Henry Gee

After the origins of humanity, the question people most like to ask about the distant past is: what killed the dinosaurs? By the end of the Cretaceous Period, 65 million years ago, they had all gone. Their disappearance has long been recognised as abrupt, at least by the leisurely standards of geological time. Nowadays, their extinction inspires and sells books and movies by the dozen. Yet for many years their disappearance was seen as something of a non-question. Textbooks concluded chapters on dinosaurs with a few desultory speculations about their demise before moving on to describe the subsequent Age of Mammals. This was partly due to lack of evidence, but it was also informed by a firm belief in evolution as a progressive force. With the inevitability of clockwork, the dinosaurs had to make way for the superior evolutionary accomplishments of mammals.

Humanity is fissile: everywhere it goes, it forms clans, Yoruba and Yanomamo, Mods and Rockers; so powerful is the urge to diverge, even shared ethnicity is optional. No wonder humanity is so hard to define. Taxonomy, designed to resolve such issues, is helpless where it matters most. Every species of animal and plant is uniquely defined as such on the basis of an objective description of its form and habits. All, that is, except one, Homo sapiens. Our entry in the Systema Naturae, devised by Linnaeus, says (more or less) ‘reader, know thyself,’ thus admitting the impossibility of seeing ourselves as others see us.

Up until the mid-19th century, humanity and the animal world were separated by an unbridgeable morphological void – there was no coherent body of evidence to suggest anything other than the standard Biblical story of human origins. Everything changed, however, in 1856, when the first Neanderthal fossils to be recognised as such were unearthed – just three years before the publication of The Origin of Species.