classification

• Classification


  The organisation of organisms into groups
• Taxonomy


  The classification of organisms into taxa: kingdom, phylum, class, order, family, genus, species
• Five kingdoms


  • Animals
  • Plants
  • Fungi
  • Protists
  • Prokaryotes
• As you move down the hierarchy of taxa

  The number of organisms in each taxon group decreases
• Traditionally, organisms were grouped based on similarities and differences in their anatomy and behaviour
• Organisms that are not closely related may look alike and behave similarly if they live in the same environment e.g. sharks and dolphins
• Some closely related species may look very different if they live in different habitats e.g. queen ants, worker ants
• Advancements in science that have led to reconsidering the five kingdoms classification system

  • Microscopes
  • Biochemistry
  • DNA and RNA analysis
• Three domains system of classification

  Organisms are initially divided into three groups: Archaea, Bacteria, Eukarya. Then kingdom, phylum, class, order, family, genus, species.
• Eukaryotic organisms belong to the domain Eukarya
• Prokaryotic organisms belong to the domains Archaea and Bacteria
• Domain Bacteria


  Consists of true bacteria e.g. E.coli
• Domain Archaea


  Consists of primitive microorganisms, contains extremophiles - adapted to live in extreme conditions e.g. hot springs