Organism
The evolutionary biologists David Queller and Joan Strassmann 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.
[17] If so, the same argument, or a criterion of high co-operation and low conflict, would include some mutualistic (e.g. lichens) and sexual partnerships (e.g. anglerfish) as organisms.
A unicellular organism is a microorganism such as a protist, bacterium, or archaean, composed of a single cell, which may contain functional structures called organelles.
A lichen consists of fungi and algae or cyanobacteria, with a bacterial microbiome; together, they are able to flourish as a kind of organism, the components having different functions, in habitats such as dry rocks where neither could grow alone.
[18][21] The evolutionary biologists David Queller and Joan Strassmann state that "organismality" has evolved socially, as groups of simpler units (from cells upwards) came to cooperate without conflicts.
[25] Such virus is a result of infection of a cell and shows all major physiological properties of other organisms: metabolism, growth, and reproduction, therefore, life in its effective presence.
[27] According to this hypothesis “organisms” emerged when RNA chains began to self-replicate, initiating the three mechanisms of Darwinian selection: heritability, variation of type and differential reproductive output.
The fitness of an RNA replicator (its per capita rate of increase) would presumably have been a function of its intrinsic adaptive capacities, determined by its nucleotide sequence, and the availability of external resources.
[28][29] The three primary adaptive capacities of these early "organisms" may have been: (1) replication with moderate fidelity, giving rise to both heritability while allowing variation of type, (2) resistance to decay, and (3) acquisition of and processing of resources[28][29] The capacities of these "organisms" would have functioned by means of the folded configurations of the RNA replicators resulting from their nucleotide sequences.
[8] Scientists and bio-engineers are experimenting with different types of synthetic organism, from chimaeras composed of cells from two or more species, cyborgs including electromechanical limbs, hybrots containing both electronic and biological elements, and other combinations of systems that have variously evolved and been designed.
The existence of chimaeras and hybrids demonstrates that these mechanisms are "intelligently" robust in the face of radically altered circumstances at all levels from molecular to organismal.
