Chapter 27, Problem 2A

Summary Introduction

To write: The distinction between madreporite and water vascular system

Introduction: Echinoderms are deuterostomes which represent a significant transition in animal phylogeny. Echinoderms are aquatic mammals, and are the only species to have a deuterosome development and an endoskeleton in evolutionary history.

Explanation of Solution

Water vascular system is the characteristic of echinoderms and is a structure of closed, fluid-filled tubes that function together to allow echinoderms to travel and get food.

The strainer like structure is called madreporite, which is the opening to the water-vascular system. Water is attracted through the madreporite, and then travels to the ring canal through the stone canal.

Conclusion

Thus, it concludes that the water travels from the madreporite to the radial canals, then finally to the tube feet.