On Darwin’s Trouble with the Finches
- Evolution’s Workshop: God and Science on the Galapagos Islands by Edward Larson
Penguin, 320 pp, £8.99, February 2002, ISBN 0 14 100503 3
Scientific discovery, as any PhD student halfway through their project will tell you, is hard work: progress is step-wise, and the steps are small. Not surprisingly, however, the popular view of science overlooks the daily grind and focuses instead on the occasional flashes of inspiration that have punctuated its history. In this view, science progresses in a series of great leaps forward, and the scientists involved are mythic heroes grappling singlehandedly with the great problems of their time. The mythology also requires that these visionary moments acquire their own icons – Newton had his apple, Watt his kettle – and intellectual history is thus handily reduced to a series of mnemonics.
Evolutionary biology’s ‘Eureka!’ moment supposedly took place some time in September or October 1835, during the Beagle’s five-week visit to the Galapagos Islands. The Beagle had been at sea for nearly four years, and, as he wrote to his Cambridge mentor, John Henslow, Charles Darwin was increasingly anxious to get home: ‘I look forward with joy and interest to [visiting the Galapagos], both as being somewhat nearer to England, & for the sake of having a good look at an active Volcano.’ He had cause to expect some pyrotechnics as the island chain had been produced by continental drift of the earth’s crust over a sporadically active volcanic ‘hot spot’. The islands’ blasted aspect, however, made them unpopular with visitors. Herman Melville, who visited in 1841, had the usual reaction: ‘Take five-and-twenty heaps of cinders dumped here and there in an outsize city lot, imagine some of them magnified into mountains, and the vacant lot the sea; and you will have a fit idea of the general aspect of the [islands].’
Melville at least got to see what Darwin had come to see: the volcanoes where ‘toil the demons of fire, who at intervals irradiate the nights with strange spectral illumination’. Darwin was not so lucky: ‘The craters are all entirely inert; consisting indeed of nothing more than a ring of cinders.’ Even a recently active crater was producing only ‘a small jet of steam’. The earthquake he had experienced earlier in Chile would have to remain Darwin’s sole direct experience of major geological forces at work.
Happily, there was plenty of biology to distract him from his geological disappointment. Because the islands had been formed de novo through volcanic action, the only animals and plants present were either migrants or modified descendants of earlier arrivals. As visitors never failed to notice, this made for a bizarre flora and fauna: giant tortoises (galápagos in Spanish), cactuses, penguins, flightless cormorants, marine iguanas. What made the islands’ natural history especially remarkable was the lack of human contact. Fray Tomás de Berlanga, the Spanish cleric who stumbled on the Galapagos in 1535 en route to Peru from Panama, found no human presence, and there is no archaeological record of pre-European colonisation. This may be one of the very few cases in the New World in which the word ‘discovery’ is not a misnomer.