atavism


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atavism

(ăt`əvizəm), the appearance in an individual of a characteristic not apparent in the preceding generation. At one time it was believed that such a phenomenon was thought to be a reversion of "throwback" to a hypothetical ancestral prototype. The term is seldom used today since science has shown that such abnormal characteristics can be explained by the inheritance of a pair of recessive genesgene,
the structural unit of inheritance in living organisms. A gene is, in essence, a segment of DNA that has a particular purpose, i.e., that codes for (contains the chemical information necessary for the creation of) a specific enzyme or other protein.
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. See MendelMendel, Gregor Johann
, 1822–84, Austrian monk noted for his experimental work on heredity. He entered the Augustinian monastery in Brno in 1843, taught at a local secondary school, and carried out independent scientific investigations on garden peas and other plants until
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.

Atavism

 

the appearance in organisms of features that are absent in their immediate ancestors but which did exist in very distant ancestors. An example of atavism could be the development of a caudal appendage in man, the appearance of two extra toes along the sides of the completely developed middle toe of the horse, or the development of pinnately compound leaves instead of phyllodes in the green wattle. Since to a certain degree individuals repeat the organizational features of their ancestors in the developmental process, a disturbance of normal development can lead to a situation in which the adult organism keeps for its entire life the ancestral features which normally appear in the embryo and usually disappear in the course of further development. An example of such atavism would be the appearance in man of a cervical fistula reminiscent of the gill slit of his mammalian ancestors, the fishes and amphibians. Polymastia in man (the formation of a larger than normal number of pairs of mammary glands), tridactylism in horses, and so forth, are also related to atavism. Atavism also includes the occurrence of features from distant ancestors in the regeneration of organs. In this instance, the organs regenerate with the features characteristic of the more ancient forms. Thus, in the regeneration of a lizard’s tail, the scale rings are sometimes formed in a more primitive shape. Upon regeneration of the anterior end of the body in certain annelids, head appendages are formed which are missing in the given form but which are inherent in its ancestors.

REFERENCE

Shimkevich, V. M. Biologicheskie osnovy zoologii. 5th ed., vols. 1–2. Moscow-Leningrad, 1923–25.

M. A. VORONTSOVA

atavism

[′ad·ə‚viz·əm]
(evolution)
Appearance of a distant ancestral form of an organism or one of its parts due to reactivation of ancestral genes.

atavism

the recurrence in a plant or animal of certain primitive characteristics that were present in an ancestor but have not occurred in intermediate generations
References in periodicals archive ?
(63) Thus, a kind of ebbing of vitalistic forces gave rise to the fantasy of going native, the atavism that haunts the pages of so many fantastic tales.
I failed to find the proper counterpart to the term 'atavism' for such case, therefore I propose to coin the term 'pronatism' ('pro-' = before; 'natus' = born).
Despite Nordau's dismissal of Zola as a degenerate artist, this article contends that Nana prefigures Nordau's emphasis on the degenerative conditions of modern life, and relates Zola's depiction of atavism in crowds to the theories of Gustave Le Bon.
Such dog destiny also played well in the Darwinian-Spenserian context--that is, atavism or species reversion, with Buck from domestic farm dog to wolf, and, White Fang, the opposite, from wolf to subjugated dog.
As in this specific case of Sikorskii, Beer seems to believe that Russian liberal experts understood backwardness as arrested development in climbing the socioeconomic ladder, further complicated by the survival of "atavisms" of previous eras (an interpretation consonant with the Bolshevik vision of progress).
(34) Lombroso, a physician, published his influential book, Criminal Man, in 1876, (35) in which he promoted his theory of atavism that claims that criminals were "throwbacks" to earlier evolutionary stages of humans.
An echo marks by its utterance the ancestral voice that birthed it, seed-word, source-word--an atavism that recalls Emerson's "Every word was once a poem," but recognizes more deeply that sounds mutate over time, do not remain static, but come clothed in audible remnants, come tattered through time as through a wilderness, speaking themselves through their bewildered form.
The case is similar for several themes that do not have chapters of their own, including atavism, courage, the extreme, the weak, dreams, education, and the problem of the actor; Nietzsche's descriptions of his task and of himself as one who has a task; his descriptions of his childhood and personal development; his discussions of the battle between melody and harmony; and his love-hate relationships with Germany, Luther and the historical sense.
All the mainstream and "decent" minor parties would willingly sign up, but the BNP, constrained by its crackpot atavism, racism and Ice Age theory of ethnic identity, would clearly fail the test and so be a proscribed organisation.
Cervical ribs in mammals are examples of atavism (reappearance of an extinct character, common to ancestral lineages that rarely occur in current populations).
In the American late modernity of the late 18th and early 19th century, the concept of atavism became pervasive in literary, scientific, and photographic discourses, Seitler (English, U.