Wonderful Life: The Burgess Shale and the Nature of History (2 page)

Chapter I lays out, through the unconventional device of iconography, the traditional attitudes (or thinly veiled cultural hopes) that the Burgess Shale now challenges. Chapter II presents the requisite background material on the early history of life, the nature of the fossil record, and the particular setting of the Burgess Shale itself. Chapter III then documents, as a drama and in chronological order, this great revision in our concepts about early life. A final section tries to place this history in the general context of an evolutionary theory partly challenged and revised by the story itself. Chapter IV probes the times and psyche of Charles Doolittle Walcott, in an attempt to understand why he mistook so thoroughly the nature and meaning of his greatest discovery. It then presents a different and antithetical view of history as contingency. Chapter V develops this view of history, both by general arguments and by a chronology of key episodes that, with tiny alterations at the outset, could have sent evolution cascading down wildly different but equally intelligible channels—sensible pathways that would have yielded no species capable of producing a chronicle or deciphering the pageant of its past. The epilogue is a final Burgess surprise—
vox clamantis in deserto
, but a happy voice that will not make the crooked straight or the rough places plain, because it revels in the tortuous crookedness of real paths destined only for interesting ends.

I am caught between the two poles of conventional composition. I am not a reporter or “science writer” interviewing people from another domain under the conceit of passive impartiality. I am a professional paleontologist, a close colleague and personal friend of all the major actors in this drama. But I did not perform any of the primary research myself—nor could I, for I do not have the special kind of spatial genius that this work requires. Still, the world of Whittington, Briggs, and Conway Morris is my world. I know its hopes and foibles, its jargon and techniques, but I also live with its illusions. If this book works, then I have combined a professional’s feeling and knowledge with the distance necessary for judgment, and my dream of writing an “insider’s McPhee” within geology may have succeeded. If it does not work, then I am simply the latest of so many victims—and all the clichés about fish and fowl, rocks and hard places, apply. (My difficulty in simultaneously living in and reporting about this world emerges most frequently in a simple problem that I found insoluble. Are my heroes called Whittington, Briggs, and Conway Morris; or are they Harry, Derek, and Simon? I finally gave up on consistency and decided that both designations are appropriate, but in different circumstances—and I simply followed my instinct and feeling. I had to adopt one other convention; in rendering the Burgess drama chronologically, I followed the dates of publication for ordering the research on various Burgess fossils. But as all professionals know, the time between manuscript and print varies capriciously and at random, and the sequence of publication may bear little relationship to the order of actual work. I therefore vetted my sequence with all the major participants, and learned, with pleasure and relief, that the chronology of publication acted as a pretty fair surrogate for order of work in this case.)

I have fiercely maintained one personal rule in all my so-called “popular” writing. (The word is admirable in its literal sense, but has been debased to mean simplified or adulterated for easy listening without effort in return.) I believe—as Galileo did when he wrote his two greatest works as dialogues in Italian rather than didactic treatises in Latin, as Thomas Henry Huxley did when he composed his masterful prose free from jargon, as Darwin did when he published all his books for general audiences—that we can still have a genre of scientific books suitable for and accessible alike to professionals and interested laypeople. The concepts of science, in all their richness and ambiguity, can be presented without any compromise, without any simplification counting as distortion, in language accessible to all intelligent people. Words, of course, must be varied, if only to eliminate a jargon and phraseology that would mystify anyone outside the priesthood, but conceptual depth should not vary at all between professional publication and general exposition. I hope that this book can be read with profit both in seminars for graduate students and—if the movie stinks and you forgot your sleeping pills—on the businessman’s special to Tokyo.

Of course, these high-minded hopes and conceits from yours truly also demand some work in return. The beauty of the Burgess story lies in its details, and the details are anatomical. Oh, you could skip the anatomy and still get the general message (Lord knows, I repeat it enough times in my enthusiasm)—but please don’t, for you will then never understand either the fierce beauty or the intense excitement of the Burgess drama. I have done everything I could to make the two technical subjects—anatomy and taxonomy—maximally coherent and minimally intrusive. I have provided insets as primers on these subjects, and I have kept the terminology to an absolute minimum (fortunately, we can bypass nearly all the crushing jargon of professional lingo, and grasp the key point about arthropods by simply understanding a few facts about the order and arrangement of appendages). In addition, all descriptive statements in the text are matched by illustrations.

I did briefly consider (but it was only the Devil speaking) the excision of all this documentation, with a bypass via some hand waving, pretty pictures, and an appeal to authority. But I could not do it—and not only for reasons of general policy mentioned above. I could not do it because any expunging of anatomical arguments, any derivative working from secondary sources rather than primary monographs, would be a mark of disrespect for something truly beautiful—for some of the most elegant technical work ever accomplished in my profession, and for the exquisite loveliness of the Burgess animals. Pleading is undignified, but allow me one line: please bear with the details; they are accessible, and they are the gateway to a new world.

A work like this becomes, perforce, something of a collective enterprise—and thanks for patience, generosity, insight, and good cheer must be widely spread. Harry Whittington, Simon Conway Morris, and Derek Briggs endured hours of interviews, detailed questioning, and reading of manuscripts. Steven Suddes, of Yoho National Park, kindly organized a hike to the hallowed ground of Walcott’s quarry, for I could not write this book without making such a pilgrimage. Laszlo Meszoly prepared charts and diagrams with a skill that I have admired and depended upon for nearly two decades. Libby Glenn helped me wade through the voluminous Walcott archives in Washington.

Never before have I published a work so dependent upon illustrations. But so it must be; primates are visual animals above all, and anatomical work, in particular, is as much pictorial as verbal. I decided right at the outset that most of my illustrations must be those originally used in the basic publications of Whittington and colleagues—not only for their excellence within the genre, but primarily because I know no other way to express my immense respect for their work. In this sense, I am only acting as a faithful chronicler of primary sources that will become crucial in the history of my profession. With the usual parochialism of the ignorant, I assumed that the photographic reproduction of published figures must be a simple and automatic procedure of shoot ’em and print ’em. But I learned a lot about other professional excellences as I watched Al Coleman and David Backus, my photographer and my research assistant, work for three months to achieve resolutions that I couldn’t see in the primary publications themselves. My greatest thanks for their dedication and their instruction.

These figures—about a hundred, all told—are primarily of two types: drawings of actual specimens, and schematic reconstructions of entire organisms. I could have whited out the labeling of features, often quite dense, on the drawings of specimens, for few of these labels relate to arguments made in my text and those that do are always fully explained in my captions. But I wanted readers to see these illustrations exactly as they appear in the primary sources. Readers should note, by the way, that the reconstructions, following a convention in scientific illustration, rarely show an animal as an observer might have viewed it on a Cambrian sea bottom—and for two reasons. Some parts are usually made transparent, so that more of the full anatomy may be visualized; while other parts (usually those repeated on the other side of the body) are omitted for the same reason.

Since the technical illustrations do not show an organism as a truly living creature, I decided that I must also commission a series of full reconstructions by a scientific artist. I was not satisfied with any of the standard published illustrations—they are either inaccurate or lacking in aesthetic oomph. Luckily, Derek Briggs showed me Marianne Collins’s drawing of
Sanctacaris
(figure 3.55), and I finally saw a Burgess organism drawn with a scrupulous attention to anatomical detail combined with aesthetic flair that reminded me of the inscription on the bust of Henry Fairfield Osborn at the American Museum of Natural History: “For him the dry bones came to life, and giant forms of ages past rejoined the pageant of the living.” I am delighted that Marianne Collins, of the Royal Ontario Museum, Toronto, was able to provide some twenty drawings of Burgess animals exclusively for this book.

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

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.