How useful is the study of the nature of body cavity and coelom in the classification of animals?
Solution and Explanation
Coelom is a fluid filled space between the body wall and digestive tract. The presence or absence of body cavity or coelom plays a very important role in the classification of animals.
Animals that possess a fluid filled cavity between body wall and digestive tract are known as coelomates. Annelids, mollusks, echinodermates, and chordates are examples of coelomates. On the other hand, the animals in which the body cavity is not lined by endoderm.
Aschelminthes is an example of pseudocoelomates.
In certain animals, the body cavity is absent. They are known as acoelomates. An example of acoelomates is platyhelminthes.
Top Questions on Classification Of Animals
- Which of the following pairs is an incorrect match?
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- Classification Of Animals
- Match List I with List II :Choose the correct answer from the options given below :
List - I List – II A. Chondrichthyes i. Clarias B. Cyclostomata ii. Carcharodon C. Osteichthyes iii. Myxine D. Amphibia iv. Ichthyophis - NEET (UG) - 2024
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- Consider the following statements :
A. Annelids are true coelomates
B. Poriferans are pseudocoelomates
C. Aschelminthes are acoelomates
D. Platyhelminthes are pseudocoelomates
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- Observe the following simplified scheme and choose the correct option that matches with the letters given in the boxes.
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- Reduced coelom is found in:
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Concepts Used:
Classification of Animals
Classification of Animal Kingdom:
One of the most fundamental forms of classification of animals is the presence or absence of the notochord. Hence, two major groups exist, namely: Chordates and Non-chordates
Non-chordates and the Chordates-
- The notochord is a flexible rod made out of a material similar to cartilage. If an animal has a notochord during any stage of its life, it is classified as a chordate. Contrary to popular belief, chordates do not exclusively include vertebrates.
- There are invertebrates that possess a notochord during some point in their lives and hence, are classified as chordates. Thus all vertebrates are chordates but not all chordates are vertebrates.
Non-chordates-
- Non-chordates are animals without a notochord – the rod-like elastic structure that supports the body. This phylum consists of a small group of worm-like, marine species with an organ-system level of organization.
- Members of phylum Porifera, Coelenterata, Ctenophora, Platyhelminthes, Aschelminthes, Annelida, Arthropoda, Mollusca, Echinodermata and Hemichordata fall under Non-chordates
Vertebrates Classification:
The subphylum Vertebrata is divided into five classes of vertebrates. These five classes of vertebrates comprise of all the species of animals and have developed vertebral column as well as an internal skeleton.
Other characteristic features of vertebrates are-
- Presence of a true vertebral column and internal skeleton with muscle attachment points for body movement.
- A front-side muscular heart with two, three or four chambers.
- Kidneys for excretion and osmoregulation
- A paired appendages which may be fins or limbs.
- Possess notochord during the embryonic stage.
- Vertebrates are the only chordates to possess a brain as a part of the central nervous system.
Classification of Vertebrates-
- Pisces
- Amphibia
- Reptilia
- Aves
- Mammalia