1. The segmented worms “annelus” - little ring ZOOLOG Y Southern Boone County High School Bill Palmer

2. TYPICAL ANNELIDS Segmented worms –Earthworms –Leeches –Bristleworms

3. ANNELIDS-Characteristics 12,000 species Tube-within-a-tube Structure Bilateral Symmetry Mouth and Anus Setae (tiny bristles) –Help annelids to move Terrestrial, Marine, and Aquatic

4. ANNELIDS-Characteristics All have segments (Like stacked donuts)

5. General characteristics segmented body closed circulatory system each segment has paired excretory nephridia, nerves nervous system with double ventral nerve cord- ganglia for brain

6. body wall with longitudinal and circular muscle setae/ bristles in skin used for locomotion respire through skin or with gills

7. 3 variations in setae structure

8. 3 classes of Annelida Class Polychaeta – mostly marine fanworms, bristle worms, tube worms Class Oligochaeta - earthworms Class Hirudinea - leeches

9. Marine tubeworms, fanworms and bristle worms Most primitive class- have well developed anterior end (head)

10. lots of variety and color in marine species

11. Setae on parapodia Marine polycheate – bristle worm

12. Bristle worms Fleshy parapodia

13. Marine fanworm Ciliated feathery tentacles for feeding tube

14. Feather duster worms ( Polychaetes) Filter feeder

15. Feather Duster worms

16. Giant tube worms ( 4 ft long) in ocean thermal vents

17. Calcareous (limestone) tubes of marine annelids

19. Earthworms are important Aerate soil Food chains

20. Bloodworm - Marine species Lives in mud at ocean bottom Great fishing bait !

21. Polychaeta worm larva – pelagic ( planktonic ) Branching nerves

22. Polychaete larva

23. the leeches parasites

24. Leech Suction disk Segmentation evident

25. Leech

26. 3 pairs of eyes

27. The earthworms plus some freshwater species

28. Flatworm meets Annelid Crime scene Scotland

29. Earthworm gathering

30. Fossil Polychaete worm Bristles and segmentation evident

31. Spriggina fossil Precambrian segmented invertebrate Segmented body ( metamerism )

32. Trochophore larva- typical of some annelids Mollusca phylum also has trochophore Larvae… suggesting related evolution

33. Wrap-ups How many species of annelida are there? What are the characteristics of annelida? What are the three classes of annelida? List three reasons why earthworms are important. How are leeches used in medicine?