472 THE STRUCTURE OF EVOLUTIONARY THEORY
biotic and abiotic realms—but war and conquest, combat and death, provide the
principal examples of competition throughout the Origin. Why else did Tennyson's
earlier line from In Memoriam (1850)—"nature red in tooth and claw"—become
the canonical characterization of Darwin's world (see Gould, 1992a)? We may not
know the particular reasons for success, but victory and battle set the appropriate
context: "Probably in no one case could we precisely say why one species has been
victorious over another in the great battle of life" (Darwin, 1859, p. 76). Two
species, previously isolated and meeting for the first time "are maiden knights who
have not fought with each other the great battle for life or death. But, whenever...
they meet, and come into competition, if one has the slightest advantage over the
other, that other will decrease in numbers or be quite swept away" (Natural
Selection, 1856 - 1858, 1975 edition, edited by Stauffer, p. 227). Calmness and
cooperation may seem to hold sway, but lift the veil and observe the struggles to
death in this vale of tears: "We behold the face of nature bright with gladness, we
often see superabundance of food; we do not see, or we forget, that the birds which
are idly singing round us mostly live on insects or seeds, and are thus constantly
destroying life; or we forget how largely these songsters, or their eggs, or their
nestlings, are destroyed by birds and beasts of prey" (1859, p. 62).
EXPLICIT STATEMENTS OF RELATIVE FREQUENCY. Darwin often contrasts the
relative strengths of relationships among organisms vs. response to physical
conditions. In each case, he stresses the greater importance of biotic competition.
Migration, for example, will affect species more by forcing them into competition
with other creatures than by exposing them to new physical environments: "These
principles come into play only by bringing organisms into new relations with each
other, and in a lesser degree with the surrounding physical conditions" (p. 351).
Speaking of movement to oceanic islands, Darwin notes the "deeply-seated error of
considering the physical conditions of a country as the most important for its
inhabitants; whereas it cannot, I think, be disputed that the nature of the other
inhabitants, with which each has to compete, is at least as important, and generally
a far more important element of success" (p. 400). And, in his baldest statement,
Darwin asserts (p. 477) "the relation of organism to organism is the most important
of all relations."
Darwin's caveats, whenever he presents a prima facie case for abiotic control,
are even more revealing. Reports of biotic competition elicit only simple
approbation, while putative examples of response to physical circumstances often
provoke reminders that we may not be viewing the matter correctly, and that biotic
competition may still be exerting a hidden sway.
The structure of every organic being is related, in the most essential yet
often hidden manner, to that of all other organic beings, with which it
comes into competition for food or residence, or from which it has to
escape, or on which it preys. This is obvious in the structure of the teeth
and talons of the tiger; and in that of the legs and claws of the parasite,
which clings to the hair on the tiger's body. But in the beautifully plumed