Classification & Taxonomy

• Classification is grouping of living organisms according to shared features
• Why do we classify species?

  • Convenience
  • Makes it easier to identify organisms
  • Helps us see relationships between species
  • Makes study organisms for manageable
• A species is a group of organisms that share:

  • Behaviour
  • Genetics
  • Morphology (appearance)
  • Reproductively isolated from other groups
  • And are capable of successfully interbreeding to produce fertile offspring
• Taxonomy - Studying the differences between species and the variation both within, and between species
• Phylogeny - Study of evolutionary relationships between organisms (how closely related they are)
• The binomial system is a classification system used as a method of identifying organisms using two names e.g homo sapiens
• Benefits of the binomial system:

  • Common names may differ from country to country
  • Translation between different languages may lead to confusion
• Rules for naming organisms:

  • The generic (genus) name is the first word and always has a capital letter e.g. Homo sapiens
  • The specific (species) name comes second - starts with a lower-case
  • Both names should be written in italics if printed/typed or underlined if handwritten
  • All species have a unique, specific name
• Current Classification System:

  • 8 taxonomic groups
  • More groups at each level of the hierarchy as you move down
• The taxonomic groups:

  Domain

  Kingdom

  Phylum

  Class

  Order

  Family

  Genus

  Species
• Five Kingdoms

  Heterotrophic - Have to consume other organisms to get their nutrition (Fungi, animals, some prokaryotes, some protoctists)

  Autotrophic - Make their own organic molecules for nutrition (Plants-photosynthesis, some prokaryotes, some protoctists)