ABSTRACT
One of the most striking contrasts between the lower and the higher latitudes is manifested by the stability of the warm-adapted floras and faunas and the instability of the ecosystems of the cooler parts of the world. The argument developed here is that this contrast suggests, among other things, that selection may apply at the level of the ecosystem as well as at the levels of the individual and the specific population. Ecosystems can compete, and evolution of the stable ecosystem can be looked upon as a process of learning, analogous to the learning of regulated behavior in the nervous systems of animals.
