Living systems

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A presentation on information flow in living systems

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.

Contents

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

James Grier Miller's living systems theory is a general theory about the existence of all living systems, their structure, interaction, behavior and development, intended to formalize the concept of life. According to Miller's 1978 book Living Systems, such a system must contain each of twenty "critical subsystems" defined by their functions. Miller considers living systems as a type of system. Below the level of living systems, he defines space and time, matter and energy, information and entropy, levels of organization, and physical and conceptual factors, and above living systems ecological, planetary and solar systems, galaxies, etc. [3] [4] [5] Miller's central thesis is that the multiple levels of living systems (cells, organs, organisms, groups, organizations, societies, supranational systems) are open systems composed of critical and mutually-dependent subsystems that process inputs, throughputs, and outputs of energy and information. [6] [7] [8] Seppänen (1998) says that Miller applied 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

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]

Morowitz's property of ecosystems

A systems view of life treats environmental fluxes and biological fluxes together as a "reciprocity of influence," [15] and a reciprocal relation with environment is arguably as important for understanding life as it is for understanding ecosystems. As Harold J. Morowitz (1992) explains it, life is a property of an ecological system rather than a single organism or species. [16] He argues that an ecosystemic definition of life is preferable to a strictly biochemical or physical one. Robert Ulanowicz (2009) highlights mutualism as the key to understand the systemic, order-generating behaviour of life and ecosystems. [17]

Rosen's complex systems biology

Robert Rosen devoted a large part of his career, from 1958 [18] 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. [19]

Complex systems biology is a field of science that studies the emergence of complexity in functional organisms from the viewpoint of dynamic systems theory. [20] The latter is also often called systems biology and aims to understand the most fundamental aspects of life. A closely related approach, relational biology, is concerned mainly with understanding life processes in terms of the most important relations, and categories of such relations among the essential functional components of organisms; for multicellular organisms, this has been defined as "categorical biology", or a model representation of organisms as a category theory of biological relations, as well as an algebraic topology of the functional organisation of living organisms in terms of their dynamic, complex networks of metabolic, genetic, and epigenetic processes and signalling pathways. [21] [22] 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. [23]

Bernstein, Byerly and Hopf's Darwinian dynamic

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. [24] [25]

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 [26] 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. [27] [28] [29] [30] 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. [31]

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. [32] This definition is extended by the evolution of novel functions over time. [33]

Budisa, Kubyshkin and Schmidt's four pillars

Definition of cellular life according to Budisa, Kubyshkin and Schmidt Definition of cellular life NB.jpg
Definition of cellular life according to Budisa, Kubyshkin and Schmidt

Budisa, Kubyshkin and Schmidt defined 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. [34]

See also

Related Research Articles

Gaia philosophy is a broadly inclusive term for relating concepts about, humanity as an effect of the life of this planet.

<span class="mw-page-title-main">Life</span> Matter with biological processes

Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from matter that does not. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction. All life over time eventually reaches a state of death and none is immortal. Many philosophical definitions of living systems have been proposed, such as self-organizing systems. Viruses in particular make definition difficult as they replicate only in host cells. Life exists all over the Earth in air, water, and soil, with many ecosystems forming the biosphere. Some of these are harsh environments occupied only by extremophiles.

Systems theory is the transdisciplinary study of systems, i.e. cohesive groups of interrelated, interdependent components that can be natural or artificial. Every system has causal boundaries, is influenced by its context, defined by its structure, function and role, and expressed through its relations with other systems. A system is "more than the sum of its parts" when it expresses synergy or emergent behavior.

<span class="mw-page-title-main">Lynn Margulis</span> American evolutionary biologist (1938–2011)

Lynn Margulis was an American evolutionary biologist, and was the primary modern proponent for the significance of symbiosis in evolution. In particular, Margulis transformed and fundamentally framed current understanding of the evolution of cells with nuclei by proposing it to have been the result of symbiotic mergers of bacteria. Margulis was also the co-developer of the Gaia hypothesis with the British chemist James Lovelock, proposing that the Earth functions as a single self-regulating system, and was the principal defender and promulgator of the five kingdom classification of Robert Whittaker.

<span class="mw-page-title-main">Superorganism</span> Group of synergistic organisms

A superorganism, or supraorganism, is a group of synergetically-interacting organisms of the same species. A community of synergetically-interacting organisms of different species is called a holobiont.

<span class="mw-page-title-main">Gaia hypothesis</span> Scientific hypothesis about Earth

The Gaia hypothesis, also known as the Gaia theory, Gaia paradigm, or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating, complex system that helps to maintain and perpetuate the conditions for life on the planet.

<span class="mw-page-title-main">Autopoiesis</span> Systems concept which entails automatic reproduction and maintenance

The term autopoiesis refers to a system capable of producing and maintaining itself by creating its own parts. The term was introduced in the 1972 publication Autopoiesis and Cognition: The Realization of the Living by Chilean biologists Humberto Maturana and Francisco Varela to define the self-maintaining chemistry of living cells.

Robert Rosen was an American theoretical biologist and Professor of Biophysics at Dalhousie University.

<span class="mw-page-title-main">Systems biology</span> Computational and mathematical modeling of complex biological systems

Systems biology is the computational and mathematical analysis and modeling of complex biological systems. It is a biology-based interdisciplinary field of study that focuses on complex interactions within biological systems, using a holistic approach to biological research.

<span class="mw-page-title-main">Mathematical and theoretical biology</span> Branch of biology

Mathematical and theoretical biology, or biomathematics, is a branch of biology which employs theoretical analysis, mathematical models and abstractions of living organisms to investigate the principles that govern the structure, development and behavior of the systems, as opposed to experimental biology which deals with the conduction of experiments to test scientific theories. The field is sometimes called mathematical biology or biomathematics to stress the mathematical side, or theoretical biology to stress the biological side. Theoretical biology focuses more on the development of theoretical principles for biology while mathematical biology focuses on the use of mathematical tools to study biological systems, even though the two terms are sometimes interchanged.

A complex adaptive system is a system that is complex in that it is a dynamic network of interactions, but the behavior of the ensemble may not be predictable according to the behavior of the components. It is adaptive in that the individual and collective behavior mutate and self-organize corresponding to the change-initiating micro-event or collection of events. It is a "complex macroscopic collection" of relatively "similar and partially connected micro-structures" formed in order to adapt to the changing environment and increase their survivability as a macro-structure. The Complex Adaptive Systems approach builds on replicator dynamics.

A metasystem transition is the emergence, through evolution, of a higher level of organization or control.

The dynamic energy budget (DEB) theory is a formal metabolic theory which provides a single quantitative framework to dynamically describe the aspects of metabolism of all living organisms at the individual level, based on assumptions about energy uptake, storage, and utilization of various substances. The DEB theory adheres to stringent thermodynamic principles, is motivated by universally observed patterns, is non-species specific, and links different levels of biological organization as prescribed by the implications of energetics. Models based on the DEB theory have been successfully applied to over 1000 species with real-life applications ranging from conservation, aquaculture, general ecology, and ecotoxicology. The theory is contributing to the theoretical underpinning of the emerging field of metabolic ecology.

Research concerning the relationship between the thermodynamic quantity entropy and both the origin and evolution of life began around the turn of the 20th century. In 1910 American historian Henry Adams printed and distributed to university libraries and history professors the small volume A Letter to American Teachers of History proposing a theory of history based on the second law of thermodynamics and on the principle of entropy.

<span class="mw-page-title-main">Biological organisation</span> Hierarchy of complex structures and systems within biological sciences

Biological organisation is the organisation of complex biological structures and systems that define life using a reductionistic approach. The traditional hierarchy, as detailed below, extends from atoms to biospheres. The higher levels of this scheme are often referred to as an ecological organisation concept, or as the field, hierarchical ecology.

<span class="mw-page-title-main">Biology</span> Science that studies life

Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary information encoded in genes, which can be transmitted to future generations. Another major theme is evolution, which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move, grow, and reproduce. Finally, all organisms are able to regulate their own internal environments.

The evolution of biological complexity is one important outcome of the process of evolution. Evolution has produced some remarkably complex organisms – although the actual level of complexity is very hard to define or measure accurately in biology, with properties such as gene content, the number of cell types or morphology all proposed as possible metrics.

The branches of science, also referred to as scientific fields or scientific disciplines, are commonly divided into three major groups:

An organism is defined in a medical dictionary as any living thing that functions as an individual. 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 commonest is that an organism has autonomous reproduction, growth, and metabolism. This would exclude viruses, despite the fact that they evolve like organisms. Other problematic cases include colonial organisms; a colony of eusocial insects is organised adaptively, and has germ-soma specialisation, with some insects reproducing, others not, like cells in an animal's body. The body of a siphonophore, a jelly-like marine animal, is composed of organism-like zooids, but the whole structure looks and functions much like an animal such as a jellyfish, the parts collaborating to provide the functions of the colonial organism.

<span class="mw-page-title-main">Artificial life</span> Field of study

Artificial life is a field of study wherein researchers examine systems related to natural life, its processes, and its evolution, through the use of simulations with computer models, robotics, and biochemistry. The discipline was named by Christopher Langton, an American theoretical biologist, in 1986. In 1987, Langton organized the first conference on the field, in Los Alamos, New Mexico. There are three main kinds of alife, named for their approaches: soft, from software; hard, from hardware; and wet, from biochemistry. Artificial life researchers study traditional biology by trying to recreate aspects of biological phenomena.

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.
  3. ↑ Miller, James Grier (1978). Living Systems. New York: McGraw-Hill. ISBN   978-0070420151.
  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.
  5. ↑ Járos, György (2000). "Living Systems Theory of James Grier Miller and teleonics". Systems Research and Behavioral Science. 17 (3). Wiley: 289–300. doi:10.1002/(sici)1099-1743(200005/06)17:3<289::aid-sres333>3.0.co;2-z. ISSN   1092-7026.
  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.
  12. ↑ Lovelock, James (1979). Gaia: A New Look at Life on Earth. Oxford University Press. ISBN   978-0-19-286030-9.
  13. ↑ Lovelock, J.E. (1965). "A physical basis for life detection experiments". Nature . 207 (7): 568–570. Bibcode:1965Natur.207..568L. doi:10.1038/207568a0. PMID   5883628. S2CID   33821197.
  14. ↑ Lovelock, James. "Geophysiology". Papers by James Lovelock. Archived from the original on 6 May 2007. Retrieved 1 October 2009.
  15. ↑ 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.
  16. ↑ Morowitz, Harold J. (1992). Beginnings of cellular life: metabolism recapitulates biogenesis. Yale University Press. ISBN   978-0-300-05483-5.
  17. ↑ Ulanowicz, Robert W.; Ulanowicz, Robert E. (2009). A third window: natural life beyond Newton and Darwin. Templeton Foundation Press. ISBN   978-1-59947-154-9.
  18. ↑ Rosen, Robert (1958). "A relational theory of biological systems". The Bulletin of Mathematical Biophysics. 20 (3): 245–260. doi:10.1007/bf02478302.
  19. ↑ Robert, Rosen (1991). Life Itself: A Comprehensive Inquiry into the Nature, Origin, and Fabrication of Life. New York: Columbia University Press. ISBN   978-0-231-07565-7.
  20. ↑ Baianu, I.C. (2006). "Robert Rosen's Work and Complex Systems Biology". Axiomathes. 16 (1–2): 25–34. doi:10.1007/s10516-005-4204-z. S2CID   4673166.
  21. ↑
    • Rosen, Robert (1958a). "A Relational Theory of Biological Systems". Bulletin of Mathematical Biophysics. 20 (3): 245–260. doi:10.1007/bf02478302.
  22. ↑
    • Rosen, R. (1958b). "The Representation of Biological Systems from the Standpoint of the Theory of Categories". Bulletin of Mathematical Biophysics. 20 (4): 317–341. doi:10.1007/bf02477890.
  23. ↑ Montévil, Maël; Mossio, Matteo (7 May 2015). "Biological organisation as closure of constraints". Journal of Theoretical Biology. 372: 179–191. Bibcode:2015JThBi.372..179M. CiteSeerX   10.1.1.701.3373 . doi:10.1016/j.jtbi.2015.02.029. PMID   25752259. S2CID   4654439. Archived from the original on 17 November 2017.
  24. ↑ Bernstein, Harris; Byerly, Henry C.; Hopf, Frederick A.; Michod, Richard A.; Vemulapalli, G. Krishna (June 1983). "The Darwinian Dynamic". The Quarterly Review of Biology. 58 (2): 185. doi:10.1086/413216. JSTOR   2828805. S2CID   83956410.
  25. ↑ Michod, Richard E. (2000). Darwinian Dynamics: Evolutionary Transitions in Fitness and Individuality. Princeton: Princeton University Press. ISBN   978-0-691-05011-9.
  26. ↑ Jagers, Gerard (2012). The Pursuit of Complexity: The Utility of Biodiversity from an Evolutionary Perspective. KNNV Publishing. pp. 27–29, 87–88, 94–96. ISBN   978-90-5011-443-1.
  27. ↑ Jagers Op Akkerhuis, Gerard A. J. M. (2010). "Towards a Hierarchical Definition of Life, the Organism, and Death". Foundations of Science. 15 (3): 245–262. doi:10.1007/s10699-010-9177-8. S2CID   195282529.
  28. ↑ Jagers Op Akkerhuis, Gerard (2011). "Explaining the Origin of Life is not Enough for a Definition of Life". Foundations of Science. 16 (4): 327–329. doi:10.1007/s10699-010-9209-4. S2CID   195284978.
  29. ↑ Jagers Op Akkerhuis, Gerard A. J. M. (2012). "The Role of Logic and Insight in the Search for a Definition of Life". Journal of Biomolecular Structure and Dynamics. 29 (4): 619–620. doi: 10.1080/073911012010525006 . PMID   22208258. S2CID   35426048. Archived from the original on 16 April 2021. Retrieved 16 April 2021.
  30. ↑ Jagers, Gerald (2012). "Contributions of the Operator Hierarchy to the Field of Biologically Driven Mathematics and Computation". In Ehresmann, Andree C.; Simeonov, Plamen L.; Smith, Leslie S. (eds.). Integral Biomathics. Springer. ISBN   978-3-642-28110-5.
  31. ↑ Korzeniewski, Bernard (7 April 2001). "Cybernetic formulation of the definition of life". Journal of Theoretical Biology. 209 (3): 275–286. Bibcode:2001JThBi.209..275K. doi:10.1006/jtbi.2001.2262. PMID   11312589.
  32. ↑ Kaufmann, Stuart (2004). "Autonomous agents". In Barrow, John D.; Davies, P.C.W.; Harper, Jr., C.L. (eds.). Science and Ultimate Reality. pp. 654–666. doi:10.1017/CBO9780511814990.032. ISBN   978-0-521-83113-0.
  33. ↑ Longo, Giuseppe; Montévil, Maël; Kauffman, Stuart (1 January 2012). "No entailing laws, but enablement in the evolution of the biosphere". Proceedings of the 14th annual conference companion on Genetic and evolutionary computation. GECCO '12. pp. 1379–1392. arXiv: 1201.2069 . Bibcode:2012arXiv1201.2069L. CiteSeerX   10.1.1.701.3838 . doi:10.1145/2330784.2330946. ISBN   978-1-4503-1178-6. S2CID   15609415. Archived from the original on 11 May 2017.
  34. ↑ Budisa, Nediljko; Kubyshkin, Vladimir; Schmidt, Markus (22 April 2020). "Xenobiology: A Journey towards Parallel Life Forms". ChemBioChem. 21 (16): 2228–2231. doi: 10.1002/cbic.202000141 . PMID   32323410.

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