Abstract: “What does the process of natural selection select?” The wrong answer of this question will obstruct the process by which Evolutionary Psychology explains the implication of mind. Modern genetics argues that the natural selection process shapes the genotype. Genotype does not mean the material structure of organism but their response model toward the environment. This article aims to analyze the interactive process between the organism and the environment. It suggests and demonstrates two propositions: (1) The function of an organism pre-exists the physical structure of organism logically; (2) An organism adapts to the environment by its function rather than its structure. In concluding, the natural selection selects the function of an organism.

Key words: Evolutionary Psychology, Natural Selection, Genotype, Function.