Bacterial Origins


One line of descent from the Last Universal Ancestor generated a group of organisms now called Bacteria and another called the Archaea. Both groups are quite diverse and each is quite different; they are collectively called prokaryotes. Before they arose the original first organism had to be able to reproduce and differentiate. This cell must have been able to execute selected chemical reactions to do this. These must have included: (1) a system to energise biosynthesis in order to drive chemical reactions in the biologically useful direction (which could often be in the nonspontaneous direction); (2) a system to duplicate nucleic acids chains by semiconservative replication and (3) an ability for these chains to serve as catalysts for specific biosynthesis. Therefore at least three facilities had to function inside the closed vesicle that then became the First Cell.

Key Concepts:

  • Few elements were needed for life to start.

  • More features are common to all life today.

  • Woese's deductions from ribosome studies of the ontogeny of life led to a breakthrough allowing a more stable taxonomy and phylogeny.

  • Bacteria are phylogenetically separated from Archaea/Eukarya.

  • In many cases the phenotypic properties of different organisms correlate with the phylogeny.

  • Lateral Transfer of Genes was important, but complicates studies of early life.

Keywords: the first cell; bacteria; eubacteria; archaea; archaebacteria; prokaryotes; eukaryotes

Figure 1.

Phylogenetic tree of Bacteria. The diagram shows a number of bacterial species and how they have originated from the ‘root’. The root is also called the Last Universal Ancestor and the progenote. The key point is that the other two domains, Eukarya and Archaea, split off in different directions from the root.


Further Reading

Brown JR and Doolittle WF (1997) Archaea and the prokaryote‐to‐eukaryote transition. Microbiology and Molecular Biology Reviews 61: 456–502.

De Bruijn FJ, Lupski JR and Weinstock GM (1998) Bacterial Genomes – Physical Structure and Analysis. New York: Chapman & Hall.

Hugenholtz P, Pitulle C, Hershberger KL and Pace NR (1998) Novel division level bacterial diversity in a Yellowstone hot spring. Journal of Bacteriology 180: 366–376.

Koch AL (1985) Primeval cells: possible energy‐generating and cell‐division mechanisms. Journal of Molecular Evolution 21: 270–277.

Koch AL (1993) Microbial genetic responses to extreme challenges. Journal of Theoretical Biology 160: 1–21.

Koch AL (1994) Development and diversification of the Last Universal Ancestor. Journal of Theoretical Biology 168: 269–280.

Koch AL (1998) How did Bacteria come to be? Advances in Microbial Physiology 40: 354–399.

Koch AL (2007) The Bacteria: Their Origin, Structure, Function, and Antibiosis. Dordrecht, The Netherlands: Springer Academic Publishers.

Madigan MT and Martinko JM (2006) Brock, Biology of Microorganisms, 10th edn. New York: Prentice‐Hall. (see particularly Chapters 12 and 13).

Olsen GJ and Woese CR (1996) Lessons from an archaeal genome: what are we learning from Methanococcus jannaschii. Trends in Genetics 12: 377–379.

Olsen GJ, Woese CR and Overbeek R (1994) The winds of (evolutionary) change: breathing new life into microbiology. Journal of Microbiology 176: 1–6.

Pace NR (1997) A molecular view of microbial diversity and the biosphere. Science 276: 734–740.

Woese C (1998) The universal ancestor. Proceedings of the National Academy of Sciences of the USA 95: 6854–6859.

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How to Cite close
Koch, Arthur L(May 2011) Bacterial Origins. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0000445.pub3]