Description of variations in with age within populations.

Within sexually reproduction populations this is especially as among females. This is because it is particularly females that are considered because it is tend to be limiting within populations of sexually reproducing organismns – that is, the reproduction of females within such a population is equivalent to the reproduction of the population as a whole.

As often varies with age, either increasing or decreasing, the for the survivorship curves displayed by species often can be explain in part as a function of reproduction rates, and vice versa. For example, substantial increases in with age will tend to select for older-age .

See also reproductive table. Contrast the of a population, which is an important if less precise than reproductive rates component of Darwinian fitness.