Time filter

Source Type

Lake Shore, IL, United States

Rieppel O.,The Field Museum
Biology and Philosophy | Year: 2010

The history of biological systematics documents a continuing tension between classifications in terms of nested hierarchies congruent with branching diagrams (the 'Tree of Life') versus reticulated relations. The recognition of conflicting character distribution led to the dissolution of the scala naturae into reticulated systems, which were then transformed into phylogenetic trees by the addition of a vertical axis. The cladistic revolution in systematics resulted in a representation of phylogeny as a strictly bifurcating pattern (cladogram). Due to the ubiquity of character conflict-at the genetic or morphological level, or at any level in between-some characters will necessarily have to be discarded (qua noise) in favor of others in support of a strictly bifurcating phylogenetic tree. Pattern analysts will seek maximal congruence in the distribution of characters (ultimately of any kind) relative to a branching tree-topology; process explainers will call such tree-topologies into question by reference to incompatible evolutionary processes. Pattern analysts will argue that process explanations must not be brought to bear on pattern reconstruction; process explainers will insist that the reconstructed pattern requires a process explanation to become scientifically relevant, i.e., relevant to evolutionary theory. The core question driving the current debate about the adequacy of the 'Tree of Life' metaphor seems to be whether the systematic dichotomization of the living world is an adequate representation of the complex evolutionary history of global biodiversity. In 'Questioning the Tree of Life', it seems beneficial to draw at least four conceptual distinctions: pattern reconstruction versus process explanation as different epistemological approaches to the study of phylogeny; open versus closed systems as expressions of different kinds of population (species) structures; phylogenetic trees versus cladograms as representations of evolutionary processes versus patterns of relationships; and genes versus species as expressions of different levels of causal integration and evolutionary transformation. © 2010 Springer Science+Business Media B.V. Source

Rieppel O.,The Field Museum
Journal of Zoological Systematics and Evolutionary Research | Year: 2011

Ernst Haeckel, who first introduced the term 'monophyly' into the biological literature, has in the past been appealed to in adjudication of the modern use of that concept. A contextual analysis of his writings reveals an inconsistent use of the term 'monophyly' by Haeckel. Morphological phylogeny was decoupled in Haeckel's thinking from the evolutionary history of taxa. Monophyly could mean the derivation of one taxon from another, ancestral one, where these taxa could be species or of supraspecific rank. Monophyly could also mean the phylogenetic differentiation of a diversity of organismal 'forms' (morphologies) from a common primitive 'form' (morphological stage). And finally, monophyly, as also polyphyly, could apply to the origin of specific anatomical structures, in which case the monophyly/polyphyly of anatomical structures needed not to correlate with the monophyly/polyphyly of the taxon characterized by these structures. With respect to the issue of the unity and reality of monophyletic taxa, Haeckel's writings again are indeterminate as is his stance on the monophyletic origin of life. © 2010 Blackwell Verlag GmbH. Source

Rieppel O.,The Field Museum
Cladistics | Year: 2013

The reconstruction of the evolutionary history of animal phyla was an integral part of Othenio Abel's paleobiology (paleozoology). Abel took issue with those phylogeneticists who, following the lead of Haeckel, would draw up phylogenetic trees on the basis of transformation series of singular characters considered to be of particular importance. Abel highlighted Louis Dollo's principle of the chevauchement des spécialisations (crossing of specializations), which transformed phylogenetics from a search for ancestor-descendant sequences to research into relative degrees of relationships. This replacement resolved the conflict, much discussed at the time, between the continuity of ancestor-descendant lineages and the discontinuity inherent in the natural (phylogenetic) system. Walter Zimmermann refined Abel's methodology, which he called character-phylogenetics (Merkmalsphylogenie), an approach that was eventually adopted by Willi Hennig. © The Willi Hennig Society 2012. Source

Rieppel O.,The Field Museum
Journal of the History of Biology | Year: 2012

The relatively late acceptance of Darwinism in German biology and paleontology is frequently attributed to a lingering of Lamarckism, a persisting influence of German idealistic Naturphilosophie and Goethean romanticism. These factors are largely held responsible for the vitalism underlying theories of saltational and orthogenetic evolutionary change that characterize the writings of many German paleontologists during the first half of the 20th century. A prominent exponent of that tradition was Karl Beurlen, who is credited with having been the first German paleontologist to present a full-fledged theory of saltational evolution and orthogenetic change. A review of Beurlen's writings reveals motives and concerns far more complex, however, and firmly rooted in contemporary völkisch thought and Aryan Science. Beurlen's mature theory of evolution can indeed be understood as his own contribution to Aryan Geology and Biology, tainted as it was with National-Socialist ideology. Evolutionary biologists of the time who opposed the theories of Beurlen and like-minded authors, i. e., idealistic morphology, typology, saltational change, orthogenesis and cyclism did so on Darwinian principles, which ultimately prevailed. But at the time when the battle was fought, their adherence to the principle of natural selection was likewise ideologically tainted, namely in terms of racial theory. National-Socialist ideology was unable to forge a unity of evolutionary theory in Germany even amongst those of its proponents who endorsed this ideology. © 2011 Springer 2011. Source

Rieppel O.,The Field Museum
Cladistics | Year: 2011

The German tradition of considering species, and higher taxonomic entities, as individuals begins with the temporalization of natural history, thus pre-dating Darwin's 'Origin' of 1859. In the tradition of German Naturphilosophie as developed by Friedrich Schelling, species came to be seen as parts of a complex whole that encompasses all (living) nature. Species were comprehended as dynamic entities that earn individuality by virtue of their irreversible passage through time. Species individuality was conceived in terms of species taxa forming a spatiotemporally located relational system (complex whole), a conception of species that was easily assimilated to an evolutionary world view. However, the dynamics of an evolutionary process driven by variation and natural selection created a tension between continuity in nature as opposed to the discreteness and relative stasis of species. As a consequence, some authors such as Ernst Haeckel and Karl August Möbius denied the reality of species, while others explicitly linked the reality and individuality of species to their temporal duration. The mature conception of species as individuals, as formulated by Ludwig von Bertalanffy and adopted by Willi Hennig, is one of an historically conditioned, spatiotemporally located, causally integrated, dynamic yet transiently homeostatically stabilized relational system. © The Willi Hennig Society 2011. Source

Discover hidden collaborations