Annelida

How many of you have come upon an earthworm in your yard or farm? Earthworms belong to the Phylum Annelida. There are several different body types in the Phylum Annelida. Annelids can be encountered in terrestrial, marine, and freshwater environments, although they require water or humidity to survive in terrestrial habitats. A Phylum Annelida includes earthworms, polychaete worms, and leeches. They’re also referred to as segmented worms due to various their metameric segmentation. Animals in this phylum create parasitic and commensal symbiotic relationships with other species in their surroundings. There are around 16,500 species in the phylum Annelida. These phylum includes earthworms, polychaete worms, and leeches.All across the embryonic level, annelids are usually referred to as “segmented worms” due to their key trait of metamerism, or true segmentation.

Annelida History

Annelida have a long history; early Zoologists classified them among other unbranched worms in the Phylum Vermis. However, a French zoologist named George Cuvier split them from the Phylum Vermis in 1798. The higher segmented worms were given the name Annelida by another French zoologist, Lamarck, in 1809. Its name Annelida comes from the Latin word “Annellus,” meaning “little rings.” Its phylum Annelida has around 16500 species.

Annelida is a phylum of plants. 

Annelida are coelomate invertebrates with a metamerically segmented body made up of little rings like segments that are triploblastic and bilaterally symmetrical.

Some Annelida Phylum Characteristics are given below 

1. Their body is segmented and lengthy.
2. Annelids are symmetrical on both sides.
3. They have a triploblastic structure.

4.They also demonstrate organ differentiation and organ system grade of organisation.

5. A narrow cuticle covers the whole body.

6.They have a coelomate relationship. There is a bodily cavity, or coelom, present.

7. Annelids like wet settings, such as damp soil, freshwater, and seawater.
8. For movement, they have parapodia and chitinous setae.

9.The presence of haemoglobin causes their body to appear red.

10.The nerve and excretory systems are both available.

11.The digestive system is well-developed and comprehensive.

12. Respiration occurs as a result of the overall surface of the body.

13.The circulatory system of these invertebrates is completely closed.

14. Hermaphrodites are people who have both male and female sexes.
15. Fertilisation can take place either internally or externally.

What is the Phylum Annelida classification?

Barnes (1987) classified Annelida into three groups. The following are the details for these three classes:

1. Polychaeta 

2.Oligochaeta  

3. Hirudinea.

Polychaeta 

(a) They are the most numerous annelids.

(b) This is mainly found in coastal areas.

(c) These have distinct tentacles and eyes on their heads.

(d) These are either monoecious or dioecious.

(e) Parapodia, which comprises numerous chitinous bristles termed setae, is employed for mobility.

(f) They are devoid of clitellum.

They are hermaphrodites, in case you didn’t know.

(h) Throughout their progress, the trochophore larva is created.

2. Oligochaeta 

(a) These are mainly terrestrial and freshwater. 

(b) They don’t have a distinguishable head. There are no tentacles or palps.

(c) They have a closed circulatory system.

(d) They are monoecious

(e) Peristalsis is the mechanism of locomotion. There are no parapodia or setae.

(f) They are hermaphrodites, in case you didn’t know.

(g) A principal excretory organ is the nephridia.

(h) Throughout development, the larval stage is not present.

3. Hirudinea 

 (a) They are mostly freshwater, with a few marine, parasitic, and terrestrial species thrown in for good measure.

(b) Body flattened dorsoventrally.

(c) The anterior and posterior suckers are responsible for locomotion.

(D) They are monoecious 

(e) There are no parapodia or setae.

(f) The majority of them are hermaphrodites.

(g) Their bodies are segmented. An annulus is a circular ring that surrounds each segment.

(h) During development, the larval stage is not present.

Some examples of Annelida 

1.Earthworm

A phylum Annelida includes earthworms, which are terrestrial invertebrates. It features a tube-within-a-tube body design, external segmentation that corresponds to internal segmentation, and setae on all segments.   It may be found everywhere there is suitable soil, water, and temperature. 

2.Leeches

Blood suckers (Leeches) are parasitic or predatory worms with segmented bodies that belong to the Hirudinea subgroup of the phylum Annelida. These are linked to oligochaetes, which also include earthworms, and have soft, muscular, segmented bodies that may extend and shrink like them.

Conclusion 

Earthworms belong to the Phylum Annelida. A Phylum Annelida includes earthworms, polychaete worms, and leeches. There are around 16,500 species in the phylum Annelida. Annelida have a long history; early Zoologists classified them among other unbranched worms in the Phylum Vermis. Annelida is a phylum of plants. Annelida are coelomate invertebrates with a metamerically segmented body made up of little rings like segments that are triploblastic and bilaterally symmetrical. A phylum Annelida includes earthworms, which are terrestrial invertebrates. Leeches Blood suckers are parasitic or predatory worms with segmented bodies that belong to the Hirudinea subgroup of the phylum Annelida.