The Beagle
Darwin at twenty-two was a genial Cambridge graduate destined for a parsonage, whose real education had been beetles and geology. The Beagle post — gentleman naturalist and captain’s companion on a survey voyage — nearly went elsewhere (Captain FitzRoy distrusted the shape of his nose), and stretched from two years to five (1831-36): Brazilian forests, pampas fossils of giant extinct mammals, the uplifted coasts of an earthquake in Chile, and the Galápagos, whose mockingbirds — varying island to island — mattered more at the time than the celebrated finches, sorted properly only later. He returned a made scientist, and never left Britain again.
The long delay
Within two years, reading Malthus on population, Darwin had the mechanism: heritable variation plus overproduction plus struggle yields natural selection — descent with modification, no designer required. He then sat on the theory for twenty years — publishing on coral reefs and barnacles (eight years of barnacles), marrying his cousin Emma Wedgwood (after a famous pro-and-con list in which “constant companion” beat “less money for books”), moving to Down House in Kent, and suffering a lifelong illness — vomiting, palpitations, misery, never diagnosed — that turned him into a semi-invalid working in fierce ninety-minute bursts. The delay’s causes are argued: rigour, the scandal of “confessing a murder” (his phrase) in a society where evolution smelled of atheism and radicalism, his devout wife’s anguish.
The alarm clock arrived by post in June 1858: a manuscript from Alfred Russel Wallace, fever-struck in the Moluccas, containing the same theory. Friends arranged the honourable fudge — a joint reading at the Linnean Society, which famously impressed no one — and Darwin compressed his planned big book into On the Origin of Species (24 November 1859), which sold out its first printing and rearranged the sciences. Darwin, constitutionally averse to combat, let others fight — above all Thomas Huxley, “Darwin’s bulldog,” of the celebrated 1860 Oxford exchange with Bishop Wilberforce.
Descent, worms, and the Abbey
The Descent of Man (1871) extended the argument to humanity and added sexual selection; late books on orchids, expression of emotions, and a bestseller on earthworms completed the portrait of a man who could make any organism carry the theory. He died an agnostic (the deathbed-conversion story is a debunked fabrication) in April 1882, intending burial in his village; Parliament and the scientific establishment secured Westminster Abbey, where he lies near Newton — the sceptic in the national church, honoured for the idea whose implications it is still metabolising. Genetics, which he lacked (Mendel’s paper went unread on the continent), turned out to supply exactly the inheritance mechanism his theory needed: the twentieth century’s synthesis made “nothing in biology makes sense except in the light of evolution” the discipline’s standing epigraph.