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Bacterial Origins

  1. Arthur L Koch

Published Online: 16 MAY 2011

DOI: 10.1002/9780470015902.a0000445.pub3



How to Cite

Koch, A. L. 2011. Bacterial Origins. eLS. .

Author Information

  1. Indiana University, Bloomington, Indiana, USA

Publication History

  1. Published Online: 16 MAY 2011


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.


  • the first cell;
  • bacteria;
  • eubacteria;
  • archaea;
  • archaebacteria;
  • prokaryotes;
  • eukaryotes