Taxonomy

• Species


  A group of organisms that are able to breed to produce fertile living offspring
• Classification


  • Organises organisms into groups based on similarities
• Purposes of classification

  • Identify new species
  • Study evolutionary relationships
  • Understand shared traits and adaptations
  • Share research globally to identify links with organisms on other continents
• Hierarchical taxonomic system

  A system from general to specific that makes research and identification more manageable across the millions of global species
• Major taxonomic ranks

  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• Binomial nomenclature

  A naming system that gives each species a two-part 'binomial' Latin name
• Genus


  The first part of the binomial name, with an uppercase first letter
• Species


  The second part of the binomial name, all lowercase
• Binomial names

  • Homo sapiens
  • Canis familiaris
• Five kingdom system

  • Plantae (plants)
  • Animalia (animals)
  • Prokaryotae (prokaryotes)
  • Protoctista (unicellular eukaryotes)
  • Fungi (such as yeasts)
• Older classification systems become outdated when new molecular and genetic data arise, so taxonomy is periodically updated
• Three domain system

  • Domain Bacteria (contains Eubacteria)
  • Domain Archaea (contains Archaebacteria)
  • Domain Eukarya (contains Animalia, Plantae, Fungi, Protoctista)
• Domain Bacteria

  • Prokaryotic unicellular organisms
  • Distinct cell membrane lipids
  • Have peptidogylcan (murein) in their cell walls
  • Unique RNA polymerase enzyme
• Domain Archaea

  • Prokaryotic unicellular organisms
  • Have histones so gene and protein synthesis is more similar to Eukarya than Bacteria
  • No peptidogylcan in their cell walls
  • Different cell membranes that contain fatty acids bound to glycerol by ether linkages
  • Have a more complex form of RNA polymerase than Bacteria
• Domain Eukarya

  • All have nuclei and membrane-bound organelles