Classification

• Key Point

  The scientific name for lion is Panthera leo and for tiger it is Panthera tigris. This shows that they are in the same genus but different species. The cheetah is called Acinonyx jubatus - it is in a different genus and species.
• How have living things traditionally been classified?

  Based on their structure and characteristics
• Who developed one of the main systems of classification?

  Carl Linnaeus
• What are the hierarchical levels of classification according to Linnaeus?

  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• What is the binomial system of naming organisms?

  Two parts to their Latin name
• What does the first part of a binomial name represent?

  The genus of the organism
• How is the genus name formatted in the binomial system?

  Starts with a capital letter and is italicized
• What does the second part of a binomial name represent?

  The species of the organism
• How is the species name formatted in the binomial system?

  Starts with a lowercase letter and is italicized
• Why were new models of classification proposed?

  • Improved microscopes revealed more about cells
  • Better understanding of biochemical processes
• Who developed the three-domain system of classification?

  Carl Woese
• What are the three domains in Woese's classification system?

  • Archaea (primitive bacteria)
  • Bacteria (true bacteria)
  • Eukaryota (including protists, fungi, plants, animals)
• Extinction

  . Throughout the history of life on Earth, different organisms have been formed by evolution and some organisms have become extinct

  . Extinction may be caused by:

  - changes to the environment over geological (long periods of) time

  - new predators

  - new diseases

  - new, more successful competitors

  - a single catastrophic event, e.g. massive volcanic eruptions or collisions with asteroids

  . For example, the great auk is now extinct due to over-hunting
• Key Point

  You need to be able to interpret the information in different evolutionary trees
• Evolutionary Trees

  . Evolutionary trees are a method used by scientists to show how they think organisms are related

  . They use current classification data, including genetic data, for living organisms and fossil data for extinct organisms