Classification of Animal Kingdom – Imaluop

Classification of Animal Kingdom: Scientists classify different animals on the basis of their similarities and dissimilarity in different properties to study them in a systematic approach. Different similarities place them in a same category while dissimilar animals are placed in different categories, based on similarities and dissimilarities among the animals are divided into different phyla – phylum Porifera, Cnidaria, annelida, Platyhelminthes, Aschelminthes, arthropoda, mollusca, echinodermata, hemichordata and chordata.  

Phylum Porifera: 

• It is the most simple group of Animal Kingdom they know as porifera due to the presence of numerous pore on their body which is a differentiating feature of this phylum. 
• Small sized pore ostia present on their whole body which helps entry of water into their body cavity or spongocoel for various requirements like nutrients. Numerous pore on their body give them spongy appearance so they are also known as sponge popularly and they have a large pore osculum through which all the water from the spongocoel exit outside. 
• They have a special type of endoskeleton and they are known for their special vascular system in which water flows through their canal system for circulation of respiratory gases, nutrients, waste materials and gametes. 
• They are multicellular non motile animals found in both freshwater and marine water and they show cellular level of organisation, spongilla and sycon is an example of this animal group. 

Phylum Coelenterata: 

• Phylum coelenterata are popular for their special defence cell cnidoblast which is stinging in nature and can help the animal to capture prey, protection against their enemy, we will discuss other features of this phylum below. 
• They have a sac-like body cavity which has only one opening for egestion and ingestion, the body cavity is known as gastrovascular cavity. 
• Sea anemone is an example of phylum coelenterata in which their mouth is surrounded by tentacles which have stinging cell cnidoblast which helps them to capture the prey. 
• Some members present in groups and make colonies like corals while others live solitary as in the case of sea anemone. 

Phylum Platyhelminthes: 

• Platyhelminthes are also known as flatworms due to their dorsoventrally flattened body and they show tissue for performing special types of function. 
• They do not have any body cavity or coelom and some of them show parasitism, for example liver Flukes are parasitic flatworms. 
• They show bilateral symmetry and they are famous for their great regeneration capacity which is a special type of vegetative reproduction in flatworm.  

Phylum Aschelminthes: 

• They are also known as roundworms due to their cylindrical shape and most of the roundworms are intestinal parasites like Ascaris which causes ascariasis in human beings. 
• They show bilateral symmetry and they show pseudocoelom which resembles a coelom but they are not actually coeloms. 
• Three germ layers give rise to different organs in their body, ectoderm, endoderm and mesoderm so they are known as triploblastic and they are known for causing various diseases in humans like elephantiasis, ascariasis. 

Phylum Annelida: 

• Annular rings present on their body make their name as annelida and their body show segmentation. 
• They show bilateral symmetry and true body cavity or coelom they present in marine water, fresh water as well as in land. 

Phylum Arthropoda: 

• Due to their high capability of adaptation they are present in all environments even if they live easily in the extreme hot desert where water availability is very poor. 
• They have segmented appendages which makes them popular as animals with jointed legs and they excrete uric acid to protect water loss. 
• Their development is indirect because of their larval stage before they attain the adult insect body. 
• They have an open circulatory system and well developed organ system level of organisation. 

Phylum Mollusca: 

• Snail and octopus are great examples of phylum Mollusca which shows bilateral symmetry and generally have limbs. 
• Their body is partially segmented and they have well developed organs system level of organisation. 
• They are triploblastic animals and their circulatory system is open which means circulation is bound in vessels. 

Phylum Echinodermata: 

• They are known as echinodermata which means they have sharp pointed structure on their body and they generally show radial symmetry. 
• They have true body cavity or coelom and they have tube feet for locomotion which functions by the hydrostatic pressure of water. 
• Sea urchin and starfish are two examples of phylum Echinodermata and they have calcareous exoskeleton. 

Phylum Hemichordata: 

• They have proboscis and single layer of epidermis with organ systems level of organisation. 
• They worm like marine animals and their circulatory system is open nature. 
• Development is direct and fertilization occurs externally and they respite through gill. 

Phylum Chordata: 

• They have a special structure notochord which makes them different from other animals in the animal kingdom. 
• Circulatory system in chordata is closed type and they show bilateral symmetry due to arrangement of different organs in their body. 

Reference: Classification of Animal Kingdom 

Read More: Characteristics of Lower Invertebrates