MARINE WORMS

Types of Marine Worms

• Phylum *Platyhelminthes – flatworms• Phylum Nemertea – ribbon worms• Phylum Nematoda – roundworms• Phylum Chaetognatha – arrow worms• Phylum Pogonophora – deep-sea tube

worms• Phylum Sipunculida – peanut worms• Phylum *Annelida - segmented worms

Phylum Nemertea – ribbon worms

Phylum Nemotoda - roundworms

Phylum Chaetognatha – arrow worms

Phylum Pogonophora – deep-sea tube worms

Phylum Sipunculida – peanut worms

Phylum Platyhelminthes – flatworms

• Includes tapeworms, freshwater planaria, parasitic flukes• Some parasites, many free-living

predators and scavengers• Can cause swimmer’s itch in

people

Phylum Platyhelminthes – flatworms

tapeworm planaria

parasitic fluke

Phylum Platyhelminthes – flatworms• Flattened

• Lack segmentation• Bilateral symmetry – simplest organisms

to have it• Acoelomate – no body cavity

Phylum Platyhelminthes – flatworms

• Mouth and anus are same spot

Phylum Platyhelminthes - flatworms

• Central nervous system (simplest organisms to posess) – bunch of nerve cells (ganglion) and two nerve cords

• Light sensitive eyespots• Three layers of cells

Phylum Platyhelminthes – flatworms

• Beginning of organ development• No true respiratory, excretory system –

diffusion through surface• Sexual (and asexual) reproduction -

hermaphrodites

Phylum Platyhelminthes – flatworms

Phylum Annelida – segmented worms

• Includes earthworm, leeches, marine polychaetes (bristle worms)

• Body divided into ring-like segments• Thousands of species

Phylum Annelida – segmented worms

Phylum Annelida - Polychaetes

• Most common types of marine annelids• Have external, paddle-shaped structures

(parapodia) with chaetae or bristles–external gills or appendages

Phylum Annelida – segmented worms

• Coelom – fluid-filled body space – between digestive tube and body wall

Phylum Annelida – segmented worms

• Hydrostatic skeleton – uses fluid in coelom – helps animal move

• One-way digestive tube - mouth and anus

• Bilateral symmetry

Phylum Annelida – segmented worms

• More developed organ systems:–Digestive system–Nervous system–Circulatory system•With hemoglobin to carry oxygen•Closed – blood in veins, arteries and

capillaries

Phylum Annelida – segmented worms

Phylum Annelida – segmented worms

• Many lifestyles:- burrow- swim- sessile- live in tubes

Phylum Annelida – segmented worms

• feeding strategies:Parasites - attach to other organisms

and feed through suckers

Phylum Annelida – segmented worms

• feeding strategies:Suspension feeders – trap particles

floating in water

feather duster worm Christmas tree worms

Phylum Annelida – segmented worms

• feeding strategies:Deposit feeders – eat particles that have

fallen to sea floor

Phylum Annelida – segmented worms

• feeding strategies:Predators – use “teeth” to grab prey

Phylum Annelida – segmented worms

• Nereis sp. – sandworm, clamworm–used for bait