Someone had a good idea about planting and growing food and other hunter-gatherers passing through copied it. In a few short years the idea spread. Looking back to us it would appear to happen all over at ounce.
“Someone had a good idea”-I’m pretty sure that is exactly right, too.
Curious creatures that we are, I’m sure humans started trading any and everything from tools and eligible mates to all sorts of planting, and animal domestication methods the first time they met and shared a fire and a meal. Sort of a stone age working lunch...