classification

• Binomial system


  First part of name is the Genus, second part is Species

  • same genus suggests closely related
• Classification systems


  • Smaller groups arranged within larger groups (Within genus there are lots of different species)
  • No overlap between groups (species in genus completely different & cannot produce fertile offspring)
  • Used to understand relationship between organisms
  • Keep track of changes
  • System is universal
• Domains


  • Broadest way to classify organisms:
  • Archaea
  • Eukaryotes
  • Prokaryotes
• Classification system


  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

  Each group is called a taxon (taxa is plural)
• Classification methods


  • DNA sequence
  • RNA sequence
  • Amino acid sequence
  • Immunological - comparing similarity in self-antibody shape
• Phylogenetic classification


  • Arranges species into groups based on evolutionary origins & relationships (which species share common ancestors)
  • Phylogeny tells us who's related to whom and how closely
  • All organisms evolved from shared common ancestors
• Different species may look similar due to

  • living in similar environment
  • similar selection pressures
  • similar advantageous allele
  • produced similar/same protein so similar characteristics