Animalia

The animals are classified into ten groups based on the body design, germinal layers, presence of notochord, etc. The ten groups are:

1. Porifera
2. Coelenterata
3. Platyhelminthes
4. Nematoda
5. Annelida
6. Arthropoda
7. Mollusca
8. Echinodermata
9. Protochordata
10. Vertebrata

Porifera:

• They are non-motile animals
• They have holes or pores all over their bodies
• Pores help in circulating water throughout the body
• Their bodies are covered with hard outside layer or skeleton
• They are mainly found in marine habitats.
• Eg: Spongilla, Sycon

Coelenterata:

• They have two layers of cells
• They live in water
• They have a cavity in the body
• They either live in colonies or in solitary
• Eg: Jellyfish, Hydra

Platyhelminthes:

• Their body is bilaterally symmetrical
• They have three layers of cells, which provides inside and outside body linings, that’s why they are known as “Triploblastic”
• Their body is flattened dorsiventrally (from top to bottom)
• They are either free-living or parasites
• Eg: Planarians, Liverflukes

Nematoda:

• Their body is bilaterally symmetrical
• They are also triploblastic
• They have cylindrical body
• A sort of cavity or pseudocoelom is present on body
• Eg: Ascaris, Roundworm

Annelida:

• They are also bilaterally symmetrical and triploblastic
• They have extensive organ differentiation in segmental fashion
• They are found in fresh water, marine water and land
• Eg: Leeches, Earthworms

Arthropoda:

• They are the largest group of animals.
• They are bilaterally symmetrical and segmented
• They have jointed legs
• They have open circulatory system
• Eg: Prawns, Butterflies

Mollusca:

• They have bilateral symmetry
• They have an open circulatory system and kidney-like organs for excretion
• They have a foot that is used for movement
• Eg: Snail, Mussels

Echinodermata:

• They are spiny skinned organisms
• They are triploblastic and have a coelomic cavity
• They have water driven tube system for movement
• They have hard calcium carbonate structures for skeletons
• Eg: Starfish, Urchins

Protochordata:

• They are bilaterally symmetrical and triploblastic
• They possess notochord which is a long rod-like support structure that runs along the back of the animal supporting the nervous tissue from the gut
• They are marine animals
• Eg: Balanoglossus, Herdemania

Vertebrata:

• They have proper vertebral column and internal skeleton
• They are bilaterally symmetrical, triploblastic, coelomic and segmented.
• They have a complex differentiation of body tissues and organs
• They are further grouped into five groups:
  • Pisces:
  • They are fish
  • Their skin is covered with scales
  • They have streamlined bodies
  • They are cold-blooded and their hearts have two chambers
  • They use their muscular tails for movement
  • Eg: Tuna, Shark
  • Amphibia:
  • They can live on land as well as in water
  • They have a three chambered heart
  • They have mucus glands in skin
  • Eg: Frogs, Salamander
  • Reptilia:
  • They are cold-blooded and breathe through lungs
  • Most of them have a three chambered heart
  • They lay eggs with tough outer coverings
  • Eg: Lizard, Turtle
  • Aves:
  • They are warm blooded and have a four chambered heart
  • Their forelimbs are modified into wings
  • They lay eggs
  • Their body is covered with feathers
  • All birds fall in this category
  • Mammalia:
  • They are warm blooded and have a four chambered heart
  • They have mammary glands
  • Sweat and oil glands are present in their skin