Pre-procreative ages in population stability and cyclicity.

ABSTRACT

"Humans' protracted maturation before childbearing is an extreme example of a general characteristic of higher organisms a positive lower bound on ages of procreation. The pre-procreative span, much discussed for its evolutionary and social ramifications, has consequences also for the mathematics of population renewal.... This paper proves the presence of a pre-procreative span sufficient, in and of itself, to guarantee the existence condition for bifurcation for all models in one important class. The class includes the best-studied examples of age-specific systems with and without homeostatic feedback in purely discrete and in purely continuous formulations."