Living systems

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Living systems are life forms (or, more colloquially known as living things) treated as a system. They are said to be open self-organizing and said to interact with their environment. These systems are maintained by flows of information, energy and matter. Multiple theories of living systems have been proposed. Such theories attempt to map general principles for how all living systems work.

Context

Some scientists have proposed in the last few decades that a general theory of living systems is required to explain the nature of life.[1] Such a general theory would arise out of the ecological and biological sciences and attempt to map general principles for how all living systems work. Instead of examining phenomena by attempting to break things down into components, a general living systems theory explores phenomena in terms of dynamic patterns of the relationships of organisms with their environment.[2]

Theories

Miller's open systems

general systems theory on a broad scale to describe all aspects of living systems.[9] Bailey states that Miller's theory is perhaps the "most integrative" social systems theory,[10] clearly distinguishing between matter–energy-processing and information-processing, showing how social systems are linked to biological systems. LST analyzes the irregularities or "organizational pathologies" of systems functioning (e.g., system stress and strain, feedback irregularities, information–input overload). It explicates the role of entropy in social research while it equates negentropy with information and order. It emphasizes both structure and process, as well as their interrelations.[11]

Lovelock's Gaia hypothesis

Main article: Gaia hypothesis

The idea that Earth is alive is found in philosophy and religion, but the first scientific discussion of it was by the Scottish geologist James Hutton. In 1785, he stated that Earth was a superorganism and that its proper study should be physiology.[12]: 10  The Gaia hypothesis, proposed in the 1960s by James Lovelock, suggests that life on Earth functions as a single organism that defines and maintains environmental conditions necessary for its survival.[13][14]

Piast's self-maintainable information

According to the theory of self-maintainable information, entities can be ranked by how alive they are, gaining the ability to evolve and maintaining distinctness.

All living entities possess

genetic information that maintains itself by processes called cis-actions.[15] Cis-action is any action that has an impact on the initiator, and in chemical systems is known as the autocatalytic set. In living systems, all the cis-actions have generally a positive influence on the system as those with negative impact are eliminated by natural selection. Genetic information acts as an initiator, and it can maintain itself via a series of cis-actions like self-repair or self-production (the production of parts of the body to be distinguished from self-reproduction, which is a duplication of the entire entity). Various cis-actions give the entity additional traits to be considered alive. Self-maintainable information is a basic requirement - a level zero for gaining lifeness and it can be obtained by any cis-action like self-repair (like a gene coding a protein that fixes alteration to a nucleic acid caused by UV radiation). Subsequently, if the entity is able to perform error-prone self-reproduction it gains the trait of evolution and belongs to a continuum of self-maintainable information - it becomes part of the living world in meaning of phenomenon but not yet a living individual. For this upgrade, the entity has to process the trait of distinctness, understood as an ability to define itself as a separate entity with its own fate. There are two possible ways of reaching distinctness: 1) maintaining an open-system (a cell) or/and 2) maintaining a transmission process (for obligatory parasites). Fulfiling any of these cis-actions raises the entity to a level of living individual - a distinct element of the self-maintainable information's continuum. The final level regards the state of the entity as dead or alive and requires the trait of functionality.[15] This approach provides a ladder-like hierarchy of entities depending on their ability to maintain themselves, their evolvability, and their distinctness. It distinguishes between life as a phenomenon, a living individual, and an alive individual.[15]

Morowitz's property of ecosystems

A systems view of life treats environmental

biochemical or physical one. Robert Ulanowicz (2009) highlights mutualism as the key to understand the systemic, order-generating behaviour of life and ecosystems.[18]

Rosen's complex systems biology

Main article:
Complex systems biology

Robert Rosen devoted a large part of his career, from 1958[19] onwards, to developing a comprehensive theory of life as a self-organizing complex system, "closed to efficient causation". He defined a system component as "a unit of organization; a part with a function, i.e., a definite relation between part and whole." He identified the "nonfractionability of components in an organism" as the fundamental difference between living systems and "biological machines." He summarised his views in his book Life Itself.[20]

Complex systems biology is a field of science that studies the emergence of complexity in functional organisms from the viewpoint of

signalling pathways.[22][23] Related approaches focus on the interdependence of constraints, where constraints can be either molecular, such as enzymes, or macroscopic, such as the geometry of a bone or of the vascular system.[24]

Bernstein, Byerly and Hopf's Darwinian dynamic

Main article: Evolutionary dynamics

Harris Bernstein and colleagues argued in 1983 that the evolution of order in living systems and certain physical systems obeys a common fundamental principle termed the Darwinian dynamic. This was formulated by first considering how macroscopic order is generated in a simple non-biological system far from thermodynamic equilibrium, and then extending consideration to short, replicating RNA molecules. The underlying order-generating process was concluded to be basically similar for both types of systems.[25][26]

Gerard Jagers' operator theory

Gerard Jagers' operator theory proposes that life is a general term for the presence of the typical closures found in organisms; the typical closures are a membrane and an autocatalytic set in the cell[27] and that an organism is any system with an organisation that complies with an operator type that is at least as complex as the cell.[28][29][30][31] Life can be modelled as a network of inferior negative feedbacks of regulatory mechanisms subordinated to a superior positive feedback formed by the potential of expansion and reproduction.[32]

Kauffman's multi-agent system

Stuart Kauffman defines a living system as an autonomous agent or a multi-agent system capable of reproducing itself or themselves, and of completing at least one thermodynamic work cycle.[33] This definition is extended by the evolution of novel functions over time.[34]

Budisa, Kubyshkin and Schmidt's four pillars

Definition of cellular life according to Budisa, Kubyshkin and Schmidt

cellular life as an organizational unit resting on four pillars/cornerstones: (i) energy, (ii) metabolism, (iii) information and (iv) form. This system is able to regulate and control metabolism and energy supply and contains at least one subsystem that functions as an information carrier (genetic information). Cells as self-sustaining units are parts of different populations that are involved in the unidirectional and irreversible open-ended process known as evolution.[35]

See also

  • Artificial life – Field of study
  • Autonomous Agency Theory
     – viable system theory
  • Autopoiesis – Systems concept which entails automatic reproduction and maintenance
  • Biological organization
     – Hierarchy of complex structures and systems within biological sciences
  • Biological systems
     – Complex network which connects several biologically relevant entities
  • Complex systems
     – System composed of many interacting components
  • Earth system science – Scientific study of the Earth's spheres and their natural integrated systems
  • Extraterrestrial life – Life not on earth
  • Information metabolism – Psychological theory of interaction between biological organisms and their environment
  • Organism – Individual living being
  • Spome – Hypothetical matter-closed, energy-open life support system
  • Systems biology – Computational and mathematical modeling of complex biological systems
  • Systems theory – Interdisciplinary study of systems
  • Viable System Theory
     – concerns cybernetic processes in relation to the development/evolution of dynamical systems

References

  1. ^ Clealand, Carol E.; Chyba, Christopher F. (8 October 2007). "Does 'Life' Have a Definition?". In Woodruff, T. Sullivan; Baross, John (eds.). Planets and Life: The Emerging Science of Astrobiology. Cambridge University Press. In the absence of such a theory, we are in a position analogous to that of a 16th-century investigator trying to define 'water' in the absence of molecular theory. [...] Without access to living things having a different historical origin, it is difficult and perhaps ultimately impossible to formulate an adequately general theory of the nature of living systems
  2. ^ Brown, Molly Young (2002). "Patterns, Flows, and Interrelationship". Archived from the original on 8 January 2009. Retrieved 27 June 2009.
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  4. ^ Seppänen, Jouko (1998). "Systems ideology in human and social sciences". In Altmann, G.; Koch, W.A. (eds.). Systems: New paradigms for the human sciences. Berlin: Walter de Gruyter. pp. 180–302.
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  6. ^ (Miller, 1978, p. 1025)
  7. ^ Parent, Elaine (1996). "The Living Systems Theory of James Grier Miller". The Primer Project. Retrieved 20 September 2023.
  8. ^ "The Earth as a System". Primer project ISSS. Retrieved 20 September 2023.
  9. ^ Seppänen 1998, pp. 197–198.
  10. ^ Kenneth D. Bailey 2006, pp.292–296.
  11. ^ Kenneth D. Bailey, 1994, pp. 209–210.
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  14. ^ Lovelock, James. "Geophysiology". Papers by James Lovelock. Archived from the original on 6 May 2007. Retrieved 1 October 2009.
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  16. ^ Fiscus, Daniel A. (April 2002). "The Ecosystemic Life Hypothesis". Bulletin of the Ecological Society of America. Archived from the original on 6 August 2009. Retrieved 28 August 2009.
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  30. S2CID 35426048. Archived
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  35. PMID 32323410
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Further reading

External links
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