Phylogenetic cladistics

Cladistics Method of classification employing genealogies alone in inferring phylogenetic relationships among organisms (see also Phylogeny). 

Jenner, R.A. (2004) Towards a phylogeny of the Metazoa evaluating alternative phylogenetic positions of Platyhelminthes, Nemertea, and Gnathostomulida, with a critical reappraisal of cladistic characters. Contributions to Zoology 73, 3. 

Phylogenetic tree construction is based on cladistics, the systematic classification of groups of organisms on the basis of shared characteristics thought to derive from a common ancestor. The basic assumptions of cladistics are ... 

Li J, Heath IB The phylogenetic relationships of the anaerobic chytridiomycetous gut fungi (Neocallimasticaceae) and the Chytridiomycota. II. Cladistic analysis of structural data and description of the Neocallimasticales ord. nov. Can J Bot 1993 71 393 07. 

For evolutionary studies, the classification of species also allows the construction of phytogenies, which may shed light on the relationship between observed pattern of speciation and the nature of evolutionary forces. A distinction should be made between phenetic and cladistic data. The phe-netic relationships are similarities based on the degree of similarity, whereas cladistic relationships contain information about ancestry and can be used to study evolutionary pathways. Both of these relationships are best portrayed as phylogenetic trees or dendrograms, respectively (57). 

The resulting relationships from cladistic analysis are most commonly represented by a phylogenetic tree ... 

Macromolecules, especially sequences, have surpassed morphological and other organismal characters as the most popular form of data for phylogenetic or cladistic analysis. It is this molecular phylogenetic analysis that we will introduce here. 

The evolutionary history inferred from phylogenetic analysis is usually depicted as branching (treelike) diagrams. The correct evolutionary tree is a rooted tree that graphically depicts the cladistic relationships that exist among the operational taxonomic units... 

Qadistics is a hierarchical classification technique which reveals evolution courses of organisms based on their shared characters. It was originally introduced and developed by Hennig (1966, republished in 1999). Cladistics generates phylogenetic trees (Fig. 1), which are acyclic tree graphs that show the relationships between the studied entities and are called cladograms. ... 

The central tenets of the falsificationist philosophy of Karl R. Popper are reviewed in detail, and the way they do or do not apply to systematics and phylogeny reconstruction is analyzed. Cladistic analysis, cast in either maximum parsimony or in maximum likelihood approaches, is not compatible with Popperian falsificationism. The main reasons are the absence of a deductive link between a hypothesis of phylogenetic relationships and character distribution on a tree, which translates into the absence of the basic asymmetry of falsification versus verification. This sets Popper s philosophy of science apart from inductive systems. In cladistic analysis, falsification (disconfirmation) is symmetrical to verification (confirmation), which reveals an inductive and hence probabilistic background. The basic problem of systematics as an empirical science resides in character conceptualization and its critical evaluation. 

Phylogenetic Cladlstlcs The Synthesis between Hennig s Method and Numerical Cladistics... 

It is very important to note that the methods implemented in computer programs replace only one of several steps of a phylogenetic analysis. The cladistic step is a purely deductive procedure that leads from a data matrix to one or more selected dendrograms. Phylogenetic cladistics, however, requires several other steps that are equally important and frequently... 

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