1 Phylum Platyhelminthes Flatworms FlukesTapeworms Monogenian.
Worm Phyla: Platyhelminthes (flatworms - acoelomates) Platyhelminthes (flatworms - acoelomates)...
-
Upload
georgia-shelton -
Category
Documents
-
view
223 -
download
1
Transcript of Worm Phyla: Platyhelminthes (flatworms - acoelomates) Platyhelminthes (flatworms - acoelomates)...
Worm Phyla:Worm Phyla: Platyhelminthes Platyhelminthes (flatworms - (flatworms -
acoelomates)acoelomates)
Nematoda Nematoda (roundworms - (roundworms - pseudocoelomates)pseudocoelomates)
Annelida Annelida (segmented worms – coelomates)(segmented worms – coelomates)
Phylum #1 Phylum #1
PlatyhelminthesPlatyhelminthes(flatworms)(flatworms)
Classes:
1. Turbellaria (free-living)
2. Trematoda (parasitic)
3. Cestoda (parasitic)
Phylum Platyhelminthes ("flatworms")
Evolved from Cnidarians, gained bilateral symmetry and developed excretory, nervous and reproductive systems. Bilateral, acoelomates. Digestion = single opening (mouth and pharnyx) and digestive cavity. Excretory = flame cells excrete wastes. No circulatory or respiratory systems; diffusion only for O2 / CO2 exchange. Sexual (hermaphrodites) and asexual reproduction regeneration.
Class #1Class #1
TurbellariaTurbellaria(Phylum Platyhelminthes)(Phylum Platyhelminthes)
free-living scavengers branched intestines with pharynx tube eyespots, can learn (chopped up & fed to others...) hermaphroditic; sexually reproduce
A variety of marine
turbellarians
Eurylepta
This turbellarian flatworm mimics a (very unsavory) sea slug
Marine Flatworms mating
Class #2Class #2 Trematoda - Trematoda -
flukesflukes (Still Phylum (Still Phylum
Platyhelminthes)Platyhelminthes) Parasitic (species-specific) Thick, protective "tegument" resists acids/enzymes No digestive system (diffusion only for gases / food) no eyespots; very little cephalization
Ex: Swimmer's itch, Schistosoma, Liver flukes
Sheep liver fluke
Sheep livers with trematode fluke
Schistosoma male/female
Schistosoma
male / female
blood flukes
Typical Schistosoma eggSchistosome eggs, which may become lodged within
the hosts intestinal wall or in liver, are the major cause of pathology in schistosomiasis.
Class # 3Class # 3
CestodaCestoda ((tapewormstapeworms)) (still Phylum Platyhelminthes)(still Phylum Platyhelminthes)
• parasites (mostly mild symptoms in well-nourished people)
scolex (head with hooks) proglottids (egg cases)
Ex: Diplydium (cat intestines feces larval fleas adult fleas another cat ingested by licking fur)
Scolex of tapeworm
Nereis closeup
Methane hydrate deposits on the ocean floor teem with Methane hydrate deposits on the ocean floor teem with life. Residents include ferocious polychaete ice worms life. Residents include ferocious polychaete ice worms that burrow into the formations and defend their lairs that burrow into the formations and defend their lairs
against intruders.against intruders.
Tapeworm (Class Cestoda)
•Scolex and proglottids
PhylumPhylum Nematodes Nematodes (roundworms)(roundworms) Evolution- gained body cavity Evolution- gained body cavity (pseudocoelom), separate sexes, (pseudocoelom), separate sexes, and complete digestive system (2 and complete digestive system (2 openings). Bilateral symmetry. openings). Bilateral symmetry. Dioeciuos– not hermaphrodites. Dioeciuos– not hermaphrodites. Complete digestive system (two Complete digestive system (two openings). Circulation and openings). Circulation and respiration through diffusion.respiration through diffusion.
Nematodes are pseudocoelomates
DISEASESPinworm (Enterobius sp.): eggs swallowed (dust/food) lg. intestine (lay eggs) anus (itching)
Lungworm (Ascaris sp.): eggs swallowed penetrate to lungs throat swallowed intestine (lay eggs)
Trichinosis: cysts ingested (pork, bear) intestine (pain, diarrhea, fever) blood muscles (lumps, pain)
Hookworm (Huck Finn disease): bloodstream push abdomen through intestine eggs outside
Brainworms, heartworms, Guinea worms (“the fiery serpent” makes great tattoos!), Filaria (clog lymph: elephantiasis), Loa loa (eyeworms)
The Fiery Serpent- Guinea Worm
Trichina-- a roundworm (nematode) common in pork• picture shows capsule embedded in muscle tissue.
• enters host via raw or poorly cooked meat
• eggs shed in the gastrointestinal tract--> feces
• eggs eaten by herbivores --> encyst in muscle
• encysted worm is resistant to antihelmithic drugs.
Heartworm-- a parasitic nematode
Pinworms-- infections of kids (itchy eggs!)
Reminder: Kingdom Animalia; Phylum Nematoda
Phylum Annelida Phylum Annelida The The Segmented WormsSegmented Worms
Evolution-development of coelom.Cephalization! Well-developed nervous system: nerve cord with ganglion in each segment and anterior brain Bilaterally symmetricalOrgans within a true coelom (cavity within mesoderm)Compartmentalization of organs / movement of parts of bodyClosed circulatory system with five pairs of “aortic arches”Most have red hemoglobin in blood (efficient) Sophisticated digestive system:
mouth pharynx esophagus crop gizzard intestine anus
Appendages: Setae &/or parapodiaExcretion- Nephridia remove nitrogenous wastes; wets skinRespiration—use diffusionMost hermaphroditic, some dioecious.
Classes of Annelids
Oligochaeta: earthworms, nightcrawlers, (aquatic) tubifex worms
20-45 tons of soil/year/acre processed by worms on organic farms each worm processes its own weight each day
Polychaeta: bristleworms, tube worms, featherdusters
marine worms with parapodia and (most) jaws!
Hirudinea: terrestrial / aquatic leeches
some parasitic, some free-living•medicinal anticoagulant “hirudin”
Fanworm
A filter-feeding A filter-feeding polychaete: feather-polychaete: feather-
dusterduster
Bristle-worm (nereis)
The medicinal leech is best known as the organism used for blood letting (people used to believe many health problems caused by "bad" blood). They are being used once again to remove blood from hematomas (areas of blood leakage) resulting from surgery (like re-attaching severed limbs, etc.).
http://www.sp.uconn.edu/~mcbstaff/graf/AvHm/MedUsemain.htm