How do annelid animals differ from arthropods?


-Priyanti, Subject Matter Expert at Edumarz

Solution: Both annelids and arthropods have segmented bodies. Annelida have metameric segmentation and their bodies are not distinguished into head, thorax and abdomen. Arthropods, however, have well-developed cephalic, thoracic and abdominal regions.

Annelids have unsegmented appendages and arthropods have segmented or jointed appendages.

Annelids have true coelom (schizocoel) while arthropods possess a coelom filled with circulatory fluid (haemocoel). This is due to the fact that the latter have an open circulatory system as opposed to the former, whose circulatory system is closed.

Annelids have red blood as they have hemoglobin as their respiratory pigment. In arthropods, blood is colorless or bluish as they lack respiratory pigments.

Annelids have organs like setae, cilia and nephridia that arthropods don’t. The latter group possess a chitinous exoskeleton which the other lacks.

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