Lack's principle

Lack's principle, proposed by the British ornithologist David Lack in 1954, states that "the clutch size of each species of bird has been adapted by natural selection to correspond with the largest number of young for which the parents can, on average, provide enough food".

[1] As a biological rule, the principle can be formalised and generalised to apply to reproducing organisms in general, including animals and plants.

Work based on Lack's principle by George C. Williams and others has led to an improved mathematical understanding of population biology.

Williams formalised the argument to create a mathematical theory of evolutionary decision-making, based on the framework outlined in 1930 by R. A. Fisher, namely that the effort spent on reproduction must be worth the cost, compared to the long-term reproductive fitness of the individual.

Wynne-Edwards proposed,[3] to increase the chances of survival of the species to which the individual belonged (group selection).