Topic: Biology - Zoology.

Fhadeea A.

Worms take part in diversity, and they go into three major groups. Namely one of them is flatworms. Although flatworms are often known for being parasitic (because of it being the majority on its species), there are a minority species of flatworms that are known to be harmless towards humans (free-living).

Flatworms are also known as platyhelminth. They belong to the phylum Platyhelminthes, they are invertebrates, meaning they do not possess vertebral column (backbones).


Other general Characteristics of Flatworms include:

Digestion and excretion of Flatworms

Nervous System


This is a video of a planarian regeneration process.

Q: How planarians can be killed?
A: Planarians live in aquatic environments, so one of the methods is they can die by being dried on land, or being burnt.

Classes of Flatworms (Click to see characteristics):





Environments of parasitic worms:

  • Primary Host: Adult form feeds and reproduces
  • Intermediate Host: Larval form feeds and reproduces

Species of concern:

  • Schistosomiasis: Bores into skin -> travels into circulatory system -> Causes body inflammation from trapped eggs under skin.
  • Chinese Liver Fluke: Lives in bile duct of cats, dogs, and humans. Causes from infection from eating raw fish.
  • Beef/Pork tapeworms: Causes from infection from undercooked meat/pork. Results in digestive problems and weight loss.

So what are the importance of flatworms towards the environment?:

End of article!

1. A flame cell is a specialized excretory cell found in the simplest freshwater invertebrates, including flatworms, rotifers and nemerteans. Bundles of flame cells are called protonephridia. These are the simplest animals to have a dedicated excretory system. Flame cells removes waste materials.