Animals kingdom of the world is divided into two sub-kingdoms :
1. Unicellular animal
2. Multi-cellular animal or Metazoans
Unicellular animals are kept in a single phylum Protozoa whereas multi- cellular animals are divided into 9 phylums.
» They are Unicellular.
» It's body is made of only one cell.
» There is one or more nuclei in its cytoplasm.
» It is parasitic and free living.
» All the metabolic activity (eating, digestion, respiration, excretion, reproduction) takes place in unicellular body.
» Respiration and excretion take place by diffusion.
Example - Amoeba, Euglena, Trypanosoma etc.
All animal of this group are found in marine water & bear pores in body.
» These are multi cellular animals but cells do not make regular tissues.
» Numerous pores known as ostia found on body wall.
» Skeleton is made up of minute calcareous or silicon spicules.
Example -Sycon, Sponge etc.
» Coelenteron is present inside body.
» Animals are aquatic and diploblastic.
» Around the mouth some thread-like structure are found known as tentacles, which help in holding the food.
» Body radial symmetry.
» Specialized cnidoblast cell are found help in catching the food.
Example - e-Hydra, Jellyfish, Sea Anemone etc.
» Its a Flat worm
» Triploblastic and nobody cavity.
» Dorso-ventraly flattened animal.
» Alimentary canal with single opening, anus absent.
» Excretion takes place by flame cells.
» There is no skeleton, respiratory organ, circulatory system etc.
» These are hermaphrodite animal.
Example - Planaria, Liver fluke, Tape worm etc.