STASIS


Paleontologists just were not seeing the expected changes in their fossils as they pursued them up through the rock record. ... That individual kinds of fossils remain recognizably the same throughout the length of their occurrence in the fossil record had been known to paleontologists long before Darwin published his Origin. Darwin himself, ... prophesied that future generations of paleontologists would fill in these gaps by diligent search ... One hundred and twenty years of paleontological research later, it has become abundantly clear that the fossil record will not confirm this part of Darwin's predictions. Nor is the problem a miserly fossil record. The fossil record simply shows that this prediction is wrong.

The observation that species are amazingly conservative and static entities throughout long periods of time has all the qualities of the emperor's new clothes: everyone knew it but preferred to ignore it. Paleontologists, faced with a recalcitrant record obstinately refusing to yield Darwin's predicted pattern, simply looked the other way.

No wonder paleontologists shied away from evolution for so long. It seems never to happen. Assiduous collecting up cliff faces yields zigzags, minor oscillations, and the very occasional slight accumulation of change over millions of years, at a rate too slow to really account for all the prodigious change that has occurred in evolutionary history.

But stasis was conveniently dropped as a feature of life's history to be reckoned with in evolutionary biology. And stasis had continued to be ignored until Gould and I showed that such stability is a real aspect of life's history which must be confronted—and that, in fact, it posed no fundamental threat to the basic notion of evolution itself. For that was Darwin's problem: to establish the plausibility of the very idea of evolution, Darwin felt that he had to undermine the older ... doctrine of species fixity. Stasis, to Darwin, was an ugly inconvenience.

Darwin's prediction of rampant, albeit gradual, change affecting all lineages through time is refuted. The record is there, and the record speaks for tremendous anatomical conservatism. Change in the manner Darwin expected is just not found in the fossil record.

The history of most fossil species include two features particularly inconsistent with gradualism:

1) Stasis - most species exhibit no directional change during their tenure on earth. They appear in the fossil record looking much the same as when they disappear; morphological change is usually limited and directionless;

2) Sudden appearance - in any local area, a species does not arise gradually by the steady transformation of its ancestors; it appears all at once and 'fully formed'.

...we must understand that nothing happens most of the time -- and we don't because our stories don't admit this theme -- if we hope to grasp the dynamics of evolutionary change. (This sentence may sound contradictory, but it isn't. To know the reasons for infrequent change, one must understand the ordinary rules of stability.) The Burgess Shale teaches us that, for the history of basic anatomical designs, almost everything happened in the geological moment just before, and almost nothing in more than 500 million years since.

"Stasis is data."

Every paleontologist knows that most species don't change. That's bothersome ... brings terrible distress. ... They may get a little bigger or bumpier. But they remain the same species and that's not due to imperfection and gaps but stasis. And yet this remarkable stasis has generally been ignored as no data. If they don't change, it's not evolution so you don't talk about it.

[S]tasis, or nonchange, of most fossil species during their lengthy geological lifespans was tacitly acknowledged by all paleontologists, but almost never studied explicitly because prevailing theory treated stasis as uninteresting nonevidence for nonevolution. [T]he overwhelming prevalence of stasis became an embarrassing feature of the fossil record, best left ignored as a manifestation of nothing (that is, nonevolution).

[W]ell represented species are usually stable throughout their temporal range, or alter so little and in such superficial ways (usually in size alone), that an extrapolation of observed change into longer periods of geological time could not possibly yield the extensive modifications that mark general pathways of evolution in larger groups. Most of the time, when the evidence is best, nothing much happens to most species.

"The fossil record of bats extends back to the early Eocene ... and has been documented ... on five continents ... [A]ll fossil bats, even the oldest, are clearly fully developed bats and so they shed little light on the transition from their terrestrial ancestor."


"The gaps in the fossil record are real, however. The absence of a record of any important branching is quite phenomenal. Species are usually static, or nearly so, for long periods; species seldom and genera never show evolution into new species or genera but replacement of one by another, and change is more or less abrupt."

It is probably only the stasis on the level of higher taxa which is both valid and differs qualitatively from the other levels of stasis. Only higher taxa lack demonstrable evidence of change ... Higher taxon-level stasis could conceivably be the result of what might be called Baraminic Stasis -- the permanent constraint of organisms under natural conditions to stay within the bounds of their baramin (Wise, 1991).