5.3  Classification of Biodiversity

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Essential Idea:

Species are named and classified

using an internationally agreed system


  • The binomial system of names for species is universal among biologists and has been agreed and developed at a series of congresses
  • When species are discovered they are given scientific names using the binomial system
  • All organisms are classified into three domains
  • Taxonomists classify species using a hierarchy of taxa
  • The principal taxa for classifying eukaryotes are kingdom, phylum, class, order, family, genus and species
  • In a natural classification, the genus and accompanying higher taxa consists of all the species that have evolved from one common ancestral species
  • Taxonomists sometimes reclassify groups of species when new evidence shows that a previous taxon contains species that have evolved from different ancestral species
  • Natural classifications help in identification of species and allow the prediction of characteristics shared by species within a group


  • Classification of one plant and one animal species from domain to species level
  • Recognition features of bryophyta, filicinophyta, coniferophyta and angiospermophyta
  • Recognition features of porifera, cnidaria, platyhelmintha, annelida, mollusca, arthropoda and chordata
  • Recognition features of birds, mammals, amphibians, reptiles and fish


  • Construction of dichotomous keys for use in identifying specimens