Phylum Platyhelminthes

flatworms

Theflatworms

Fact Sheet Review

SymmetryandBodyPlan:– Truetissue– bilateralsymmetry– acoelomate (nocavity)

Review cont’dExcretion:wasteismovedoutbyflamecells;leavesthroughpores.

Respiration:gassescandiffusedirectlythroughskin.

Nervous/controlsystem:simple,ladder-likenervoussystem(primitiveanteriorbrain,nervecords,light-sensitiveeyespots).

Review cont’d

Movement:ciliaonbodyallowsforslidingalongmucus.

Reproduction:Bothasexualandsexual.• Asexual:regeneration– ifoneiscutinhalf,youwillhave2!(reallyannoyingtohavetheminyourfishtank)

Representative Organisms

Flatworms1. Tapeworms– internalparasites(mustliveIN

ahostorganism).• Upto20metreslong!