On the nature of global classification.
Molecular sequencing technology has brought biology into the era of global (universal) classification.  Methodologically and philosophically, global classification differs significantly from traditional, local classification.  The need for uniformity requires that higher level taxa be defined on the molecular level in terms of universally homologous functions.  A global classification should reflect both principal dimensions of the evolutionary process:  genealogical relationship and quality and extent of divergence within a group.  The ultimate purpose of a global classification is not simply information storage and retrieval; such a system should also function as an heuristic representation of the evolutionary paradigm that exerts a directing influence on the course of biology.  The global system envisioned allows paraphyletic taxa.  To retain maximal phylogenetic information in these cases, minor notational amendments in existing taxonomic conventions should be adopted.
Wheelis
M L
ML
Department of Microbiology, University of California, Davis 95616.
Kandler
O
O
Woese
C R
CR
D005075:Biological Evolution; D002965:Classification; D018534:Earth, Planet; D005057:Eukaryotic Cells; D005827:Genetics, Microbial; D010802:Phylogeny; D012335:RNA, Ribosomal
D012335:RNA, Ribosomal