Why do tapeworms not need a digestive system?
Tapeworms in general have no digestive tract at all. They don’t need a digestive system since they only absorb the nutrients from already digested food from its hosts. They survive this way just like any other parasite which coincide and co evolve with their hosts.
A tapeworm is a type of parasitic flatworm which feeds on the blood, tissue fluids or pieces of cells inside the hosts’ body. It is an intestinal parasite which latches itself onto the intestinal wall of the host by using hooks or suckers to feed by absorbing the food that has already been broken down by different digestive enzymes. It appears to have a long and flat body made up of a head, neck and a chain of segments. Each chain can consist of 3 up to 4,000 segments stretching at least one inch to more than 75 feet.
The body of a tapeworm consists of many tail segments and an anchoring organ called the scolex which enables them to hook themselves in the hosts’ intestinal walls. They don’t have a mouth and they don’t have a digestive system. This deficiency is compensated by their body walls which can directly absorb digested food from the hosts’ intestines. What they do have left is the reproductive system because the need to reproduce is vital to its existence. Tapeworms are hermaphroditic and can fertilize its eggs by itself.
Once it attaches itself to the hosts’ intestinal walls, the tapeworm begins to grow a tail a long tail. Each segment within a tapeworm’s body is independent to itself can absorb nutrients and can reproduce. As the tapeworm continuous to absorb nutrients, new segments are being produced in the neckpiece and older segments are pushed towards the tip of the tail. When the old segment reaches the end of the tail, the segment drops resulting in a sac of tapeworm eggs.
In conclusion, tapeworms lack a digestive system because they don’t need it and it even without it, they can still survive through absorbing the already digested nutrients from the hosts’ body.