Question

According to the byju video, the Platyhelmithus has 2 different holes for the intake of food and for excretion but, according to my text book there is only one hole in Platyhelminthes. Which one is the right one?

Answer 1

Platyhelminthes – Have a GVC (gastro vascular cavity)and an incomplete digestive system. Free living worms use extracellular digestion, while parasitic worms use intracellular digestion, absorbing nutrients from their environment. Nematoda – Have a more advanced digestive system with a mouth, intestine and an anus.
The Phylum Nematoda differs from the Phylum Platyhelminthes in two significant ways. First, roundworms have a complete digestive system. This means that there are two opening to the digestive system. The mouth at the anterior ingests or swallows food, and the anus at the posterior releases digestive waste. A complete digestive system is much more efficient than a cul-de-sac gut. The complete digestive system allows continuous processing of food. A roundworm can eat continuously, food digestion can occur continuously, and waste material can be released continuously. Animals with a cul-de-sac gut must wait until a meal has been digested, release digestive waste from the mouth, and only then swallow the next meal.