MEMBRANE SYSTEM PATTERN AS APPLIED TO CYTOLOGICAL CONCEPTUALISM - IS THE PROKARYOTE EUKARYOTE DICHOTOMY TO BE REJECTED

The evolutionary tree reconstructed from the molecular palaeontology d ata conflicts with global phenetic dichotomy: the orthodox interpretat ion of rRNAs sequences similarity (Stackebrandt and Woese, 1981) argue s for an early divergence of Bacteria, Archaea (both prokaryotic), and Eucarya domains, even though a preferable relatedness issues from cor rected estimations of the initial branching order (Wheelis et al., 199 2). Besides, to formulate the prokaryote/eukaryote distinction, a cata logue of structure-functional characteristics of anucleate/nucleate ce lls is needed that substitutes for a conceptual definition (Cavalier-S mith, 1981). To overcome these restrictions, a novel subdivision of ce ll morphotypes into the archaeal unimembrane, eucaryal bimembrane, and bacterial trimembrane ones is put forward. This substitute for the pr okaryote/eukaryote concept generally agrees with the currently estimat ed phylogeny and accentuates a role of the membrane system pattern in natural classification.