Morphology (biology)

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The morphology (from ancient Greek μορφή morphé , 'shape', 'form' , and -logie (from λόγος lógos , teaching ')) as part of the field of biology is the study of the structure and form of the organisms . Morphological descriptions initially only related to macroscopically visible features such as organs or tissue ; in some cases morphology was also divided into anatomy (as a study of the structure of the internal organs) and eidonomy (to describe the external shape). As early as the 19th century, with the improvement of optical instruments and various staining methods, corresponding investigations could be extended to the cellular and subcellular level (ultrastructural research). In the Anglo-American language area, molecular morphology is also used, i.e. the description of the shape of macromolecules such as ribosomal DNA . In German-speaking countries, the term morphology is usually reserved for structures above the molecular level.

The term morphology was developed by Johann Wolfgang von Goethe , who already used it in his diary on September 25, 1796, but whose considerations from the years 1796 to 1807 were only published from 1817 to 1824 (in the journal Zur Morphologie founded by Goethe ), and in 1800 by the German anatomist and physiologist Karl Friedrich Burdach (in the script Propaedeutics for the Study of All Healing Art ).

Historical review

Morphologists of earlier times did not yet understand the classification systems they established as a description of a gradual emergence from a common precursor. Instead, there was talk of an “ideal type” or “archetype” that can be assigned to certain groups of organisms.

In the organisms one also saw the Platonic ideas in part. The best-known example of such an endeavor is Goethe's attempt to infer an ideal type of "original plant" from the appearance of all known plant forms. This line of thought is now considered the first step towards modern evolutionary biology and is historically classified as "idealistic morphology".

Disciplines

Morphological investigations can be carried out according to very different objectives; accordingly, various disciplines have emerged in the course of research history.

A possible distinction would be e.g. B. that between comparative, functional and experimental morphology.

  • In comparative morphology , one tries to recognize certain basic patterns or characteristics of a group of organisms in the variety of shapes of the individuals and, if necessary, to derive a classification of the organisms on the basis of characteristic characteristics.
  • The aim of functional morphology is to study a structure in terms of a specific function. The investigation focuses on individual elements of an organism that are relevant for a specific function. A structure is therefore understood as specialization in a certain function (i.e. the adaptation of an organism to its way of life). The totality or the interaction of the individual functions can flow into a so-called construction morphological description.
  • In experimental morphology , the development of an organism is usually examined. Here z. B. changed the environmental conditions in the experiment in order to determine development laws in terms of a causal morphology (comparison between normal and disturbed development process, causal justification of the observed differences).

Morphological investigations can therefore form the basis of very different research directions. The purely descriptive recording of shapes and changes in shape in development often results in a certain classification of organisms in modern biology . Thus the morphology forms the basis for the systematics and the theory of evolution (see also phylogenetics ).

Certain aspects of the morphology are related to the geographical region, see Ecogeographical Rule .

See also

literature

  • A. Ender, Bernd Schierwater: Placozoa are not derived cnidarians: Evidence from molecular morphology. In: Molecular Biology and Evolution 20. 2003, pp. 130-134. (English)
  • Wolfgang Lefèvre: The emergence of the biological evolution theory. Ullstein, Frankfurt / Berlin / Vienna 1984, ISBN 3-548-35186-7 .
  • Manfred Wenzel: Morphology. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. Walter de Gruyter, Berlin and New York 2005, ISBN 3-11-015714-4 , p. 1010 f.

Web links

Individual evidence

  1. ↑ Ender & Schierwater 2003 (see section Literature )
  2. ↑ Manfred Wenzel (2005), p. 1010.
  3. ^ Karl Mägdefrau : History of Botany. 2nd edition, Gustav Fischer Verlag , Jena 1992, ISBN 3-437-20489-0 .
  4. ^ Adolf Remane : The foundations of the natural system, comparative anatomy and phylogenetics: Theoretical morphology and systematics I. Academic publishing company, Leipzig 1954.
  5. ↑ Lefèvre 1984 (see section literature )