Dystelia

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Dystelia is a term from the reception history of Darwinian descent doctrine . On the one hand, in the first half of the 20th century, especially in Germany (e.g. at Plate ), people were still skeptical about the mechanism of selection because of its "flatness" ( Nietzsche therefore considered Darwin to be "British and therefore mediocre anyway." "Abqualified), on the other hand also skeptical about fossil and also recent forms of life (in inaccessible habitats such as the deep sea), whose expressions of life we ​​cannot observe, but which deviate so strongly from the familiar in their forms that they seem" inappropriately "( pterosaurs , Chauliodontidae ). This inadequacy, even inappropriateness (dystelia: from (Greek) dys- miss-, un-, counter-; telos goal, purpose) of their structure could at the same time be interpreted as an indication of an inner purposefulness of evolution (after perfection: orthogenesis , Lamarckism ) as well as initially possibly completely purposeless forms (atelie), which the selection first had to eradicate. In this way, the Eutelian (functional) forms would have increased steadily in the course of life, the dystelian would recently only be found as relics in extremely remote habitats, where they would not be exposed to any competition.

In contrast, the paleontologists Louis Dollo ( Dollosche Rule ) and even more Othenio Abel took the (" actualistic ") point of view that is still valid today that all forms of life were and are always at least so adapted that they can multiply (if not, they die yes off). Individual features can of course become dystelian - e.g. B. (as a popular example) the peacock wheel - when the sexually selective females drive it too far. It is much less clear whether this is where the long but very narrow (therefore prone to break) canines of the " saber-toothed cats " belong. The functional interpretation of the pronotum outgrowths of the larger Membracidae (humpback chirps) is still extremely uncertain. The ammonites with a complicated line of praise were also long discussed as "one-sided, ultimately dystelian specializing" ( Otto Heinrich Schindewolf ). However, there is not a single fossil form that is clearly known to have disappeared because of "dystelia".

For, so to speak, excessive eutelia (expediency), the term hypertelia was coined - the teeth of Chauliodus could serve as an example . Living nature is full of such dubious "adaptations", so that today it is better to avoid worrying about it, for example with the help of the neutral theory of molecular evolution ( genetic drift without selection); but the problem persists.

literature

  • Gerald Kopp: Evolution and Gap. Potentials of the historical geosciences and life sciences for environmental education . Kiel 2000, p. 173, (Dissertation to obtain the doctoral degree of the educational science faculty of the Christian-Albrechts-Universität zu Kiel).
  • Gerhard von Frankenberg : About dystelia . In: Jena magazine for medicine and science . Volume 70, Jena 1935, pp. 33-69.
  • Anton Handlirsch : Hypertelia and Adaptation . In: Negotiations of the Imperial-Royal Zoological-Botanical Society in Vienna . Volume 65, Vienna 1915, pp. 119-135, (online) .