Note 95 — II THE BASIS OF THE POPULATION PROBLEM: (1) THE QUANTITATIVE ASPECT

For the sake of simplicity fecundity has been spoken of as though it was fixed at a certain strength for each species. As a matter of fact it varies within fairly wide limits—increasing with better conditions. In this fact lies the explanation of the increase of species under favourable conditions which has often been observed, although, when conditions are less favourable, there is little or no evidence of starvation among such species.