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

  Wonderful Life

  To NORMAN D. NEWELL

  Who was, and is, in the most noble

  word of all human speech, my teacher

  Contents

  Preface and Acknowledgments

  CHAPTER I. The Iconography of an Expectation

  A PROLOGUE IN PICTURES

  THE LADDER AND THE CONE: ICONOGRAPHIES OF PROGRESS

  REPLAYING LIFE’S TAPE: THE CRUCIAL EXPERIMENT

  Inset: The Meanings of Diversity and Disparity

  CHAPTER II. A Background for the Burgess Shale

  LIFE BEFORE THE BURGESS: THE CAMBRIAN EXPLOSION AND THE ORIGIN OF ANIMALS

  LIFE AFTER THE BURGESS: SOFT-BODIED FAUNAS AS WINDOWS INTO THE PAST

  THE SETTING OF THE BURGESS SHALE

  WHERE

  WHY: THE MEANS OF PRESERVATION

  WHO, WHEN: THE HISTORY OF DISCOVERY

  CHAPTER III. Reconstruction of the Burgess Shale: Toward a New View of Life

  A QUIET REVOLUTION

  A METHODOLOGY OF RESEARCH

  THE CHRONOLOGY OF A TRANSFORMATION

  Inset: Taxonomy and the Status of Phyla

  Inset: The Classification and Anatomy of Arthropods

  The Burgess Drama

  Act 1. Marrella and Yohoia: The Dawning and Consolidation of Suspicion, 1971–1974

  The Conceptual World That Whittington Faced

  Marrella: First Doubts

  Yohoia: A Suspicion Grows

  Act 2. A New View Takes Hold: Homage to Opabinia, 1975

  Act 3. The Revision Expands: The Success of a Research Team, 1975–1978

  Setting a Strategy for a Generalization

  Mentors and Students

  Conway Morris’s Field Season in Walcott’s Cabinets: A Hint Becomes a Generality, and the Transformation Solidifies

  Derek Briggs and Bivalved Arthropods: The Not-So-Flashy but Just-As-Necessary Final Piece

  Act 4. Completion and Codification of an Argument: Naraoia and Aysheaia, 1977–1978

  Act 5. The Maturation of a Research Program: Life after Aysheaia, 1979-Doomsday (There Are No Final Answers)

  The Ongoing Saga of Burgess Arthropods

  Orphans and Specialists

  A Present from Santa Claws

  Continuing the March of Weird Wonders

  Wiwaxia

  Anomalocaris

  Coda

  SUMMARY STATEMENT ON THE BESTIARY OF THE BURGESS SHALE

  DISPARITY FOLLOWED BY DECIMATION: A GENERAL STATEMENT

  ASSESSMENT OF GENEALOGICAL RELATIONSHIPS FOR BURGESS ORGANISMS

  THE BURGESS SHALE AS A CAMBRIAN GENERALITY

  PREDATORS AND PREY: THE FUNCTIONAL WORLD OF BURGESS ARTHROPODS

  THE ECOLOGY OF THE BURGESS FAUNA

  THE BURGESS AS AN EARLY WORLD-WIDE FAUNA

  THE TWO GREAT PROBLEMS OF THE BURGESS SHALE

  THE ORIGIN OF THE BURGESS FAUNA

  THE DECIMATION OF THE BURGESS FAUNA

  CHAPTER IV. Walcott’s Vision and the Nature of History

  THE BASIS FOR WALCOTT’S ALLEGIANCE TO THE CONE OF DIVERSITY

  A BIOGRAPHICAL NOTE

  THE MUNDANE REASON FOR WALCOTT’S FAILURE

  THE DEEPER RATIONALE FOR WALCOTT’S SHOEHORN

  WALCOTT’S PERSONA

  WALCOTT’S GENERAL VIEW OF LIFE’S HISTORY AND EVOLUTION

  THE BURGESS SHOEHORN AND WALCOTT’S STRUGGLE WITH THE CAMBRIAN EXPLOSION

  THE BURGESS SHALE AND THE NATURE OF HISTORY

  Inset: A Plea for the High Status of Natural History

  CHAPTER V. Possible Worlds: The Power of “Just. History”

  A STORY OF ALTERNATIVES

  GENERAL PATTERNS THAT ILLUSTRATE CONTINGENCY

  THE BURGESS PATTERN OF MAXIMAL INITIAL PROLIFERATION

  MASS EXTINCTION

  SEVEN POSSIBLE WORLDS

  EVOLUTION OF THE EUKARYOTIC CELL

  THE FIRST FAUNA OF MULTICELLULAR ANIMALS

  THE FIRST FAUNA OF THE CAMBRIAN EXPLOSION

  THE SUBSEQUENT CAMBRIAN ORIGIN OF THE MODERN FAUNA

  THE ORIGIN OF TERRESTRIAL VERTEBRATES

  PASSING THE TORCH TO MAMMALS

  THE ORIGIN OF Homo sapiens

  AN EPILOGUE ON PIKAIA

  Bibliography

  Credits

  Index

  Other Titles By Stephen Jay Gould

  Copyright

  Preface and Acknowledgments

  This book, to cite some metaphors from my least favorite sport, attempts to tackle one of the broadest issues that science can address—the nature of history itself—not by a direct assault upon the center, but by an end run through the details of a truly wondrous case study. In so doing, I follow the strategy of all my general writing. Detail by itself can go no further; at its best, presented with a poetry that I cannot muster, it emerges as admirable “nature writing.” But frontal attacks upon generalities inevitably lapse into tedium or tendentiousness. The beauty of nature lies in detail; the message, in generality. Optimal appreciation demands both, and I know no better tactic than the illustration of exciting principles by well-chosen particulars.

  My specific topic is the most precious and important of all fossil localities—the Burgess Shale of British Columbia. The human story of discovery and interpretation, spanning almost eighty years, is wonderful, in the strong literal sense of that much-abused word. Charles Doolittle Walcott, premier paleontologist and most powerful administrator in American science, found this oldest fauna of exquisitely preserved soft-bodied animals in 1909. But his deeply traditionalist stance virtually forced a conventional interpretation that offered no new perspective on life’s history, and therefore rendered these unique organisms invisible to public notice (though they far surpass dinosaurs in their potential for instruction about life’s history). But twenty years of meticulous anatomical description by three English and Irish paleontologists, who began their work with no inkling of its radical potential, has not only reversed Walcott’s interpretation of these particular fossils, but has also confronted our traditional view about progress and predictability in the history of life with the historian’s challenge of contingency—the “pageant” of evolution as a staggeringly improbable series of events, sensible enough in retrospect and subject to rigorous explanation, but utterly unpredictable and quite unrepeatable. Wind back the tape of life to the early days of the Burgess Shale; let it play again from an identical starting point, and the chance becomes vanishingly small that anything like human intelligence would grace the replay.

  But even more wonderful than any human effort or revised interpretation are the organisms of the Burgess Shale themselves, particularly as newly and properly reconstructed in their transcendent strangeness: Opabinia, with its five eyes and frontal “nozzle”; Anomalocaris, the largest animal of its time, a fearsome predator with a circular jaw; Hallucigenia, with an anatomy to match its name.

  The title of this book expresses the duality of our wonder—at the beauty of the organisms themselves, and at the new view of life that they have inspired. Opabinia and company constituted the strange and wonderful life of a remote past; they have also imposed the great theme of contingency in history upon a science uncomfortable with such concepts. This theme is central to the most memorable scene in America’s most beloved film—Jimmy Stewart’s guardian angel replaying life’s tape without him, and demonstrating the awesome power of apparent insignificance in history. Science has dealt poorly with the concept of contingency, but film and literature have always found it fascinating. It’s a Wonderful Life is both a symbol and the finest illustration I kn
ow for the cardinal theme of this book—and I honor Clarence Odbody, George Bailey, and Frank Capra in my title.

  The story of the reinterpretation of the Burgess fossils, and of the new ideas that emerged from this work, is complex, involving the collective efforts of a large cast. But three paleontologists dominate the center stage, for they have done the great bulk of technical work in anatomical description and taxonomic placement—Harry Whittington of Cambridge University, the world’s expert on trilobites, and two men who began as his graduate students and then built brilliant careers upon their studies of the Burgess fossils, Derek Briggs and Simon Conway Morris.

  I struggled for many months over various formats for presenting this work, but finally decided that only one could provide unity and establish integrity. If the influence of history is so strong in setting the order of life today, then I must respect its power in the smaller domain of this book. The work of Whittington and colleagues also forms a history, and the primary criterion of order in the domain of contingency is, and must be, chronology. The reinterpretation of the Burgess Shale is a story, a grand and wonderful story of the highest intellectual merit—with no one killed, no one even injured or scratched, but a new world revealed. What else can I do but tell this story in proper temporal order? Like Rashomon, no two observers or participants will ever recount such a complex tale in the same manner, but we can at least establish a groundwork in chronology. I have come to view this temporal sequence as an intense drama—and have even permitted myself the conceit of presenting it as a play in five acts, embedded within my third chapter.

  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 befor
e 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.