Unreferenced stub auto yes date December 2009 Homeorhesis , derived from the Greek language Greek for similar flow , is a concept encompassing dynamical systems which return to a trajectory, as opposed to systems which return to a particular state, which is termed homeostasis . Biology The word itself is a little used term of art in biology, where it describes the tendency of developing or changing organisms to continue development or change towards a given state, even if disturbed in development. The term was first coined by C.H. Waddington , on or before 1940, along with the related term chreod , meaning necessary path , which is the trajectory to which the system tends to return. Gaia hypothesis wiktionary In ecology the concept is important as an element of the Gaia hypothesis , where the system under consideration is the ecological balance of different forms of life on the planet. It was Lynn Margulis , the coauthor of Gaia hypothesis, who wrote in particular that only homeorhetic and not homeostatic balances are involved in the theory. Citation needed date March 2011 That is, the composition of Earth s atmosphere, hydrosphere, and lithosphere are regulated around set points as in homeostasis, but those set points change with time. Category Systems theory Category Ecology Category Homeostasis Ecology stub Systemstheory stub et Hom orees lt Homeorez ro Homeorezie ... more details
In the theory of cybernetics , teleogenesis from the Greek language Greek teleos purpose and genesis creation is the creation of goal creating processes. According to Peter Corning A cybernetic system is by definition a dynamic purposive system it is designed to pursue or maintain one or more goals or end states . Teleogenesis refers from an extension of classical cybernetics, as proposed by Norbert Wiener , Ashby and others in late 1950s. See also homeostasis homeorhesis References Corning, Peter A. Thermoeconomics Beyond the second law from www.complexsystems.org Category Cybernetics Soft eng stub ... more details
Chreod, is a portmanteau term coined by 20th century biologist Conrad Hal Waddington that combines the Greek language Greek word for determined or necessary and the word for pathway. The term was used along with homeorhesis , which describes a system that returns to a steady trajectory in contrast to homeostasis which describes a system which returns to a steady state. Architectural Theorist Sanford Kwinter described the concept of the cherod as the most important concept of the 20th century. ref Sandford Kwinter, Lecture Excerpt What Is Life?, GSD 08 Platform, Harvard University Graduate School of Design, page 40. ref The word chreod also closely describes paths of decision within what Christopher Alexander has called, configuration space , his term for what he notes that Stuart Kaufmann calls tness landscape. ref Christopher Alexander, http www.katarxis3.com SCIENTIFIC 20INTRODUCTION.pdf New Concepts in Complexity Theory Arising from Studies in the Field of Architecture , page 17. ref Configuration space is a conceptual landscape which contains all possible outcomes and points of decision within the design of a structure or the growth of an organism or system. Because so very few of the possible outcomes will be good ones, paths to the infinitesimally rare possible and good solutions must be followed to get good results. These paths or, Cherods appear to be followed automatically in the biological world. see the cited Kwinter excerpt By Alexander s theory, because conscious human design decisions do not need to follow these cherods, conscious human design can lead to mixed results. Therefore, he proposes that discovering ways to allow architecture to follow these paths is the best way to get good results in the built environment. Alexander sees his theories of The Fundamental Process, structure preserving transformations and 15 fundamental properties which he outlines in his four volume work, The Nature of Order as instrumentally shaping paths through configurati ... more details
Infobox scientist name Conrad Hal Waddington image width 80 caption Conrad Hal Waddington, FRS, FRSE birth date 8 November 1905 birth place Evesham , Worcestershire , England death date 26 September 1975 death place Edinburgh , Scotland residence UK citizenship UK ethnicity British field Developmental biology , Genetics , Paleontology work institution Cambridge University , Christ s College, Cambridge Christ s College br University of Edinburgh br Wesleyan University alma mater Cambridge University doctoral advisor known for Epigenetic landscape , canalisation genetics canalisation , homeorhesis , genetic assimilation , chreod influences Alfred North Whitehead influenced Jean Piaget , Sanford Kwinter , Gregory Bateson , Margaret Mead prizes Conrad Hal Waddington Fellow of the Royal Society FRS Royal Society of Edinburgh FRSE 1905&ndash 1975 was a developmental biologist , paleontology paleontologist , geneticist , embryologist and philosopher who laid the foundations for systems biology . He had wide interests that included poetry and painting , as well as left wing political leanings. Citation needed date June 2007 Life Waddington, known as Wad to his friends and Con to family, was born to Hal and Mary Ellen Warner Waddington, 8 November 1905. Until nearly three years of age, Waddington lived with his parents in India, where his father worked on a tea estate in the Wayanad district . In 1910, at the age of four, he was sent to live with family in England including his aunt, uncle, and Quaker grandmother. His parents remained in India until 1928. During his childhood, he was particularly attached to a local druggist and distant relation, Dr. Doeg. Doeg, who Waddington called Grandpa , introduced Waddington to a wide range of sciences from chemistry to geology. ref Robertson, Alan. 1977. Conrad Hal Waddington. 8 November 1905&ndash 26 September 1975. Biographical Memoirs of Fellows of the Royal Society 23 , 575 622. Pp. 575 76. ref During the year following the compl ... more details
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