The Western belief that the world is divided into the "human" and the "natural" stems from the philosophy, first propounded by the ancient Greeks, notably Aristotle, that all living organisms could be placed in a Scale of Nature or Great Chain of Being with "primeval slime" at its base and "Man" at its summit. This belief, which is imbued in Christianity and in all aspects of western civilization, has led to a great divide with "the wild" on one side and "the tame", that is all the animals and plants that are exploited by human, on the other.
Clutton-Brock, J. (1995). Wildlife conservation zoos and animal protection: Examining the issues. In A. Rowan (Ed.) Wildlife Conservation, Zoos and Animal Protection: A Strategic Analysis (pp. 49-62).