AP BIOLOGY

Detailed explanation-1: -annelid, phylum name Annelida, also called segmented worm, any member of a phylum of invertebrate animals that are characterized by the possession of a body cavity (or coelom), movable bristles (or setae), and a body divided into segments by transverse rings, or annulations, from which they take their name.

Detailed explanation-2: -Annelids are often called “segmented worms” because they possess true segmentation of their bodies, with both internal and external morphological features repeated in each body segment.

Detailed explanation-3: -Annelida segmentation is metameric, meaning their bodies are externally divided into similar segments by annuli. These segments are also divided internally by interior walls called septa .

Detailed explanation-4: -Segmented Worms: Phylum Annelida. The worms in the phylum Annelida (from the Latin root word annelus meaning ring) typically have complex segmented bodies (Fig. 3.43). The body of an annelid is divided into repeating sections called segments with many internal organs repeated in each segment.

Detailed explanation-5: -The characteristics of the organisms present in the Phylum Annelida are as follows: The Annelids are coelomate and triploblastic. They exhibit organ system level organization. Their body is segmented.