What Chapter 6 is really talking about is why people chose to farm rather than to continue as hunter-gatherers. Diamond argues that there are four reasons why they made this choice:
- Availability of wild food. He says that many kinds of wild foods were becoming less available over time. This made farming a more rewarding lifestyle.
- At the same time, more plant species were becoming domesticable.
- People were developing more technology for harvesting and storing food. As these technologies built up, they helped make farming more rewarding.
- Populations grew and that made farming necessary. As groups started to farm a little their populations grew. Once this happened, they had to farm more to continue to support these larger populations.