Q.What is the water vascular system? State two functions it performs in Echinodermata.

Step 1. The water vascular system is a unique organ system found only in Echinodermata, consisting of a network of water-filled canals running through the body.

Step 2. This system hydraulically extends and retracts numerous small, external tube feet that project from the body surface.

Step 3. These tube feet serve at least two major functions: locomotion (allowing the animal to move slowly over the substratum) and, in many species, capturing and manipulating food, and they can also aid attachment to a surface.

Define the water vascular system and recall at least two of its stated functions (locomotion, attachment, feeding).

• Confusing the water vascular system (Echinodermata) with the water-transport/canal system of Porifera — the two are named similarly but are structurally and functionally unrelated.
• Naming only one function when the question specifically asks for two.