The Invention of Nature

Humboldt discussed how plants and animals ‘limit each other’s numbers’ as well as noting their ‘long continued contest’ for space and nourishment. It was a relentless battle. The animals that he had encountered in the jungle ‘fear each other’, Humboldt observed, ‘benignity is seldom found in alliance with strength’ – an idea that would become essential to Darwin’s concept of natural selection.

At the Orinoco Humboldt had commented on the population dynamics of capybaras, the world’s largest rodents. As he had paddled along the river, he had observed how rapidly the capybaras reproduced, but also how jaguars chased them on land and how crocodiles devoured them in the water. Without these ‘two powerful enemies’, Humboldt had noted, capybara numbers would have exploded. He had also recorded how jaguars pursued tapirs and that monkeys screamed ‘affrighted at this struggle’.

‘What hourly carnage in the magnificent calm picture of Tropical forests,’ Darwin scribbled in the margins. ‘To show how animals prey on each other,’ he noted, ‘what a “positive” check.’ Here, written in pencil in the margins of Humboldt’s fifth volume of Personal Narrative, Darwin recorded for the first time his ‘theory by which to work’.

In September 1838 Darwin wrote in his notebook that all plants and animals ‘are bound together by a web of complex relations’. This was Humboldt’s web of life – but Darwin would take this a step further and turn it into a tree of life from which all organisms stem, with the branches leading to extinct and to new species. By 1839 Darwin had formulated most of the basic ideas that underpinned his theory of evolution, but he continued to work on it for twenty more years before he published the Origin of Species

in November 1859.

Fittingly, even the last paragraph of the Origin of Species was inspired by a similar section in Personal Narrative, highlighted by Darwin in his own copy. Darwin took Humboldt’s evocative description of thickets teeming with birds, insects and other animals⁷ and turned it into his famous entangled bank metaphor:

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.

Darwin was standing on Humboldt’s shoulders.

¹ Worried about the little space in the poop cabin, Darwin had asked the captain before the departure if he was allowed to take his own copy of Personal Narrative

. ‘You are of course welcome to take your Humboldt,’ the captain assured him.

² The Beagle also carried a missionary and three Fuegians whom FitzRoy had taken hostage on his previous voyage and brought to England. They were now to return home to Tierra del Fuego where FitzRoy hoped that they would convert their fellow Fuegians to Christianity once he had set up a missionary settlement there.

³ The entire description reads very similarly. Humboldt’s ‘the earth is shaken on its old foundations, which we had deemed so stable’, becomes in Darwin’s journal: ‘the world, the very emblem of all that is solid, moves beneath our feet.’ Humboldt wrote, ‘we mistrust for the first time a soil, on which we had so long placed our feet with confidence,’ and Darwin followed with: ‘one second of time conveys to the mind a strange idea of insecurity.’

⁴

Darwin also secured government funding to publish Zoology of the Voyage of H.M.S. Beagle – to ‘resemble on a humbler scale’ Humboldt’s magnificent zoological publications, he said.

⁵ In the corner of the fixed species argument were those who believed that animals and plants became extinct and that God regularly created new ones. Their opponents argued that there was an underlying unity or a blueprint from which different species developed as they adapted to their particular environment – variants of what Goethe had called ‘urform’. They argued that the wings of a bat or the paddle of a porpoise, for example, were all variations of forelimbs.

⁶ There are several hundred references to Humboldt in Darwin’s manuscripts – ranging from Darwin’s pencil marks in Humboldt’s books to notes on Humboldt’s work in Darwin’s notebooks such as ‘In Humboldt great work’ or ‘Humboldt has written on the geography of plants’.