How the Giraffe Got Its Neck

Darwin was impressed by Paley’s rhetoric, but at the same time he was also vaguely aware of some less respectable ideas about how life came to take its current form. Some of them came from his own family. His grandfather, Erasmus Darwin, had died seven years before Charles was born, but even in death he was impossible to ignore. A doctor by trade, he was also a naturalist, an inventor, a botanist, and a best‑selling poet. In one of his poems, entitled The Temple of Nature, he argued that all animals and plants now living were originally derived from microscopic forms:

Organic Life beneath the shoreless waves

Was born and nurs’d in Ocean’s pearly caves;

First forms minute, unseen by spheric glass,

Move on the mud, or pierce the watery mass;

Then as successive generations bloom,

New powers acquire and larger limbs assume.

Erasmus Darwin’s personal life was as scandalous as his scientific views. After the death of his first wife, he began reveling in natural love, fathering two children out of wedlock. “Hail the Deities of Sexual Love!” he declared, “and sex to sex the willing world unite.” His son Robert always considered Erasmus something of an embarrassment, and so his grandson Charles, growing up at the tranquil, proper Mount, did not learn much about him.

But when Charles Darwin traveled to Edinburgh, a city where radical ideas thrived, he discovered that his grandfather had many admirers. One of them was Robert Grant, the zoologist who became Charles’s mentor. Grant studied sponges and sea pens not out of idle interest, but because he thought they lay at the root of the animal kingdom. From forms like them, all other animals might have descended. When Grant and Darwin went hunting for specimens in tide pools along the shore, Grant would explain to young Charles his admiration for Erasmus Darwin and his ideas of transmutation, a process by which one species changes into another. And Grant explained to Erasmus’s grandson that there were French naturalists who had also dared to contemplate the possibility that life was not fixed–that it evolved.

Grant described a colleague of Cuvier’s at the National Museum of Paris named Jean‑Baptiste Pierre Antoine de Monet, chevalier de Lamarck. In 1800, Lamarck shocked Cuvier and the rest of Europe by declaring that the fixity of species was an illusion. Species had not all been created in their current form at the dawn of time, Lamarck proposed. Throughout the course of Earth’s history, new species formed through spontaneous generation. Each came into existence equipped with a “nervous fluid” that gradually transformed it, over the course of generations, into new forms. As species evolved, they achieved higher and higher levels of complexity. The continual emergence of species and their ongoing transformation created the Great Chain of Being: lower members of the chain had simply started their upward journey later than higher members.

Life could change in another way, Lamarck claimed: a species could adapt to its local environment. Giraffes, for example, live in places where the leaves are far from the ground. The ancestors of today’s giraffes might have been short‑necked animals that tried to eat the leaves by stretching their neck upward. The more an individual giraffe stretched, the more nervous fluid flowed into its neck. Its neck grew longer as a result, and when it produced baby giraffes, it passed on its longer neck to them. Lamarck suggested that humans might have descended from apes that left the trees, stood upright, and walked out onto the plains. The very effort of trying to walk on two legs would have gradually changed their bodies to our own posture.

Most other naturalists in France and abroad were appalled by Lamarck’s ideas. Cuvier led the attack, challenging Lamarck for evidence. The nervous fluid that made evolution possible was a complete conjecture, and the fossil record didn’t back him up. If Lamarck were right, the oldest fossils should on the whole be less complex than species are today. After all, they had had less time to rise up the scale of organization. Yet in the oldest rocks that were known in 1800, there were fossils of animals as complex as anything alive today. Cuvier found another opportunity to attack Lamarck when Napoleon’s armies invaded Egypt and discovered mummified animals buried in the tombs of the pharaohs. Cuvier argued that the skeleton of the sacred ibis, which was thousands of years old, was no different from the sacred ibis alive in Egypt today.

Most naturalists in Great Britain, steeped in Paley’s natural theology, were even more repulsed than Cuvier. Lamarck was reducing mankind and the rest of nature to the product of some unguided, earthly force. Only a few heretics such as Grant admired Lamarck’s ideas, and for their heresy they were shut out of Britain’s scientific inner circle.

Grant’s praise of Lamarck took the young Darwin by surprise. “He one day, when we were walking together, burst forth in high admiration of Lamarck and his views on evolution,” Darwin later wrote in his autobiography. “I listened in silent astonishment, and as far as I can judge, without any effect on my mind.”

By the time Darwin boarded the Beagle four years later, evolution had sunk away from his thoughts altogether. Only after he had returned from his voyage would it rise back again, and in a radically different form.