In the book Guns, Germs, and Steel, why does the fertile crescent's domesticated plants and animals give it such a head start over the rest of the world?
Author Jared Diamond contends that food production was indirectly a prerequisite for the development of guns, germs, and steel:
In geographic locations where the soil was fertile and fine enough that man could till it, crops could be produced in centralized areas where people could live. By selecting the plants that could be eaten and by domesticating those animals that could also be consumed and/or used, more and more people could live together.
That strength of brute numbers was the first of many military advantages that food-producing tribes gained over hunter-gatherer
Since there were resulting food surpluses, storage was begun which then brought about the permanency of the population as they had to remain to guard their food. Once food could be stored, not all men had to farm, so then a society could be formed as a political elite could evolve, an elite that would control the food production, tax others, etc. Therefore, food surpluses, according to the author, were essential to
...politically centralized, socially stratified, economically complex, technologically innovative societies.
For, food storage also meant that there was nourishment to supply soldiers. In any kind of prolonged warfare, men supplied with food could defeat other warriors who did not have this advantage. Later on, because men could devote themselves to other occupations with such a plentiful supply of nourishment, priests who supplied religious justification for wars or conquest could be supported as could artisans who fashioned such things as swords and other weapons and scribes to record information that needed to be remembered. In addition, since crops yielded fibers for clothing, blankets, nets, rope, etc. and domestic animals provided such materials as wool or leather, armies were able to stay clothed and warm in war.
Clearly, domesticated animals also provided people with advantages over populations that did not have them. These animals could not only supply food, they could do work that men could not, so soil that was harder to till could become farmland; horses and oxen could pull equipment, transport people and their belongings. A key advantage came with the military use of horses and camels over foot soldiers.
As another advantage, Diamond alludes to the diseases which domestic animals spread. For, those who had these domesticated animals had over time developed immunity to such diseases. But, when these animals were introduced into other areas during military conquests, entire populations were wiped out by the germs to which they had no defense. In Chapter 4, Diamond writes,
The military uses of horses and camels, and the killing power of animal-derived germs, complete the list of major links between food production and conquest....