<Li> The Demographic theories proposed by Carl Sauer and adapted by Lewis Binford and Kent Flannery posit an increasingly sedentary population that expanded up to the carrying capacity of the local environment and required more food than could be gathered . Various social and economic factors helped drive the need for food . </Li> <Li> The evolutionary / intentionality theory, developed by David Rindos and others, views agriculture as an evolutionary adaptation of plants and humans . Starting with domestication by protection of wild plants, it led to specialization of location and then full - fledged domestication . </Li> <Li> Peter Richerson, Robert Boyd, and Robert Bettinger make a case for the development of agriculture coinciding with an increasingly stable climate at the beginning of the Holocene . Ronald Wright's book and Massey Lecture Series A Short History of Progress popularized this hypothesis . </Li> <Li> The postulated Younger Dryas impact event, claimed to be in part responsible for megafauna extinction and ending the last glacial period, could have provided circumstances that required the evolution of agricultural societies for humanity to survive . The agrarian revolution itself is a reflection of typical overpopulation by certain species following initial events during extinction eras; this overpopulation itself ultimately propagates the extinction event . </Li>

How did the dry climate of mesopotamia affect the neolithic revolution