What did Ishmael emphasize about the agricultural revolution?

The human relationship to food is central to Ishmael's lesson. Quinn draws a contrast between the way food is handled and distributed in civilization, and how it is done in the wild. In the wild, food is plentiful and free for the taking, even though humans are subject to natural rules of population control, unable to expand past their means. Before "totalitarian" agriculture, earth was a paradise, with food free for the taking. As the Takers have forced agriculture on the rest of the world, the natural balance between food and population has been disrupted.