Chapter 32.2, Problem 2R

Summary Introduction

To review:

The ways in which the echinoderms obtain food using their tube feet. The comparison between this feeding mechanism with that of the hemichordates.

Introduction:

The echinoderms and the hemichordates fall under the deuterostome class. The former possesses a radial symmetry, while the latter possesses a bilateral symmetry. The body symmetry of these organisms enables two modes of feeding mechanisms.

The echinoderms possess water canals systems, which extend into tube feet outside their body. The tube feet functions as locomotor organs and at the same time, also serves the gaseous exchange. Along with the water, the food and gases diffuse into the water canal system through the tube feet.