Organism

<p>An organism is any <a href="/facts/Life/DNw7NUId">living</a> thing that functions as an <a href="/facts/Individual/hJbTjS2x">individual</a>. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Many criteria, few of them widely accepted, have been proposed to define what an organism is. Among the most common is that an organism has autonomous <a href="/facts/Reproduction/nNu0F5Dy">reproduction</a>, <a href="/facts/Cell_growth/wbArMaJU">growth</a>, and <a href="/facts/Metabolism/WxDrm8k5">metabolism</a>. This would exclude <a href="/facts/Virus/mf88Bcbl">viruses</a>, despite the fact that they <a href="/facts/Evolution/qE5amP6a">evolve</a> like organisms. Other problematic cases include <a href="/facts/Colonial_organism/b5QfltwY">colonial organisms</a>; a colony of <a href="/facts/Eusocial_insect/RrNadVME">eusocial insects</a> is organised adaptively, and has <a href="/facts/Germ-Soma_Differentiation/A83jHAlE">germ-soma specialisation</a>, with some insects reproducing, others not, like cells in an animal's body. The body of a <a href="/facts/Siphonophore/eWY9zmjw">siphonophore</a>, a jelly-like marine animal, is composed of organism-like <a href="/facts/Zooid/c3cJ1zeT">zooids</a>, but the whole structure looks and functions much like an animal such as a <a href="/facts/Jellyfish/oLmExpvU">jellyfish</a>, the parts collaborating to provide the functions of the colonial organism.
</p><p>The evolutionary biologists <a href="/facts/David_C._Queller/vPFeAPsR">David Queller</a> and <a href="/facts/Joan_E._Strassmann/0SnJ47Mc">Joan Strassmann</a> state that "organismality", the qualities or attributes that define an entity as an organism, has evolved socially as groups of simpler units (from cells upwards) came to cooperate without conflicts. They propose that cooperation should be used as the "defining trait" of an organism. This would treat many types of collaboration, including the <a href="/facts/Fungus/BHo5DP59">fungus</a>/<a href="/facts/Algae/U1ftVKU3">alga</a> partnership of different species in a <a href="/facts/Lichen/lUrd6Sn7">lichen</a>, or the permanent sexual partnership of an <a href="/facts/Anglerfish/oTpyBSjS">anglerfish</a>, as an organism.
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Organism open-in-new

Organism