Animal Kingdom
Kingdom animalia is divided on the basis of many features
Level of Organisation
Cellular level: Porifera
Tissue level: Cnideria, Ctenophora
Organ level: Platyhelminthes
Organ system level: Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata,
Hemichordata, Chordata
Incomplete digestive system: Platyhelminthes
Symmetry
Asymmetrical: Porifera
Radial: Cnidaria (Coelenterata), Ctenophora
Bilateral: All others
Cell Organisation
Diploblastic: Porifera, Cnidaria, Ctenophora
Triploblastic: All others
Nature of Coelom
Acoelomate: Platyhelminthes
Coelomate: All others (except Aschelminthes)
Pseudocoelomate: Aschelminthes
Phylums:
Porifera, Coelenterata, Cnideria, Platyhelminthes, Aschelminthes, Annelida, Arthropoda,
Mollusca, Echinodermata, Hemichordata, Chordata
Porifera
• Animals are never unicellular, so isn't Porifera. Also known as Sponges
• Primitive, marine, attached to the floor, multicellular and have a cellular level of
organisation
• A skeleton formed by Spicules or Spongin fibres
• Specialised water canal system called Ostia through which water enters into a common
cavity called Spongocoel, comes out through Osculum
• The Spongocoel and Osculum are lined by special cells called Choanocytes or Collar cells
helping in ingestion of food particles followed by intracellular digestion
• They are Hermaphrodites. May form fragments in case of asexual reproduction or
gametes. Fertilisation is internal with indirect development.
Eg: Sycon, Spongilla, Euplectella
Coelenterata
• Members are mostly aquatic, marine, sessile or free swimming (motile)
, • Some coelenterates like corals may have a skeleton of calcium carbonate
• Some of them have Cnidoblasts or tentacles on their body and are thus called Cnidaria.
Cnidoblasts help in anchorage, defense and to catch prey.
• Single Gastro Vascular opening called Hypostome
• Digestion is both intracellular and extracellular
• Show two forms throughout life, polyp and medusa. Polyp being sessile, eg: Hydra and
Adamsia. Medusa being umbrella shaped and free swimming, eg: Aurelia.
• Aurelia shows both Polyp and Medusa form
• Physalia, Pennatula, Gorgonia, Meandrina
Ctenophora
• Commonly called sea walnuts or comb jellies
• Marine and free living
• 8 ciliated comb plates helping in locomotion
• Digestion is extracellular and intracellular
• Bioluminescence is a characteristic feature
• They are hermaphrodites with external fertilization and indirect development
• Pleurobrachia and Ctenoplana
Platyhelminthes
• Dorsoventrally flattened body and thus called Flat worms and are aquatic
• Incomplete digestive system
• They have specialised cells called flame cells used for osmoregulation and excretion.
• The members are hermaphrodite, fertilisation is internal and development occurs via larval
stages, ie indirect
• Some members like Planaria have high regeneration capacity
• Taenia and Fasciola
Aschelminthes
• Circular body thus called round worms and possess pseudocoelom
• Complete digestive system and a well developed muscular pharynx
• Maybe aquatic or terrestrial, free living or parasitic in plants or animals
• First Organ system level of organisation
• They are Dioecious (sexual organs are on different bodies) and females are slightly longer
than males
• Fertilisation is internal and development is direct or indirect
• Ascaris and Wuchereria
Annelida
• Circular ring like body (Annulus = ring)
• Maybe Aquatic, Terrestrial, Parasitic and free living
• Contain metameres
• They move via Longitudinal muscles, Circular muscles and Setae
• Nereis have parapodia for swimming
Kingdom animalia is divided on the basis of many features
Level of Organisation
Cellular level: Porifera
Tissue level: Cnideria, Ctenophora
Organ level: Platyhelminthes
Organ system level: Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata,
Hemichordata, Chordata
Incomplete digestive system: Platyhelminthes
Symmetry
Asymmetrical: Porifera
Radial: Cnidaria (Coelenterata), Ctenophora
Bilateral: All others
Cell Organisation
Diploblastic: Porifera, Cnidaria, Ctenophora
Triploblastic: All others
Nature of Coelom
Acoelomate: Platyhelminthes
Coelomate: All others (except Aschelminthes)
Pseudocoelomate: Aschelminthes
Phylums:
Porifera, Coelenterata, Cnideria, Platyhelminthes, Aschelminthes, Annelida, Arthropoda,
Mollusca, Echinodermata, Hemichordata, Chordata
Porifera
• Animals are never unicellular, so isn't Porifera. Also known as Sponges
• Primitive, marine, attached to the floor, multicellular and have a cellular level of
organisation
• A skeleton formed by Spicules or Spongin fibres
• Specialised water canal system called Ostia through which water enters into a common
cavity called Spongocoel, comes out through Osculum
• The Spongocoel and Osculum are lined by special cells called Choanocytes or Collar cells
helping in ingestion of food particles followed by intracellular digestion
• They are Hermaphrodites. May form fragments in case of asexual reproduction or
gametes. Fertilisation is internal with indirect development.
Eg: Sycon, Spongilla, Euplectella
Coelenterata
• Members are mostly aquatic, marine, sessile or free swimming (motile)
, • Some coelenterates like corals may have a skeleton of calcium carbonate
• Some of them have Cnidoblasts or tentacles on their body and are thus called Cnidaria.
Cnidoblasts help in anchorage, defense and to catch prey.
• Single Gastro Vascular opening called Hypostome
• Digestion is both intracellular and extracellular
• Show two forms throughout life, polyp and medusa. Polyp being sessile, eg: Hydra and
Adamsia. Medusa being umbrella shaped and free swimming, eg: Aurelia.
• Aurelia shows both Polyp and Medusa form
• Physalia, Pennatula, Gorgonia, Meandrina
Ctenophora
• Commonly called sea walnuts or comb jellies
• Marine and free living
• 8 ciliated comb plates helping in locomotion
• Digestion is extracellular and intracellular
• Bioluminescence is a characteristic feature
• They are hermaphrodites with external fertilization and indirect development
• Pleurobrachia and Ctenoplana
Platyhelminthes
• Dorsoventrally flattened body and thus called Flat worms and are aquatic
• Incomplete digestive system
• They have specialised cells called flame cells used for osmoregulation and excretion.
• The members are hermaphrodite, fertilisation is internal and development occurs via larval
stages, ie indirect
• Some members like Planaria have high regeneration capacity
• Taenia and Fasciola
Aschelminthes
• Circular body thus called round worms and possess pseudocoelom
• Complete digestive system and a well developed muscular pharynx
• Maybe aquatic or terrestrial, free living or parasitic in plants or animals
• First Organ system level of organisation
• They are Dioecious (sexual organs are on different bodies) and females are slightly longer
than males
• Fertilisation is internal and development is direct or indirect
• Ascaris and Wuchereria
Annelida
• Circular ring like body (Annulus = ring)
• Maybe Aquatic, Terrestrial, Parasitic and free living
• Contain metameres
• They move via Longitudinal muscles, Circular muscles and Setae
• Nereis have parapodia for swimming
