What are the motifs in Rendezvous with Rama by Arthur C. Clarke?

Nature and technology are recurring ideas In the novel, the only "natural" elements are the human beings. Everything else, including the pets carried by Endeavour, is essentially a product of technology. Everything is artificial and at least partly engineered. From the onset of the story, nature is described as an intrusive and often destructive element that is nothing but a hurdle set in the middle of the evolution path of the human race.