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In the Blink of an Eye by Andrew Parker, Free Press, £18.99, ISBN 0743219805 Reviewed by Douglas Palmer

THE Cambrian explosion, sometimes called the “big bang” in animal evolution, was “perhaps the most dramatic event in the history of life”, says Andrew Parker, when “all the major animal groups found today evolved”. He tries to pin down its cause in his book In the Blink of an Eye. It happened “precisely 543 million years ago”. According to Parker, “544 million years ago there were…three animal phyla…but at 538 million years ago there were 38.” Sounds dramatic alright, but Parker will have more than a few palaeontologists choking on their cornflakes.

Parker is an Australian-born zoologist now at the University of Oxford, where he has been investigating the evolution of coloration and light reception in living sea creatures. He has become fascinated and increasingly embroiled in a long-running debate about the nature of the Cambrian explosion. His explanation is that the light on the road to the evolutionary Damascus was the sudden appearance of the eye.

This visionary event is indeed recorded by the appearance of fossil trilobites close to the beginning of the Cambrian. The record of the major increase in diversity, however, is linked to the appearance of the Chengjiang fossil biota of about 515 million years ago. How many millions of years can a big bang last before it becomes a prolonged, if energetic, fizzle?

Parker argues that eye evolution caused the explosion because it was linked to the evolution of actively swimming predators and a rapid development of the ensuing arms race. The evidence shows that fossilised armour plating bears the scars of conflict. That the Cambrian “explosion” had an ecological basis is widely accepted, but the academic parliament will be divided: “eyes” right, “nos” left, but I think we still don’t have the result of the division.