5.2 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Charles Darwin | 3/12 | https://en.wikipedia.org/wiki/Charles_Darwin | reference | science, encyclopedia | 2026-05-05T06:45:39.623188+00:00 | kb-cron |
On their first stop ashore at St Jago in Cape Verde, Darwin found that a white band high in the volcanic rock cliffs included seashells. FitzRoy had given him the first volume of Charles Lyell's Principles of Geology, which set out uniformitarian concepts of land slowly rising or falling over immense periods,[II] and Darwin saw things Lyell's way, theorising and thinking of writing a book on geology. When they reached Brazil, Darwin was delighted by the tropical forest, but detested the sight of slavery there, and disputed this issue with FitzRoy. The survey continued to the south in Patagonia. They stopped at Bahía Blanca, and in cliffs near Punta Alta, Darwin made a significant find of fossil bones of huge extinct mammals beside modern seashells, indicating recent extinction with no signs of change in climate or catastrophe. He found bony plates like a giant version of the armour on local armadillos. From a jaw and tooth, he identified the gigantic Megatherium, then from Cuvier's description thought the armour was from this animal. The finds were shipped to England, and scientists found the fossils of great interest. On rides with gauchos into the interior to explore geology and collect more fossils, Darwin gained social, political, and anthropological insights into both native and colonial people at a time of revolution, and learnt that two types of rhea had separate but overlapping territories. Further south, he saw stepped plains of shingle and seashells as raised beaches at a series of elevations. He read Lyell's second volume and accepted its description of "centres of creation" of species, but his discoveries and theorising challenged Lyell's ideas of smooth continuity and of extinction of species. In Tierra del Fuego, Darwin formed the incorrect belief that the archipelago was devoid of reptiles. Three Fuegians on board, who had been seized during the first Beagle voyage and then given Christian education in England, were returning with a missionary. Darwin found them friendly and civilised, yet at Tierra del Fuego he met "miserable, degraded savages", as different as wild from domesticated animals. He remained convinced that, despite this diversity, all humans were interrelated with a shared origin and potential for improvement towards civilisation. Unlike his scientist friends, he now thought there was no unbridgeable gap between humans and animals. A year on, the mission had been abandoned. The Fuegian they had named Jemmy Button lived like the other natives, had a wife, and had no wish to return to England.
Darwin experienced an earthquake in Chile in 1835 and saw signs that the land had just been raised, including mussel beds stranded above high tide. High in the Andes, he saw seashells and several fossil trees that had grown on a sand beach. He theorised that as the land rose, oceanic islands sank, and coral reefs around them grew to form atolls. On the geologically new Galápagos Islands, Darwin looked for evidence attaching wildlife to an older "centre of creation". He found mockingbirds allied to those in Chile but differing from island to island. He heard that slight variations in the shape of tortoise shells showed which island they came from, but failed to collect them, even after eating tortoises taken on board as food. In Australia, the marsupial rat-kangaroo and the platypus seemed so unusual that Darwin thought it was almost as though two distinct Creators had been at work. He found the Aboriginal Australians "good-humoured & pleasant", their numbers depleted by European settlement. FitzRoy investigated how the atolls of the Cocos (Keeling) Islands had formed. The survey supported Darwin's theorising. FitzRoy began writing the official Narrative of the Beagle voyages, and after reading Darwin's diary, he proposed incorporating it into the account. Darwin's Journal was eventually rewritten as a separate third volume, on geology and natural history. In Cape Town, South Africa, Darwin and FitzRoy met John Herschel, who had recently written to Lyell praising his uniformitarianism as opening bold speculation on "that mystery of mysteries, the replacement of extinct species by others" as "a natural in contradistinction to a miraculous process". When organising his notes as the ship sailed home, Darwin wrote that, if his growing suspicions about the mockingbirds, the tortoises and the Falkland Islands fox were correct, "such facts undermine the stability of Species", then cautiously added "would" before "undermine". He later wrote that such facts "seemed to me to throw some light on the origin of species". Without Darwin's knowledge, extracts from his letters to Henslow had been read to scientific societies, printed as a pamphlet for private distribution among members of the Cambridge Philosophical Society, and reported in magazines, including The Athenaeum. Darwin first heard of this at Cape Town, and at Ascension Island read of Sedgwick's prediction that Darwin "will have a great name among the Naturalists of Europe".
=== Inception of Darwin's evolutionary theory ===