After Darwin published On The Origin Of Species in 1859, he discovered an orchid with a rather unusual trait. Its nectaries were sat at the bottom of a duct nearly 25cm below its petals. For such a plant to exist, Darwin predicted that there must be a moth with a tongue long enough to feed on it and therefore pollinate it. At the time Darwin’s theory was met with ridicule. But nearly 20 years after his death the fabled moth, now known as Morgan’s Sphinx (Xanthopan morgani), was discovered, giant tongue and all.
In her new series Origins Of Us, Dr Alice Roberts borrows this Darwinian logic to illustrate how ancient environmental pressures have left their mark on the modern human body. For example, our first bipedal ancestors would have run across the African Savannah, so Alice visits Harvard’s Department of Human Evolutionary Biology to demonstrate how running in these conditions would have led to narrower hips and fleshier buttocks.
Though for Alice, the aspect of human physiology that really sets us apart from our ancestors isn’t the ability to walk but our unique brain. “We left the forest and populated the world,” says Alice. “Less than 1.3 per cent difference in our DNA led to a different trajectory that’s ended with us dominating the planet, while other primates are on the brink of extinction. The organ that has allowed for that is the brain.”
An expression of this early intelligence sits in Olorgesailie, Kenya, where some of the first hominid tools were found – a dig site Alice had been hoping to see since her former career as a university lecturer. “I’d taught about this place and seen photographs in textbooks but to actually go there and see this amazing scatter of million-year-old handaxes was jaw-dropping. Suddenly I’d understood things more than I had ever done before.”
It’s not just ancient fossils and tools that Alice will be showing us in her new series. In the final episode, she met some wild chimps in Kigali, Uganda that had been habituated to humans. But off-camera she had one rather unnerving experience: “A big male chimpanzee walked very close to me, and I was terrified. I was rooted to the spot and I could feel the tears pricking in my eyes. I was very aware that he could do some real damage. It was a very raw experience but when I looked into his eyes you could feel that there was something almost human there.”
Visit the BBC Two site for more clips and info on the show
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