Question

Match the locomotory organs given with the phylum in which they are seen. Choose the answer which gives the correct combination of alphabets of the two columns.

Locomotory organs	Phylum
A. Pseudopodia	p. Mollusca
B. Parapodia	q. Chondrichthyes
C. Muscular foot	r. Protozoa
D. Fins	s. Annelida

A. A-r, B-p, C-s, D-q
B. A-p, B-r, C-s, D-q
C. A-s, B-r, C-q, D-p
D. A-r, B-s, C-p, D-q

Answer 1

Locomotion is the process by which animals move from one place to another. The organs that help an animal to locomote, are known as locomotory organs. The locomotory organs vary widely in shape, size and origin. typical locomotory organs are fins, legs, muscular foot, wings, pseudopodia, etc.

Complete answer:
Protozoans locomote with the help of pseudopodia. The word ‘pseudopodia’ originates from two words: ‘pseudo’ meaning false and ‘podia’ meaning feet, that is false feet. This is because the pseudopodia are extensions of the cell membrane, rather than being an organ. The pseudopodia are temporary projections and are composed of actin filaments. The projections ‘move’ with the help of actin polymerization. There are different types of pseudopodia like Lobopodia, Filopodia, Reticulopodia, Axopodia. Apart from locomotion, pseudopodia also help in prey capture.
Annelids locomote with the help of parapodia. These are lateral extensions from the body of the organisms that have it. The word ‘parapodia’ originates from two words – ‘para’ meaning beside and ‘podia’ meaning feet. The parapodia in the annelids are unsegmented and fleshy, and arise from both the sides of each segment. Parapodia are also involved in gaseous exchange, protection and anchorage, apart from locomotion.
Molluscs move with the help of muscular feet. It is present on the ventral side of the organism’s body. The structure contains nerves from the pedal ganglia and the pedal nerve cord. The muscular foot in the molluscs, apart from locomotion, also helps in reproduction, swimming, burrowing, etc. The structure of the foot varies according to the type of physiological function undertaken by a particular species of mollusc.
Chondrichthyes are cartilaginous fishes. The members of this group locomote with the help of fins. The fins are actually spines that extend from the body of aquatic animals. However, the spines of fins do not have any connection with the spinal cord of fishes. The spines of the fins are covered with a layer of skin. According to evolutionary theories, the fins of the fishes have evolved into forelimbs of terrestrial tetrapods.

Hence, the correct answer is option (D).

Note: Locomotory organs help in the movement of organisms from one place to another. The morphology and anatomy of the organs vary according to the media through which the animal moves. Locomotory organs can be found in fishes, muscular feet in molluscs, parapodia in annelids and pseudopodia in protozoa.