Individual

==Biology<!--Linked from 'Extraterrestrial life'-->==
In [[biology]], the question of the individual is related to the definition of an [[organism]], which is an important question in biology and [[philosophy of biology]], despite there having been little work devoted explicitly to this question.<ref name=Wilson>{{Cite journal | last = Wilson | first = R | title = The biological notion of individual | journal = Stanford Encyclopedia of Philosophy | year = 2007|url=http://plato.stanford.edu/entries/biology-individual/}}</ref> An individual organism is not the only kind of individual that is considered as a "unit of [[Selection (biology)|selection]]".<ref name=Wilson/> [[Gene]]s, [[genome]]s, or groups may function as individual units.<ref name=Wilson/>

[[Asexual reproduction]] occurs in some colonial organisms so that the individuals are genetically identical. Such a colony is called a [[genet (biology)|genet]], and an individual in such a population is referred to as a ramet. The colony, rather than the individual, functions as a unit of selection. In other colonial organisms the individuals may be closely related to one another but differ as a result of [[sexual reproduction]].

One of the most accepted hypotheses is the definition of an organism that emerged from Piast's ladder of lifeness. According to this idea, life can be described as a phenomenon (continuum of self-maintainable information) and its individual [[organism]] can be described as a distinct element of this [[Continuum mechanics|continuum]]. The ability to define entity boundaries is a key trait of distinctness, which can be achieved either through physical means, such as maintaining an open system through a cell, or through informational means, such as maintaining transmission to another host as seen in parasitic entities like [[Virus|viruses]].<ref>{{Cite journal |last=Piast |first=Radosław W. |date=2019-06-07 |title=Shannon's information, Bernal's biopoiesis and Bernoulli distribution as pillars for building a definition of life |url=https://www.sciencedirect.com/science/article/pii/S0022519319301109 |journal=Journal of Theoretical Biology |language=en |volume=470 |pages=101–107 |doi=10.1016/j.jtbi.2019.03.009 |pmid=30876803 |issn=0022-5193}}</ref>