Phylum Platyhelminthes

Basic Facts

Name meaning: flatworm Phylum divided into 3 classes Invertebrate Bilateral Symmetry Cephalization Contains body organs

Digestive, reproduction, excretory and nervous

Basic Facts cont….

Habitat: some species are free-living, most are parasites

Contain a blind gut digestive system Exchange gases through diffusion Flattened body Reproduction:

Primarily asexual, hermaphroditic Fission

Class Turbellaria Free living flatworms May contain ocelli Ex. Planarian

Class Trematoda

Parasitic flatworms known as flukes Cause a disease known as Schistosoma Live in liver, lung and blood of host Passed through water that is contaminated by

human feces, urine or blood. Have an intermediate host in life cycle

Aquatic snail

Schistosoma life-cycle

Infection with a blood fluke

Class Cestoda

Parasitic tapeworms Live in the intestines of hosts Can grow to the length of host intestine or

longer Infection caused by ingesting eggs of

worm

Typical Tapeworm Body Plan

Scolex w/hooks and suckers for attachment

Immature Proglottid: Sections of tapeworm body

Mature Proglottid: Sections of tapeworm body (contain eggs)

Tapeworm Photos

HooksScolex

Cycle of Infection

Tapeworm Infection

Flatworms

Platyhelminthes Cephalization Blind Gut Diffusion Fission Ocelli Intermediate Host

Fluke Scolex Proglottid

Name that Vocab Term A digestive system with only one opening Eyespots used for detecting light A body plan characteristic of organisms

that have an identifiable head A type of asexual reproduction where the

organism splits in half to create a copy A grouping of animals common referred to

as flatworms. The exchange of gases through a

membrane or skin.