Punctuated Equilibrium and the Validation of Macroevolutionary Theory 939
a differential production of small-corallite species from large-corallite ancestors, as
well as a southward expansion of the clade's geographic range. Limited and
directionless speciation, accompanied by predominant stasis within established
species prevailed during intervals 2 and 3. Between intervals 3 and 4, large-
corallite species radiated from small-corallite ancestors, and the geographic range
of the clade became more restricted. In other words, the general pattern at the end
of interval 4 differed little from the initial spread of morphology and geographic
range at the outset of interval one, the inception of the study itself.
But the montastraeids remained a vigorous, successful, and evolutionarily
active clade throughout Cretaceous times. Who are we to proclaim their pattern
"boring" or unworthy of study because the evolutionary history of these corals
does not resonate well with human preferences about "interesting" or "instructive"
stories? Perhaps we should force ourselves to learn that patterns traditionally
shunned for such quirky reasons of human appetite may hold unusual interest and
capacity to teach—precisely because we have never sought messages that might
challenge our complacencies. The predominant pattern of life's history cannot fail
to be instructive—and such non-trending may well mark a norm of this magnitude,
even if heretofore hidden in plain sight because we also see with our minds, and
conventional concepts can be more blinding than mere ocular failure.
PUNCTUATIONAL ANALOGS IN LINEAGES: THE PACE OF MORPHOLOGICAL
INNOVATION. I do not wish to resuscitate one of the oldest canards, and least
fruitful themes of evolutionary debate: the claim for truly saltational, or
macromutational—that is, effectively one generational, or ecologically
"overnight"—origin of new species or morphotypes. This ultimate extreme in
punctuational change has never been supported by punctuated equilibrium, or by
any sensible modern account of punctuational change in any form. Even if older
evolutionists did advocate this mode of change (see my discussions of de Vries on
pp. 415-451 and of Goldschmidt on pp. 451-466), they granted no exclusivity to its
operation, and they also defended more continuationist, and more structurally
plausible, accounts of rapid origin for morphological novelties—as in the
developmentally rooted and theoretically sensible concept, based on mutations in
"rate genes," embodied in Goldschmidt's unwisely named "hopeful monster," in
contrast with the speculative scenario that he built upon his later concept of
"systemic mutations"—see Schwartz (1999) for an interesting modern retelling and
defense of this notion.
Just as punctuated equilibrium scales the geologically abrupt (but ecologically
slow and continuous) process of speciation against the long duration of most
species in subsequent stasis, punctuational hypotheses at higher levels regard the
pacing of substantial phenotypic change in the origin of novel morphotypes as
similarly episodic, with origins concentrated in very short episodes relative to
periods of stability in basic design during the normal waxing and waning of
clades—and perhaps with the ecologies, or the structural and developmental bases,
of such episodes belonging to a distinctly different