title: 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."
authors.forename: K W
authors.initials: KW
authors.lastname: Wachter
mesh_terms: D000367:Age Factors; D003710:Demography; D005583:Fourier Analysis; D008722:Methods; D008962:Models, Theoretical; D011153:Population; D011154:Population Characteristics; D011157:Population Dynamics; D012098:Reproduction; D012106:Research
keywords: Age Factors; Cyclic Analysis; Demographic Factors; Methodological Studies; Models, Theoretical; Population; Population Characteristics; Population Dynamics; Population Replacement; Reproduction; Research Methodology; Theoretical Studies; World