5.3.2 classification 2

• Evolutionary trees

  • used to show how scientists believe organisms are related
• Evolutionary trees

  • the start of the tree is a common ancestor
  • the branches show the species that have evolved from the common ancestor
• DNA sequencing

  • tells scientists how closely related different species are by sequencing their DNA
  • because DNA sequences change at a rate that is approximately constant over time and across different living organisms
  • working out how species are related in this way is called "molecular phylogenetics"
• Classification

  • current classification data is used for living organisms
  • fossil data is used for extinct organisms