| Popis: |
This chapter assesses character polarity and homology. Prior to the advent of computer-based analyses, German entomologist and systematic theorist Willi Hennig and other cladistic pioneers routinely used prepolarized characters to construct their phylogenetic hypotheses and developed a specialized terminology to describe their practices. In Hennig's view, all the states of a character — be they plesiomorphic, apomorphic, or homoplastic — are homologous. He argued that synapomorphies — shared derived characters — provide the only evidence for the existence of natural groups. This is the fundamental aspect of his arguments for the phylogenetic system; all of Hennig's other principles are subsidiary to it. Thus, in the Hennigian view, synapomorphy is the only “kind” of homology that bears upon patterns of relationship, a distinction that has led many cladists to equate the two terms. |
