Phylum: Annelida

1. Phylum: Annelida • “ringed”, commonly called segmented worms • Examples: earthworms, marine worms, leeches

2. Traits • Segmented, round, wormlike bodies

3. Traits • Bilateral symmetry

4. Traits • cephalized

5. Traits • Ventral nerve cord

6. Traits • Tube-in-a-tube digestive system with specialized regions

7. Traits • Closed circulatory system – blood doesn’t leave the vessels

8. Traits • Paired nephridia

9. Traits • Respire through their skin

10. Typical invertebrates • Earthworms are about halfway between the simplest and most complex invertebrates

11. Classes Oligochaeta Polychaeta Hirudinea

12. Oligochaeta • “few bristles”, no parapodia • E.g. – earthworms, tubifex worms

13. Benefits of Earthworms • improves aeration • increases water and nutrient movement through the soil  • Castings are rich in nutrients

14. Usually feed on decaying organic matter – can eat ½ -1 times their weight

15. Charles Darwin went so far as to say of earthworms, “It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.” He believed that earthworms are wholly responsible for the top layer of rich soil on the Earth

16. Earthworms vary in size from a centimeter to several meters long

17. Giant Gippsland Earthworm in Australia Up to 15 feet stretched out!

19. Blue luminescent earthworms in Australia

20. Striped earthworm in Australia just discovered in 2007

21. Worm Farming • Used for compost • Sold for fishing bait

22. Tubifex Worms

23. Polychaeta • “many bristles”, have parapodia, largest class of annelids • E.g. – marine worms, tube worms

24. Parapodia • mainly used in respiration

27. Blood worm

28. Bristle worm

29. Venomous Setae If touched, the setae will detach and lodge in the skin causing burning, itching, and numbness from the toxins they contain

32. Tube Worms – make a tube for protection

37. Marine worms

38. Oligochaeta Polychaeta Hirudinea

39. Hirudinea • No bristles or parapodia, have suckers • E.g. – leeches (blood suckers)

43. Leeches are Ectoparasites

44. Leach attacking a slug

45. Leech Removal? • use your fingernail or something flat to break the seal of their suckers Irritating them can cause them to regurgitate their stomach contents in the wound, risking infection or disease

46. Medicinal uses • Past – to suck out evil blood, to remove bruises

47. Medicinal uses • Present – reattachment surgery, blood thinner

48. Leech saliva contains compounds that reduce pain, prevent clotting and dilate blood vessels. This prevents the tissue from dying off and allows the body to reestablish good blood flow to the reattached part.

49. Summary: A 45-year-old, white male patient who suffered a complete avulsion of the upper two-thirds of his right ear. The ear was reattached by doing a microvascularanastomosis of a small artery anteriorly. No veins were available for anastomosis. Soon after anastomosis, there was obvious venous congestion. Medicinal leeches were used for treating venous congestion 48 Hours:3 leeches have been applied every 8 hours. Following the initial application, obvious improvement was noted • 24 Hours:Photograph shows severe venous congestion in the reimplanted ear following complete avulsion. • 6 Days:The entire reimplanted ear was viable and healing well. • 72 Hours:3 leeches have been applied every 8 hours for periods of 15 to 30 minutes. Marked improvement in color with decreased swelling and congestion was noted. • Two Months:Complete survival of re-attached ear

50. Also testing to be able to… •  treat arthritis, blood clotting disorders, and varicose veins.