1. Annelida
dissection
annelids

2. Taxonomy Kingdom Animalia Phylum Annelida
Class Hirudinea Class Polychaeta
(Leeches) (segmented sea worms)
Class Oligochaeta
(earthworms)

3. Annelida Annelid = ringed
Examples: earthworms, leeches, segmented sea worms, feather duster worms, tube worms

4. General Characteristics
Found in all place on Earth
Over 15,000 named species
Made up of many segments called metameres
True coelomates with well-developed internal organs and systems
Have hair-like structures called setae made of chiton

5. Body Plan Body Plan: 3 regions: head, metameres and pygidium (tail)
Segmented (metameres) and have bristles (setae or chaetae)

6. Segments
Segments:
Metameres: external segments that contain muscles for movement
Septa: internal segments that contain vital organs
Clitellum: large segment containing reproductive organs during times of mating
Pygidium: the un-segmented tail end of the worm

7. Digestion
Digestion: mouth  pharynx  esophagus  crop  gizzard  intestines anus
Some are filter feeders some feed on decaying matter in the soil

8. Circulation
Circulation: closed circulatory system with an aortic arch with 5 hearts
Blood vessels bring gases and nutrients to all parts of the body

9. Respiration System
Respiration: in most annelids, gas exchange occurs through the skin so they have to be kept moist
Other marine worms have gills

10. Nervous System
Nervous System: consists of a brain and a central nerve cord
Sensory organs include eyes, taste buds, tentacles, and equilibrium sensors

11. Movement
Movement: movement is made possible by muscles and bristles (setae)

12. Reproduction
Sexual: Monoecious or Dioecious but do NOT fertilize their own eggs
Asexual: fragmentation, budding, or fission

13. Ecological Importance
Feed on decaying matter
Recycle nutrients making soil fertile
Aerate soil and give it structure
Food source to many other organisms
Used in medical treatments: leeches
leech therapy

15. Class Polychaeta Over 10,000 known species
Live in all oceans and at all depths
Have many bristles called chaetae
Predators, scavengers, parasites or filter feeders

16. Fire Worm

17. Fire Worm

18. Coco Worm

19. Feather Duster Worm

20. Tube Worms

21. Lugworm

22. Sand worm

23. Class Oligochaeta Over 10,000 known species
Very few or small bristles called setae
Move with peristaltic muscle movement
Feed on decaying mater or are predators
Live in water or in soil

24. Night crawlers

25. Mekong worm

26. Pot worm

27. Ice worm

28. Black worm

29. Class Hirudinea Most are parasitic, Over 700 species
Do not have bristles
Have suckers at each end of their bodies
Used in medical treatments
annelid dissection

30. Leeches