Chapter 35, Problem 40A

Summary Introduction

To analyze:

The radial symmetry of the Cnidaria involved in the feeding process.

Introduction:

The Cnidaria comes in two specific structures a polyp that is sea anemones and medusa that are jellyfish type. Polyps are usually tube-shaped and passive with a ring of tentacles all around the mouth. Medusae are shaped like an umbrella or a bell, live free, and have a central projection within the umbrella supporting the mouth and tentacles along the umbral surface.

Explanation of Solution

Cnidarian is also termed as coelenterate, they are found in marine water that includes hydras, jellyfish, corals, sea anemones, sea whips, sea pens, and sea fans. This phylum consists of four classes; hydrozoa, Anthozoa, scyphozoan, and cubozoa. It includes the group of diploblastic organisms that are mostly acellular mesogloea that is formed from ectoderm. There is a specialized cell found in Cnidaria called cnidocytes. Cnidarians have different shapes and sizes, they have medusa or polyp body plans. The polyp body plan is cylindrical in which one end is attached to one surface and the other consists of a mouth that is surrounded by tentacles. The cnidarian is a radial symmetry, making them somewhat distinct from the creatures that existed before them. Radial symmetry implies that they have a circular body plan and every cut through the animal’s middle divides them into two halves. Because of this radial symmetry cnidarian, the tentacles through which they capture the prey are divided into equal halves. They release the stinging nematocysts that make the prey paralyzed.

Conclusion

The radial symmetry divides the organism into equal half. This also divides the tentacles equally and therefore helps them to trap the prey from any side.