flatworms

general description

marine and freshwater, mostly endoparasites
bilateral and flatenned

acoelomates - ecto meso endo

acoelomates

invertebrates that lack a fluid-filled body cavity between its digestive system and outer body wall

body covering

epidermis

body support

hydrostatic skeleton

respiratory system

diffusion

muscular system

muscles in gastrovascular cavity

digestive system

incomplete + diffusion

circulatory system

none

excretory system

protonephridia made from flame cells - osmoregulation

nervous system

simple with 2 nerve cords running through the brain + 2 simple ganglia

sensory system

ocelli + statocysts

reproductive system

mostly hermaphrodites

planarians

true flat worms, free-living or scavangers

s3xual reproduction - hermaphrodites without gonads

as3xual reproduction - cloning or budding

ex.: flatworm

flukes

parasites with holdfasts, rhomboid shape

ex.: common liver fluke

fluke life cycle

cow → fluke in liver → eggs in feces → MIRACIDIUM LARVAE → intermediate snail host (SPOROCYST) → CERCARIA → METACERCARIAE CYSTS in grass

tapeworms

slender long bodies, found in the digestive tract

no mouth or digestive system, hermaphrodites

osmotrophy, anaerobic metabolism

ex.: beef/pork tapeworm

structure of a tapeworm

head (scolex) with hooks, proglottids (segments) formed via strobilation FROM THE NECK!!!