EVERYDAY SCIENCE

Detailed explanation-1: -The two halves of a radially symmetrical animal may be described as the side with a mouth (“oral side”) and the side without a mouth (“aboral side”). This form of symmetry marks the body plans of animals in the phyla Ctenophora (comb jellies) and Cnidaria (corals, sea anemones, and other jellies).

Detailed explanation-2: -Radially symmetrical aquatic animals typically have an oral mouth surface and an aboral surface on the opposite side (Fig. 3.11). Sensory and feeding structures are often concentrated around the center point.

Detailed explanation-3: -The main axis is heteropolar-i.e., with unlike ends, one of which bears the mouth and is termed the oral, or anterior, end, and the other of which, called the aboral, or posterior, end, forms the rear end of the animal and may bear the anus. The main axis is hence termed the oral-aboral, or anteroposterior, axis.

Detailed explanation-4: -Special forms of radial symmetry are tetramerism (having four identical parts around a central axis) and pentamerism (with five identical parts around a central axis). Biradial symmetry is a combination of radial and bilateral symmetries, such as that of ctenophores (comb jellies). Synonym(s): radiosymmetry.

Detailed explanation-5: -People, dogs, cats, and elephants all have bilateral symmetry. Animals with radial symmetry have body parts arranged around a central point. Any line drawn from one side through the center to the opposite side will divide the animal into two symmetrical halves. Animals with radial symmetry have many lines of symmetry.