Classification

• Three domain classification system

  • Archaea (primitive bacteria found in extreme conditions)
  • Bacteria (true bacteria like those in the human digestive system)
  • Eukaryota (animals, plants, fungi, protists like amoeba)
• Using evolutionary trees to show relationships between organisms

  1. Classify living organisms based on data like DNA

  2. Use fossils to classify extinct organisms (but fossil records are often incomplete)
• Linnaeus divided all living organisms into two kingdoms: animal and plant
• Linnaeus' classification categories

  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• Linnaeus' classification system is based on the structure and characteristics of organisms that can be observed
• The binomial system names organisms using their genus and species
• Advances in biology like microscopes and biochemistry analysis have expanded classification beyond Linnaeus' system
• Evolutionary trees show how closely related organisms are to each other