  Most population models assume that individuals within a given population are
identical, that is, the fundamental role of variation is ignored. Here we
develop a general approach to modeling heterogeneous populations with discrete
evolutionary time step. The theory is applied to population dynamics of natural
rotifer populations. We show that under particular conditions the behavior of
the inhomogeneous model possesses complex transition regimes, which depends
both on the mean and the variance of the initial parameter distribution and the
final state of the population depends on the least possible value from the
domain of the parameter. The question of persistence of the population is
discussed.
