The ancient West Eurasian populations of the Fertile Crescent were the first to invent/discover agriculture (Levant Natufians, Zagros Iranians, Anatolians). They homogenized around the Bronze Age and then spread across West Eurasia, with farmers from Anatolia spread westward into Europe; farmers related tothose of the Levant spread southward into North East Africa; farmers related to those from Iran spreadnorthward into the Eurasian steppe; and people related to both the early farmers of Iran and to thepastoralists of the Eurasian steppe spread eastward into South Asia.

Is it coincidence that the spread of these farmers is related to 3/5 developments of the earliest civilizations? (Nile Valley, Mesopotamia, Indus River Valley)

Cochran et al. argue that the transition to agriculture was a human adaptation to a selective pressure from the environment. Agriculture imposed a new way of living on humans (new diets, new diseases, new cognitive demands and new social structures). Another effect of agriculture was a huge population boom. With an increase in numbers came an increase in mutations, with some of them potentially advantageous. Is it plausible that the new selective pressures introduced by agriculture exploited the new range of mutations available? As such, agriculture created many new problems, but also indirectly produced many new solutions.

Commensurate to the genetic responses to agriculture were cultural responses. An increased population size had a similar impacton the generation of new ideas. All else equal, a large populationwill produce many more new ideas than a small population, andnew ideas can spread rapidly even in large populations. Agriculture increased the not only the number of people, but the size of their societies.

Jared Diamond observed: “A larger area orpopulation means more potential inventors, more competingsocieties, more innovations available to adopt—and more pressureto adopt and retain innovations, because societies failing todo well will be eliminated by competing societies.” Therefore, culture adapted to changes brought about via agriculture just as much as our genomes did and both culture and genes informed another.

Thus, is it plausible that there was a positive feedback loop in which:
-humans adapted to environmental pressures and invented farming
-farming imposed new environmental pressures on humans
-humans adapted both culturally and genetically to these pressures from farming
-civilization emerged from this self-propelled adaptive process.

This would explain why the worlds first civilizations trace their lineages to regional agricultural populations. It also means that earlier and faster rates of adaption would have conferred greater competitive advantage over others, influencing migrations and differential success in innovation.