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 Scolex Hooks

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.