Question

Give distinguishing characters of phylum Annelida and give five examples of this phylum.

Answer 1

The Phylum Annelida is part of the kingdom of Animalia and is a very large phylum. The Annelids are found in marine and terrestrial ecosystems. Invertebrate animals are bilaterally symmetrical. Their segmented body distinguishes them from any other species.

Complete answer:
Characters of phylum Annelida are:
1. Symmetrical and vermiform in bilateral terms.
2. The cavity of the body is a genuine Coelom.
3. The gut of the body comprises the mouth and anus.
4. There are 3 different parts in the body, a prostomium, a trunk and a pygidium.
5. It has an anterior nerve ring, ganglia, and ventral nerve cord in the nervous system.
6. There is a genuine closed circulatory system in it.
7. Sexual reproduction and hermaphroditic reproduction are seen.
8. The Annelids have a very common feature of regeneration.
9. Setae support them with movement, via their corporal surface, they breathe.
10. The excretory organs are Nephridia.
11. They have a well-developed mechanism that is circulatory and digestive.
12. Haemoglobin is found in their bodies, which gives them a red hue.
13. Earthworms, Leeches, Polychaetes, Nereis (Sandworms), and Syllis are members of the Annelida phylum.

Note: Polychaeta is a class of phylum Annelida. The body of animals belonging to this class is elongated into segments and separated. They are found in the marine world. There are true coelomates in this class, worms that are bilaterally symmetrical. They are eliminated by metanephridia and protonephridia. Fertilization is internal. Oligochaeta is another class of the same phylum. The species belonging to this phylum are both terrestrial and freshwater organisms. The body is metamerically segmented. The head, eyes, and tentacles are not different from each other. They're hermaphrodites, so there's cross-fertilization. The fertilization is external.