Primary kingdoms

Archaebacteria the third most recently recognized primary kingdom and are characterized as living in extreme environments, such as anaerobic methanogens and halophilic bacteria. 

Wallin IE (1927) Symbionticism and the origin of species. Williams and Wilkins, Baltimore Watasd S (1893) On the nature of cell organization. Woods Hole Biol Lect 83-103 Wilson EB (1896) The cell in development and inheritance. Macmillan, New York Wilson EB (1925) The cell in development and heredity, 3rd edn. Macmillan, New York Woese CR (1977) Endosymbionts and mitochondrial origins. J Mol Evol 10 93-96 Woese CR (1998) The universal ancestor. Proc Natl Acad Sci 95 6854-6859 Woese CR, Fox GE (1977) Phylogenetic structure ofthe prokaryotic domain the primary kingdoms. Proc Natl Acad Sci USA 74 5088-5090... 

The experimental data that prove the existence of the three primary kingdoms do not tell us much about the last common ancestor, but we can still say that such a progenitor must have existed, because all cells of the three kingdoms have the same genetic code, the same metabolic currency based on ATP, and roughly 50% of bacterial genes have homologues in eukaryotes. 

Woese, C.R. and Fox, G.E. 1977a. Phylogenetic structure of the prokaryotic domain the primary kingdoms. Proceedings of the National Academy of Sciences USA, 74,5088-5090. 

The three primary kingdoms of cells are Eukaryotes, Bacteria, and Archae. 

The rumen offers an abundant and complex microbial population. It is composed of representatives of all the primary kingdoms (archaebacteria, eubacteria, and eukaryotes), including anaerobic fungi and protozoa in addition to the better described bacteria. 

Figure l. The universal unrooted phylogenetic tree showing three distinct primary kingdoms Eubacteria, Archaebacteria and Eukaryotes (from Woese 1987a). 

Woese, C. R. and G. E. Fox. 1977. Phylogenetic structure of the procaryotic domain The primary kingdoms. Proc. 

Woese, C.R. and Fox, G.E. 1977. Phylogenetic structure of the prokaryotic domain the primary kingdoms. Proceedngs of the National Acaderr of Sciences USA 74, 5088-5090. Woese, C.R., Kindler, O. and Wheelis, M.l. 1990. Towards a natural system of oiganisms proposal for the domains Archaea, Bacteria, and Eucaiya. Proceedings of the National Academy of Sciences USA 87,4576-4579. 

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