The Five Kingdoms

• The first division of living things in the classification system is to put them into one of five kingdoms. They are:

  • Animals

  • Plants

  • Fungi

  • Protoctists

  • Prokaryotes

  
  

• Main features of all animals:

  • they are multicellular

  • their cells contain a nucleus but no cell walls or chloroplasts

  • they feed on organic substances made by other living things

  
  

A typical animal cell

• Main features of all plants:

  • they are multicellular

  • their cells contain a nucleus, chloroplasts and cellulose cell walls

  • they all feed by photosynthesis

A typical plant cell

The Animal Kingdom

• Several main features are used to place organisms into groups within the animal kingdom

Vertebrates

• All vertebrates have a backbone

  • There are 5 classes of vertebrates

  
  

Vertebrate Table

Vertebrate classification

Invertebrates

• Invertebrates do not possess a backbone

• One of the morphological characteristics used to classify invertebrates is whether they have legs or not

• All invertebrates with jointed legs are part of the phylum Arthropods

• They are classified further into the following classes:

Arthropod classes table

Arthropod classification

Exam Tip

Make sure that you are aware of the distinction between the main features of a group of organisms and the defining features of a group:

• An exam question might ask you to state the main features of a group of organisms; these are given above, and some of these main features are shared between the groups, e.g. all of the vertebrates have a backbone, and all of the arthropods have segmented bodies

• It is also possible that an exam question might ask you to give a defining feature of one of these groups, i.e. a feature that sets a group apart from the other groups, e.g. mammals have fur while the other vertebrates do not, and crustaceans have 2 pairs of antennae while this is not the case for the other groups of arthropods