Worms, Worms, Worms!

1. Worms, Worms, Worms! The wiggly world of wild and wonderful worms

2. Taxonomy Road Map • Kingdom: Animalia • Phylum : Platyhelminthes(Flatworms) • Class: Turbellaria (Turbellarians) • Class: Cestoda (Tapeworms) • Class: Trematoda(Flukes) • Phylum: Nematoda(Roudworms) • Family: Oxyuridae(Pinworms) • Family: Ancylostomatidae (Hookworms) • Family: Filariidae(Filarial Worms) • Family: Ascaridae(Ascarids)

3. Flatworms • only a few cells thick • bilateral symmetry • muscles to move • no circulatory or respiratory system • have 3 tissue layers • ectoderm • mesoderm • endoderm • free-living or parasitic p.663

4. Flatworms - Anatomy • cephalization – nerve bundling at one end • primitive “head” • two main nerves • acoelomate – lack of a true body cavity • one body opening • hermaphrodite – have both male and female reproductive cells • sexual reproduction (don’t self-fertilize) • asexual reproduction (by fragmentation) “head” Planarian (Turbellarian) p.664

5. Flatworms - Turbellarians • marine • most are predators • some move with cilia in addition to muscles p.665

6. Flatworms - Tapeworms • endoparasites in intestine of host • 1mm – 10m long • hooks and suckers for attachment to host • absorb nutrients through their skin • proglottid – body segment with reproductive organs that break off when mature p.665

7. Flatworms - Flukes • endoparasites in intestine or ectoparasites on fishes • tegument – protective outer layer • hooks and suckers for attachment to host p.666

8. Flatworm – Flukes - Disease Schistosoma - blood fluke 4-stage life cycle • eggs are found in water (Africa, Asia, S.America) • first larval stage enter intermediate host (snails) • second larval stage can reproduce asexually • larvae enter human host through skin or ingestion and cause damage to liver and intestine (schistosomiasis) • eggs are shed in urine and feces

9. Taxonomy Road Map • Kingdom: Animalia • Phylum : Platyhelminthes(Flatworms) • Class: Turbellaria (Turbellarians) • Class: Cestoda (Tapeworms) • Class: Trematoda(Flukes) • Phylum: Nematoda(Roudworms) • Family: Oxyuridae(Pinworms) • Family: Ancylostomatidae (Hookworms) • Family: Filariidae(Filarial Worms) • Family: Ascaridae(Ascarids)

10. Roundworms • round in cross-section • bilateral symmetry • better muscle movement than flatworms • has 3 tissue layers • ectoderm • mesoderm • endoderm • free-living or parasitic

11. Roundworms - Anatomy • cephelization – nerve bundling at one end • primitive “head” • two main nerves • pseudocoelom • two body openings • acts as circulatory system (nutrients and oxygen) • separate sexes • sexual reproduction

12. Roundworms - Pinworms • 1 cm long • 50% of school age kids have had it • itching around anus • fecal- oral transmission (from feces to mouth)

13. Roundworms - Hookworms • 1/5 of world population affected • can cause mild diarrhea/ cramps/ anemia • larvae enter through bare feet • move through bloodstream, into lungs, into intestine • attach and suck blood

14. Roundworms – Filarial Worms • live in blood or lymphatic system • mosquito vector • some cause elephantiasis • lymphatic fluid collects in tissues • some cause heartworm in dogs • weakness and fatigue, can lead to death

15. Roundworms - Ascarids • most common human worm infection • contracted through contaminated food/water • lives in intestine of pigs/horses/humans • can cause blockage • feed on host’s food • eggs shed through feces and can live in soil for many years