Biomass Growth and the Language of Dynamic Systems

Abstract

Key concepts of the dynamical systems approach are introduced on examples supplied by biomass growth kinetics, a process fundamental to the existence of all life forms. Continuous-time models are considered first, which demonstrate how biomass, or the population size, can settle into steady states that are defined by the parameters describing the organism-organism interactions and the species’ interaction with its environment. Stability of the steady states is analyzed, revealing existence of unstable equilibria and their relationship, in the system phase space, to stable equilibria. Dependence of the system trajectory and occupancy of the steady states on the system history and the history of parameter changes illustrates the concepts of irreversibility and hysteresis. Populations with generations are treated next, which display oscillations, multiperiodicity, and apparent chaos.