Dinosaur In a Haystack - A Website About Stephen Jay Gould's ...

two sisters in praising him excessively. As the only one of his daughters who truly loveshim, she feels her only two options are to succumb and lie, or to remain faithful – byremaining silent. She chooses the latter, which the king misconstrues; rather thaninterpreting her silence as an act of faith and love, he takes it for what it appears to be:nothing. By analogy, Gould argues, Cordelia’s dilemma in science is to interpret “nochange over time” as “no data.”Gould, of course, has a personal stake in this issue. Stasis, one of the key concepts ofpunctuated equilibrium, involves the identification of “no change” as, itself, important; inthe famous phrase from the first paper he and Niles Eldredge wrote on PE in 1972, “stasisis data.” Gould describes how his graduate advisor used certain statistical techniques toidentify changes in 50 species of Devonian brachiopods over an extended period; notfinding any, he did not publish, and in fact changed fields! In the operating paradigm ofhis advisor and almost everyone else in the profession, evolution is a continuous, ongoingprocess. Therefore, the absence of change (Cordelia’s silence) was not an indication ofsomething important, but simply “nothing.” Gould tells us that, whether punctuatedequilibrium holds up in the long run or not, he takes pride in motivating the communityto look for stasis, and to recognize its theoretical importance.Gould was motivated to write this essay, he tells us, by the contemporary (1992)publication of a study of stasis at the next higher taxonomic level – that of genus – byAnn Budd and Anthony Coates. PE refers only to the origin and continuity of species.When most or all of the species in that genus evolve in a similar direction, whether byabrupt punctuations or gradual and continuous phyletic gradualism, the community refersto this as a trend. Gould states that there are many trends in the fossil record, such as theincreasing brain size of hominids over the past few million years [see ESD 22] andreduction in the number of toes on horses. [He notes in BFB 11 that the horse is actuallya bad example. Also, in their original 1972 paper, Gould and Eldredge argue that trendsin natural history can be explained in terms of both phyletic gradualism and punctuatedequilibrium.] In an analogy to Cordelia’s dilemma at the species level, a commonlyunrecognized assumption is that all trends are directional; that is, gradual but continuouschange toward “something.” Budd and Coates examined species of the coral genusMontastraea (still important today) over the 80 million year span of the Cretaceousperiod. What they found was that, while species came and went, the attributes of thegenus as a whole appeared to oscillate back and forth between certain limits; after 80million years, species looked pretty much the same as they did at the beginning. Buddand Coates refer to this as “non-progressive evolution.” Gould is delighted, primarily onthe grounds that twenty years earlier this phenomenon would almost certainly not havebeen reported.He is careful not to claim that there are no trends in most of natural history. Rather, it isthat they are not as universal as was commonly believed; this should be recognized, heclaims, if for no other reason than to better appreciate the importance of the “real” trends.[However, his 1996 book Full House – written a few years later – argues that progressiveevents and trends are actually quite rare in natural history.]13