Simple growth laws and selection consequences

It is commonly thought that various types of population growth can be satisfactorily modelled as deviations from an inherently exponential (malthusian) growth law. Consideration of kinetic results from research on the origin of life, laser physics and more-conventional population dynamics makes it clear, however, that in certain cases the simplest and mechanistically most satisfactory assumption is either a basic subexponential or a hyperbolic growth law. Although these simple growth laws cannot be used instead of more-complicated models of density-dependent population growth when exact quantities are important, the insight gained by thinking them over can be substantial. Ideas about species packing, for example, await reconsideration.