Classification

Overview of Classification

  • Classification is the process of organising diverse forms of life into categories based on their evolutionary relationships and similarities.
  • It uses a hierarchical system, starting from broad categories and narrowing down to specific ones.
  • This hierarchical system is known as Linnaean taxonomy, named after Carl Linnaeus.

The Hierarchy of Classifications

  • The main hierarchical levels are: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.
  • Note the acronym to remember this hierarchy: Do Keep Ponds Clean Or Frogs Get Sick.

Binomial Naming System

  • Species are given a two-part scientific name in Latin, in the binomial naming system.
  • The first name is the genus, which is capitalised, and the second is the species, which is in lowercase and italicised.

The Five Kingdom Classification

  • This includes Prokarya (bacteria), Protoctista (algae and protozoans), Fungi (fungus), Plantae (plants), and Animalia (animals).

The Three Domains

  • Life forms can also be divided into three domains: Bacteria, Archaea, and Eukarya.
  • Both Bacteria and Archaea are composed of prokaryotes, while Eukarya contains all eukaryotes including plants, animals, fungi and protists.

Phylogenetic Classification

  • In the phylogenetic system, organisms are classified according to their evolutionary relationships.
  • This classification is based upon the concept of common descent - implying all species, living and extinct, have descended from a common ancestor.

Importance of Classification

  • Classification provides a framework for the study of the relationships between organisms.
  • It also helps in identifying organisms and in highlighting the basic features, similarities, and differences between organisms.
  • Moreover, classification assists in the prediction of characteristics of new species or subspecies.

Tackling Misclassification

  • Misclassifications can occur due to convergent evolution or limitations in our ability to classify organisms.
  • Molecular phylogenetics, which involves the analysis of DNA, RNA, or protein sequences, can be used to correct these misclassifications.