Q33-3TYU. The water vascular system of ech... [FREE SOLUTION]

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Chapter 33: Q33-3TYU. (page 715)

The water vascular system of echinoderms
(A) functions as a circulatory system that distributes nutrients to body cells.
(B) functions in locomotion and feeding.
(C) is bilateral in organization, even though the adult animal is not bilaterally symmetrical.
(D) moves water through the animal鈥檚 body during filter feeding.

Short Answer

Expert verified

(A) The statement鈥渇unctions as a circulatory system that distributes nutrients to body cells鈥� is false.

(B) The statement 鈥渇unctions in locomotion and feeding鈥� is true.

(D) The statement 鈥渕oves water through the animal鈥檚 body during filter feeding鈥� is false.

Step by step solution

Deuterostomia

In the phylogenetic tree of animals, the term Deuterostomia is used for denoting one of the descended clades of the bilateria group. This clade is characterized by animals that have radial cleavage during embryonic growth and formation of the anus from the blastospore structure.

Explanation of option ‘(A)’

In echinoderms, the organisms lack a true circulatory system, and the distribution of nutrients does not occur through blood; instead, the movement of water in the water vascular system helps distribute nutrients as an extra function.

Thus, the water vascular system does distribute nutrients, but it does not function as a true circulatory system.

Therefore, the given statement is false.

Explanation of option ‘(B)’

The presence of the water vascular system in the echinoderm body is mainly used for locomotion and feeding. The water vascular system absorbs the external water and transports it to the tube feet, facilitating locomotion. The force of absorbed water also facilitates predation.

Thus, the main function of the echinoderm鈥檚 water vascular system is feeding and locomotion.

Therefore, the given statement is true.

Explanation of option ‘(C)’

The echinoderms belong to the bilateria division of the phylogeny, but the adult body organization exhibits radial symmetry. The larval phase of the echinoderm displays bilateral symmetry.

Thus, the water vascular system does not exhibit bilateral symmetry.

Therefore, the given statement is false.

Explanation of option ‘(D)’

Filter feeding is the mechanism found in some marine animals that includes the absorption of nutrients from the seawater by filtering the water inside the body. This mechanism is predominantly found in the phylum Porifera.

Thus, the movement of water by the water vascular system is not restricted to the filter-feeding mechanism.

Therefore, the given statement is false.