All creatures great and small

With the publication of “The Selfish Gene” in 1976, biologist Richard Dawkins announced his intention of concentrating on various interpretations of evolution. A self-proclaimed philosophical descendant of Charles Darwin, Dawkins believes that DNA reveals the basic blueprint for life on Earth, without benefit of a designer, intelligent or otherwise. He is a vocal opponent of the idea that evolution was designed to produce us. “It makes no more sense (and no less) to aim our historical narrative towards Homo sapiens than towards any other modern species -- Octopus vulgaris, say, or Panthera leo, or Sequoia sempervirens [the common octopus, the lion, and the redwood tree],” he writes in his newest book, “The Ancestor’s Tale.” “In other words, evolution is a process that affects every living (and extinct) being, but it moves in no particular direction, and we are not at the top of the pyramid of mammals, any more than the common octopus (if you are so proud of your opposable thumbs, think of controlling eight arms simultaneously) is at the top of the heap of cephalopods.”

In “The Selfish Gene,” Dawkins, Oxford University’s Charles Simonyi professor of the public understanding of science, explained that every living thing exists because its genes dictated its evolutionary development, that every animal has evolved as it has because it fits into its environment. Though most of the species that have ever lived on Earth are extinct, no animal (or plant) is individually destined for extinction. If the environment changes, however, or new predators emerge, the equation might become unbalanced and a species endangered.

“The Ancestor’s Tale” takes its form and title from Chaucer’s “Canterbury Tales,” but where Chaucer’s story is told by 30 pilgrims on the road to Canterbury, Dawkins’ is much more ambitious. His “pilgrimage” consists of “a journey in a time machine in quest of our ancestors.” Along the road, he picks up traveling companions: an assortment of apes, monkeys, mice, hippos, platypuses, birds, amphibians, fishes, insects, jellyfishes, sponges and bacteria. Such a traveling menagerie would be rather cumbersome, so it is only their stories he carries. (Though Dawkins sometimes resorts to such constructions as, “Our pilgrimage is now a milling horde, having amassed all the vertebrates, together with their primitive cousins, amphioxus and the sea squirts,” suggesting that everything is actually traipsing along this backward road.) Thus, we read “The Howler Monkey’s Tale,” “The Dodo’s Tale,” “The Sponge’s Tale” and so on. Chaucer gave us only one life-form (Homo sapien) on the way to Canterbury -- the noble Knight, the drunken Miller, the wife of Bath and the impoverished Parson -- and each has to tell two stories on the way out and two on the way back. In “The Ancestor’s Tale,” the voice is not that of the salamander or the fruit fly but of Dawkins about them. (Since one chapter is titled “The Cauliflower’s Tale,” it’s just as well that Dawkins is the speaker.)

En route, we learn about the evolutionary history of everything, from blue-green algae and brine shrimp to Homo sapiens. More to the point, Dawkins explains how everything is connected because there is a common ancestor of all life. The various “Tales” are interspersed with assorted passages in which we meet various ancestors. (Dawkins calls them “Concestors” to show that they are the ancestors of what will follow.) Some of the tales are brief, some are lengthy, and some barely exist at all. In “The Leafy Sea Dragon’s Tale,” where I expected to find an explanation of the seaweed-like decorations on this spectacular seahorse, Dawkins says only that his daughter, Juliet, didn’t think it looked much like a fish.

This is a rich, heavy plum pudding of a book, replete with zoological surprises. Did you know that marsupials see in color, whereas most other mammals do not? That we have no idea why beavers build dams? That whales are closely related to hippos? There are passing mentions of extinct animals (the journey opens with a discussion of various ancestors to humans), but for the most part, Dawkins writes about species that are alive today, showing how (and sometimes when and even why) they acquired the characteristics that define them. The voyage through time is really a trip through contemporary zoology, liberally seeded with prescient insights on evolutionary theory.

Throughout the history of life on earth, an enormous number of species died out, leaving only fossils as evidence of their existence. Though Dawkins explains fossils brilliantly, he devotes little space to the creatures we know only from the fossil record, such as archaeopteryx, pterodactyls, ichthyosaurs, mammoths, saber-toothed cats and ground sloths. Was their DNA not passed along to living creatures? Were they evolutionary dead ends? He does point out that the fossils we have found are only a smattering of the life-forms that have existed, so we have an incomplete picture of what lived where and when. But unless I have misinterpreted the rationale for this pilgrimage through time, we ought to have met a few more dinosaurs along the way. They did, after all, dominate the planet for 100 million years. (That birds are now considered the descendants of dinosaurs seems more than enough justification for including something like “The Tyrannosaur’s Tale.”)

Maybe “The Ancestor’s Tale” is not supposed to be about the history of life on earth; maybe it’s just supposed to be about how we got to where we could write books like this one -- in which case, it would be completely anthropocentric, exactly what Dawkins says evolution is not. *