It has taken biologists some 230 years to identify and describe three quarters of a million insects; if there are indeed at least thirty million, as Erwin (Terry Erwin, the Smithsonian Institute) estimates, then, working as they have in the past, insect taxonomists have ten thousand years of employment ahead of them. Ghilean Prance, director of the Botanical Gardens in Kew, estimates that a complete list of plants in the Americas would occupy taxonomists for four centuries, again working at historical rates.

For fossils to thrive, certain favorable circumstances are required. First of all, of course, remnants of life have to be there. These then need to be washed over with water as soon as possible, so that the bones are covered with a layer of sediment.

My father used to say that, through culture, humans effectively domesticated themselves.

Whether or not all this came to pass in an East African ditch, I wouldn't like to say. Perhaps it happened in North Africa or further west, but Africa was definitely the place.

The whole story is about change. We are very lucky that the earth's history is recorded in fossilized remains. And we can see the changes. Unfortunately, there will always be gaps in our knowledge, but there is no doubt that we and everything living today has evolved.

It occurred to me that if I did not handle the crash correctly, there would be no survivors.

To have arrived on this earth as a product of a biological accident, only to depart through human arrogance, would be the ultimate irony.