Question

What is bilateral and biradial symmetry? Give examples. 

Answer 1

• Animals which possess two pairs of symmetrical sides are said to be biradially symmetrical.
• Biradial symmetry is a combination of radial and bilateral symmetry as seen in ctenophores. 
• There are only two planes of symmetry, one through the longitudinal and sagittal axis and the other through the longitudinal and transverse axis. eg. Comb jellyfish - Pleurobrachia.
• Animals which have two similar halves on either side of the central plane show bilateral symmetry. 
• It is an advantageous type of symmetry in triploblastic animals, which helps in seeking food, locating mates and escaping from predators more efficiently. 
• Animals that have dorsal and ventral sides, anterior and posterior ends, right and left sides are bilaterally symmetrical.