I like to summarize what I regard as the pedestal-smashing messages of Darwin's revolution in the following statement, which might be chanted several… - Stephen Jay Gould

These arguments led Darwin to his denial of progress as a consequence of the “bare bones mechanics” of natural selection—for this process yields only local adaptation, often exquisite to be sure, but not universally advancing. The mammoth is every bit as good as an elephant—and vice versa. Do you prefer a marlin for its excellent spike; a flounder for its superb camouflage; an anglerfish for its peculiar “lure” evolved at the end of its own dorsal fin ray; a seahorse for its wondrous shape, so well adapted for bobbing around its habitat? Could any of these fishes be judged “better” or “more progressive” than any other? The question makes no sense. Natural selection can forge only local adaptation—wondrously intricate in some cases, but always local and not a step in a series of general progress or complexification.

Evolution is a theory of organic change, but it does not imply, as many people assume, that ceaseless flux is the irreducible state of nature and that structure is but a temporary incarnation of the moment. Change is more often a rapid transition between stable states than a continuous transformation at slow and steady rates. We live in a world of structure and legitimate distinction. Species are the units of nature's morphology.

Independent derivation meshed beautifully with the triumph, from the 1930's on, of a strict version of Darwinism based on the near ubiquity of adaptive design built by natural selection... Arthropods and vertebrates do share several features of functional design. But those similarities only reflect the power of natural selection to craft optimal structures independently in a world of limited biomechanical solutions to common functional problems - an evolutionary phenomenon called convergence.