Gaps and errors have likely occurred. For more accurate citations, please consult the original presenters. Differentiate between systems which evolve vs. ones which emerge. In emergence, start with no structure, with a some accident on a steep gradient giving positive feedback, and therefore emergent structure. Biology discusses evolution a lot, but not emergence.
Complexity emerges from hierarchy.
Need the elaborate structure, pay in advance from energy. The amount of material you get is concave function. Pick the lowest apple on the tree, but usually quit before you need a cherry-picker. Society tends to work evolutionary Before the average product gets to you, the marginal product turns down first. The Spanish, bringing gold from the new world, stopped when the marginal product turned down.