Segmented Worms

Segmented worms

3 major classes:

Polychaeta

Oligochaeta

Hirudinea

Segmentation - Allows movement with maximum protection.

• Each segment contains repetition of excretory, movement organs.

Polychaetes

1. Live in the ocean (marine)

2. Many chaetae (chitinous hairs)

3. Movement

a. Each segment has paired parapodia for

swimming/crawling.

b. May burrow, using peristalsis

Oligochaeta

1. Live in freshwater, land, ocean

2. Few chaetae (chitonous hairs)

3. Movement

a. Most burrow with peristalsis.

Muscular contractions of body, using both

longitudinal and circular muscles.

b.Use chaetae as anchors.

Hirudinea

1. Mostly freshwater, some marine.

Like to live in ponds.

2. No chaetae

3. Movement

a. Have suckers on both ends

b. Move like inchworms

Examples:

Earthworm

Arenecola

Bristle worms