Question

Classify the following organisms based on the absence/ presence of True Coelom. (I.e. Acoelomate, pseudocoelomates, and coelomates).
Spongilla, sea anemone, Planaria, liver fluke, Wuchereria, Ascaris, Nereis, Earthworm, Scorpion, Birds, Fish, Horse.
a) (i) Acoelomate: Spongilla, Sea Anemone, Planaria, Liver fluke
(ii) Pseudocoelomates: Wuchereria, Ascaris
(iii) Coelomates: Nereis, Earthworm, Scorpion, Birds, Fish, Horse
b) (i) Acoelomate: Wuchereria, Ascaris
(ii) Pseudocoelomates:Spongilla, Sea Anemone, Planaria, Liver fluke
(iii) Coelomates: Nereis, Earthworm, Scorpion, Birds, Fish, Horse
c) (i) Acoelomate: Nereis, Earthworm, Scorpion, Birds, Fish, Horse
(ii) Pseudocoelomates: Spongilla, Sea Anemone, Planaria, Liver fluke
(iii) Coelomates: Wuchereria, Ascaris
d) (i) Acoelomate: Nereis, Earthworm, Sea Anemone, Planaria, Liver fluke
(ii) Pseudocoelomates: Spongilla, Scorpion, Birds, Fish, Horse
(iii) Coelomates: Wuchereria, Ascaris

Answer 1

Hint: Body cavity is the space between the body wall and the alimentary canal which is produced by the splitting of the mesoderm. Organisms of the various phylum are different due to the presence or the absence of coelom.

Complete answer:
The mesoderm is a germ layer present in animal embryos that will give rise to specialized tissue types. It goes on to form many central structures including the skeletal system, muscular system, and the notochord.
-In some animals, the body cavity or coelom is absent, hence they are called acoelomate. The space between the body wall and the alimentary canal is filled with parenchymatous tissues. For example -Spongilla, sea anemone, planaria, liver fluke.
-In Pseudocoelomates, the body cavity is not completely lined by mesoderm, hence it is called Pseudocoel and the animal is called pseudocoelomates. Example roundworms like Ascaris and Wuchereria.
-The body cavity in coelomates animals is a true body cavity that is filled with coelomic fluid. The mesoderm splits into two layers enclosing the coelom. The outer layer lines the body wall while the inner layer covers the alimentary canal. Example: Earthworm, Nereis, Scorpion, Birds, Fish, Horse.

So, the correct option is ‘(i) Acoelomate: Spongilla, Sea Anemone, Planaria, Liver fluke
(ii) Pseudocoelomates: Wuchereria, Ascaris
(iii) Coelomates: Nereis, Earthworm, Scorpion, Birds, Fish, Horse’.

Note:
Animals can be classified based on various categories such as symmetry, levels of the organization, based on germ layers, based on segmentation, based on notochord. Based on these structural differences, all organisms on this planet are classified into 5 main kingdoms i.e. protista, monera, Plantae, Animalia, and fungi. Further, each kingdom has many phylums and so on.