Wonderful Life: The Burgess Shale and the Nature of History

by Stephen Jay Gould

  Since the current restudy of all the Burgess Shale arthropods is revealing that the detailed morphology of these forms is not as previously thought, the present author considers further discussion of the affinities of Burgessia as premature.… What is apparent from this restudy is that Burgessia did possess a mixture of characters … many of which are to be found in modern arthropods of various groups (1975, p. 434).

  3.27. Reconstruction of Burgessia by Hughes (1975).

  The arthropod story was becoming more and more curious.

  MENTORS AND STUDENTS

  Universities operate one of the few survivors of the old apprenticeship system in their programs for awarding doctoral degrees. Consider the anomaly. You spend your entire educational career, from kindergarten to college, becoming more and more independent of the power of individual teachers; (cross your first-grade teacher and your life can be hell for a year; displease a college professor, and the worst you can do is fail a single course). Then you become an adult, and you decide to continue for a Ph.D. So what do you do? You find a person whose research intrigues you, and sign on (if he will accept and support you) as a part of a team.

  In some fields, particularly those with large and expensive laboratories dedicated to the solution of definite problems, you must abandon all thought of independence, and work upon an assigned topic for a dissertation (choice in research is a luxury of later postdoctoral appointments). In more genial and individualistic fields like paleontology, you are usually given fair latitude in choosing a topic, and may emerge with a project uniquely your own. But in any case you are an apprentice, and you are under your mentor’s thumb—more securely than at any time since the early years of primary school. If you and he have a falling out, you quit, or pack up and go elsewhere. If you work well together, and your mentor’s ties to the profession are secure, you will get your degree and, by virtue of his influence and your proven accomplishments, your first decent job.

  It’s a strange system with much to criticize, but it works in its own odd way. At some point, you just can’t proceed any further with courses and books; you have to hang around someone who is doing research well. (And you need to be on hand, and ready to assimilate, all the time, every day; you can’t just show up on Thursday afternoon at two for a lesson in separating parts from counterparts.) The system does produce its horrors—exploitive professors who divert the flow of youthful brilliance and enthusiasm into their own dry wells, and provide nothing in return. But when it works (as it does rather more often than a cynic might expect, given the lack of checks and balances), I cannot imagine a better training.

  Many students don’t understand the system. They apply to a school because it has a general reputation or resides in a city they like. Wrong, dead wrong. You apply to work with a particular person. As in the old apprenticeship system of the guilds, mentor and student are bound by mutual obligations; this is no one-way street. Mentors must, above all, find and provide financial support for students. (Intellectual guidance is, of course, more fundamental, but this part of the game is a pleasure. The real crunch is the search for funding. Many leading professors spend at least half their time raising grant support for students.) What do mentors get in return? This reciprocation is more subtle, and often not understood outside our guild. The answer, strange as this may sound, is fealty in the genealogical sense.

  The work of graduate students is part of a mentor’s reputation forever, because we trace intellectual lineages in this manner. I was Norman Newell’s student, and everything that I ever do, as long as I live, will be read as his legacy (and, if I screw up, will redound to his detriment—though not so seriously, for we recognize a necessary asymmetry: errors are personal, successes part of the lineage). I happily accept this tradition and swear allegiance to it—and not for motives of abstract approbation but because, again as with the old apprenticeship system, I get my turn to profit in the next generation. As my greatest joy in twenty years at Harvard, I have been blessed with several truly brilliant students. The greatest benefit is an exciting lab atmosphere for the moment—but I am not insensible to the custom that their future successes shall be read, in however small a part, as mine also.

  (By the way, this system is largely responsible for the sorry state of undergraduate teaching at many major research universities. A student belongs to the lineage of his graduate adviser, not to the teachers of his undergraduate courses. For researchers ever conscious of their reputations, there is no edge whatever in teaching undergraduate courses. You can do it only for love or responsibility. Your graduate students are your extensions; your undergraduate students are ciphers in your fame. I wish that this could change, but I don’t even know what to suggest.)

  This system is even more exaggerated in England. In the United States you apply through a department to work with an adviser. In England, you apply directly to a potential mentor, and he secures the funds, almost always earmarked for particular projects. Harry Whittington knew that the ultimate success of the Burgess project—its expansion from the detailed description of a few odd animals to an understanding of an entire fauna—depended upon graduate students. Of the two ingredients, he could influence one—the garnering of funds; for the other he could only pray to the goddess of good fortune—the interest of brilliant students.

  Harry did his job on the first score. He had two projects outstanding (in both senses of that word)—bivalved arthropods and “worms.” He secured funding for two students—for one, from government grants, and for the other, from private monies administered by his college, Sidney Sussex. Lady Luck came through on the second score (with a boost from Harry’s own successes, for good students keep their eyes open and gravitate toward mentors doing the most exciting work). In 1972, at exactly the right stage in the flow of Burgess developments, events disproved my cherished theory of academic spacing—that brilliant students come but once in five years (since five years is the usual length of graduate study, you never have more than one at a time for very long). At the same time, Harry Whittington—lucky, lucky man—received applications from two brilliant students: Derek Briggs, an Irishman who had done undergraduate work at Trinity College, Dublin; and Simon Conway Morris, a Londoner who had just completed his first degree at Bristol University (where Harry had sat, as external examiner, on the committee to judge his undergraduate thesis). From then on, however restricted the daily contact, and despite an individuality in working styles that precluded any cohesive research group, the Burgess work became a joint effort of three increasingly equal partners—Briggs, Conway Morris, and Whittington (in nonjudgmental alphabetical order), three men with a common purpose and a common set of methods, but as different as could be in age and in general approaches to science and life.

  Harry Whittington knows the rules and the score. In our conversations, he has emphasized above all else, and with no false modesty, that the Burgess revision became a complete and coherent project—not just a sequence of monographs—when he secured the dedication of Briggs and Conway Morris. For he could then forge a goal that he might live to complete, and not, like the architect of a medieval cathedral, just draft a blueprint and lay a foundation, but never hope to see the entire building.

  CONWAY MORRIS’S FIELD SEASON IN WALCOTT’S CABINETS: A HINT BECOMES A GENERALITY, AND THE TRANSFORMATION SOLIDIFIES

  Odd couples are a staple of drama and comedy. Conservative intellectuals of quality will often embrace radical students with outlandish life styles because they sense the light of brilliance and nothing else then counts. Bernie Kummel, who threatened to take a rubber hose to radical students in the 1970s, and who despised (and feared) any eccentricity of manner or dress, loved Bob Bakker (then our student, now the spearhead of new ideas about dinosaurs) like a son, despite his shoulder-length hair and radical notions about absolutely everything. (Bernie’s judgment was not always so good. At one time, he and Harry Whittington formed the invertebrate-paleontology group at Harvard. Bernie regarded Harry as too traditional, and
was pleased when he chose to leave for Cambridge. Bernie then hired me as a very junior replacement. Not much of a trade.)

  Simon Conway Morris, who described himself to me as “bloody-minded as a teen-ager, and usually antisocial,” struck Whittington as the best candidate for the craziest of all Burgess challenges—Walcott’s “worms.” Simon’s teachers at Bristol had described him to Harry as a man who “sits in the corner of the library reading, and wears a cloak.” Harry remembers his first reaction to this news: “The anarchist, I thought … Oh Lord.” But Harry had also sensed the spark of brilliance, and as I said, nothing else really counts.

  Worms presented both the biggest headache and the greatest promise for a project now explicitly searching for oddballs since the resolution of Opabinia. For if oddballs existed in abundance, previous investigators would have shoveled most misfits into the old category Vermes, or “worms.” Worms are the classic garbage-pail group of taxonomy—the slop bucket for the dribs and drabs (Simon calls them “odds and sods”) that don’t fit anywhere, but need to be shunted someplace when you are trying to landscape the estate into rigorous order. Worms have played this role ever since Linnaeus himself, who shoved a remarkably heterogeneous group of creatures into his Vermes. Most animals are basically elongate and bilaterally symmetrical. So if a creature displays this form, and you don’t know what it is, call it a worm.

  Harry, a remarkably kind man, trembled at the idea that he might be ending a promising career at the beginning by giving such an intractable project to a greenhorn. To this day, he seems almost wracked with anxiety when he remembers what he did—even though the results have been spectacular: He reminisced to me: “With fear and trepidation, I suggested this to Simon.… I felt awful; of all ghastly things to start a research student on! Gosh, how could I dare to do that to anybody? Yet I had a wild hunch he could do it.”

  Simon was delighted; he has been running ever since. The solid centerpieces of this project are his two fine monographs on Burgess worms that truly belong to modern phyla—the priapulids (1977d) and the polychaetes (1979). I shall discuss these works in their proper sequence. But Simon did not begin with this conventional material; would you really expect such a traditional start from a man who wears a cloak and won’t come to morning coffee?

  In the spring of 1973, Whittington sent both Briggs and Conway Morris to Washington to draw Walcott’s “type” specimens (the ones used in the original descriptions of the species, and the official bearers of Walcott’s names), and to select specimens for loan to Cambridge. An old saying, attributed to Pasteur, proclaims that fortune favors the prepared mind. Simon, a man of ideas, had chosen to work with Harry, and reveled at receiving the worms as a project, because he sensed that the prospect for a larger message from the Burgess centered upon the documentation of oddballs—both their anatomy and their relative frequency. Opabinia had forced its attention upon Harry. Simon, in stark contrast, went hunting for Burgess oddballs. “I have a natural temptation to emphasize the unusual,” Simon told me. “A new brachiopod from Northern Ireland is no competition for a new phylum.”

  Imagine the situation, and the opportunity. Simon faced some eighty thousand specimens in Walcott’s collection. Most had never been described, or even gazed upon. No one had ever examined this treasure with the idea that taxonomic oddballs might abound. So Simon did something both simple and obvious in concept, yet profoundly different from any previous approach to the Burgess—and therefore courageous. He went on a protracted fishing expedition in the Smithsonian drawers of Burgess material. He opened every cabinet and looked at every slab, consciously searching for the rarest and most peculiar things he could find. The rewards were great, the success almost dizzying. At first, you jump up and down; after a while, the richness benumbs you. By the time he found Odontogriphus (see page 147), he could only say to himself, “Oh fuck, another new phylum.”

  I cannot imagine a greater contrast (and, therefore, better seeds of drama) than the disparate styles of Whittington and Conway Morris—Harry, the older conservative systematist, about to start the greatest project of a full life, versus Simon, the radical beginner, consciously seeking to overturn established opinion. Their working procedures could not have been more different. Harry began with greatest caution, choosing the most common animal in the Burgess. He proceeded with a series of monographs on individual genera, each taking years of preparation: Marrella (1971), Yohoia (1974), trilobite limbs (1975b), Opabinia (1975a), and as we shall see, Naraoia (1977) and Aysheaia (1978). He confined his work (or so he thought when he began) to the arthropods, the group that he knew best. He started with conventional views about the taxonomy of Burgess organisms, changing his mind only when unexpected evidence forced itself upon his consciousness. Simon, by contrast—with the innocence of Pearl Pureheart and the proven skill of Alvin Allthumbs, but armed with the sublime confidence of Muhammad Ali as his youthful avatar Cassius Clay—began with an explicit search for embodiments of the most radical interpretation of Burgess anatomy. The rarer the better; several of Simon’s weird wonders are reconstructions based upon single specimens. In two years, 1976 and 1977, Conway Morris initiated his career by publishing five short papers, on five creatures with the anatomical uniqueness of new phyla.*

  Such differences should breed dissension and open conflict. Nothing of the kind occurred—intellectual drama of the highest order, yes, but no juicy stories of overt battle. Oh, Derek does remember Harry mumbling a bit about people running before they learned to walk, and some private feelings may be left unsaid to this day. But when I asked Harry how he felt about a student who published five short papers before his Ph.D., sometimes basing new phyla upon single specimens, he replied: “I stood by and smiled. I wouldn’t dream of discouraging a research student.”

  I know that the following comment is trite, but the foundation of banality is often evident truth: The final coalescence of the Burgess transformation emerged from a lovely synergism between these two disparate approaches. Perhaps the process of interpretation would have led to the final outcome in any case. Perhaps either the slow sequence of descriptive monographs or the rapid succession of short papers with radical claims would eventually have compelled assent by itself. But nothing can beat the one-two punch of laborious description so careful that it cannot be gainsaid combined with overt claims so sparsely documented and so divergent from tradition that they can only inspire fury—and attention. I know that this combination “just happened” along one of the odd and unpredictable pathways of human affairs, but if anyone is up there regulating the progress of knowledge, he could not have acted with better or more deliberate purpose than by arranging this synergism of youth and experience, caution and daring.

  I stopped the narrative once before (with Opabinia) to announce a key moment meriting special type for emphasis, and I shall do so just once again (for Anomalocaris); but Simon’s field season in the cabinets of the Smithsonian marks the second of three major transitions, as I read the story of the Burgess. When Simon began, Opabinia was hinting at something strange, but no one knew either the extent or the nature of the phenomenon; I believe that Harry was still favoring an interpretation of oddballs as stem groups, primitive combinations of characters that would later sort themselves into discrete phyla living today, rather than as uniquely specialized experiments in multicellular design, separate lineages without later issue. When Simon completed his initial sequence of five papers on curiosities, the tentative and peculiar had become a Burgess norm, and the notion of separate lineages beyond the realm of modern anatomy had displaced the conventional fallback to “primitive” and “precursor.” Whittington recalled his gradually dawning reaction to Simon’s discoveries: “The whole atmosphere changed. We were not just dealing with predecessors of known groups. The whole thing was beginning to make a picture.”

  Simon’s five oddballs span a remarkable range of anatomy and life style. Their only common theme is peculiarity.

  1. Nectocaris. Walcott did single
out this peculiar animal, represented by only one specimen lacking a counterpart—for Conway Morris found a photo, retouched as usual, next to the well-prepared specimen. But Walcott had published nothing, and left no notes. Conway Morris justified his decision to publish on such scant information: “The fine preservation and unusual anatomy warrant notice being taken of this unique specimen” (1976a, p. 705).

  From the “neck” forward, Nectocaris looks mostly like an arthropod (figure 3.28). The head bears one or two pairs of short, forward-projecting, but apparently unjointed (and therefore not arthropod-like) appendages. A pair of large eyes, probably borne on stalks, lies just behind. The back part of the head is enclosed by a flattened oval shield, perhaps bivalved. But the rest of the body evokes no particular hint of arthropod, and gives off more than an intriguing whiff of chordate—our own phylum. The body is laterally compressed and built of some forty segments (a common characteristic of arthropods and several other phyla, including our own). Conway Morris found no hint of the defining arthropod character—jointed appendages. Instead, both the dorsal and ventral (top and bottom) surfaces bear continuous structures that, at least superficially, look like chordate fins supported by fin rays! (With a single specimen, one cannot proceed much beyond the superficial, so this crucial issue remains tantalizingly unresolved.)

  Three features of these fins and fin rays deny arthropod affinities and hint chordate: First, a thin and continuous structure, preserved as a dark film on the rock, seems to connect the parallel series of short, stiffening rays into a coherent fin; arthropod limbs, by contrast, are discrete. Second, the fins run along the top and bottom edges of the animal, as in early chordates; arthropod appendages generally attach to the sides of the body. Third, the fins of Nectocaris have about three stiffening rays per body division; one pair of appendages per original segment is a defining character of arthropods. (Tagmosis, or coalescence of arthropod segments, is identified by the presence of more than one appendage per division. The segments of Nectocaris are too narrow and too numerous for interpretation as amalgamations of several ancestral divisions.)