In the Blink of an Eye
The Cause of the Most Dramatic Event in the History of Life
By Andrew Parker
Free Press, 336pp, .95
Vision is the window through which our consciousness stares. Eyesight is an astonishing innovation, and its arrival on earth must have been the cause of much evolutionary mayhem. But what is colour? How do eyes work? From what do eyes evolve? What happened when the first creature saw the world?
These mind-bending considerations are fodder for Andrew Parker's new book. I first encountered Dr Parker, who is now a Royal Society Research Fellow at Oxford University's department of zoology, when he was a visiting scientist at the Australian Museum in the mid-'90s.
He approached me to do a story about his "light-switch theory", which argued that one of the most significant events in evolution, the Cambrian Explosion 543 million years ago, was caused when trilobites evolved eyes. The Cambrian Explosion refers to the sudden appearance - in the space of a few million years - of life as we know it. The Cambrian is the birthplace of the hunter and the hunted, the decorated, the armed and the colourful.
Parker's idea looked so simple it seemed almost a statement of the obvious - life was stalled until the first creature evolved vision and then, once an eye was in the world, the food chain as we know it exploded onto the stage. Parker is the first scientist to make this claim.
His thesis is that it was the birth of an eye that allowed creatures to see each other, opening the way for predation, camouflage, decoration and an end to the worm world that had existed for hundreds of millions of years.
It was also Parker who made a truly awesome discovery - that Cambrian creatures were covered in diffraction gratings. Diffraction gratings are microscopic lines that break up light, creating the same colourful sparkles we see when we move a CD under light. In other words, he proved that Cambrian animals were spectacularly coloured.
Unfortunately, his book is not an easy read. It is marketed as popular science but is hard work even for someone like myself who has had the benefit of many hours with Parker discussing his work. He alludes to this fact himself as late as page 268:
"At this point I feel like a university lecturer who has just finished teaching a foundation course - weary but relieved. Not a single educational stone has been left unturned in the bid to reveal the facts and figures needed to progress to a new stage in learning. There is a certain amount of relief because this is where things become interesting and exciting. We are now equipped to tackle evolution's grandest event of all. We can now go back 543 million years, to the beginning of the Cambrian."
Sadly, at this point the book is just a few minutes away from ending and some of the most important questions are glossed over. The toughest question of all he admits that he cannot answer: "What triggered the evolution of the eye?"
This fundamental problem is dealt with in the final seven pages and left me deeply dissatisfied. None of these criticisms, however, can detract from what will be to every reader a book with dozens of revelatory moments.
"Just think," Parker writes, "all those wonderful colours we see around us, wherever we are, do not actually exist. In the environment there is no colour, only objects that happen to deflect different types of electromagnetic radiation. Roses are not beaming out reds, nor do leaves generate greens."
This is a book that can genuinely claim to change the way you see the world.
