Flatworm Characteristics

1. Flatworm Characteristics --Flat bodies (gases move by diffusion)--bilateral symmetry--gastrovascular cavity--some flatworms are parasitic, some are freeliving--they have anterior and posterior heads and exhibit cephalization

2. Types of Flatworms (planarian, tapeworm, fluke) Planarian(also known as Dugesia)--lives in freshwater--mostly a scavenger, also feeds on protists--hermaphrodites--has a simple brain (ganglia) and nervous system, plus 2 eyespots--they can regenerate (regrow parts)

3. Anatomy of the Planarian Brain (ganglia) - planarian can process information about their environmentPharynx - used for suckling food in (the mouth is at the end of the pharynx)Eyespot - simple eye, can detect lightIntestine - digestion (does not have an anus)

5. Tapeworms--parasitic worms that live in the digestive system.Diffuse nutrients into body --they have segmented bodies (each segment is called a proglottid)--each proglottid is a reproductive organ--tapeworms can grow very long (40 feet!)--attach to the intestine with hooks and suckers on the head

7. Flukes--most have complex life cycles involving more than one host--Schistosoma (blood fluke) spends part of its life in a snail, humans get infected when they wade in the water containing the snails, the larva then invade the human's blood vessels--eggs are passed thru human feces into water where the snail is infected

9. Roundworms --have a complete digestive tract Ascaris -common roundworm infection in humans and dogsTrichinella -roundworms that invade muscle tissue, get by eating undercooked porkVinegar eel - free living roundworm

10. Roundworms- Ascaris

11. Trichinella worm

12. Hookworm