Creatures of Accident The Rise of the Animal Kingdom

Chapter One HAND LUGGAGE ONLY Human thinking about the nature of life has been constrained by dogmatic ideological stances, not just religious and political ones, but also adherence to the scientific orthodoxy of the day. Such "philosophical baggage" needs to be jettisoned at the outset of our journey so that we open our minds to the maximum range of possibilities. Science should be all about open-mindedness and questioning. It is an honest search for the truth about the nature of "life, the universe and everything," to use that famous phrase introduced by Douglas Adams in his bookThe Hitchhiker's Guide to the Galaxy. This book, like the animal kingdom, had an accidental origin. The seed from which it eventually germinated was sown by a newspaper article I read a few years ago. The retention of this seed of information for several years is a bit odd, because newspapers, unlike books, are ephemeral things. If you have already read today's paper, how many articles can you remember? What about yesterday's? Or last week's? We pass our time on trains and planes perusing the papers, but we don't commit much to memoryor at least to the long-term version of that everyday miracle. However, occasionally something sticks. The article whose message stuck with me was in the color supplement of one of the Sunday papers. It was about evolution. A particular sentence is all that I retain, and doubtless in imperfect form. But, to an approximation, here it is: "Complex creatures, like humans, are a mere epiphenomenon in the history of Life." What did its author mean by describing us as an "epiphenomenon," that is, a sort of blip on the periphery of something altogether more important? What was the deep philosophical point he was trying to impart? Well, his point was something like this. Since life began about four billion years ago, the vast majority of the creatures that have lived out their lives in every corner of our planetary home have been bacteria. This in itself is hardly surprising, because bacteria are very small, and small creatures tend to be much more numerous than large ones. You and I are both individual humans, but we are also both roving vehicles transporting millions of bacteria from place to placemost of them in our guts and on our skin. But the point goes further. Not only are there far more bacteria than animals or plants; there are also more different types of bacteria. In other words, species. We all recognize different species of animals, whether very different, like humans and houseflies, or only slightly different, like horses and donkeys. In contrast, different species of bacteria require more than the naked eye to see, let alone distinguish. Indeed, the whole concept of a speciesbounded by its members' inability to breed with other than same-species partnersis hard to apply in the bacterial realm, where reproduction is hardly sex as we know it. Such difficulties aside, it is probably true that both now and at all other points in evolutionary time the living world has been dominated by bacteria, both in numbers of individual creatures and in numbers of types of creatures. This fact is at odds with a curious human practicenaming particular periods of the earth's history after a particular kind of animal, as in the Age of Fishes. Such names have a rationale but also serve to mislead. They are normally used to refer to a type of animal that diversified rapidly in the period concerned and consequently contributed much to its fossil record. But unlike fish, most bacteria have no hard parts and rarely fossilize. So fossil frequencies are a poor guide to the dominant creatures of the past. In reality, thArthur, Wallace is the author of 'Creatures of Accident The Rise of the Animal Kingdom', published 2007 under ISBN 9780809037018 and ISBN 0809037017.