1. Annelida
The segmented worms

2. Defining Characteristics
Circular rings of muscle allow back and forth movement.
Segmented body
Tube (digestive system) within a tube body plan.

3. Segments of Annelids
Each segment is identical, but adapted for specific function.
Two nerve cords connect each segment to a central brain.

4. Setae
Bristles on each segment
Anchor the worm in soil & give traction

5. One-way Digestive System
Mouth to pharynx to esophagus (throat) to crop (storage area) to gizzard (grinds food) to intestines (digestion) to anus
Feces are called castings – fertilize soil

6. Reproduction
Earthworms are hermaphrodites – have both male and female parts.
During mating, both worms inseminate the other
Both worms
become
pregnant

7. Clitellum The clitellum is only found on a sexually mature worm
The clitellum is used to hold the embryo after mating.

8. 3 main groups of segmented worms:
Bristleworms: setae cover each segment
Earthworms: a few setae per segment
Leeches: no setae; flat-bodies; parasitic

9. Earthworms Live mostly underground
Earthworms are very important to vegetation because:
They create channels underground for water and air to flow
Channels allow roots to spread
They loosen soil and fertilize it with castings

10. Earthworm Anatomy

12. Bristleworms Many setae per segment
Parapodia on each segment are used to swim or crawl

13. Leeches Flat body No setae
Most are freshwater parasites that suck blood
Saliva contains anesthetic and anticoagulants so host can’t feel bite and blood will flow quickly.
Ingests 2 – 5 times its weight in one meal
May only eat once yearly

14. Name that worm…. 2.

15. Name that worm…. bristleworm 2. flatworm - planarian
3. Annelid - leech 4. roundworm - Ascaris

16. Name that worm….

17. Name that worm…. 1. Flatworm - fluke 2. annelid - earthworm
3. Roundworm - pinworm 4. Flatworm - tapeworm

18. Name the worm & the part….1. 2. 3. 4.

19. Name the worm & the part….
Setae – annelid
(bristleworm)
2. Scolex – flatworm
(tapeworm)
3. Proglottids - flatworm
4. Clitellum – annelid
(earthworm)