Comparing man with monkey or orangutan, the hair at the back of human head has evoluted. But this evolution has no function to fit the environment. 2 Seeking Cause Human head has evoluted to the looks of today. There is a general law in the course of organic evolution. It is the coordination of various organs to fit the environment.
Man evolute to be intelligent.
Observing and learning our real life, we will discover the function of human looks. The looks is one factor to select spouse. Although it is not the whole factor, it has a certain rate of action to select spouse. Bear the later generations after selecting spouse. Thus form the natural selection of human head.