The complete digestive system of the platyhelminthes consists of mouth, a tube similar to pharynx and the intestine that could be branched to enlarge the area of absorption of nutrients. Notice that the digestive system presents a single opening, therefore the wastes are eliminated through the same place the food enters into the pharynx, such as, in flatworms, the mouth plays also the role of anus.
Taenia Solium (Pork Tapeworm)
The pork tapeworm is a parastic worm that actually doesn't have a digestive system of its own, and there is a reason for that. The pork tapeworm feeds only on the food in organisms that has already been pre-digested and broken down, so why have a digestive system when someone or something else does it for you? That is the reason why pork tapeworms do not have their own digestive system, although their feeding style is different from that of nematodes but similar in that they feed in the bodies of organisms such as pork.
Even though there is not one universal digestive system in pork tapeworms, the body segments of the worm called proglottids each have their own independent digestive system. What happens is that the tapeworm anchors to the host's intestinal wall, in which the tapeworm absorbs nutrients through its skin as the food being digested by the host flows past it and begins to grow a long tail, with each segment containing an independent digestive system and reproductive tract. By this process of feeding on the already digested and broken down food in the organism, the tapeworm can successfully asexually reproduce by dropping off eggs and having them then feed off of the host's digested matter as well. |
Leucochloridium Paradoxum (Green-Banded Broodsac)
The Green-Banded Broodsac is a parasitic flatworm that primarily attacks the internal systems of snails and birds primarily. As a larvae, what happens is that the larvae will enter a snail through the digestive tract, invade the snail's eyestalks with broodsacs, and then takes over the brain of the snail, making it leave their dark and gloomy places and going to the highest points where they can attract birds as food. Once the bird ingests this so-called "snail." The Green-Banded Broodsac then feeds off of the nutrients that the bird intakes as a result of entering into its system. The interesting thing is that the flatworm will not really harm the bird, but only absorb its nutrients because if the bird dies, then so does the Green-Banded Broodsac. This flatworm also lays eggs in the digestive tract of the bird and possesses both sexes so that it can reproduce by itself inside the bird, causing the whole feeding cycle to start over again in the bird.
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Pseudobiceros Bedfordi (Bedford's Flatworm)
The digestive system of the Bedford Flatworm has an extremely simple structure, similar to that of any flatworm in the phylum. It consists of only two parts: the foregut and the midgut. The foregut has an ectodermal origin and is also called pharynx (tubellaria use pharynx for catching food and can put it out, just like the Bedford Flatworm). The midgut also has an ectodermal origin. The hindgut is like a projectile in which it puts out of the mouth any non-digested materials.
There is nothing too exotic or strange about what Bedford Flatworm eats. It feeds on ascidians as well as crustaceans that are small enough to swallow. The flatworm lives on coral rubble, ledges in back reefs, coastal bays, and lagoons, so much of its food is located on the seabed in which it needs small things to eat since its mouth is not large in size. The Bedford Flatworm also moves very fast by undulating its body, in which it can catch up to any prey that it needs to eat or can even beat another marine flatworm to a location of food which is critical in survival for the worm. |