Richard Dawkins’ 2004 popular science book, The Ancestor’s Tale, is loosely

modelled on Chaucer’s Canterbury Tales. Instead of pilgrims journeying to

Canterbury, Dawkin’s protagonists are living species, journeying back through

evolutionary time. In real time, individual species diverged and speciated. But in

the backwards time of The Ancestor’s Tale, separate species start the

journey apart, in the present, and “converge” together as they descend into the

past. Humans “meet” the chimpanzee and the bonobo around 6 million years ago.

We all continue back in time together, rendezvousing with gorillas another

million years earlier. The time doubles before the next convergence, with

orang utans, at 14 million years ago. Dawkins takes his readers back and back and

back. We eventually meet rodents and rabbits at 75 million years, amphibians at

340 million years, lungfish at 417 million years. Insects, spiders, worms, snails

and other protostomes are all more closely related to one another than to us, so

on their own journey they have already converged. We meet them as one huge

scuttling, crawling, sliding band at around 590 million years ago. The common

ancestor – the “concestor” in backwards time – which we share with the

protostomes, was probably worm-like, segmented, with a mouth at the front, and

probably had eyes.

Dawkins reversal of time is designed to exorcise the “conceit of hindsight”,

in which all of evolution is seen as something inevitably progressing

towards the human and in which we lazily describe one species as

“more evolved” than another, for example. The Ancestor’s Tale is a

fascinating overview of all life on earth. Our small hope is that the

Ancestor’s Trail will help to illustrate the tree of life by symbolically

walking the journey back to the origin of life.      Bob Churchill.