This video blew my mind:
It describes how, in some species, monogamy leads to a system where families are so interrelated that they become the effective "individual" in evolution. This then leads to further evolution, producing the creation of cooperation between individuals and, in extreme cases, a caste system.
What's fascinating is how humans do all this in a half-hearted way. We dabble in monogamy to various degrees. We cooperate a lot. We sometimes have caste systems. I certainly believe that a lot of this arose when we lived in villages and travelling groups that were substantially inbreed. We need to think about where we are now headed.
Another hint in the video is that once a species achieves these powerful cooperative behaviours, there is evolutionary pressure that weakens them. So evolution doesn't go in straight lines, it leads to oscillations. We see something similar in human societies, as we oscillate between social control and high levels of individual freedom.
