748 THE STRUCTURE OF EVOLUTIONARY THEORY
The inferences, which I draw from these facts, are not opposed to one of the
leading propositions of Darwin's theory. With him I have no faith in the
opinion that the Mammoth and other extinct Elephants made their
appearance suddenly, after the type in which their fossil remains are
presented to us. The most rational view seems to be, that they are in some
shape the modified descendants of earlier progenitors. But if the asserted
facts be correct, they seem clearly to indicate that the older Elephants of
Europe... were not the stocks from which the later species... sprung, and
that we must look elsewhere for their origin (pp. 253-254).Falconer thus anticipates a primary inference of punctuated equilibrium—
that a local pattern of abrupt replacement does not signify macromutational
transformation in situ, but an origin of the later species from an ancestral
population living elsewhere, followed by migration into the local region. Falconer
suggests that the ancestry of later European species may be sought among Miocene
species in India: "The nearest affinity, and that a very close one ... is with the
Miocene ... of India" (p. 254).
Falconer then summarizes the puzzles that such stability—of such long-
lasting, widespread forms in such variable environments—raises for evolutionary
theory: "The whole range of the Mammalia, fossil and recent, cannot furnish a
species which has had a wider geographical distribution, and at the same time
passed through a longer term of time, and through more extreme changes of
climatal (sic) conditions, than the Mammoth. If species are so unstable, and so
susceptible of mutation through such influences, why does that extinct form stand
out so signally, a monument of stability?" (p. 254).
Darwin's reaction to these famous pages in the history of paleontology make
fascinating reading, especially in the light of persistence (or reemergence) of all
major issues in our modern debate about punctuated equilibrium. First, with his
usual insight into the mechanics of his own theory, Darwin expresses special
surprise that teeth should be so stable within species—for the same features vary so
greatly among species. As many modern evolutionists have remarked—though
Darwin did not use the same terminology—natural selection works by converting
variation within populations to differences among populations: a primary
expression of the extrapolationist principle in Darwinian logic. But the stasis of
species challenges such continuationism. (Darwin included his remarks in a long
letter to Falconer, written on October 1, 1862, as a response to the manuscript on
elephants that Falconer had sent Darwin, and that would become the 1863
publication quoted above): "Your case seems the most striking one which I have
met with of the persistence of specific characters. It is very much the more striking
as it relates to the molar teeth, which differ so much in the species of the genus,
and in which consequently I should have expected variation."
Darwin then searches for ways to mitigate the surprise of such stasis in the
face of environmental changes that should have altered selective pressures. He
suggests, first, that the global fluctuations of ice-age climates might not have
seemed so extensive to elephants. Perhaps they migrated with a favored climatic
belt, therefore experiencing little fluctuation, and perhaps no major