Chapter 27, Problem 35A

Summary Introduction

To write:

About the symmetry of the given diagram

Introduction:

Echinoderms are marine animals with spiny endoskeletons, water-vascular systems, and tube feet; they have radial symmetry as adults. Echinoderms are deuterostomes. The approximately 6000 living species of echinoderms are marine animals and include sea urchins, sea stars, and sand dollars, sea cucumbers, brittle stars, sea lilies and feather stars, and sea daisies.

Explanation of Solution

Bilateral symmetry is shown in a given diagram which is a larva. All echinoderms have radial symmetry as adults. Echinoderm larvae have bilateral symmetry. The bilaterally symmetrical larva undergoes metamorphosis to change into the radially symmetrical adults. Echinoderm larvae have bilateral symmetry and can be divided along one plane into mirror-image halves. Adult echinoderm has radial symmetry and can be divided through a central axis, along any plane, into equal halves.

Conclusion

All echinoderms are bilaterally symmetrical as larvae. During their development into adults, the larvae’s body plan becomes radially symmetrical.