1. Ribbonworms, Roundworms, and Rotifers

2. Phylum Rhynchocoela (Ribbon-worm) Longest worm Longest worm Free living, marine Free living, marine Long proboscis (muscular thin tube that thrust out to capture prey) Long proboscis (muscular thin tube that thrust out to capture prey) Acoelomate  no body cavity Acoelomate  no body cavity Digestive tube with opening at both ends Digestive tube with opening at both ends Have circulatory system Have circulatory system Thought to have evolved from flatworms Thought to have evolved from flatworms

3. Nematode (Round-worm) Bodies shaped like sharpened pencil Bodies shaped like sharpened pencil Free living, active hunters Free living, active hunters Have a complete gut Have a complete gut Most parasitic Most parasitic Separate sexes- diecous Separate sexes- diecous It is thought that eggs could last thousands of years It is thought that eggs could last thousands of years

4. Nematodes May be most important animal group May be most important animal group They are everywhere They are everywhere 1 apple – 50,000 to 90,000 (no such thing as a vegetarian) 1 apple – 50,000 to 90,000 (no such thing as a vegetarian) Bilateral symmetry Bilateral symmetry No cilia or flagella – only amebode No cilia or flagella – only amebode

5. Nematodes Pseudocoelom  body cavity located between endoderm and mesoderm Pseudocoelom  body cavity located between endoderm and mesoderm This evolution of a body cavity allows for This evolution of a body cavity allows for Circulation but no heart Circulation but no heart Movement-makes body more rigid Movement-makes body more rigid Organ function-body organs can function without being distorted Organ function-body organs can function without being distorted

6. Ascaris Ascaris  can infect humans-eggs in soil for years-eggs get into blood and is carried to the lungs where the larva cause respiratory distress and can also get in your intestines Ascaris  can infect humans-eggs in soil for years-eggs get into blood and is carried to the lungs where the larva cause respiratory distress and can also get in your intestines Most common human worm infection Most common human worm infection Common in tropical and subtropical areas where sanitation and hygiene are poor. Common in tropical and subtropical areas where sanitation and hygiene are poor. Past by human or pig fecal material Past by human or pig fecal material

7. Necator Necator  Hookworm-moist soils of the tropics-bores into soles of the feet-causes anemia Necator  Hookworm-moist soils of the tropics-bores into soles of the feet-causes anemia Infects host when an infective larva penetrates the host's skin. The juvenile worm migrates through the host's body and finally ends up in the host's small intestine where it grows to sexual maturity. Infects host when an infective larva penetrates the host's skin. The juvenile worm migrates through the host's body and finally ends up in the host's small intestine where it grows to sexual maturity. A hookworm’s mouthparts are modified into cutting plates. Attachment of hookworms to the host's small intestine causes on form of hemorrhages, and the hookworms feed on the host's blood. A hookworm’s mouthparts are modified into cutting plates. Attachment of hookworms to the host's small intestine causes on form of hemorrhages, and the hookworms feed on the host's blood.

8. Trichinella Trichinella  found in pigs-can infect humans if eat pork that isn’t cooked well-infects muscles in humans Trichinella  found in pigs-can infect humans if eat pork that isn’t cooked well-infects muscles in humans Worse than eating raw chicken Worse than eating raw chicken Mealy grainy pork – DON’T EAT!!!!!!!!!!!!! Mealy grainy pork – DON’T EAT!!!!!!!!!!!!! Higher in prevalence in people living in parts of Europe, Asia, and Southeast Asia than in the United States. Higher in prevalence in people living in parts of Europe, Asia, and Southeast Asia than in the United States. The life cycle is completed with the larvae encysting in striated muscle, hence why you can get it by eating uncooked meat. The life cycle is completed with the larvae encysting in striated muscle, hence why you can get it by eating uncooked meat. Causes fever, edema, muscle weakness and tenderness Causes fever, edema, muscle weakness and tenderness

9. Pinworm Pinworm  females crawl out of anus and lay eggs- 50% of college students have pinworm at sometime. Pinworm  females crawl out of anus and lay eggs- 50% of college students have pinworm at sometime. Intestinal infection Intestinal infection Biggest symptom is an itchy butt Biggest symptom is an itchy butt

10. Filarial Filarial worms  cause elephantitis- enlargement of body parts due to blocked ducts. Filarial worms  cause elephantitis- enlargement of body parts due to blocked ducts. Mosquitoes are reservoir host Mosquitoes are reservoir host Infects 120 million people a year, infects mostly in India, Africa and Asia. Infects 120 million people a year, infects mostly in India, Africa and Asia. These worms lodge in the lymphatic system, the network of nodes and vessels. These worms lodge in the lymphatic system, the network of nodes and vessels.

11. Rotifers Free swimming hunters (mostly freshwater that is still) Free swimming hunters (mostly freshwater that is still) Swim with cilia- crown head called Corona Swim with cilia- crown head called Corona Makes them appear to whirl like a wheel Makes them appear to whirl like a wheel Feed on bacteria and protist Feed on bacteria and protist Some species have been known to be cannibalistic Some species have been known to be cannibalistic One way gut One way gut Pseudocoelom Pseudocoelom 99% female 99% female

12. Homework 1. Why might it be accurate to describe ribbonworms as a transitional group between flatworms and roundworms? 2. Compare and contrast ascaris and necator.