If for no other reason than stubborn curiosity, I suspect that humans will colonize Mars at some point. That, “just to prove we can” action we justify as proving the concepts of science and technology. When we begin the costs will be prohibitive for shipping large amounts of materials, so the emphasis will be to utilize available materials. Housing being a major issue will naturally move underground, copying Sci-fi classical concepts of course. We need to dig for ice, may as well use the holes for living areas and farming. Keep expanding and next thing you know, Moletown! The most exciting metropolis on the planet!
Assuming we can survive long enough for it to matter, the trip alone should prove long enough, sex will become an issue. Are we shipping enough men and women for normal marriage and reproduction. Population replacement is essential for a colony. Hopefully population growth, assuming live birth is even possible in reduced gravity. I don’t know, ask Doc if he didn’t die in a cave in. Is marriage even an option?
Currency will probably be replaced with some type of calory exchange. A 100 calory chit is the new dollar. Knowing humans, it will probably drift into “Cals” quickly enough. Subsistence living is the new fad. Dig out your own hole. Hord your sewage, you need it for the farm. Sterilization is as simple as leaving it outside to freeze, he same for unproductive males. We can’t afford to have them taking up space. The colony will quickly revert to the oppressive patriarchal models of old.
The golden rule will become common law again. It will also become the common form of natural selection. If you are too selfish to help your neighbor, you probably won’t live long. It is the “manufacture a pencil” equation writ large. One person cannot possibly perform all of the tasks necessary for survival. It takes a village, literally. I doubt that communism will take hold. If a persons need exceeds their ability, why support them?
It will be interesting, if nothing else.
The New Word Wars 