Question

"Water Canal System" is a unique characteristic of animals belonging to which of the following Phylums?
A. Porifera
B. Coelenterata
C. Mollusca
D. Echinodermata

Answer 1

Hint: The water circulatory system of sponges, also known as the canal system, is a distinguishing feature of the phylum Porifera.


Complete step-by-step answer:

Aquiferous system is another name for canal system. Sponge canal systems aid in food acquisition, respiratory gas exchange, and excretion.

The canal system's main constituents are the numerous perforations on the body surface of the sponges for water current ingression and egression. The water current flows through a specific system of spaces within the body, where food is captured from the incoming water and excretory material is expelled into the outgoing water.

Functions of the water canal system-The water current that enters the sponges' bodies via the canal system serves the following purposes:
i. This current maintains all exchanges between the sponge body and the external medium.
ii. Food and oxygen are brought into the body by this water current, and excreta are removed from the body by this water current.
iii. The water current transports the sponges' reproductive bodies out and into their bodies.

Types of canal systems- Different sponges have different internal channel arrangements and degrees of complexity, so the canal system is classified into three types:
1. Canal system of the Ascon type- This canal system is the most basic of the three. It is found in asconoid sponges such as Leucosolenia as well as some developmental stages of all syconoid sponges.
2. Canal system of the Sycon type- The sycon canal system is more complex than the ascon canal system. Scypha and other syconoid sponges have this type of canal system.
3. Canal system of the Leucon type- This type of canal system is caused by further folding of the body wall of the sycon canal system. This canal system is characteristic of leuconoid sponges such as Spongilla.

So, option A is correct answer.

Note: Poriferans are commonly known as sponges. An early-branching event in animal evolution separated sponges from other metazoans.