Wonderful Life: The Burgess Shale and the Nature of History Read online

  This collective work binds the generations. I spoke extensively with Bill Schevill, who quarried with Percy Raymond in the 1930s, and with G. Evelyn Hutchinson, who published his first notable insights on Burgess fossils just after Walcott’s death. Having nearly touched Walcott himself, I ranged to the present and spoke with all active workers. I am especially grateful to Desmond Collins, of the Royal Ontario Museum, who in the summer of 1988, as I wrote this book, was camped in Walcott’s original quarry while making fresh discoveries at a new site above Raymond’s quarry. His work will expand and revise several sections of my text; obsolescence is a fate devoutly to be wished, lest science stagnate and die.

  I have been obsessed with the Burgess Shale for more than a year, and have talked incessantly about its problems with colleagues and students far and wide. Many of their suggestions, and their doubts and cautions, have greatly improved this book. Scientific fraud and general competitive nastiness are hot topics this season. I fear that outsiders are getting a false view of this admittedly serious phenomenon. The reports are so prominent that one might almost envision an act of chicanery for each ordinary event of decency and honor. No, not at all. The tragedy is not the frequency of such acts, but the crushing asymmetry that permits any rare event of unkindness to nullify or overwhelm thousands of collegial gestures, never recorded because we take them for granted. Paleontology is a genial profession. I do not say that we all like each other; we certainly do not agree about very much. But we do tend to be helpful to each other, and to avoid pettiness. This grand tradition has eased the path of this book, through a thousand gestures of kindness that I never recorded because they are the ordinary acts of decent people—that is, thank goodness, most of us most of the time. I rejoice in this sharing, in our joint love for knowledge about the history of our wonderful life.

  Wonderful Life

  CHAPTER I

  The Iconography of an Expectation

  A PROLOGUE IN PICTURES

  And I will lay sinews upon you, and will bring up flesh upon you, and cover you with skin, and put breath in you, and ye shall live.—Ezekiel 37:6

  Not since the Lord himself showed his stuff to Ezekiel in the valley of dry bones had anyone brought such grace and skill to the reconstruction of animals from disarticulated skeletons. Charles R. Knight, most celebrated of artists in the reanimation of fossils, painted all the canonical figures of dinosaurs that fire our fear and imagination to this day. In February 1942, Knight designed a chronological series of panoramas, depicting the history of life from the advent of multicellular animals to the triumph of Homo sapiens, for the National Geographic. (This is the one issue that’s always saved and therefore always missing when you see a “complete” run of the magazine on sale for two bits an issue on the back shelves of the general store in Bucolia, Maine.) He based his first painting in the series—shown on the jacket of this book—on the animals of the Burgess Shale.

  Without hesitation or ambiguity, and fully mindful of such paleontological wonders as large dinosaurs and African ape-men, I state that the invertebrates of the Burgess Shale, found high in the Canadian Rockies in Yoho National Park, on the eastern border of British Columbia, are the world’s most important animal fossils. Modern multicellular animals make their first uncontested appearance in the fossil record some 570 million years ago—and with a bang, not a protracted crescendo. This “Cambrian explosion” marks the advent (at least into direct evidence) of virtually all major groups of modern animals—and all within the minuscule span, geologically speaking, of a few million years. The Burgess Shale represents a period just after this explosion, a time when the full range of its products inhabited our seas. These Canadian fossils are precious because they preserve in exquisite detail, down to the last filament of a trilobite’s gill, or the components of a last meal in a worm’s gut, the soft anatomy of organisms. Our fossil record is almost exclusively the story of hard parts. But most animals have none, and those that do often reveal very little about their anatomies in their outer coverings (what could you infer about a clam from its shell alone?). Hence, the rare soft-bodied faunas of the fossil record are precious windows into the true range and diversity of ancient life. The Burgess Shale is our only extensive, well-documented window upon that most crucial event in the history of animal life, the first flowering of the Cambrian explosion.

  The story of the Burgess Shale is also fascinating in human terms. The fauna was discovered in 1909 by America’s greatest paleontologist and scientific administrator, Charles Doolittle Walcott, secretary (their name for boss) of the Smithsonian Institution. Walcott proceeded to misinterpret these fossils in a comprehensive and thoroughly consistent manner arising directly from his conventional view of life: In short, he shoehorned every last Burgess animal into a modern group, viewing the fauna collectively as a set of primitive or ancestral versions of later, improved forms. Walcott’s work was not consistently challenged for more than fifty years. In 1971, Professor Harry Whittington of Cambridge University published the first monograph in a comprehensive reexamination that began with Walcott’s assumptions and ended with a radical interpretation not only for the Burgess Shale, but (by implication) for the entire history of life, including our own evolution.

  This book has three major aims. It is, first and foremost, a chronicle of the intense intellectual drama behind the outward serenity of this reinterpretation. Second, and by unavoidable implication, it is a statement about the nature of history and the awesome improbability of human evolution. As a third theme, I grapple with the enigma of why such a fundamental program of research has been permitted to pass so invisibly before the public gaze. Why is Opabinia, key animal in a new view of life, not a household name in all domiciles that care about the riddles of existence?

  In short, Harry Whittington and his colleagues have shown that most Burgess organisms do not belong to familiar groups, and that the creatures from this single quarry in British Columbia probably exceed, in anatomical range, the entire spectrum of invertebrate life in today’s oceans. Some fifteen to twenty Burgess species cannot be allied with any known group, and should probably be classified as separate phyla. Magnify some of them beyond the few centimeters of their actual size, and you are on the set of a science-fiction film; one particularly arresting creature has been formally named Hallucigenia. For species that can be classified within known phyla, Burgess anatomy far exceeds the modern range. The Burgess Shale includes, for example, early representatives of all four major kinds of arthropods, the dominant animals on earth today—the trilobites (now extinct), the crustaceans (including lobsters, crabs, and shrimp), the chelicerates (including spiders and scorpions), and the uniramians (including insects). But the Burgess Shale also contains some twenty to thirty kinds of arthropods that cannot be placed in any modern group. Consider the magnitude of this difference: taxonomists have described almost a million species of arthropods, and all fit into four major groups; one quarry in British Columbia, representing the first explosion of multicellular life, reveals more than twenty additional arthropod designs! The history of life is a story of massive removal followed by differentiation within a few surviving stocks, not the conventional tale of steadily increasing excellence, complexity, and diversity.

  For an epitome of this new interpretation, compare Charles R. Knight’s restoration of the Burgess fauna (figure 1.1), based entirely on Walcott’s classification, with one that accompanied a 1985 article defending the reversed view (figure 1.2).

  1.The centerpiece of Knight’s reconstruction is an animal named Sidneyia, largest of the Burgess arthropods known to Walcott, and an ancestral chelicerate in his view. In the modern version, Sidneyia has been banished to the lower right, its place usurped by Anomalocaris, a two foot-terror of the Cambrian seas, and one of the Burgess “unclassifiables.”

  2.Knight restores each animal as a member of a well-known group that enjoyed substantial later success. Marrella is reconstructed as a trilobite, Waptia as a proto-shrimp (see figure 1.1),
though both are ranked among the unplaceable arthropods today. The modern version features the unique phyla—giant Anomalocaris; Opabinia with its five eyes and frontal “nozzle”; Wiwaxia with its covering of scales and two rows of dorsal spines.

  3.Knight’s creatures obey the convention of the “peaceable kingdom.” All are crowded together in an apparent harmony of mutual toleration; they do not interact. The modern version retains this unrealistic crowding (a necessary tradition for economy’s sake), but features the ecological relations uncovered by recent research: priapulid and polychaete worms burrow in the mud; the mysterious Aysheaia grazes on sponges; Anomalocaris everts its jaw and crunches a trilobite.

  4.Consider Anomalocaris as a prototype for Whittington’s revision. Knight includes two animals omitted from the modern reconstruction: jellyfish and a curious arthropod that appears to be a shrimp’s rear end covered in front by a bivalved shell. Both represent errors committed in the overzealous attempt to shoehorn Burgess animals into modern groups. Walcott’s “jellyfish” turns out to be the circlet of plates surrounding the mouth of Anomalocaris; the posterior of his “shrimp” is a feeding appendage of the same carnivorous beast. Walcott’s prototypes for two modern groups become body parts of the largest Burgess oddball, the appropriately named Anomalocaris.

  Thus a complex shift in ideas is epitomized by an alteration in pictures. Iconography is a neglected key to changing opinions, for the history and meaning of life in general, and for the Burgess Shale in stark particulars.

  1.1. Reconstruction of the Burgess Shale fauna done by Charles R. Knight in 1940, probably the model for his 1942 restoration. All the animals are drawn as members of modern groups. Above Sidneyia, the largest animal of the scene, Waptia is reconstructed as a shrimp. Two parts that really belong to the unique creature Anomalocaris are portrayed respectively as an ordinary jellyfish (top, left of center) and the rear end of a bivalved arthropod (the large creature, center right, swimming above the two trilobites).

  1.2. A modern reconstruction of the Burgess Shale fauna, illustrating an article by Briggs and Whittington on the genus Anomalocaris. This drawing, unlike Knight’s, features odd organisms. Sidneyia has been banished to the lower right, and the scene is dominated by two specimens of the giant Anomalocaris. Three Aysheaia feed on sponges along the lower border, left of Sidneyia. An Opabinia crawls along the bottom just left of Aysheaia. Two Wiwaxia graze on the sea floor below the upper Anomalocaris.

  THE LADDER AND THE CONE: ICONOGRAPHIES OF PROGRESS

  Familiarity has been breeding overtime in our mottoes, producing everything from contempt (according to Aesop) to children (as Mark Twain observed). Polonius, amidst his loquacious wanderings, urged Laertes to seek friends who were tried and true, and then, having chosen well, to “grapple them” to his “soul with hoops of steel.”

  Yet, as Polonius’s eventual murderer stated in the most famous soliloquy of all time, “there’s the rub.” Those hoops of steel are not easily unbound, and the comfortably familiar becomes a prison of thought.

  Words are our favored means of enforcing consensus; nothing inspires orthodoxy and purposeful unanimity of action so well as a finely crafted motto—Win one for the Gipper, and God shed his grace on thee. But our recent invention of speech cannot entirely bury an earlier heritage. Primates are visual animals par excellence, and the iconography of persuasion strikes even closer than words to the core of our being. Every demagogue, every humorist, every advertising executive, has known and exploited the evocative power of a well-chosen picture.

  Scientists lost this insight somewhere along the way. To be sure, we use pictures more than most scholars, art historians excepted. Next slide please surpasses even It seems to me that as the most common phrase in professional talks at scientific meetings. But we view our pictures only as ancillary illustrations of what we defend by words. Few scientists would view an image itself as intrinsically ideological in content. Pictures, as accurate mirrors of nature, just are.

  I can understand such an attitude directed toward photographs of objects—though opportunities for subtle manipulation are legion even here. But many of our pictures are incarnations of concepts masquerading as neutral descriptions of nature. These are the most potent sources of conformity, since ideas passing as descriptions lead us to equate the tentative with the unambiguously factual. Suggestions for the organization of thought are transformed to established patterns in nature. Guesses and hunches become things.

  The familiar iconographies of evolution are all directed—sometimes crudely, sometimes subtly—toward reinforcing a comfortable view of human inevitability and superiority. The starkest version, the chain of being or ladder of linear progress, has an ancient, pre-evolutionary pedigree (see A. O. Lovejoy’s classic, The Great Chain of Being, 1936). Consider, for example, Alexander Pope’s Essay on Man, written early in the eighteenth century:

  Far as creation’s ample range extends,

  The scale of sensual, mental powers ascends:

  Mark how it mounts, to man’s imperial race,

  From the green myriads in the peopled grass.

  And note a famous version from the very end of that century (figure 1.3). In his Regular Gradation in Man, British physician Charles White shoehorned all the ramifying diversity of vertebrate life into a single motley sequence running from birds through crocodiles and dogs, past apes, and up the conventional racist ladder of human groups to a Caucasian paragon, described with the rococo flourish of White’s dying century:

  Where shall we find, unless in the European, that nobly arched head, containing such a quantity of brain … ? Where the perpendicular face, the prominent nose, and round projecting chin? Where that variety of features, and fullness of expression, … those rosy cheeks and coral lips? (White, 1799).

  1.3. The linear gradations of the chain of being according to Charles White (1799). A motley sequence runs from birds to crocodiles to dogs and monkeys (bottom two rows), and then up the conventional racist ladder of human groups (top two rows).

  This tradition never vanished, even in our more enlightened age. In 1915, Henry Fairfield Osborn celebrated the linear accretion of cognition in a figure full of illuminating errors (figure 1.4). Chimps are not ancestors but modern cousins, equally distant in evolutionary terms from the unknown forebear of African great apes and humans. Pithecanthropus (Homo erectus in modern terms) is a potential ancestor, and the only legitimate member of the sequence. The inclusion of Piltdown is especially revealing. We now know that Piltdown was a fraud composed of a modern human cranium and an ape’s jaw. As a contemporary cranium, Piltdown possessed a brain of modern size; yet so convinced were Osborn’s colleagues that human fossils must show intermediate values on a ladder of progress, that they reconstructed Piltdown’s brain according to their expectations. As for Neanderthal, these creatures were probably close cousins belonging to a separate species, not ancestors. In any case, they had brains as large as ours, or larger, Osborn’s ladder notwithstanding.

  1.4. Progress in the evolution of the human brain as illustrated by Henry Fairfield Osborn in 1915.

  1.5. A personally embarrassing illustration of our allegiance to the iconography of the march of progress. My books are dedicated to debunking this picture of evolution, but I have no control over jacket designs for foreign translations. Four translations of my books have used the “march of human progress” as a jacket illustration. This is from the Dutch translation of Ever Since Darwin.

  Nor have we abandoned this iconography in our generation. Consider figure 1.5, from a Dutch translation of one of my own books! The march of progress, single file, could not be more graphic. Lest we think that only Western culture promotes this conceit, I present one example of its spread (figure 1.6) purchased at the bazaar of Agra in 1985.

  1.6. I bought this children’s science magazine in the bazaar of Agra, in India. The false iconography of the march of progress now has cross-cultural acceptance.

  The march of progress is the c
anonical representation of evolution—the one picture immediately grasped and viscerally understood by all. This may best be appreciated by its prominent use in humor and in advertising. These professions provide our best test of public perceptions. Jokes and ads must click in the fleeting second that our attention grants them. Consider figure 1.7, a cartoon drawn by Larry Johnson for the Boston Globe before a Patriots–Raiders football game. Or figure 1.8, by the cartoonist Szep, on the proper place of terrorism. Or figure 1.9, by Bill Day, on “scientific creationism.” Or figure 1.10, by my friend Mike Peters, on the social possibilities traditionally open to men and to women. For advertising, consider the evolution of Guinness stout (figure 1.11) and of rental television (figure 1.12).*

  1.7. A cartoonist can put the iconography of the ladder to good use. This example by Larry Johnson appeared in the Boston Globe before a Patriots–Raiders game.

  The straitjacket of linear advance goes beyond iconography to the definition of evolution: the word itself becomes a synonym for progress. The makers of Doral cigarettes once presented a linear sequence of “improved” products through the years, under the heading “Doral’s theory of evolution.”† (Perhaps they are now embarrassed by this misguided claim, since they refused me permission to reprint the ad.) Or consider an episode from the comic strip Andy Capp (figure 1.13). Flo has no problem in accepting evolution, but she defines it as progress, and views Andy’s quadrupedal homecoming as quite the reverse.