Question

The main features of annelids. How can they be described according to examples of representative species, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction?

Answer 1

Earthworm is one of the most familiar annelids. Other common example of annelid is leech.

Characteristics:

1) They have bilateral symmetry

2. Triploblastic

3. coelomate

4. they have external segmentation that corresponds to internal segmentation and each segment has same sets of organs

5. They are protostomes

6. They have ladderlike nervous system; the narvous system is of ganglion type, two ganglion are present in the anterior portion of the annelid that extends as two nerve chords along the length of the invertebrate.

7. Closed circulatory system

8. Complete digestive system, with mouth, esophagous and excretory outlet

9. Respiration is through the skin of the annelid

10. Excretory system- metanephridia for removal of liquid waste.

11.They may behermaphrodites,male or female.

12. They undergo both sexual and asexual reproduction (by budding)

13. fertilization is external, the egg develops in trocophore larvae that metamorphosizes into adult annelid