Annelida Phylum

The Annelida phylum consists of the segmented worms. They lack a backbone and have bodies divided up into many segments. This phylum includes earthworms, leeches, and feather duster worms. Some species are terrestrial, while others are found in marine environments.

Animals in this phylum have segmented bodies. Most of the segments have the same internal organs. However, the forward and rear segments are slightly different. The forward segments have the mouth and brain. The rear segments have a growth area and an anus. Some annelids breathe through their skin. Others have gills. Some species reproduce asexually, but most reproduce sexually. Most annelids have a pair of body cavities (coelem) in each segment.


Within the phylum there are two main classes. These are the Polychaetes and the Clitellates. The Polychaetes includes the bristle worms. The Clitellates include the earthworms and leeches.

There are over 22,000 species in the phylum Annelida.


Annelids are found throughout the world. They may be terrestrial or aquatic in terms of their habitat.

Humans and Annelida

Many species of Annelida are important to human life. Earthworms and other terrestrial annelids loosen the soil and help fertilize it with their waste. Marine annelids also modify their environments by burrowing into the ocean bottom.

Historically, leeches were used for medicinal purposes – through blood letting. Today, some leeches are still used in some types of surgery.

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The Phylum Annelida,


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12 comments on "Annelida Phylum: the Segmented Worms"

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Ronand Abella

Ang mga hayop ay nag pakita nang mang anito.Kaya ito ay nag halag nag mga ibat ibat tao .Kayito ay nag papahalaga patramarami tayo agawa.

Ronand Abella

Annelida Phylum’is in the Animalia kingdom or animal kingdom.
Annelida – They have no legs, and no hard skeleton.(invertebrates).
An invertebrate is an animal that does not backbone.
The other is vertebrates, have vertebrate is an animal that backbone.

Webster Gabiana

Ang Annelida phylum ay at segmented worm.

Webster Gabiana

The Annelida phylum is the segmented worms.
The phylum consists of earthworms, leeches and bristle worms.
Some species play an important role in agriculture and coastal environments.

Webster Gabiana

ang natotonanko ay ang mang worms ay kaparihas lang ng tao.