1. Phylums: Platyhelminthes Nematoda Annelida Nemertea
Aquatic Worms
Phylums:
Platyhelminthes
Nematoda
Annelida
Nemertea

2. General Characteristics of Worms
Long, slender soft bodies
Bilateral Symmetry
Classified according to the shapes of their bodies
Phylum Platyhelminthes--flatworms
Phylum Nematoda--roundworms
Phylum Annelida--segmented worms
Phylum Nemertea--ribbon worms
Phyla are pronounced pretty much like they are spelled
Platy-hell-min-these
Knee-ma-toad-uh
Anull-leed-uh
Nem-er-tea-uh

3. Phylum Platyhelminthes a.k.a. Flat Worms

4. Phylum Platyhelminthes
Dorsoventrally flattened- flat back and belly
Simplest animals that contain tissues and organ systems
Acoelomates: no body cavity
Triploblastic: three fundamental cell layers
Epidermis
Mesoderm (parenchyma tissue), which becomes muscle tissue
Gastrodermis
A-see-lo-mates
Ter-bell-are-ee-uh
Tree-ma-toad-uh
Cest-toad-uh

5. Nervous System Auricle: used to sense surroundings
Eyespot: cluster of light-sensitive cells
Ganglia: cluster of nerves that send impulses along two ventral nerve cords to the rest of the body; found near eyespots (primitive brain)
Ladder-like nerve cord
Auricle is article without the t 
Are-ick-le

6. Digestive System Sac-like: one opening; mouth/anus
Intestines distribute food
throughout the body
Fair-inks

7. No circulatory or respiratory system:
Their flat thin bodies allow diffusion to occur through skin and cells
Excretory system:
Flame cells connected to excretory ducts

8. Phylum Platyhelminthes
Both aquatic (freshwater and marine) and parasitic species
Classes:
Turbellaria (flatworms)
Trematoda (flukes)
Cestoda (tapeworms)

9. Class Turbellaria Most are free-living carnivores Most are marine
Some have toxins for protection
Exhibit warning coloration
Characterized by beautiful colors and patterns, many have frilly edges

10. Class Turbellaria

11. Class Turbellaria Movement: Reproductive system:
Benthic: glides along the bottom using well developed muscles and cilia
Reproductive system:
Asexual
stretch its body and break in half; each half can regenerate
Sexual
Hermaphroditic--have both sets of gonads and ducts
Internal fertilization, but NOT self-fertilization
Exchange of egg and sperm from different organisms must occur
Her-maff-ro-did-ic

12. Class Turbellaria

13. Class Turbellaria
Planaria
Can you see the eyespots and intestines?

14. Class Trematoda a.k.a Flukes
All are parasitic
Most adults parasitize vertebrates
Common parasite in fishes, seabirds and whales
Over 6,000 species

15. Class Trematoda
Characterized by having one or two holdfast devices (suckers)
The life cycle of a fluke has two hosts (digenic)
First host is usually a snail, second host is usually a vertebrate.
Examples
Liver flukes
Blood flukes (schistosomes)
common liver fluke Fasciola hepatica

18. Class Cestoda a.k.a. Tapeworms
Adult lives in a host’s intestines, head attaches to the walls by hooks or suckers.
Absorb nutrients from their hosts’ guts directly across their body wall (diffusion)
No digestive system of their own
No respiratory organs
Have both sex organs in segments called proglottids which are released in the host’s feces.
Pro-glot-ids

19. Class Cestoda
Longest tapeworm recorded was found in a sperm whale it was 15 m long (50 ft)!

21. Phylum Nematoda a.k.a. Roundworms

22. Phylum Nematoda a.k.a Round worms
Largest phylum of worms
Cylindrical body shape with tapered ends
No circulatory or respiratory system
Hydrostatic Skeleton
Complete digestive system
Some are parasitic and live in the intestines of other organisms others free living
Sue-doe-see-loam

23. Phylum Nematoda

24. Anisakis (Why I don’t eat sashimi)

25. Hookworms

26. Guinea Worm infection - Roundworm

28. 1.5 billion people worldwide were infected in 2002
Ascaris

29. Wuchereria bancrofti causes elephantaisis

30. Phylum Annelida

31. Phylum Annelida a.k.a. Segmented worms
Segmentation: body consists of similar compartments (rings of an earhtworm)
Triploblastic
Found in freshwater, saltwater and soil
Coelomates; coelom: fluid filled cavity that surrounds the gut and serves as the hydrostatic skeleton

32. Phylum Annelida Digestive system: Circulatory system: Respiration:
Complete, one way
Circulatory system:
Closed (blood does not leave the vessels)
Hemoglobin: binds oxygen
Respiration:
Gills in some species
Diffusion across epidermis is most
Excretory system:
One pair of nephridia per segment (nephridia is an organ = to our kidneys)
Removes waste from coelom and bloodstream

33. Phylum Annelida Muscular system: Nervous system: Reproductive system:
Circular and longitudinal muscles
Nervous system:
Pair of cerebral ganglia (brain) connected to a nerve cord that extends the length of the body
Nerve cord is connected to lateral nerves in each segment
Has sensory cells for touch, taste and perception of light
Reproductive system:
Can have separate sexes or can have both sex organs
Some species can reproduce asexually by budding

34. Classes of the Phylum Annelida
Class Polychaeta
Almost all marine annelids are in this class
Each body segment has a pair of flattened extensions, parapodia, with setae (bristles)
Name means many bristled worms

35. Class Polychaeta Nereis: sandworm Carnivore
Proboscis and jaws to capture prey

36. Class Polychaeta Fanworms and Feather-duster worms
Feathery tentacles covered with cilia used to filter feed
Tubes are made from calcium carbonate or bits of particles semented together with mucus

37. Class Polychaeta
Tube worms

38. Class Polychaeta
Riftia pachyptila Giant Tube Worms

39. Giant Tube Worm
Vestimentiferans

40. Class Polychaeta Giant tube worms: Vestimentiferans
Live near hydrothermal vents
3 meters in length (10 ft)
Bright red tentacles contain hemoglobin
No mouth, stomach or gut
Symbiotic bacteria perform chemosynthesis and provide nutrition to the worm.

41. Class Polychaeta
Hesionidae Onuphidae
Eurythoe complanata

42. Class Polychaeta Tomopteris A bioluminescent polychaete
Lives in abyssal environments
When attacked, they release luminescent particles from their legs to confuse the predator and get away unnoticed

43. Class Polychaeta
Chaetopterus pugaporcinus Yes, it means pig butt worm!
Lives in abyssal environments
This species is so new...they don’t know if this is the adult or larval stage...but they haven’t found sex organs yet...what do you think?

44. Classes of the Phylum Annelida
Class Oligochaeta
Earthworms and other aquatic relatives, found in the mud
Feed on organic matter
Lack parapodia
Name means few bristles
Class Hirudinea a.k.a leeches
Freshwater or moist ground
Sucker at one end
Feed on fish and marine invertebrates
Leeches

45. Class Oligochaeta Branchiura sowerbyi Earthworms Lumbricus terrestris

46. Class Hirudinea

47. Phylum Nemertea

48. Phylum Nemertea a.k.a. Ribbon Worms
Most are marine, usually in shallow waters,
Digestive system:
Complete
Long flexible proboscis to capture food
No respiratory system: diffusion of gases across the skin
Circulatory system: primitive, two pulsating vessels

49. Phylum Nemertea Examples: Lineus longissimus
Has been recorded at 30 meters long, some scientists estimate they may reach up to 60 meters in length while still being only a few millimeters wide

50. Phylum Nemertea