Free In The Blink Of An Eye by Andrew Parker

correct answer to the what of the Cambrian explosion in this chapter, I will set out in the remainder of this book to present my new explanation of the why of the Cambrian explosion, something that has become known as the ‘Light Switch’ theory. To uncover the real cause of the Cambrian explosion we need to put together all the pieces of the puzzle. The next seven chapters of this book will be given over to the more significant pieces. In the course of these chapters I will construct a multidimensional picture of how life works today, what happened during the course of evolution on Earth and, consequently, how life worked at different times in the past.
    The following chapters will bring together the most unlikely of subjects, from ancient churches to impressionist paintings. At the turn of the twentieth century, the president of the Inventors’ Association resigned his position after claiming, ‘Everything that could be invented has been invented.’ He was not missed. This book will demonstrate the rewards of exploring laterally and how science can benefit from an interdisciplinary approach.
    In the next chapter I will examine fossils in more detail, providing examples of the information they have yielded in the past. But an explanation of the Cambrian explosion needs more than palaeontological evidence; it needs biological evidence too. As many clues can be found from studying living ecosystems as can be found in the fossils of the Cambrian animals themselves. The solution I propose draws on clues from all over science. By moving through time to the living world and on to my own specialist subjects, I will explain, in Chapter 3, how modern animals appear coloured or invisible. I will demonstrate the sophistication of the colour-producing systems of today’s animals, something we know very little about in extinct animals. A central theme will be that light is the most important stimulus to animal behaviour in the vast majority of today’s environments - those exposed to light.
    The case for light as a major stimulus today will be strengthened in Chapter 4 by examining the other side of the story - life in the dark, in caves and in the deep sea. Here, the importance of light will become even more apparent, not just in animal behaviour but also in evolution. In Chapter 5 I will compare the rates of evolution in two groups of
seed-shrimps which began their histories in different environments. One group lives in the open sea, the other in marine caves. By taking a closer look at the group from the open sea, it will emerge that light has driven their evolution, while those in the dark have barely changed from their primitive ancestors. The result is that the open-sea seed-shrimps are considerably more diverse than they are in dark caves. The role that light can play in evolution will also be demonstrated using marine isopod crustaceans (to which woodlice, or slaters, belong), where we will join Jim Lowry’s SEAS expedition in the Pacific Ocean, and also using crabs and flies.
    In Chapter 6 I will lighten the mood a little with an exploration for colour in ancient, extinct animals. Bones and other hard parts that may become fossils are physical structures. Some colours today result from physical structures, albeit microscopic. Could such micro-structures also preserve in the fossil record? Potential will be unearthed in fifty-million-year-old beetles and 180-million-year-old ammonites. Then the pages of the history book will be turned back even further … If the original colour alone of an Egyptian statue can tell us that it once housed the Book of the Dead, just think how much can be learnt from finding colour in fossils.
    To balance the information provided on colour in animals, Chapter 7 will introduce the variety of eyes. It will show that all animals have to be adapted to the existence of eyes not only in terms of their colour, but also in their shape and behaviour - all factors affecting