“I shall try to show that life is response to the order of nature.... But if it be admitted, it follows that biology is the study of response, and that the study of that order of nature to which response is made is as well within its province as the study of the living organism which responds, for all the knowledge we can get of both these aspects of nature is needed as a preparation for the study of that relation between them which constitutes life.”
“To study life we must consider three things:
first, the orderly sequence of external nature;
second, the living organism and the changes which take place in it; and,
third, that continuous adjustment between the two sets of phenomena which constitutes life.”
“The physical sciences deal with the external world, and in the laboratory we study the structure and activities of organisms by very similar methods; but if we stop there, neglecting the relation of the living being to its environment, our study is not biology or the science of life.”
W. K. BROOKS.
ANIMAL ECOLOGY