The Evolution of Charles Darwin- page 5 | Science | Smithsonian
Current Issue
July / August 2014  magazine cover
Subscribe

Save 81% off the newsstand price!

Portrait of Charles Darwin (J. Cameron)

The Evolution of Charles Darwin

A creationist when he visited the Galápagos Islands, Darwin grasped the significance of the unique wildlife he found there only after he returned to London

Smithsonian Magazine | Subscribe

(Continued from page 4)

It is certainly testimony to Darwin’s intellectual boldness that he had conceived of the theory of evolution some eight years earlier, when he still harbored doubts about how to classify Galápagos tortoises, mockingbirds and finches. To bolster the unorthodox theory, he engaged in an exhaustive, 20-year program of research that ultimately became so convincing that he did not need the inspirational Galápagos evidence to make his case. As a consequence, Darwin devotes only 1 percent of the Origin of Species to the Galápagos, barely more than he allotted to the Madeiras Islands or New Zealand.

I have often wondered why Darwin, prior to the publication of Origin of Species in 1859, was the only person known to have become an evolutionist based on evidence from the Galápagos —especially after Hooker’s compelling botanical study. After all, Captain FitzRoy, John Gould, Joseph Hooker and numerous scientific specialists who helped Darwin with the analysis and publication of his voyage findings were fully aware of the unusual nature of his Galápagos collections. In the end, it is perhaps a question of courageous willingness to consider new and unconventional ways of thinking. When Darwin’s uncle, Josiah Wedgwood, was trying to convince Darwin’s father that young Charles should be allowed to sail on the Beagle, Josiah noted Charles was “a man of enlarged curiosity.”

One repeatedly sees the truth of Wedgwood’s observation. Charles Darwin’s undeniable knack for asking the right questions, bolstered by his five-week visit to an extraordinary workshop of evolution brimming with unasked and unanswered questions, ultimately precipitated the Darwinian revolution. In posing novel questions, Darwin voyaged back to the Galápagos Islands again and again in his mind, reassessing his imperfect evidence in the light of his maturing theory and benefiting from new and better evidence obtained by other researchers.

Although much of what one sees in the Galápagos today appears to be virtually identical to what Darwin described in 1835, the biology and ecology of the islands have been substantially transformed by the introduction of exotic plants, insects and animals. Completely gone from Santiago, for example, are the golden-colored land iguanas, described as so numerous by Darwin in 1835 that “we could not for some time find a spot free from their burrows, on which to pitch our tent.” The principal culprits in this extinction, besides Beagle crew members and other people who found these iguanas very good eating, were the rats, dogs, cats, goats and pigs introduced by mariners and would-be settlers who left their animals to run wild. Along with visiting whalers, early settlers also hunted the giant land tortoises to extinction on some islands, and they nearly wiped them out on other islands. Recently introduced insects and plants—including fire ants, wasps, parasitic flies and quinine trees—have also become highly invasive and threaten the Galápagos ecosystem.

When I first visited the Galápagos, 37 years ago, quinine was not yet a serious problem, and feral goats, which later invaded Isabela’s Volcán Alcedo (home to about 5,000 giant land tortoises), had yet to reach epidemic numbers. But by the 1990s, more than 100,000 goats were devastating the volcano’s vegetation. Darwin himself would doubtless have applauded the indefatigable efforts of the Charles Darwin Research Station and the National Park Service to stem the tide of destruction to the fragile ecosystem, and he would also have marveled at some of the occasional success stories, such as the recent eradication of feral pigs from Santiago.

From the many times I have followed in Darwin’s footsteps to better understand his voyage of discovery, I have come to believe that the Galápagos continue to epitomize one of the key elements of Darwin’s theories. As he argued, over long periods of time natural selection is ultimately responsible for the “endless forms most beautiful and most wonderful” around us. Empowering this evolutionary process on a day-to-day basis is what Darwin termed “the struggle for existence.” This evolutionary engine works its slow but unrelenting biological effects primarily through accidents, starvation and death. Perhaps nowhere else is this harsh biological principle more evident than in the strange islands that inspired Darwin’s scientific revolution.

Tags

Comment on this Story

comments powered by Disqus