Biology XI:4 Animal Kingdom(2 Characteristics Features of Dif Phyla

Characteristics Features of Different Phyla Phylum − Porifera Members commonly known as sponges are generally marine. They are primitive, multicellular, asymmetrical, and have cellular level of organization. They have a water transport system or canal system. Canal system is helpful in gathering food, exchange of respiratory gases, and excretion of waste. The spongocoel and canals are lined by collar cells (choanocytes). Digestion − Intracellular Skeletal system − Skeleton consists of spicules or sponging fibres. Reproduction: Asexual (by fragmentation) or sexual (by gamete formation) Sponges are hermaphrodite. Fertilization - Internal Development - Indirect (have morphologically distinct larval stage) Examples of sponges − Sycon, Spongilla (fresh water sponge), and Euspongia (Bath sponge) Phylum − Coelentrata (Cnidaria) Name cnidaria derived from cnidoblasts or cnidocytes, which are used for anchorage, defence and capture of prey Coelenterates are aquatic (mostly marine), sessile, or free swimming. Radially symmetrical Diploblastic and have tissue level of organization Digestion can be internal, extracellular, and intracellular. Skeletal system - Skeleton is composed of calcium carbonate (corals). Alternation of generation (metagenesis) is exhibited by those occurring in both forms. In this: Polyps →medusa (asexually) and medusa →polyps (sexually) (Example − Obelia) Examples of coelenterates − Physalia (Portugese man of war) Adamsia (sea anemone) etc. Phylum − Ctenophora Common name - Sea walnuts and comb jellies Exclusively marine Radially symmetrical Diploblastic and have tissue level of organization Digestion - Extracellular or intracellular Locomotory organ - Eight rows of ciliated comb plates located externally Reproduction - Sexual only Fertilization - external Development - indirect Exhibit the property of bioluminescence (emit light) Examples of ctenophores − Pleurobrachia and Ctenoplana