Deconstructing morphology: reply to Scholtz (2010)

Szucsich, N.U., Wirkner C.S. and Pass G. 2011. Deconstructing morphology: reply to Scholtz (2010). Acta Zoologica (Stockholm) 00: 13 Abstract Whenever concepts are taken over into new fields scientists have to take care that these concepts do not become unsubstantial due to ambiguities regarding their applicability. Here we argue why it makes sense to define the homology-concept in a way, so it is applicable for phylogenetic purposes. If used to define the relation among structures of organisms assigned to the same character state of a phylogenetic character, homology has to represent an equivalence relation, with the properties of transitivity and symmetry. This is exactly the reason why correspondence, not similarity should be used to define homology, since the latter is not transitive. Homology then also cannot be used to define the relation among character states of the same phylogenetic character, since this relation necessarily is asymmetric.