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A unidirectional evolutionary change among a related group of animals.



the hypothesis that evolution proceeds directly toward higher adaptive states.

Orthogenesis is rooted in the views of J. B. Lamarck. The German scientists W. Haacke, who introduced the term “orthogenesis,” and G. H. T. Eimer, who used this term extensively, proceeded from the mechanistic Lamarckian position that the direction of evolution is controlled by the immediate influence of the environment and that the internal organization of an individual can change only in certain set directions. Subsequently, “orthogenesis” was often used to describe evolution as being controlled by an internal driving force as well as by the immediate influence of the environment.

Modern evolutionary theory, according to which the direction of evolution is a result of natural selection, usually contradicts the concept of orthogenesis. Although linearity is a feature of evolutionary change, modern theory attributes it to limitations imposed on the structural features of the organism; linearity essentially is the result of natural selection in past generations. (See AUTOGENESIS, LAMARCKISM.)


Simpson, G. G. Tempy i formy evoliutsii. Moscow, 1948. (Translated from English.)
Shmal’gauzen, I. I. Problemy darvinizma, 2nd ed. Leningrad, 1969.
Haacke, W. Gestaltung und Vererbung, Leipzig, 1893.
Eimer, G. H. T. Die Entstehung der Arten. part 2: Die Orthogenesis der Schmetterlinge. Leipzig, 1897.


References in periodicals archive ?
Although neither trained in biology, nor involved in teaching the subject, he displays a firm grasp of traditional Darwinian, neo-Lamarckian, orthogenetic and saltational options.
Applied to personal constructs, the orthogenetic principle suggests that more developed systems of constructs will be more differentiated (contain greater numbers of constructs), articulated (consist of more refined elements), abstract and integrated (organized and interconnected).
The orthogenetic implications are obvious, however the "force" that is driving the evolutionary change is not intrinsic or "vital" but extrinsic--originating from the structure of the Ecosystem it's self.
Heesterman 1985: 38-41, on the other hand, emphasizes the orthogenetic character of this process.
136-143), reinscription of the orthogenetic categor y of 'Stone-Age people' (p.
1978), who organized this genus into gene pools, with the common bean and the Lima bean at the extremes of an orthogenetic sequence.
As Vernon Kellogg wrote, "Selection will inexorably bar the forward movement, will certainly extinguish the direction of any orthogenetic process .
Below it will be discussed whether the heterochronic shift of mesentoblast formation shown in Figure 17 has been realized along a single orthogenetic line, or independently along several evolutionary lines.
There is little point in reviewing the content of the already-published essays, especially since the orthogenetic interpretive framework deployed in them looks increasingly antique, as do the bias against rhetoric and in favor of "science," the bloody-minded quest for "reality" beneath the texts, the construction of "traditions" (complete with assessment of points for "contributions") and so forth.
The "internal" metaphor, in this setting, usually takes the shape of orthogenetic and Lamarckian mechanisms of organic development.
Several lines of work in social cognitive development are interpreted with Werner's Orthogenetic principle (1948), which posits that with age and attendant social experience thought becomes more differentiated, abstract, and integrated.