Why did, according to the article, farming cause deep class and gender divisions?

Hunter collector societies have no warehoused food and find their food on a day-to-day basis. Agricultural societies have stored food and hierarchies in such civilizations lead to privileged who are able to exploit the stored food and enjoy a better diet than those in a lower class. The writer gives the illustration of skeletons of Greek royalty having better teeth and being considerably taller than those in common graves. In terms of gender, women were able to work in fields as they were no longer compulsory to bring their children as they had to as wanderers or nomads. Women became both beasts of burden and breeding factories to yield the numbers required to tend crops.