-Priyanti, Subject Matter Expert at Edumarz
Solution: Poriferans have a cellular level of organization and do not have any notable physical symmetry, belonging to the subkingdom parazoa. In contrast, coelenterates have a tissue level of organization (eumetazoa) and are radially symmetrical.
Porifera typically have cells designed to perform specific functions such as providing food (trophocytes), collecting pigment granules and excretory products (chromocytes), totipotent cells (archaeocytes), etc. Coelenterates exhibit better division of labour as their specialized cells for digestion (nutritive cells) and sensation (sensory cells), among others, are organized as tissues.
Sponges (porifera) lack sensory or nerve cells while cnidarians (coelenterates) have such cells.
Poriferans do not have any specialized offense mechanism whereas cnidarians possess special stinging cells called cnidocytes or cnidoblasts. These cells, in addition to attacking prey and defending from predators, assist in food capture and adhesion.
Sponges are not polymorphic, but colonial cnidarians exhibit a great degree of polymorphism. They have a polyp or sedentary form, and a medusa or a free swimming form. Polyps and medusae occur in many different forms, carrying out different functions. These include gastrozooids (nutritive zooids), blasto zooids (reproductive zooids) and dactylozooids (protective zooids).
Larvae of porifera are called amphiblastula larva and that of coelenterates are known as planula larva.