Titans of History полностью

As a boy, Darwin was quiet and unassuming, with a keen interest in collecting minerals, coins and birds’ eggs. After an unexceptional schooling he was sent to university in Edinburgh to study medicine. He found the dissection of dead bodies repellent and left without taking a degree, but his interest in natural history and geology had blossomed and it continued when he went on to study at Cambridge.

After Darwin graduated in 1831, his professor of botany recommended him to the Admiralty for the position of unpaid ship’s naturalist on board HMS Beagle as it made a five-year surveying voyage around the world. The Beagle took Darwin around the coasts of South America, across the Pacific to the Antipodes, then on to South Africa, before returning to England. The experience opened his eyes to the wondrous variety of life forms around the planet—and the differences and similarities between them.

During the voyage Darwin read Charles Lyell’s revolutionary Principles of Geology, which argued that geological features were the result of slow, gradual processes occurring over vast eons of time. This “uniformitarianism” was at odds with the orthodox “catastrophism,” which argued that such features were the result of sudden, violent upheavals over a relatively short timescale—and so conformed with the Church’s view that the earth was of very recent creation, as described in Genesis. On his travels Darwin collected more evidence in favor of Lyell’s theory, such as fossil shells in bands of rock at a height of 12,000ft (3660m).

By the time Darwin reached the Galapagos Islands, a remote archipelago off the west coast of South America, his mind was open to new ways of thinking about the natural world. He had already noticed how the rheas—the large flightless birds of the South American pampas—looked like the ostriches of Africa, and yet were clearly different species. In the Galapagos he collected specimens of finches from the different islands, which were similar to each other yet also subtly different. Back home, closer study made it clear that the finches from the different islands were actually different species. Darwin realized they must all have had a common ancestor, but over time they had undergone a process of transmutation.

Ideas of evolution were not new, although they were not widely accepted. Darwin’s own grandfather, Erasmus, had held the view—shared with the French scientist Jean-Baptiste Lamarck (1744–1829)—that species evolved over time by inheriting acquired characteristics. What Darwin himself came to realize was that animals (and plants), in order to survive, adapt over time to changes in their natural habitat, and if they are geographically isolated for long enough these adaptations will become so pronounced that the rhea of South America, for example, emerges as a different species from its cousin, the African ostrich.

Darwin’s big breakthrough followed his reading in 1838 of Thomas Malthus’s Principles of Population, which argued that human population growth is always checked by limits in the food supply, or by disease or war. Darwin realized that the variations or adaptations he saw in animals resulted from the “struggle for existence,” in which those individuals who possessed or inherited a characteristic that better fitted them to survive in their environment were more likely to breed and pass on this favorable characteristic. He called this process natural selection.

It was an idea of great simplicity, and yet of enormous explanatory power. Through the 1830s, 1840s and 1850s Darwin continued to amass evidence, reluctant to put his theory before the public, aware as he was of the devastating impact it would have on religious belief and the comforting notion of a moral and purposeful world.

Darwin agonized and prevaricated, suffering more and more from the psychosomatic, but nevertheless painful, illnesses that were to plague him for the rest of his life. Then in 1858 he received a letter from a young naturalist, Alfred Russell Wallace, who had, it was clear, independently come up with the idea of natural selection. On July 1, 1859 the two presented a joint paper at the Linnaean Society in London. And in November of that year Darwin published On the Origin of Species by Means of Natural Selection.

It was a knockout blow to the old, comfortable certainties. Any reasonable, thinking person found it almost impossible to dissent, such was the compelling nature of the argument and the overwhelming volume of the evidence. The big guns of the Church of England were wheeled out to mount a counteroffensive, but to no avail. In place of “All things bright and beautiful, all creatures great and small” came, as Tennyson had foreseen, “Nature, red in tooth and claw.”