprehensive guide to the wildlife. This compares to nearly 1600 for the mainland of Ecuador. In Britain there are around a dozen species of hawks, in the Galapagos only one. 14 or so (there is some dispute as to the exact number) of the bird species are finches, a particular group of finches now known collectively as 'Darwin's finches'. Small brown or black birds, they hardly look of great significance. Yet they have been described as having had the most profound impact of any group of animals on our understanding of our place in the world. There is something of a myth about Darwin, his time on the Galapagos and his finches. Hollywood style the story has it that Darwin, observing the differences between the beaks of these little birds with each one adapted to fill a specific ecological niche, had a 'eureka' moment where he realised that they were all descended from a single ancestor but had evolved into new species through the pressure of having to compete for food. In fact when on the Galapagos Darwin thought so little of them that he failed to properly label his specimens and had to rely on ones collected by other people, including his servant, when several months after he returned to England he really began to realise their importance. It was only when taxonomists in England identified the birds from different islands as belonging to different species did Darwin finally begin to appreciate their significance. The adaptive radiation demonstrated by the finches showed that species were not immutable, all created in one fell swoop, by an almighty God, as was the Christian orthodoxy at the time (and for long afterwards) but evolved over time through the process we now refer to as natural selection or, more commonly, the survival of the fittest (or more accurately, survival of the fitter as evolution never stops). And Darwin's finches continue to play an important role in developing our understanding of evolution. A long-running experiment on one small island in the Galapagos, Daphne Major, is showing that, contrary to what was previously believed, evolution isn't something that happens over millennia. Rather it takes place constantly, on an almost daily basis, as animals and plants respond to the environmental pressures they face. Of course most people who come to the Galapagos do not come to see Darwin's finches. Rather they want to see the more iconic Galapagos species, the ones unlike anything anywhere else. The Galapagos Penguin that lives on the equator, the Galapagos Cormorant that can't fly, the Waved Albatross that nests nowhere else, the Blue-footed Booby with its, yes you guessed it, bright blue feet (although you can see that in other places in South America), the Marine Iguana, the world's only sea-going lizard, the undeniably cute Galapagos Sea Lion and, of course, the animal that gave the islands their name, the giant Galapagos Tortoise ('galapagos' is an old Spanish word for saddle and the carapaces of several of the tortoises resemble a saddle). Collectively now known as the 'Big 15' we should see 12 or 13 of them as we journey around the eastern islands. Come back next time to find out if we do!