Phylum Porifera and its Morphological Features - Practice Questions & MCQ

Digestion in Porifera

• Sponges lack a digestive system. 
• The nutrition is performed by choanocytes that trap the phytoplanktons and digest them through phagocytosis. 
• Hence, digestion is intracellular. 
• The amoebocytes transfer food from choanocytes to other cells. 
• The pinacocytes digest larger plankton. 

Respiration in Porifera

• Sponges do not have a respiratory system. 
• The exchange of gases occurs via diffusion across the cell surface. 
• The oxygen is diffused in from water current and carbon dioxide diffuses out. 

Excretion in Porifera

• The excretory system is absent. 
• Nitrogenous waste is disposed from the cells through the process of diffusion. 
• Ammonia is the principal excretory waste.