classification

• Why do we need to classify species on Earth?

  To organize millions of different species
• How did our ancestors classify species?

  Based on their physical appearance
• What is a limitation of using simple names for species?

  They don't indicate species' relationships
• What classification system did Carl Linnaeus propose?


  The Linnaean system
• What are the main categories in the Linnaean classification system?

  Kingdom, phylum, class, order, family, genus, species
• Why are the names in the Linnaean system mostly in Latin?

  To make it usable by all countries
• How should species names be formatted in writing?

  Italicized with genus capitalized
• What is the binomial naming system proposed by Linnaeus?

  It uses genus and species names
• What did Carl Woese propose in the 1990s?

  The three domain system
• What are the three domains introduced by Woese?

  Eukaryota, bacteria, archaea
• What does the domain Eukaryota include?

  Organisms with eukaryotic cells
• What type of organisms does the domain Bacteria contain?

  Single-celled prokaryotic organisms
• What distinguishes Archaea from Bacteria?

  Archaea thrive in extreme conditions
• What are evolutionary trees used for?

  To show evolutionary relationships
• How do evolutionary trees illustrate common ancestors?

  By linking species through branches
• What does a split in an evolutionary tree represent?

  A common ancestor splitting into species
• What methods do scientists use to learn about species relationships?

  Comparing structure and DNA
• What is the order of classification groups in the Linnaean system?

  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• How do the Linnaean system and three domain system interact?

  • Linnaean system groups species
  • Three domain system adds higher categories
  • Both systems help classify organisms