Polychaete Worms polikeet Classification Kingdom Animalia Phylum Annelida

Polychaete Worms (pol-i-keet)

Classification • Kingdom Animalia – Phylum Annelida (segmented worms) • Class Polychaeta Ø 5000 species ØNearly all marine

Structure • Segmentation – Compartments – Separated by septa (shallow partitions) • Organs – Systems • Digestive • Circulatory • Nervous

Examples

Clam Worm • Nereis – Minimal specialization • Typical polychaete body – Repeated identical body segments – Parapodia » Paired paddle-shaped appendages • Setae move parapodia and are connected to muscles

• Nereis structure – Head • 2 segments – Prostomium » Sensory – Light, chemical, tactile – Peristomium » Mouth • Contains the proboscis • Folded structure that can extend from body with muscles • Holds jaws that move with body’s fluid pressure

Clam Worm • Diet – Carnivores – Omnivores • Including scavengers – Herbivores • Habitat – Rocky intertidal – Burrow into mud and sand flats

Blood Worm • Glycera – Structure • Possesses large proboscis – 1/5 of body length – Has 4 short antennae » Each with a poison gland » Sense changes in water pressure • Can be as large as 20 in – Makes nest of galleries (burrows)

Lug Worm • Arenicola – Deposit feeder • Makes an L-shaped burrow – Opens its mouth to pass sand through it’s digestive system – Removes organic matter (nutrients) – Creates a fecal mound (caste)