Classification

• Three domain classification system


  • Archae (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 kingdom and plant kingdom
• Linnaeus' classification system is based on the structure and characteristics of organisms that can be observed
• 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
• Species 1 and 2 are closely related, while species 3 is more distantly related, but they all share a common ancestor