B6

• 3 domain system

  Due to evidence available from chemical analysis, there is now a ‘three-domain system’ of classification

  • This was developed by Carl Woese in 1990
  • In this system, organisms are divided into three large groups called domains
• • These domains are:
  • Archaea (primitive bacteria usually living in extreme environments such as hot springs and salt lakes)
  • Bacteria (true bacteria such as coli and Staphylococcus)
  • Eukaryota (which includes protists, fungi, plants and animals)
  • These domains are then subdivided into the smaller groups: kingdom, phylum, class, order, family, genus, species
• The three domains were identified using DNA sequencing techniques which allowed scientists to compare sequences of genes between different organisms.