Dictionary > Flatworm

Flatworm

Definition
noun, plural: flatworms
Any of the worms (e.g. tapeworms, trematodes, planarians, etc.) belonging to the phylum Platyhelminthes, characterized by a flattened and bilaterally symmetrical body
Supplement
The flatworms make up the phylum Platyhelminthes (i.e. etymologically, platy meaning flat and helminth meaning worm) that are distinguished by their flat and bilaterally symmetrical body. Some of them are free-living whereas others are parasitic. The phylum is divided into four groups: (1) turbellarians, (2) trematodes, (3) monogeneans, and (4) cestodes. Turbellarians are mostly free-living. Most of them are scavengers and predators. Their length ranges from 1 mm to 600 mm. Pseudoceros dimidiatus is an example of a turbellarian. Trematodes include the groups Digenea and Aspidogastrea. They are distinguished by their holdfasts resembling suckers that aid them to anchor within the host. Monogeneans are mostly ectoparasites of fish, amphibians, and aquatic reptiles. They have haptors, which are attachment organs they use to attach to their host. Cestodes are parasitic tapeworms. Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm), and Diphyllobothrium spp. (fish tapeworm) are some of the tapeworms that can infest humans.
The flatworms are unsegmented, soft-bodied invertebrates. They do not have specialized circulatory and respiratory organs and therefore rely on diffusion to move oxygen and nutrients through their bodies. They have an incomplete digestive system. There is only one opening where food enters and where the non-digested particle leaves.
Scientific classification:

  • Kingdom: Animalia
  • Phylum: Platyhelminthes

Variant(s):

  • flat worm

See also:


You will also like...

green leaf - close up view
Leaves

Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this ..

Genetic engineering
Genetic Engineering Advantages & Disadvantages

This tutorial presents the benefits and the possible adverse eventualities of genetic engineering. Know more about this ..

human respiratory system
Respiration

The human respiratory system is an efficient system of inspiring and expiring respiratory gases. This tutorial provides ..

Body temperature regulation by the hypothalamus
Temperature Regulation in Animals

This tutorial elucidates body temperature regulation. Know the details here to learn how the body sets the body temperat..

Schematic diagram of bacterial lactose operon
Gene Action – Operon Hypothesis

Learn how the way genes control and determine every aspect of the body. This lesson uses lac operon as an example. ..

..

Cell Respiration
Cell Respiration

Cell respiration is the process of creating ATP. It is "respiration" because it utilizes oxygen. Know the different stag..

Related Articles...

No related articles found

See all Related Topics