Question

Describe types of symmetry in animals.

Answer 1

• Spherical Symmetry:
  

In this type of symmetry, the body of the individual can be divided into similar halves by any plane passing through the center, e.g. Volvox, some sponges, and some corals.

• Radial Symmetry:
  

In this type of symmetry, the body of the individual divided into equal halves by any plane passing through the center from top to bottom. This type of symmetry is found in some sponges (Sycon), cnidarians (e.g. Hydra jelly), and echinoderms (e.g. starfish). When the body can be divided into two similar halves by one or two vertical planes only, the radial symmetry is called biradial symmetry. It is present in the sea anemones.

• Bilateral Symmetry:
  

In this type of symmetry, the body can be divided into two equal halves by a single plane only because the important body organs are paired and occur on the two sides of a central axis. Bilateral symmetry is found in many invertebrates and all vertebrates. The right and left sides of the body are called the lateral sides.