Table of Contents
Table of Contents
- Phylum Aschelminthes
– Different Systems in Roundworms
- Summary
- What’s Next?
In the previous segment of the chapter ‘Diversity in Living Organisms’, we studied about the
phylum Platyhelminthes. In this segment, let us get introduced to the phylum Aschelminthes.
What is Phylum Aschelminthes?
- Aschelminthes are the organisms that have a cavity inside their body. They are also called
Roundworms or Nematodes.
- They are a step higher than the Platyhelminthes on the scale of evolution.
Roundworm
- They have an organ system grade of organisation. The body is usually cylindrical and has a tapering end.
- The mouth consists of prominent structures like suckers and hooks to attach to the host body and derive nutrition from it.
- The body is bilaterally symmetrical and can be divided into equal halves when cut through the central axis. They are triploblastic with three proper embryonic layers namely endoderm, mesoderm, and ectoderm.
- They also contain a pseudocoelom, a pseudo cavity, present between the gut and the body wall.
- They are very rarely found in marine or freshwater habitats. Most of them are endoparasites, live inside the body of a host organism.
For example, Ascaris, Wuchereria, etc.
