Kingdom Animalia - Phylum - Annelida - (Segmented Worms) | 9th Science : Living World of Animals - Diversity in Living Organism - Kingdom Animalia
Chapter: 9th Science : Living World of Animals - Diversity in Living Organism - Kingdom Animalia
Phylum - Annelida - (Segmented Worms)
Phylum - Annelida - (Segmented Worms)
Earthworms, leeches and a group of marine worms are
included in this phylum. The name Annelida comes from the Greek word “annulations” which are ring like
structures joined together. This is called metamerism
which means the property of having repeated homologous organs in each segment
functioning in coordination with each other. Further these animals are
characterized by the possession of a body cavity called coelom. Some of them have movable bristles called setae involved in locomotion .
The body is covered by a moist outer cuticle, a
thick multi-layered structure outside the epidermis providing protection.
Nephridia are excretory structures and help to remove metabolic wastes. They
have a nervous system with brain (cerebral
ganglia). The most common larva is trochophore.
When you dig garden soil, you may come across
earthworms which are often called-‘the
friend of farmers’. Why are they called so?
Have you heard about leeches? How are they
different from earthworms in feeding habits?
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