New Animal Phylogeny

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The designation “New Animal Phylogeny” , or “ New Phylogeny of Animals”, or New Phylogeny was given in 2000 by a French research team for a family tree of multicellular animals ( Metazoa ) based on molecular biology . As early as 1995, based on molecular biological investigations, a new family tree for the main lineages of the animal kingdom and thus for the evolution of the various animal blueprints was suggested. This “molecular” family tree was largely in contradiction to previous (i.e. morphologically based) textbook knowledge on blueprint or macroevolution . As the corresponding results increased in the following years, the specialist literature initially spoke of a “new view”, ie a “new view” of the evolution of the approximately 35 main lineages of the animal kingdom . Since the turn of the millennium, the article by Adoutte et al. the term "New Animal Phylogeny" or "New Phylogeny" for short.

Key results

A molecular-biological investigation from 1995 showed that the pods (Brachiopoda, representatives of the wreath sensor ) do not belong to the trunk of the new mouths (deuterostomia), as expected , but to the primordial mouths (protostomia). The group of wreath sensors is of critical importance in many models of building plan evolution, since in addition to their position in the system, it is extremely controversial whether it is a community of descent at all and whether it is very primitive or relatively derived animals. In all three points, genetic investigations underpinned the hypotheses traditionally considered to be less likely: In addition to the classification of the primordial mouths, it could not be shown that the wreath antennae were a community of descent, and at least for the armfeet the results indicated a comparatively derived position . The new large group Lophotrochozoa was proposed together with some other Urmünder strains, which grouped close to the wreath antennae in genetic studies . Another significant change in the traditionally advocated family trees came with the emergence of the Ecdysozoa hypothesis in 1997. According to this, the arthropods are not related to the annelid worms , as was previously assumed almost without exception. Instead, the arthropods are grouped with representatives of the tube worms in molecular biological studies . Since both arthropods and the representatives concerned, tube worms periodically shed their skin (ecdysis), the name Ecdysozoa (= molting animals) was given to this new community of descent. Overall, the most profound changes occurred within the trunk of the original mouths. But there were also several unexpected revisions among the newcomers, above all the new division into the two large groups Ambulacraria and Chordata (of which only the latter was generally accepted on a traditional morphological basis). Another key to understanding the new division of the animal kingdom could be developmental genetic studies, the results of which point to a multi-segmented animal as the ancestor of almost all bilaterally symmetrical animals ( Bilateria ). This hypothesis would also be in sharp contradiction to traditional reconstructions of blueprint evolution, according to which multiple segmentation emerged much later and also several times independently.

Evaluation and acceptance of the results

The recognition of the New Animal Phylogeny depends primarily on the recognition of the molecular biological methods on which the results are based. Usually only the sequences of genes or non-coding DNA and RNA segments are examined here (recently even entire genomes ), but sometimes also gene functions, in particular genes relevant to developmental biology. Sequence similarities are evaluated using various algorithms, the usability of which must be discussed separately. For the evaluation of functional similarities, the Reman's homology criteria are often used, i.e. criteria from traditional morphology. At the developmental genetic level, there is an interface to traditional evolutionary biology, which worked by comparing morphological features. In general, it can be said that the individual results determined by molecular biology receive stronger or weaker approval depending on their subsequent compatibility with morphological comparisons of characteristics. The Ecdysozoa hypothesis is therefore to be regarded as the most controversial individual result of the New Animal Phylogeny, since this community of descent in the present form cannot claim any compatibility with older, morphologically justified proposals. Other individual results, such as the new division of the new mouths into ambulacraria and chordata, are much less controversial in this regard, because the ambulacraria can be reconciled with at least one morphological model from the 19th century, and the chordata were a generally accepted community of descent anyway. In its entirety, the New Animal Phylogeny family tree cannot be compared with any older family tree drafts based on comparison of morphological characteristics. However, since there is a certain compatibility in some areas, which is also confirmed with the help of new morphological investigations, New Animal Phylogeny has become an integral part of biology textbooks despite all the explanatory problems.

Remarks

  1. ↑ Adoutte et al. 2000
  2. ↑ Halanych et al. 1995
  3. ↑ cf. z. B. Mallat & Winchell 2002
  4. ↑ a b Halanych et al. 1995
  5. ↑ Aguinaldo et al. 1997
  6. ↑ Balavoine & Adoutte 2003

literature

  • A. Adoutte, G. Balavoine, N. Lartillot, O. Lespinet, B. Prud'homme & R. de Rosa (2000): The New Animal Phylogeny: Reliability and Implications. Proceedings of the National Academy of Sciences 97, pp. 4453-4456
  • AM Aguinaldo, JM Turbeville, LS Linford, MC Rivera, JR Garey, RA Raff & JA Lake (1997): Evidence for a clade of nematodes, arthropods and other moulting animals. Nature 387, pp. 489-493
  • G. Balavoine & A. Adoutte (2003): The segmented Urbilateria: A testable scenario. Integrative and Comparative Biology 43, pp. 137-147
  • KM Halanych, JD Bacheller, AMA Aguinaldo, SM Liva, DM Hillis & JA Lake (1995): Evidence from 18S ribosomal DNA that the lophophorates are protostome animals. Science 267, pp. 1641-1643
  • J. Mallatt & CJ Winchell (2002): Testing the New Animal Phylogeny: First Use of Combined Large-Subunit and Small-Subunit rRNA Gene Sequences to Classify the Protostomes. Molecular Biology and Evolution 19, pp. 289-301
  • Syed, T. (2003): How new is the "New Animal Phylogeny"? A possible synthesis of morphological and molecular findings on blueprint evolution. Yearbook for the History and Theory of Biology, 9: 33–76
  • Syed, T., Gudo, M. & Gutmann, M. (2007): The New Large Phylogeny of the Animal Kingdom: Dilemma or Progress? - Denisia, 20 23-36.
  • Gudo, M. & Syed, T. (2008): 100 Years of Deuterostomia (Grobben, 1908): Cladogenetic and Anagenetic Relations within the Notoneuralia Domain, 14 p., 8 fig. (online: PDF )