Aspects of organisms that impact the number or timing of their reproduction.

The concept of life history is in effect everything about an organism as well as how these things change over the course of an organism's life or even generations (i.e., such as in the case of alternation of generations).

Ultimately, from a perspective, these are things that affect an organism's ability to as well as reproduce, that is, it's . The organisms that best optimize their life histories, in light of inevitable tradeoffs, will be those that are most fit.

One can also speak of and . See in addition generation time, , iteroparity, and semelparity. as well as K selection versus r selection.