PalZ

Tobias, Phillip

doi: 10.1007/BF02990307pmid: N/A

doi: 10.1007/BF02990308pmid: N/A

Hölder, Helmut

doi: 10.1007/BF02990309pmid: N/A

Reflections on the actual problematics of the palaeontological evolution research are observed under epistemological aspects. When discussing new or only pretended new beginnings, sometimes with claim to neutral-point elucidations, success and merit of the traditional methods in palaeontology should not be forgotten. Gradualism and punctualism reduce the multilateral reality of nature.

Rieppel, Olivier

doi: 10.1007/BF02990310pmid: N/A

The models of punctuated and gradual evolution are put in a historical perspective and contrasted with each other. Mechanisms of saltational change are discussed. A synthesis of the two models might be achieved on the basis ofC. H. Waddington’s theory of developmental canalization as recently discussed byA. Hoffman.

Vogel, Klaus

doi: 10.1007/BF02990311pmid: N/A

[Arguments against the hypothesis of “punctuated equilibria”.] The main point of my critical comment against the hypothesis of punctualism in evolution refers to the incomplete conception of selection, on which this hypothesis is based. There is no reason for the assumption that “organic design”, developmental and phylogenetic limitations, allometry and pleiotropism are not exposed to and modifiable by selection. Selection also improves efficiency and economy of the organismic construction. This insight reduces the role of nonadaptations, chance and limitations during speciation “events”. Geological instants are not as resolvable as claimed by the authors, nor is it justified to take even the examples of most favorable stratigraphic documentation hitherto described as a model for macroevolutionary processes. Up to now there are existing neither observations nor theoretic probability for the punctualistic view of evolution.

Remane, Jürgen

doi: 10.1007/BF02990312pmid: N/A

Some authors (mainlyBonik, Gutmann, andPeters) have tried to revise current evolutionary concepts, fraught — in their opinion — with “1paleodarwinistic dogmas”. Some points of their theories are reviewed critically in the present paper: (1) Evolution is of course inimaginable without selection, but an “internal selection” eliminating misshaped embryos has nothing to do with evolution. This is stabilizing selection which reduces genetic variation and would even block evolutionary change completely if it was perfect. When this kind of internal selection was “neglected” by earlier authors, this cannot be qualified as paleodarwinistic dogmatism being in contradiction with the premises of evolutionary theory. — (2) Energetic rationalisation of organisms is certainly an important factor in selection but not an absolute law explaining everything about evolution. There are many adaptive processes resulting in less “economic” formations; e.g. heavy armors like those of tortoises, ankylosaurs, and stegosaurs. Among others, protective functions justify a certain waste of energy. — (3) Comparing organisms with technical machines provides an interesting analogy, but again this cannot be considered as the only possible approach for evolutionary models. »Maschinenanalogie« combined with a generalized »internal selection« (i.e. with the nature of adaptive changes determined by the internal construction of organisms) leads inevitably to an underestimation of selective pressures resulting from the ecologic and biocoenotic context. The simple fact of diverging evolutionary lineages shows that the same species (“machine”) can be improved in different ways under the influence of different external factors.

Fahlbusch, Volker

doi: 10.1007/BF02990313pmid: N/A

Based on new material of the rodent genus Pseudotheridomys from the lower Miocene fissurefilling of Schaffhausen near Harburg (Nördlinger Ries, Bavaria) the process of continuous development from Pseudotheridomys to Ligerimys can be demonstrated. Within homogeneous populations of Pseudotheridomys the origin of a new morphotype can be observed. In following populations from several biostrati-graphic levels in southern Germany this type becomes more and more dominant, up to homogeneous populations of Ligerimys florancei. For this example of microevolutionary origin of a new genus — for a long time separated from its forerunner by a large gap in documentation — it is shown that neither a dichotomy nor any special mechanism of macroevolution nor a speciation in the sense of punctualism is necessary to explain its development. The process continued for at least 3 million years. It quite corresponds to the synthetic theory of evolution.

Kullmann, Jürgen

doi: 10.1007/BF02990314pmid: N/A

On the basis of evolutionary rates several maxima and minima in the diversity of ammonoids can be recognized during Upper Devonian and Carboniferous times. The development of new characters, the beginning and continuation of phylogenetic trends and the origination as well as the extinction of bradytelic genera are restricted to diversity maxima.

Rödder, Gerhard; Wahlefeld, Günter

doi: 10.1007/BF02990315pmid: N/A

On the basis of some theoretical doubts concerning the principal abilities of explication of the “modern synthetic thEorie”, and, in addition the Homologienforschung, some well known problems of evolution beyond the species level are mentioned. Subject of special reflection is the problem of “Stammesalterung”. Recent developments of the scientific knowledge make renewed approaches to the topic possible.

Reif, Wolf-Ernst

doi: 10.1007/BF02990316pmid: N/A

Die Funktionsmorphologie klärt die physiko-chemischen Eigenschaften und die biologischen Rollen von Organen auf. In bezug auf fossile Organe ist diese Arbeitsweise mit einigen methodologischen Problemen verbunden. Es müssen evolutive, funktionelle und bautechnische Limitierungen berücksichtigt werden, die die Evolution beeinflussen. Darüber hinaus ist der Einfluß des Verhaltens fossiler Arten auf die biologische Rolle ihrer Organe schwer zu beurteilen. Anwendungsbereiche der Funktionsmorphologie in der Paläontologie sind anatomische Rekonstruktion, phylogenetische Ableitung von Organen, phylogenetische Systematik, Rekonstruktion von Verhaltensmustern von Arten und von synökologischen Beziehungen. In Form eines Arbeitskonzeptes wird gezeigt, wie sich die Ergebnisse der Funktionsmorphologie zu einer Darstellung der evolutionären ökologie fossiler Taxa integrieren lassen.