Annelida

1. Annelida

2. Introduction & General Characteristic • Annulus = ring • The nearly 1200 species comprising the phylum Annelida are vermiform. • These animals are soft bodies, • The bodies consist of a series of repeating segments. • The serial repetition of segments is known as metamerism.

3. Introduction & General Characteristic…. • The Annelid outer body wall is generally flexible and can play an active role in locomotion. • The thin body wall can serve as a general surface for gas excange. • The cuticle remains permeable to both water and gases (annelids are restiricted to moist environment).

4. Introduction & General Characteristic…. • Annelids segments are generally separated from each other to large degree by septa. • Although some wastes are excreted across the general body surface, excretion generally occurs by means os structure called nephridia • This type nephridium is called a metanephridium. • Annelids distributed among three classes: Oligochaeta, Polychaeta and Hirudinea.

5. Class Oligochaeta (G; few setae) • Approximatelly 3,500 species are described • Only 6,5% are marine, most are found in freshwater or terrestrial habitats. • This organism become widely used as a biomonitor pollution stress. • Have few cetae without parapodia. • The prostoium have no eyes and tentacles. • Gas exchange is accomplisged by diffusion across a body wall.

6. Earthworms: ecological importance • Earthworms bury decomposing plant material from the surface, which builds organic constituent of soils. • • Burrowing aerates the soil and improves drainage. • • "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 organised creatures.“ Charles Darwin, 1881 • • “…the intestines of the earth…” Aristotle

7. Cindy Hale, forest ecologist at Natural Resources Research • Institute at the University of Minnesota-Duluth • Cindy Hale, forest ecologist at Natural Resources Research Institute at the University of Minnesota-Duluth

8. Megascolidesaustralis • Gippsland area of Victoria, Australia. Up to 13 feet (4 meters) in length. Rapid movement in the burrows is accompanied by a distinct gurgling sound. Endangered.

10. Giant Palouse earthworm, Driloleirusamericanus.Specimen collected in 2005 by University of Idaho graduate student Yaniria Sanchez-de Leon, at Washington

11. Anatomy of earthworms • Anterior ¼-1/3 contains the differentiated portions of the digestive tract and the reproductive organs

12. Closed circulatory system • Separation of coelomic fluid and blood. This figure shows capillaries associated with nephridia, presumably for secretory exchanges

13. Chloragogue tissue • surrounds gut and major blood-vessels “liver-like” in synthesizing fat and glycogen

15. Pheretima

17. Mating position

18. Class Polychaeta

19. Complex head, followed by repetitive body segments. • Segments usually have appendages called parapodia

20. Pharynx of some polychaetes is eversible and has mineralized jaws

21. Ventral view of a polychaete head with jaws visible within the pharynx.

22. Polychaetes are very diverse • • Errantia- the errant polychaetes are active predators, such as Nereis • • Sedentaria- the sedentary polychaetes are tubicolous or burrowing forms

25. Fan worm Choelia Acrocircus Portula

26. Deposit feeders tentacles and mucociliary mechanisms to gather small particles from the substrate • • Suspension feeders- ciliated tentacular fans or mucus nets in ventilated burrows to filter food from the water.

29. Some sedentary (menetap) polychaete groups Tubicolous suspension feeders Sabellids- “feather-duster” worms with crowns of tentacles, tubes constructed of mucus and detritus Serpulids- tentacles like sabellids, but hard calcareous secreted tube, sometimes spiral

33. Chaetopterus (parchment tube worm)

34. Weird/aneh sex in polychaetes • Many have sexual stage called an epitoke that is morphologically and behaviorally specialized for sexual reproduction • The epitoke may be produced by metamorphosis, or it may be produced by longitudinal fission (budding).

36. The Palolo worm story • Eunice viridis, Fiji and Samoa. “Explosive” spawning 1-3 nights each year, usually 7th night after the first full moon following autumnal equinox (siangmalamwaktunyasama). • Epitokes swims to surface, millions burst/pecah in unison, forming a slurry of eggs and sperm • Local people feast on the raw worms. • Marks the first day of the traditional Samoan year

37. Trochophore larva of polychaetes

38. A spider crab crawling through a colony of Lamellibrachia sp. Tubeworms.

39. Class Hirudinea • Carnivorous, with oral and caudal suckers used for locomotion and feeding • Not all are bloodsuckers- freshwater leeches that prey on invertebrates are more diverse and common than blood-feeders • There are few marine leeches- they are mainly ectoparasites on fishes, including sharks Use in medicine for bloodletting

40. Characteristics of the Hirudinea

41. Many leeches lay their eggs singly or in groups within cocoons

42. In one clade, the females carry the egg cocoon and the juveniles on their ventral body surface. • Includes common Placobdella (turtle leeches)

43. Significance of leeches • Medical use in blood-letting • Source of useful proteins, esp. anticoagulants Model system for neurobiologylarge, identifiable neurons, simple motor patterns • Popular sport-fishing bait

44. Leech salivary secretions • 1. Anesthetic • 2. Vasodilator (histamine-like) • 3. Antibiotic properties, useful in the treatment of glaucoma. • 4. Anticoagulants/antiproteolytics • hirudin, inhibits thrombin (which activates fibrinogen), bdellin, inhibitor of trypsin, plasmin and acrosin, eglin- potent inhibitor of elastase, cathepsin G, chymotrypsin and subtilisin- blocks inflammatory response • Decorsin- inhibits platelet aggregation

48. Leech anatomy

49. hirudine Haemadipsa/Pacet Haemadipsa