Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility,[1][2][3] the natural capability to produce offspring,[4] measured by the number of gametes (eggs), seed set, or asexual propagules.
The term fecundity in population biology is often used to describe the rate of offspring production after one time step (often annual).
In this sense, fecundity may include both birth rates and survival of young to that time step.
It can be equally applied to sexual and asexual reproduction, as the purpose of fecundity is to measure how many new individuals are being added to a population.
For example, some studies use apparent fecundity to describe that their data looks at a particular moment in time rather than the species' entire life span.
Semelparity occurs when an organism reproduces only once in its lifetime, with death being a part of its reproductive strategy.
Reginald Morean proposed this hypothesis, the explanation being that there is higher mortality in seasonal environments.
He also accounts for a drop in fecundity at the poles due to their extreme amounts of day lengths, which can exhaust the parent.
This idea suggests that shorter breeding seasons select a larger clutch size to compensate for the reduced reproduction frequency, thus increasing those species' fecundity.
[9] Infecundity is a term meaning "inability to conceive after several years of exposure to the risk of pregnancy."
Indeed, it is considered impossible to cease reproduction based on social factors, and fecundity tends to rise after a brief decline.