What is a Platyhelminth?
Platyhelminthes or Flatworms are the simplest of the worm groups. The animals of the phylum Platyhelminthes are worm like animals with soft and unsegmented bodies. They are characterized by bilateral symmetry, no body cavity, no respiratory and circulatory organs. There are about 20,000 species in this group. They are found many places and can be free living or parasitic. A parasite lives off of another living thing called a host and can be harmful. One of the best known flatworms is the tapeworm. The tapeworm can get into a person's digestive tract and grow to enormous lengths. The tapeworm then eats off the host and is dangerous to the host as it grows and consumes more of the host and its food.
Characteristics of Platyhelminthes
1)Bilaterally symmetrical.
2)Body having 3 layers of tissues with organs and organelles.
3)Body contains no internal cavity.
4)Possesses a blind gut (i.e. it has a mouth but no anus)
5)Has Protonephridial excretory organs instead of an anus.
6)Has normally a nervous system of longitudinal fibres rather than a net.
7)Generally dorsoventrally flattened.
8)Reproduction mostly sexual as hermaphrodites.
9)Mostly they feed on animals and other smaller life forms.
10)Some species occur in all major habitats, including many as parasites of other animals
Characteristics of Platyhelminthes
1)Bilaterally symmetrical.
2)Body having 3 layers of tissues with organs and organelles.
3)Body contains no internal cavity.
4)Possesses a blind gut (i.e. it has a mouth but no anus)
5)Has Protonephridial excretory organs instead of an anus.
6)Has normally a nervous system of longitudinal fibres rather than a net.
7)Generally dorsoventrally flattened.
8)Reproduction mostly sexual as hermaphrodites.
9)Mostly they feed on animals and other smaller life forms.
10)Some species occur in all major habitats, including many as parasites of other animals
Do Platyhelminthes have a Skeletal System?
These animals however, possess no internal body cavity. Coelomate means body cavity present and since body cavity or coelom is absent, they are termed as acoelomate. Mesenchyme, which is a connective tissue, fills the space between the skin and gut in these animals. It consists of two kinds of cells: fixed cells and stem cells. Fixed cells have fluid filled vacuoles and stem cells are the cells capable of transforming into any type of cell. This mesenchyme is reinforced by collagen fibers that give attachment points for the muscles. Mesenchyme comprises internal organs and permits the passage of nutrients, oxygen and waste products.
There are 5 Classes of Platyhelminthes
Turbellaria
Cestoda
Monogenea
Trematoda
Aspidogastrea
There are 5 Classes of Platyhelminthes
Turbellaria
Cestoda
Monogenea
Trematoda
Aspidogastrea