1) Recent studies agree that the Egyptian agriculture must have originated at Marimdah and Faiyum in Lower Egypt, under the influence of the Middle and Near East, about 2000±500 years later, and then extended to Upper Egypt and Nubia.
The northern hemisphere in the Post-Glacial Period had passed through several climatic fluctuations. These fluctuations not only put severe restrictions on the ecological distribution of plants and animals but also gave a remarkable effect on the pattern of life and migration of the food gathering-hunting and nomadic peoples, and therefore greatly decided the formation of Egyptian history in the Nile valley.
2) The southern Sahara and its circumferences, Nubia, hilly areas of the eastern Upper Egypt, must have held various and plentiful fauna, judging from such numerous relics as the rock-drawings remaining in those districts. As for the domestication of wild animals, we may presume that it extended from the southern Sahara and its environment to Nubia and Upper Egypt, contrary to the advance in the development of Egyptian agriculture. The principal promoters were gatheringhunting tribes of Sahara and the eastern Hamites who were half cattle-breeding nomads.
3) A little moist “Sub-Pluvial Period” fluctuated at the middle of the fourth millenium B.C., When the climatic conditions of the northern Africa began to get greater degree of aridity. Then the first fauna-break occured unquestionably in those areas of Sahara and its circumferencs, Sudan, Nubia, Upper Egypt.
Devastation started from the Nile valley and Upper Egypt, diminishing the particular savanna landscapes in the environment, and elephants, rhinoceroses, giraffes began to disappear first, and then various sorts of gazelles and other savanna fauna also decreased.
4) The transition to“Sub-Pluvial Period” played a role of a trigger to the “Neolithic Revolution”, viz. the commencement of the agriculture and domestication of wild animals. The end of “Sub-Pluvial Period” and the following climate of aridity brought about the second agricultural revolution, viz. building an open road to the history of Egyptian Old Kingdom (Pyramid Age) through the new productive mode of agriculture using the basin system of irrigation and drainage together with cattle-breeding.