yes, planarians have one opening in their digestive system
Not all animals have two openings in their digestive tracts. For instance, jellyfish don't. :-)
yes an earthworm has two openings
they have more than one opening
A digestive system with only one opening is called an incomplete digestive tract. Organisms with this type of digestive system ingest food and eject waste through their mouth.
in a one opening digestive system the organism must wait for the food to be released before consuming new foods.
if i got this right snakes are the only one opening animals and have to puke their food after digestion while two opening animals like us just get rid of the waste the way we do.
Oysters have a two way digestive system. This means that they only have on opening for both food to go in and to come out.
They cannot eat continuously (there mouth and anus are present in the same opening)
Parasites such as tapeworm, planarian and live fluke have digestive systems that are saclike. Their digestive tracts have one opening and they live inside a host animal.
An open digestive system is one where there is an entrance "mouth" in one end of the organism and an "exit" or anus of some sort in the other end of the organism. (think of worms or people). A closed digestive system is in something like a hydra or anemone where there is just one cavity and one opening that acts as both mouth and anus.
The stomach
No bats have a one way digestive system. Food goes in the mouth, is digested, and comes out the other end. In two way digestive systems food is taken in and waste is excreted through the same opening.
Organisms that have only one opening in their digestive tract through which food enters and waste exits are known as having an incomplete digestive system. Some organisms with incomplete digestive systems are jellyfish, sea anemones, flatworms, and corals.
one disease of the digestive system is crohns disease! < !!!>
gastrovascular cavity