Question

liverfluke belongs to phylum platyhelminthes which possess a blind sac body plan having a single opening for ingestion and egestion. then how does liverfluke have both mouth and an excretory pore??

Answer 1

Liver fluke belongs to the class Trematoda which are evolutionary descendents of Phylum Annelida. During the course of evolution first time in Phylum Platyhelminthes, a primitive excretory organ like structure is developed called as ‘Protonephridia’. This primitive type of nephridia is concerned with osmoregulation primarily and not with excretion. That’s why we find two types of opening in liver fluke which belongs to this class unlike other organisms of Phylum Platyhelminthes which has only single opening for ingestion and excretion.