classification

• Linnaeus further divided each kingdom into smaller categories: Kingdom, Phylum, Class, Order, Family, Genus, Species
• Classification system is based on physical characteristics like body shape or number of toes
• Advances in biology allow analysis of internal structures and biochemistry like DNA for similarity
• Classification of organisms

  Based on their characteristics
• Use of evolutionary tree

  To describe relationships between organisms
• There are millions of different species on planet Earth with common characteristics
• Scientist Carl Linnaeus classified species based on structure and characteristics
• Linnaeus divided all living organisms into two kingdoms: Animal Kingdom and Plant Kingdom
• Organisms are named using the binomial system: Genus and Species
• Three domain system by scientist Carl Woese: Archaea, True bacteria, Eukaryota
• Three domain classification system

  Key: Archaea(primitive bacteria), True bacteria, Eukaryota
• Archaea are often found in extreme conditions like hot springs
• True bacteria include those living in the human digestive system
• Eukaryota include animals, plants, fungi, and protists like amoeba
• Evolutionary trees show the relations of organisms using classification data like DNA
• For extinct organisms, scientists use fossils to create evolutionary trees