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, the natural capability to produce offspring, measured by the number of gametes (eggs), seed set, or asexual propagules. Superfecundity refers to an organism's ability to store another organism's sperm (after copulation) and fertilize its own eggs from that store after a period of time, essentially making it appear as though fertilization occurred without sperm (i.e. parthenogenesis). Human demography Human demography considers only human fecundity, at its culturally differing rates, while population biology studies all organisms. 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. While levels of fecundity vary geographically, it is generally a consistent feature of each culture. Fecundation is another term for fertilization. In obstetrics and gynecology, fecund-ability is the probability of being pregnant in a single menstrual cycle, and fecundity is the probability of achieving a live birth within a single cycle. Population ecology In ecology, fecundity is a measure of the reproductive capacity of an individual or population, typically restricted to the reproductive individuals. 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. Fecundity may be defined differently for different ecological studies to explain the specific data the study examined. 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. In other studies, these definitions are changed to better quantify fecundity for the organism in question. This need is particularly true for modular organisms, as their modular organization differs from the more typical unitary organism, in which fecundity is best defined through a count of offspring. Life history patterns (parity) Parity is the organization of fecundity into two distinct types, semelparity, and iteroparity. Semelparity occurs when an organism reproduces only once in its lifetime, with death being a part of its reproductive strategy. These species produce many offspring during their one reproductive event, giving them a potential advantage when it comes to fecundity, as they are