Generation time has previously been the focus of comparative life
history analyses. Here we examine three metrics: generation time
Tc, reproductive dispersion S (the
distribution of ages of reproduction), and damping time τ (time
to converge to stable (st)age distribution). We use data on 633 species
of animals and plants, and perform phylogenetically corrected analyses.
First we find that S varies allometrically and isometrically with
Tc. As a result, τ varies allometrically
with either Tc or S but not both. Second,
we find a trade-off between τ and S, so that τ does
not vary isometrically with Tc. This trade-off is
a novel demographic component to the relationship between τ,
Tc and S that is otherwise partly
determined by their similarity as biological times. Our results indicate
that species at the slow end of the slow-fast continuum take longer to
converge to stable distribution than species with fast life-histories.