am 28. November 2004
A magnum opus from a scientist isn't common these days. Usually, their writings are in stacks of journal papers, with the occasional monograph highlighting a career. Journal articles remain buried in academic libraries, down the aisle from dusty tomes. Dawkins, however, is charged with the task of improving the "public understanding of science". With such a mandate, he is free to indulge in some innovative techniques. In this epic journey through time, he accomplishes that with his usual finesse. Add the lavish illustrations enhancing the text, and you have an outstanding depiction of evolution's saga.
Unlike most general surveys of evolution, this one offers some novel approaches. First, of course, is its structure. Instead of vague beginnings, Dawkins opens with a period familiar to all his readers - the scenes around us today. Moreover, that focus is on the part of Nature of most concern to us - "All Humankind". We like to consider ourselves the "point" of evolution? So be it, Dawkins declares, but warns that a change in outlook will likely result as you read this book. From that point, he begins to work backward in time. He stands Chaucer on his head by adding "pilgrims" to our journey at certain waypoints. The "pilgrims" are the Most Recent Common Ancestor of the present population of creatures. Since he begins with Homo sapiens, the most recent common ancestor, which Dawkins [rather, one of his graduate assistants] deems a "concestor", is of course the ancestor of today's chimpanzee.
It is a shock to most readers to learn we can make the traverse of nearly 4 billion years in but 39 steps [Hitchcock would have loved it!]. In tracing our mammalian ancestry, Dawkins is able to aid us in peering at the innermost secrets of our bizarre relatives. We meet colugos and tree shrews, mammoths with tusks like shovels, tarsiers and tigers. Nearly halfway along the track we are confronted with a superb essay on our nervous system. Using recent studies of the Platypus, we learn how our brain interacts with the rest of our bodies. A model human, proportioned to show how much our limbs are represented in the brain confronts us. Huge hands and lips extend from a minuscule torso perched on spindly legs. Our grasping abilities clearly helped drive the enlargement of that organ taking so much of our body's resources. In Platypus' case, the lips play the major role, since this creature uses its unusual properties to investigate its environment.
As we progress along the path, the information about our ancestors grows less certain. Is this creature in the proper genus? Is this miniature swimmer indeed unique in its classification? What is the divergent point between mammals and reptiles? With the introduction of reptiles, the birds finally join the trek. Dinosaurs, not being in the direct line leading to humans, are given short shrift. No matter, the books on these long-successful creatures are beyond counting - and the number grows constantly. Further back, he is able to introduce the unicellular world. It gives him an opportunity to explain the lifestyle of some of our planet's most fascinating life forms. Hair-trigger cells that capture food prey or ward off predators. Glorious, worm-like creatures "too good for a goddess", despite their human-derived appellation.
In his educational role, Dawkins must confront the insidious spread of Christian-inspired simplistic hype over evolution. He must take up space refuting its propaganda and invalid assumptions. With so much to cover, this is an unfortunate aside. Yet in dealing with their rants about "irreducible complexity", Dawkins demonstrates yet again that Darwinian principles provide the mechanisms for all life. The energy nodes in our cells, the mitochondria, he reminds us, are the vestiges of bacterial invaders, co-opted to a new role. Flagella, the great bugaboo of "intelligent design" adherents, are simply another chemical process. In his concluding way stations, Dawkins shows how these elements originally lived.
Although Dawkins notes throughout the book that science has a formidable task still ahead, with many mysteries to be resolved, this book will long endure. With its comprehensive scope coupled with the author's always compelling style, it belongs on every bookshelf. We need more such writers and their books. [stephen a. haines - Ottawa, Canada]