Ecology may be called the science of the relations of animals and plants to their environment and to one another. But this is only true if we remember that the word “animals” includes man.

We like to think of man as in a class by himself, spiritually or intellectually. But as an influence on the earth, man's role is that of an animal that has managed to multiply enormously, both in numbers and in capacity to affect other parts of nature, usually for the worse, and usually without noticing it.