Creating hierarchical orders is nature's way of guaranteeing the survival of organisms. Starting from the simplest organism that consists of two cells relating to each other, we enter into the realm of emergent structures that, at some moment in biogenesis, move from re-acting to environmental influences to pre-acting towards them. That capacity culminates in the case of Homo sapiens that not only pre-acts but also pre-plans to pre-act, and reflects upon that pre-planning.
Multicellular organisms live according to some hierarchical order—the emerging functional organs in the anatomy are structurally related through such orders. Once the central nervous system emerges, it regulates the behaving of the organism as a whole.