As a result of the neolithic agricultural revolution, humans began to

Causes of the Neolithic Revolution
There could have been many causes for the neolithic revolution. 
It could have been because of a population increase that forced the people to stop hunting and gathering because the fruits of their labor were only sufficient for a short amount of time. They needed a sure-fire way to insure that they had a steady food supply for all of their people. Thus, they planted the seeds they were gathering and cultivated some of the most basic types of plants such as wheat and barley. 
It also could have been because of over hunting and over gathering that left all of the land they migrated to virtually barren. This, of course, posed a problem to their survival. It could have made them so desprate as to intrude into other peoples hunting grounds leading to conflicts between the two groups. So, war could have been another reason. You would want to avoid confrontation if you were starving, right? 
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The basic impetus could have been to avoid conflicts with stronger tribes, or it could have been that a tribe found the most lush and plentiful area they had ever found, and decided to stay there. They then had to build more durable homes, and set up sanitary facilities to keep their water fresh. It could be that people and animals had begun accidentally fertilizing wild "farms" with their travels. In any event, farming was probably the equivalent of the Amerindian tribes, who learned to rotate crops and simply bring back gathered foods to some more-or-less permanent spot that they were comfortable in.
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