Ahistorical Theory

"[Robert] MacArthur and [Edward O.] Wilson's predecessors had commonly explained the pattern in historical terms. Remoteness was an impediment that only eons could overcome. Impoverishment together with remoteness suggested that an island's history had been relatively brief. Colonization of any new oceanic island took time-vast sweeps of time, if the island was remote-and remote islands were generally not ancient enough to have acquired great richness of species. So said the historical hypothesis.

But MacArthur and Wilson suspected that history wasn't the answer. Time was the limiting factor only during the earliest period on a new oceanic island, they believed, and most of the world's island ecosystems had long since come to maturity, to a state of balance, to equilibrium, with the number of species on each a reflection of ongoing processes, not historical circumstances. The ongoing processes that most shaped balance, they argued were immigration and extinction."

David Quammen in The Song of the Dodo.. (Scribner, 2004) p. 422.