Jimmy visits the experiments that Darwin did immediately after the publication of On The Origin Of Species in 1859 and therefore concentrates, mostly, on his ingenious work on plants.
Darwin knew his theory would be controversial so, while he chose plants as an easier field upon which to experiment, he also knew they'd prove a less contentious testing-ground than animals.
Jimmy starts with Darwin’s work on insect-eating plants, in particular why the sundew traps and digest insects. Darwin explored this topic by feeding the sundew with many different types of foods. Jimmy, like Darwin finds out that they go for the nitrogen in the food. Darwin concluded that because insect-eating plants live in marshes where there is little nitrogen they have evolved to get their nitrogen supply by eating insects rich in the element.
Darwin was interested in the relationship between plants and animals and he was always looking for parallels between the two. This is why he tried to chloroform a Venus fly trap; he also became fascinated by climbing plants. Jimmy recreates the apparatus that Darwin used to follow the slow movements of climbing plants.
One topic that particularly interested Darwin was sexual reproduction. He was puzzled as to why peacocks had such long and elaborate tails, and also whether plants had sex.
Darwin, more than any other botanist, discovered how most flowers go to extraordinary lengths to ensure they have sex with another flower. Jimmy uses a pencil to probe a catesetum orchid.
And with the help of David Kohn and John Parker, Jimmy does an ambitious plant-breeding experiment. This reveals that the offspring of self-fertilised plants fare much worse than cross-fertilised plants, a subject that pre-occupied Darwin, partly because of his first cousin marriage with his wife Emma Wedgewood.
The film concludes with the Oxford Debate when Thomas Huxley and Samuel Wilberforce argue about the merits of Darwin’s theory. It becomes clear from the debate that the subject the general public is most interested in is human evolution, a topic that up to that point Darwin had rarely spoken about…
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