I wasn't really "narrowing it down" as much as clarifying that ecological systems include human ecology. And themes can be overarching or they can be relatively specific. Here, I'm referring to an overarching theme that is related to several of the more specific themes, such as several of the ones that Dom mentions in his reply in this subthread.

Again, the Earth Day comment was mostly to place the novel in a historical context. Basically, before anything resembling the modern environmentalist movement(s) began, there was this interesting SF novel that used ecosystems (encompassing more than just plant/non-human animal life) to complement and to strengthen the narrative being told.




I'm very aware of that. You misinterpreted what I wrote. I know quite well the influences on each of the three Abrahamic faiths and that those major influences on the genesis of those three branches come from the Fertile Crescent, the Nile Valley, and the Arabian Desert. I could talk about pigs for a while, but let's just say there's an environmental reason why pig eating was taboo in much of that region during the development of those faiths (with the exception of Pauline Christianity, which was heavily Hellenized).