Theory of Evolution Funny Monkey Oin the Tertiary Period
SURVIVAL OF THE LUCKIEST
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October 22, 1989
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WONDERFUL LIFE The Burgess Shale and the Nature of History. By Stephen Jay Gould. Illustrated. 347 pp. New York: W. W. Norton & Company. $19.95.
One fine day a half-billion years ago, an underwater mud slide (or some other catastrophe) buried a mob of strange creatures in what has now become a slab of exposed rock known as the Burgess Shale, high up in western Canada's Yoho National Park. They are certainly the weirdest animal fossils ever found, and they could easily be - as Stephen Jay Gould argues in his extraordinary book ''Wonderful Life'' - the most important.
It was not long before this lucky accident that earthly life began its copious parade. True, for a few billion years before that, single-cell algae and bacteria filled the planet's seas and swamps, but these organisms were not doing much to engage the interest of future paleontologists. Then, suddenly, life as we know it - complex, multifarious, beastly life - exploded into existence all across the planet and began evolving in earnest.
Eons later, a certain hairy, two-legged species has come to think of itself as the crowning achievement of this process. We are the capable and well-designed creature atop the evolutionary ladder. We have survived because we are fittest. If most of us have abandoned the idea that God designed the world for our personal benefit, we may nevertheless be clinging to a few prejudices of a different sort - that evolution means progress, for example. Mr. Gould, a great believer in the importance of cultural iconography, has spent years collecting cartoons and advertisements that illustrate the conventional view of human evolution, the view we all carry around in our heads. It is a procession of taller and taller primates, from a stoop-shouldered monkey dragging its long arms in the mud, to a more upright but still rather slovenly looking Neanderthal, to a clean-shaven country-club version of Homo sapiens.
The conventional view is wrong - just how wrong, scientists are only beginning to realize. Those who study evolution have lately been undertaking some serious mental housecleaning. They have been throwing out some preconceptions that they had not examined for generations. They are, reluctantly or enthusiastically, accepting the idea that humans are as much an accident of nature as a product of orderly development. As Mr. Gould sees it, the bizarre menagerie trapped in the Burgess Shale stands as both the perfect emblem and the proximate cause of this remaking of the history of life.
''Wonderful Life'' - the title is a self-conscious echo of the Frank Capra movie - tells a set of interlocking stories. One is the discovery of the Burgess fossils in 1909 by a powerful American geologist, Charles Doolittle Walcott, the longtime head of the Smithsonian Institution, who then proceeded to misunderstand and misclassify the thousands of ancient animals he had found. A second is the discovery of Walcott's error and the revelation of the fossils' true message by three paleontologists in Britain, who conducted a monumental re-examination of the fossils in the 1970's and 80's.
These tales join some broader ones: stories of how science's seemingly neutral facts shape our attitudes and myths and are shaped by them in turn and, finally, how astonishingly chancy and accident-prone was the pageant of evolution that produced the planet's countless millions of existing species, and one in particular.
Mr. Gould is an exceptional combination of scientist and science writer, one of America's foremost paleontologists and the author of many books on evolution and on scientific history. He is thus exceptionally well placed to tell these stories, and he tells them with fervor and intelligence. He attempts a rare thing in science writing: a book meant to hold the interest of both specialists and lay readers, in this case those who have and have not committed to memory the words Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Tertiary and Quaternary. He explicitly warns that he will not pull his technical punches, that the beauty of his case study lies in the anatomical details.
Actually, I think more than a few readers will find themselves skipping over the anatomical details, but no matter - the outline of the adventure is straightforward and clear. Walcott, in analyzing and classifying the bounty he reaped from the Burgess Shale, is mentally bound to a view of evolution as linear and progressive. He knows, without even looking at the fossils, that they must be simple ancestors of the species we see on earth today. And sure enough, that is what he decides he has found: simple ancestors of the species we see on earth today. As Mr. Gould says, Walcott ''shoehorns'' his specimens into the existing categories. Half a century passes. Three percipient colleagues of Mr. Gould's - Harry Whittington of Cambridge University and two graduate students, Simon Conway Morris and Derek Briggs - undertake a fresh look at the Burgess fossils. They have some technical advantages over Walcott; most important is a painstaking procedure for reconstructing a three-dimensional animal from the invisibly thin layers crushed together in a two-dimensional fossil. And for the first time, they really ''see'' these creatures in all their glorious strangeness.
Marrella, a delicate animal nicknamed lace crab, the most prevalent of the Burgess creatures, looked to Walcott, for want of anything better, like a trilobite. It isn't - it's something new. Opabinia, a much rarer animal, looked to Walcott like a fairly ordinary two-eyed sort of worm, at any rate some primitive member of the arthropod phylum. Mr. Whittington realized that it did not belong with the arthropods or with any other modern classification. It had not two but five eyes, four of them on a pair of stalks. It had a protruding frontal nozzle that may have functioned like a vacuum cleaner. And so on - to even eerier creatures, like the whimsically named Hallucigenia and Sanctacaris (Santa Claws), some found by Mr. Conway Morris when he embarked on a new program of ''fieldwork'' in the drawers and cabinets of the Smithsonian in Washington. ''Wonderful Life'' is richly illustrated with drawings of these and many other animals.
When the movies try to design alien life forms, they unwittingly reveal our lack of imagination about the different paths life can take. They tend to fall back on a standard body plan - with crusty or gnarly skin, perhaps, but basically the same old animal. The Burgess Shale provides a heady antidote to lack of imagination. This one slab of rock, now abetted by more recent fossil discoveries, reveals more disparate basic body plans, Mr. Gould says, than all the creatures now swimming or floating in the earth's oceans. ''Little taller than a man, and not so long as a city block!'' he writes of the site. ''How could such richness accumulate in such a tiny space?''
Mr. Gould may be the last great apologist for a style of intellectual work that has mostly fallen from favor: the business of classifying, categorizing and pigeonholing. We think of this as a sterile occupation. Who cares, really, what the eras, periods and epochs are named? And who cares whether a given specimen belongs in this phylum or that? Mr. Gould not only makes the case for memorizing the eras, periods and epochs; he also argues vehemently that classification is a high and creative calling. ''Taxonomy is a fundamental and dynamic science,'' he says, ''dedicated to exploring the causes of relationships and similarities among organisms. Classifications are theories about the basis of natural order, not dull catalogues compiled only to avoid chaos.'' In the case of the Burgess Shale, he argues, the work of placing fossils in categories, carefully weighing similarities and differences and occasionally discarding an old category and inventing a new one leads, inexorably, to a new view of the history of life.
Why? Because somehow paleontologists must now account for the disappearance of all those interesting body types. The number of species has grown with time, but, surprisingly, their disparity, their anatomical range, has diminished. In one way, at least, life on earth was never richer than in the era of the Burgess fossils. Rather than primitive ancestors of existing animals, the fossils emerge as complex, well-developed beasts in their own right - and as ancestors of creatures that for some reason failed to exist.
''The history of life is a story of massive removal followed by differentiation within a few surviving stocks,'' Mr. Gould concludes, ''not the conventional tale of steadily increasing excellence, complexity, and diversity.'' Furthermore, he argues that the vanished body plans seem, functionally speaking, every bit as ''fit'' as the survivors. Chance must have played a central role in choosing the victims of this decimation.
Replay the tape of life, he says - his favorite metaphor - and see what happens. Tiny accidents early in history would create altogether different outcomes. How likely is it that, among the planet's millions of species, virtually all insects, one would develop conscious intelligence? Mr. Gould takes a position that remains radical within the paleontological community: that only a series of exceedingly unlikely accidents made possible the emergence of anything like Homo sapiens. ''We are an improbable and fragile entity . . . an item of history, not an embodiment of general principles,'' he writes.
The best scientific history conveys the grand themes without losing sight of the small, the gritty details of research as it is carried out by human beings. Mr. Gould revels in both the big and the small, and he weaves his stories together well. It is fascinating to watch the slow revolution in the mentality of these scientists, like an ocean liner slowly turning in a harbor. As always in his writing for nonspecialists, Mr. Gould draws clever connections to popular culture. Occasionally, though, he carries his command of vernacular imagery to an irritating extreme (he describes one scientist ''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''). For my taste, also, he devotes too much prose to another, unnecessary narrative thread: why he is writing this book, how he is writing it, how he considered writing it differently and why he decided to write it this way after all. He virtually reviews his own book (and the review is favorable).
Mr. Gould himself notes one awkward feature of his role: he is a scientist, not a journalist, and he must tell this story - about colleagues and friends - from the inside. He gains the advantage of technical sophistication; he gladly accepts the lack of distance that an outsider would have. He lets us know that he will refer to his protagonists as Harry, Simon and Derek. He mocks the idea of the author as impartial interviewer: ''Oh, I did my duty in this regard. I visited them all, pad and pencil in hand. The exercise made me feel rather foolish.''
In spite of himself, he makes a decent journalist. Without the anecdotal recollections he gets from the participants, the human side of his narrative would be neither vivid nor convincing. But I think that Stephen Jay Gould, the insider, falls into a trap that Stephen Jay Gould, the historian, has often warned against. A myth about science suggests that new theories arise when they are necessary to explain new facts. The messy and more interesting reality is that ''facts'' themselves tend to depend on the theories of the fact finders. When writing about Walcott's mistakes, safely in the past, Mr. Gould shows in detail how scientific decisions were colored by cultural and philosophical prejudices. Walcott was rushed and careless, yes, but ultimately he ''shoehorned'' his fossils into standard categories - he failed to see their wondrous oddity - because he believed in a standard view of evolution as progress.
Yet when writing about his colleagues, Mr. Gould lets his readers take away a simpler impression, that a rational group of scientists developed a new view of evolution because they received new evidence from the Burgess fossils. He lets himself describe scientific judgments as purely that: scientific. Messrs. Whittington, Conway Morris and Briggs were hardly working in a vacuum. They were surely guided, as much as their hapless predecessor, by the assumptions of their discipline and their culture. The last two decades have seen many other sciences, without benefit of Burgess Shales, evolve a stronger appreciation of the roles of contingency and catastrophe. And within paleontology, quite apart from the evidence of the Canadian fossils, many voices have been making the case for a more chance-ridden, less progress-oriented view of life - none, in fact, more vigorously than Mr. Gould.
Did these three scientists revise our understanding of the Burgess fossils only because they were brilliant and hard-working, only because they ''took the time to converse adequately with the Burgess fossils, and because they were willing to listen''? Or is it possible, too, that Harry, Simon and Derek had been listening to Steve? THE ODDS WERE AGAINST US
In writing ''Wonderful Life,'' Stephen J. Gould said, his intent was to determine the extent of the ''predictability of life. The old view is that our ancestors were a small number of primitive forms. This view was based on the fossil record, which is not informative, because a lot of species didn't have hard parts to make an imprint.''
The book was inspired by the work of a Cambridge University scientist, Harry Whittington, who, with two graduate students, re-evaluated the findings of the Burgess Shale, first discovered by Charles Doolittle Walcott at the beginning of the century: ''Whittington re-examined the Burgess Shale and found that Walcott's interpretation was false and that there was an immense variety of forms. Nothing about the forms that didn't make it suggests that they shouldn't have made it. This idea challenges the long-held notion that from early life forms such as those found in the Burgess Shale we could tell which species would emerge later on.''
Mr. Gould said that one of the conclusions of ''Wonderful Life'' is that there is ''no predictability'' in evolution and that the determination of the life forms that emerged from the Cambrian period is random.
''Darwinian history of life held that there was progress in evolution,'' he said in a telephone interview from Beaumont, Tex. ''What the re-examination of the Burgess Shale tells us is that there isn't any progress at all and that human evolution is highly improbable. If you could, like Marty McFly in the movie 'Back to the Future,' go back in time and visit the Burgess Shale in the Cambrian period, and then replay history, odds are that we humans wouldn't exist at all. We are just one of an infinite number of possibilities.'' Mr. Gould, who teaches biology, geology and the history of science at Harvard University, is at work on a book on the structure of evolutionary theory. ''That work,'' he said, unlike ''Wonderful Life,'' ''is technical and for specialists.'' MAX BERLEY NOBODY WOULD LISTEN
In no other way but [ the ] false ordering by status among the sciences can I understand the curious phenomenon that led me to write this book in the first place - namely, that the Burgess revision has been so little noticed by the public in general and also by scientists in other disciplines. . . .
An interesting contrast . . . might be drawn between the Burgess revision and the [ Luis ] Alvarez theory linking the Cretaceous extinction to extraterrestrial impact. I regard these two as the most important paleontological discoveries of the past twenty years. I think that they are equal in significance and that they tell the same basic story (as illustrations of the extreme chanciness and contingency of life's history: decimate the Burgess differently and we never evolve; send those comets into harmless orbits and dinosaurs still rule the earth, precluding the rise of large mammals, including humans). I hold that both are now well documented, the Burgess revision probably better than the Alvarez claim. Yet the asymmetry of public attention has been astonishing. Alvarez's impact theory has graced the cover of Time, been featured in several television documentaries, and been a subject of comment and controversy wherever science achieves serious discussion. Few nonprofessionals have ever heard of the Burgess Shale. . . .
I do understand that part of this difference in attention simply reflects our parochial fascination with the big and the fierce. Dinosaurs are destined for more attention than two-inch ''worms.'' But I believe that the major ingredient - particularly in the decision of science writers to avoid the Burgess Shale - lies with the stereotype of the scientific method, and the false ordering of sciences by status. . . . The Burgess redescriptions . . . struck many observers as one funny thing after another . . . odd animals from early in life's history. From ''Wonderful Life.''
Source: https://www.nytimes.com/1989/10/22/books/survival-of-the-luckiest.html
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