Classification

General Information

“Nothing remains as it is.” This sentence is true in particular with respect to the recent situation of taxonomy, which – since its beginnings – has tried to reflect relationships between taxa. The earlier classifications were based on morphological and developmental similarities; and individuals resembling each other were grouped together as a species, similar species as genera, and so on. So much information accumulated that finally two different kingdoms – plants and animals – arose among the eukaryotic organisms, the origin of which, however, remained under constant discussion. Nowadays, the use of molecular biological methods delivers new and deeper insights into the genetic repertoire of organisms and thus other interpretations are called for. When considering the ideas actually discussed (Fig. 1, p. 255), that all recent organisms are a mixture of different hereditary lines, including the genomes of former autotrophic prokaryotes, heterotrophic prokaryotes,...