  r-selection refers to evolutionary competition in the rate of a population's
exponential increase. This is contrasted with K-selection, in which populations
in steady-state compete in efficiency of resource conversion. Evolution in
nature is thought to combine these two in various proportions. But in modeling
the evolution of life histories, theorists have used r-selection exclusively;
up until now, there has not been a practical algorithm for computing the target
function of K-selection. The Malthusian parameter, as computed from the
Euler-Lotka equation, is a quantitative rendering of the r in r-selection,
computed from the fundamental life history variables mortality and fertility.
Herein, a quantitative formulation of K is derived in similar terms. The basis
for our model is the logistic equation which, we argue, applies more generally
than is commonly appreciated. Support is offered for the utility of this
paradigm, and one example computation is exhibited, in which K-selection
appears to support pleiotropic explanations for senescence only one fourth as
well as r-selection.
