The study of cultural ecology emphasizes relationships between environment and human societies. The ecological approach attempts to separate cultural values and elements of social organization closely related to the environment from others. 1 Environmental features, such as climate, take on significance in terms of their functional importance rather than their inherent properties. Cultural traits viewed in this way become dependent variables; environment becomes the independent variable. 2 Steward summarized the approach succinctly; cultural ecology "introduces the local environment as the extra-cultural factor in the fruitless assumption that culture comes from culture." 3