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


Types of Flatworms (planarian, tapeworm, fluke)

Planarian (also known as Dugesia)--lives in freshwater
--mostly a scavenger, also feeds on protists
--has a simple brain (ganglia) and nervous system, plus 2 eyespots
(see handout on planarian)
--they can regenerate (regrow parts)

Anatomy of the Planarian

Brain (ganglia) - planarian can process information about their environement
Pharynx - used for suckling food in (the mouth is at the end of the pharynx)
Eyespot - simple eye, can detect light
Flame cells - located along the lateral edges, used for excretion
Intestine - digestion (does not have an anus)