BioConcepts

gradedegré d’organisation (fr.); Organisationsstufe (ger.)

• A group of organisms that share certain morphological characteristics but are not necessarily related in evolutionary terms. For example, all organisms that possess a coelom can be regarded as a grade. A grade can be contrasted with a clade, which represents phylogenetic lineage. (Oxford Dict. of Biology 2009)  
  category organization

  1761

  [Quel seroit aussi, je supose,1e degré d’organisation jaillissant de ce chaos?

  Formey, J.-H.-S. (1761). Choix des mémoires et abrégé de l’histoire de l’Académie de Berlin, vol. 3: 66.]

  1761

  Que sert donc aux animaux l’instinct qui leur indique ce qui leur convient & ce qui leur est contraire. Ce n’est pas assurément à éviter les miseres attachées à tel degré d’organisation qui constitue leur être, auxquelles il ne leur est pas plus possible de se soustraire, que de reformer l’économie universelle, changer le cours immuable des choses, violer l’ordre, des tems.

  Robinet, J.B. (1761). De la nature, vol. 1: 105; cf. vol. 4 (1766): 233.

  1803

  Individuen von dieser Organisationsstufe 

  Wagner, J.J. (1803): Von der Natur der Dinge: 522 (§520); cf. 317 (§344); 424 (§432).

  1806

  Die Hauptsysteme des thierischen Organismus, so wie dann selbst des menschlichen, als höchster Organisationsstufe sind das Nerven- und Muskelsystem

  Wolf, S. (1806). Die Natur einwirkender Potenzen: 115 (§171).

  1809

  j’ai partagé en six degrés, qui sont très-distincts, tous les modes d’organisation qu’on a reconnus dans toute l’étendue de l’échelle animale. De ces six degrés d’organisation, les quatre premiers embrassent les animaux sans vertèbres

  Lamarck, J.B. de (1809). Philosophie zoologique, 2 vols.: I, 275.

  1818

  Organisationsgrad der Ordnung

  Blainville, H.M.D. de (1818). Vorläufe Anzeige einer neuen systematischen Eintheilung des Thierreichs. Isis 1818 (1), 1365-1384: 1371.

  1825

  Organisationsstufe der Insecten

  Müller, J. (1825). Über die Entwickelung der Eier im Eierstock bei den Gespenstheuschrecken. Nova acta physico-medica Academiae Caesareae Leopoldino-Carolinae Naturae Curiosorum 4(2), 553-672: 642.

  1826-27

  Stufen der Organisation

  Baer, K.E. von (1826-27). Beiträge zur Kenntniss der niedern Thiere. Nova Acta Physico-Medica 13(2), 523-762: 740.

  1877

  Whilst all other terms indicate branches of the pedigree diverging from a very nearly common point […] the various ‘grades’ are introduced to separate the starting-points of the branches; a certain advance in differentiation of structure separates the branches of a higher grade from those of a lower.

  Lankester, E.R. (1877). Notes on the embryology and classification of the animal kingdom; comprising a revision of speculations relative to the origin and significance of the germlayers. Quart. J. Microscop. Sci. n.s., 17, 399-454: 440.

  1927

  It is possible to classify by lineages or by grades, but equal insistence on both makes your system look more like a cross-word puzzle than either a tree or a key.

  Bather, F.A. (1927). Biological classification: past and fututre. Quart. J. Geol. Soc. London 83, lxii-civ: ciii.

  1955

  I personally would like to see a new, evolutionary classification, which would combine the advance and ancestry principles. We would then have groups of common ancestry—Classes, Orders, and other familiar designations, and grades of advance (advance sometimes independently achieved, sometimes in common), for which new designations would have to be coined. I would hope that Metazoa would be restored to its original use as a grade label, and that Man would be placed in a new major grade, which might be called Psychozoa.

  Huxley, J. (1955). Evolution, cultural and biological.Yearbook of Anthropology 1955, 3-25: 23.

  1961

  groups of animals similar in general levels of organization as distinct from groups of common genetic origin. J. Huxley […] has proposed that the former groups be called grades, the latter, clades.

  Simpson, G.G. (1961). Principles of Animal Taxonomy: 125.