XX.3.5 The category of ethological species logically includes the biotope recognition concept, defining species on the basis of shared traits allowing the individuals to recognize their usual biotope
Within some taxons, the species differ primarily in the type of biotope that they chose for the lives of their members in the typical case.For example, it is known that individual species of birds divide up the landscape that they inhabit in great detail.For example, some species are strictly bound to the lower level of forest stands, while others are linked to the middle level and others, for example, to isolated bushes outside of continuous forest stands.Simultaneously, it is not very probable that such a detailed division of the biotope would be a consequence of disruptive selection, possibly supplemented by evolutionary character displacement (see XXI.4.4).For example, bird species bound to the lower level of a forest stand could probably inhabit isolated bushes just as well, but are not encountered there under normal circumstances, even when potential competitors bound to this type of biotype are missing.
Some authors are of the opinion that this speciation of individual species and thus their primary mutual limitations are a result of differences in the characteristics according to which the members of the individual species recognize their normal biotope (Storch & Frynta 1999).These characteristics were chosen more or less at random in the evolution of the particular evolutionary line and basically only very loosely reflect the suitability of the particular biotope for the life of the given species.As indicated by the relevant models, the evolution of characteristics employed by the individual species for choice of a suitable biotope is a cumulative process and is, to a substantial degree, a one-way process – characteristics gradually accumulate during the evolution of a particular developmental line rather than some of them being ignored by younger species.This necessarily leads to a situation where the species gradually divide up the available biotopes in great detail.Thus, specialization of the individual species is not primarily related to the diversification of their phenotypes as a consequence of diversification of natural selection, but rather to more or less autonomous diversification of their cognitive apparatus and the relevant concept of a species can be denoted as the biotope recognition concept.