448 THE STRUCTURE OF EVOLUTIONARY THEORY
in a population; and "variety-testing" for sorting among discrete elementary species
produced by mutation. In a remarkable passage, de Vries then names this second
mode "species selection,"* and also denies that this higher-level process can be
equated with natural selection:
The word selection has come to have more than one meaning. Facts have
accumulated enormously since the time of Darwin; a more thorough
knowledge has brought about distinction, and divisions at a rapidly
increasing rate, with which terminology has not kept pace. Selection
includes all kinds of choice... Selection must, in the first place, make a
choice between the elementary species of the same systematic form. This
selection of species or species selection [my italics] is now in general use in
practice where it has received the name of variety testing. This clear and
unequivocal term however, can hardly be included under the head of
natural selection. The poetic terminology of selection by nature has already
brought about many difficulties that should be avoided in the future. On the
other hand, the designation of the process as a natural selection of species
complies as closely as possible with existing terminology, and does not
seem liable to any misunderstanding. It is a selection between species.
Opposed to it is the selection within the species (1905, pp. 742-744).
De Vries then develops this concept, of species selection as a set of guidelines
for a general theory of macroevolution. He argues that sustained evolutionary
trends must arise by species selection for two reasons: (1) Variation among species
represents the only available "fuel" for an effective process of selection. (2) Trends
are clearly adaptive and accumulative, but the mutational origin of elementary
species is both nonadaptive and discretely sudden. Mutations, therefore, cannot
produce trends by themselves; a "higher-order" selection upon discrete mutational
phenotypes must occur:
The differentiating characteristics of elementary species are only very
small. How widely distant they are from the beautiful adaptive
organizations of orchids, of insectivorous plants and of so many others!
Here the difference lies in the accumulation of numerous elementary
characters, which all contribute to the same end. Chance must have
produced them, and this would seem absolutely improbable, even
impossible, were it not
*De Vries wrote this book in English, so "species selection" represents his own
chosen term and not the product of a translation. I note this fact with personal chagrin.
"Species selection" has been a central component in the debates about punctuated
equilibrium, and paleontologists have been discussing this idea intensely since the mid
1970's. We have all attributed the term to Stanley (1975), who brilliantly articulated the
concept and its implications. No one recognized that de Vries—in a book written in
English by the world's leading evolutionist at the time—not only developed the idea, but
designated the concept by the same name (and realized the full set of implications). De
Vries did not emphasize "species selection" or discuss the concept at length, but I can
offer no excuse beyond my own inadequate research for my ignorance of this point. See
Gould (1993b) for my attempt at amends to this great scientist.