  We adopt the so--called \emph{occupation number representation}, originally
used in quantum mechanics and recently adopted in the description of several
classical systems, in the analysis of the dynamics of some models of closed
ecosystems. In particular, we discuss two linear models, for which the solution
can be found analytically, and a nonlinear system, for which we produce
numerical results. We also discuss how a damping effect could be {\em
effectively} implemented in the model.
