Biology Notes: Taxonomy and Classification

Carolus Linnaeus

• Introduced the concept of Binomial Nomenclature.
  • A system for assigning two names to every organism.
    • First word: Genus (more general).
    • Second word: species (more specific).
• Initial classification system based on physical features.
  • Problem: This approach resulted in numerous inaccuracies.
  • Solution: DNA analysis is now used to accurately determine the relatedness of organisms.

Domains & Kingdoms

• Three Domains:
  • Bacteria.
  • Archaea.
  • Eukarya.

Domain: Bacteria

• Prokaryotic.
• Peptidoglycan present in the cell wall.

Domain: Archaea

• Prokaryotic.
• No peptidoglycan in the cell wall.
• Ability to survive in extreme environments.

Domain: Eukarya

• Eukaryotic.
• Cells contain a nucleus and membrane-bound organelles.

Examples of Classification

• Rabbit:
  • Domain: Eukarya
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Lagomorpha
  • Family: Leporidae
  • Genus: Oryctolagus
  • Species: cuniculus
• Lion:
  • Domain: Eukarya
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Carnivora
  • Family: Felidae
  • Genus: Panthera
  • Species: leo
• Leopard:
  • Domain: Eukarya
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Mammalia
  • Order: Carnivora
  • Family: Felidae
  • Genus: Panthera
  • Species: pardus

Domains & Kingdoms (cont.)

• Three Domains:
  • Bacteria
  • Archaea
  • Eukarya
• Six Kingdoms:
  • Eubacteria (Domain: Bacteria)
  • Archaea/Archaebacteria (Domain: Archaea)
  • Protista (Domain: Eukarya)
  • Fungi (Domain: Eukarya)
  • Plantae (Domain: Eukarya)
  • Animalia (Domain: Eukarya)

Taxonomy

• Taxonomy: The science of classifying life based on shared characteristics.

• Taxon: Individual levels used to classify organisms.

• Taxonomic Levels (Broadest to Most Specific):

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