taxonomy

• classification allows scientists to:

  • identify new species
  • study evolution relationships
  • understand shared traits and adaptations
  • share research globally to identify links with organisms on other continents
• A species is a group of organisms that are able to breed to produce fertile living offspring. Classification organises organisms into groups based on similarities.
• 1. Domain
  2. Kingdom
  3. Phylum
  4. Class
  5. Order
  6. Family
  7. Genus
  8. Species
• The binomial naming system gives each species a two-part ‘binomial’ Latin name. This binomial name is italicised when typed and underlined when written down.
• The name consists of:

  1. The genus - This has an uppercase first letter.
  2. The species - This is all lowercase.
• the 5 Kingdom system:

  1. Plantae (plants)
  2. Animalia (animals)
  3. Prokaryotae (prokaryotes)
  4. Protoctista (unicellular eukaryotes)
  5. Fungi (such as yeasts)
• taxonomy is periodically updated and reorganised to reflect progressing scientific knowledge, as reflected by the new three domain system.
• The three domain system proposes six kingdoms instead of five, because there is evidence for splitting the kingdom Prokaryotae into two separate kingdoms: Eubacteria and Archaebacteria. It recognises differences between Bacteria, Archaea, and Eukarya (all eukaryotic organisms). 
• Domain Bacteria

  • Contains the kingdom Eubacteria only, found in all environments.
  • Prokaryotic unicellular organisms.
  • Distinct cell membrane lipids.
  • Have peptidogylcan (murein) in their cell walls.
  • Unique RNA polymerase enzyme.
• Domain Archaea

  • Contains the kingdom Archaebacteria only, typically found in extreme environments.
  • Prokaryotic unicellular organisms.
  • Have histones so gene and protein synthesis is more similar to Eukarya than Bacteria.
  • No murein 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

  • Contains four kingdoms from the five kingdom system: Animalia, Plantae, Fungi, Protoctista.
  • All have nuclei and membrane-bound organelles.
• what is the sequence of taxa in the biological heirachy from largest to smallest?

  Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• what are the 3 recognised domains of life?

  Bacteria, Archaea, Eukarya
• what is the generally accepted definition of species?

  a group of organisms that are able to breed to produce fertile living offspring.