Charles Darwin was referring to living organisms. I am quoting him here because the complex, interrelated environmental problems which the world is seeing at the end of the 20th century reveal that his observation is equally applicable to the checks and relations between human political and administrative organizations.
We are at last realizing that everything is connected to everything else and that the world operates as a complex process with characteristics which ensure that it will function chaotically. That is to say, precise predictions of events and states a long time ahead will not be possible.
The best reaction to such a situation is to proceed strategically — that is, to adopt policies that will put us in advantageous positions from which to take specific actions which will contribute to our attaining our objective. Our goal is, of course, ecologically sustainable development.