Free In The Blink Of An Eye by Andrew Parker Page A

an animal’s appearance on a retina. When this retina belongs to a predator, the image formed on it becomes a matter of life and death for the potential prey. But is the danger of visual appearance a recent one? The history of predation will be discussed in Chapter 8. By returning to the fossil record I will show that eyes, predators and probably the link between them go back a long way. But exactly how long? This will become a fundamental question.
    By the beginning of the penultimate chapter the reader will have all the clues necessary to decipher the probable cause of the Cambrian explosion. In many ways it seems the most obvious explanation, but to reach it one must take this indirect, winding road. Encountered along the way will be a number of unfamiliar but fascinating examples of the
sophisticated and finely balanced ecosystems that exist in nature - but to begin with, it’s back to the bare bones and a modern perspective on the lifeless rocks once kept safely within dusty Victorian display cases. Now we are bringing the past to life.

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    The Virtual Life of Fossils
    Nothing ever becomes real until it is experienced
    JOHN KEATS
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    Beginning, as it were, with the very beginning, Chapter 1 summarised a history of life on Earth. In this chapter, the evidence used to create such a story will be examined, making a closer inspection of the rocks. But here time shall be traversed from today, travelling back to the Cambrian via some landmark attractions. And good old-fashioned fossils will provide the attractions.
    Although the study of evolution is increasingly becoming consumed by genetic studies, the inferences from genetics are, and always will be, theoretical. The genes of many living species have been exposed, but the animals we see today did not evolve directly from each other. Intermediate stages were involved - species, for instance, that became extinct. So in order to reveal evolution, the genetics of the living and the extinct are required. And of course the extinct genes are, barring a few exceptions, subject to theoretical fabrication.
    Fossils, on the other hand, are factual. They are literally hard facts that we cannot ignore. Around a decade ago, molecular sequences pointed to a Cambrian explosion that occurred way back in the Precambrian. The fossil record, which places an Early Cambrian label on the grand event, was thus contradictory and appeared to be standing in the way of progress. But palaeontologists stood firm, reminding us that fossils were
not optical illusions. When 350-million-year-old rocks are split to reveal the fine details of a bony fish, then bony fish did swim in Earth’s waters 350 million years ago. When rocks formed under similar conditions, but from 550 million years ago, are consistently found without bony fish, eventually we must conclude that bony fish did not exist during this time. However, it would be equally foolish to ignore the genetic evidence, and indeed by reconciling the fossils and the genes a true picture of the Cambrian explosion has been painted. But whichever way they are looked upon, fossils are precious to the study of evolution. And they certainly justify a chapter of their own in this book, where the subject of fossils will surface again during discussion of seemingly unrelated topics.
    It was the role of fossils in revealing the paths taken by evolution which contributed heavily to the previous chapter. The main purposes of this chapter are to expose the tricks used in creating this knowledge, but also to demonstrate that fossils have much more to say. The history book, ‘The History of Life’, conceptualised here contains two-dimensional pages. The next task is to pump blood into the flattened veins of fossils and let them spring from the pages, so ancient animals can be seen doing what they once did. The application of engineering, physics, chemistry and biology can indeed transform a load of old bones into a virtual 3D world,