Why is There Only One Species of Human?

The world is populated by an estimated 5-10 million species of animal and plant. Often, an ecological niche is home to two or more species that are closely related. Such ‘sibling species’ are frequently indistinguishable to the human eye and yet remain as two distinct populations due to subtle differences in behaviour or courtship patterns.

Humans, though, are alone. Homo sapiens is the only species within the genus and, as far as we know, our closest living cousins are chimpanzees and bonobos, rather than another bipedal naked ape. Why?

Talk by Robin May Professor of Infectious Diseases at the University of Birmingham, Gresham Professor of Physic, and Chief Scientific Adviser, Food Standards Agency