What is Phylum Platyhelminthes?
Flatworm Tapeworms
- The phylum Platyhelminthes includes the organisms with a flat
- They are flatworms with a dorso-ventrally flattened
For example, tapeworms.
- Their body is symmetrical bilaterally and can be divided into two equal parts when cut through the central
Embryonic layers
- These organisms do not have a true body cavity which makes them acoelomate organisms. Their bodies are triploblastic, formed from three proper embryonic layers namely endoderm, mesoderm, and
- There are no complex organs developed in these
- A proper digestive system is
- Respiration occurs with simple diffusion through the body
- The body does not have a specialised excretory organ but has specialised cells called
flame cells which perform excretion.
- Most of them are parasitic and found in the body of their target
For example, liver fluke.
- Some of them are free-living and found mostly in marine or freshwater
For example, planaria.
Liver fluke Planaria
How do flatworms reproduce?
- These organisms reproduce
- In some cases, which are hermaphrodites, the fusion of gametes occurs within the same body.
- Fertilisation is always