The Origin of Agriculture and Civilisation :

There is no historical evidence to tell us exactly how agriculture arose.  We can only imagine what may have happened. Cultivation of grain may have arisen without any violent break from food gathering.  In regions well stocked with wild grains, enough seeds would get scattered around to produce crops worth reaping. Agriculture, probably, resulted from the understanding that plants could be grown from seeds and that the crops had  some relation to the seasons. And, probably, the availability of water helped  in this process. Cultivation, however, marked a break  from  the primitive era,  as human beings stopped being dependent on nature and started  to control their livelihood and destiny. Cultivation necessarily meant permanent or semi-permanent settlements around regions that were climatically and soil-wise suitable for crop production. These settlements grew into villages, with some community life and  leisure. It is but natural that the settlements established in  regions most suitable for cultivation, developed the fastest. Thus, we see that in this period, from about 4000 B.C.  to  1500  B.C.,  the four great civilisations of Egypt, Mesopotamia.  India and China came into existence in the wide river valleys of the Nile, the Tigris and the Euphrates, the Indus, and the Hwang Ho  respectively. The Indus Valley Civilisation,  of which we are  the descendants, is dated  between 2700B.C. to 1750 B.C.