/awr'theuh jen"euh sis/, n.
1. Biol.
a. Also called orthoselection. evolution of a species proceeding by continuous structural changes in a single lineage without presenting a branching pattern of descent.
b. a theory that the evolution of a species in a continuous, nonbranching manner is due to a predetermined series of alterations intrinsic to the species and not subject to natural selection.
2. Sociol. a hypothetical parallelism between the stages through which every culture necessarily passes, in spite of secondary conditioning factors.
[1890-95; < NL; see ORTHO-, GENESIS]

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also called  straight-line evolution 

      theory that successive members of an evolutionary series become increasingly modified in a single undeviating direction. That evolution frequently proceeds in orthogenetic fashion is undeniable, though many striking features developed in an orthogenetic group appear to have little if any adaptive value and may even be markedly disadvantageous. A variety of theories have attempted to explain orthogenesis, but with only partial success. One underlying view in orthogenesis, as espoused by some paleontologists, is that variation in nature is directed toward fixed goals and that species evolve in a predetermined direction irrespective of selection.

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Universalium. 2010.

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  • Orthogenesis — Orthogenesis, orthogenetic evolution, progressive evolution or autogenesis, is the hypothesis that life has an innate tendency to evolve in a unilinear fashion due to some internal or external driving force . The hypothesis is based on… …   Wikipedia

  • orthogenesis — orthogenesis. См. ортоэволюция. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Orthogeněsis — (griech., »geradlinige [bestimmt gerichtete] Entwickelung«), die allmählich verstärkte Ausprägung bestimmter Merkmale, die dadurch hervorgerufen wird, daß die aufeinander folgenden Generationen einer Tier oder Pflanzenart stets in gleicher… …   Meyers Großes Konversations-Lexikon

  • orthogenesis — [ôr΄thō jen′ə sis] n. [ModL: see ORTHO & GENESIS] 1. Biol. a now discredited theory that states that the progressive evolution of certain organisms in a restricted direction throughout successive generations is independent of outside influences… …   English World dictionary

  • orthogenesis — noun Etymology: New Latin Date: 1895 variation of organisms in successive generations that in some especially former evolutionary theories takes place in some predestined direction resulting in progressive evolutionary trends independent of… …   New Collegiate Dictionary

  • orthogenesis — n. [Gr. orthos, straight; genesis, beginning] Evolution following a predetermined rectilinear pathway, independent of natural selection …   Dictionary of invertebrate zoology

  • orthogenesis — noun A series of similar in successive , producing evolutionary change …   Wiktionary

  • orthogenesis — The doctrine that evolution is governed by intrinsic factors and occurs in predictable directions. [ortho + G. genesis, origin] * * * or·tho·gen·e·sis .ȯr thə jen ə səs n, pl e·ses .sēz variation of organisms in successive generations that in… …   Medical dictionary

  • orthogenesis — directional evolution of organisms Causation and Formation …   Phrontistery dictionary

  • orthogenesis — n. theory that evolution of a species is predetermined and is unaltered by outside influences (Biology); theory that all cultures must pass through determined identical stages (Sociology) É”rθə dÊ’É™nɪsɪs / ɔːθ …   English contemporary dictionary

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