 Eventually, modern humanity dies out and technology disappears.With subsequent human species having been engineered to be unintelligent and animal-like in order to repopulate the Earth's ecosystems, concepts like culture and civilization disappear and the lives of most human descendants revolve around gathering food and surviving the harsh conditions of nature.Dixon's previous speculative evolution book projects, "After Man" (1981) and "The New Dinosaurs" (1988), used fictional examples to exemplify real-life factual natural processes.