Phylum Platyhelminthes Flashcards
“Platy-“ meaning
“-helminthes” meaning
flat
worm
Platyhelminthes common names
tapeworms, flukes, free-living flatworms
Platyhelminthes
Acoelomate
No space between gut and body wall
Platyhelminthes digestive tract type?
incomplete digestive tract
Platyhelminthes feeding mechanisms
predators, herbivores, fluid feeding, surface nutrient absorption
Fluid feeding
Consume liquids from “prey”
surface nutrient absorption
Nutrients diffuse into body
What class can do surface nutrient absorption? Where do they live?
Cestoda (tapeworms)
Live in intestine
What Platyhelminthes class has no digestive tract?
Cestoda; tapeworms
Platyhelminthes have High surface area-to-volume ratio for
High air supply for low volume
Platyhelminthes structure for excretion?
Protonephridium
cephalization
Concentration of sensory neurons up at the front
Platyhelminthes
Structure that receive sensory info and coordinate a response
Ganglia
Do Platyhelminthes need a circulatory system?
No
How are Platyhelminthes flattened?
Dorsoventrally
Are Platyhelminthes parasitic or free living?
Both
Lophotrochozoa group characteristics
Similar larvae
Non-molting
Triploblastic
Bilateral symmetry
Class Turbellaria common name
Free living flatworms
Platyhelminthes synapomorphy
similar larvae
Where can you find Class Turbellaria?
Freshwater, marine, terrestrial
Class Turbellaria locomotion structures?
Cilia
Longitudinal muscles
Where is Class Turbellaria cilia located?
Ventral only
What are Class Turbellaria longitudinal muscles for?
Swimming
Class Turbellaria 3 muscle layers
Circular muscles
Longitudinal muscles
Class Turbellaria circular muscles are for
Fragmentation
Asexual reproduction
Class Turbellaria dorsoventral muscles are for
Internal movement and flattening
Class Turbellaria feeding
Herbivores, predators
Detritivores (eat dead stuff)
Class Turbellaria eyes are called?
ocelli or simple eyes
Class Turbellaria ocelli characteristics
Photosensitive
light/dark
Class Turbellaria “ears” are called?
Auricles
Class Turbellaria Auricles sensitivity type?
Chemosensitive
Aware of smells in the environment
Chemosensitive means
Aware of smells in the environment
Class Turbellaria have generalized ____
Mechanoreceptors
Class Turbellaria sexual reproductive parts?
Monoecious
Class Turbellaria often reproduce via
Bidirectional sperm exchange
Class Turbellaria sometimes reproduce via
Penis fencing
Class Turbellaria asexual reproduction type?
Fragmentation
Class Trematoda common name
Flukes
Class Trematoda glycocalyx
non-living outer layer that helps with diffusion and protective against host’s immune system
Class Trematoda are all
Parasitic
Class Trematoda
Sheep Liver Fluke life cycle
Adult fluke is in sheep liver -> eggs in feces -(hatch) -> miracidia - (burrow/ingest)-> snail -(encyst)-> Sporocyst -(asexual reproduction)-> rediae -(asexual reproduction)-> cercariae -(exit snail)-> (aquatic plant) -> (encyst)-> metacercariae -(ingest)-> Adult in sheep liver
Class Trematoda
Sheep Liver Fluke determinate host
The Sheep
Class Trematoda
Sheep Liver Fluke indeterminate host
Snail, aquatic plant
Class Cestoda common names
Tapeworms
Class Cestoda are all
Parasitic on vertebrate animals
in small intestine
Class Cestoda length
1mm-25m
Most developed Class Cestoda system
Reproductive system
Class Cestoda top “head” region is called
Scolex
Class Cestoda region after scolex?
Strobila
Class Cestoda strobila proglottid development sucession
Immature proglottid
Male proglottid
Female proglottied
Protandrous
Male first then develop female parts
Protogynous
Female first then develop male parts
Class Cestoda tegument
Protective non-living layer
Class Cestoda tegument protects from
Host’s immune system and digestive system
Class Cestoda
Beef tapeworm life cycle
Adult in human small intestine -(eggs in feces)-> -(ingested by cattle)-> -(encyst in skeletal muscle)-> Rare meat ingested -> Adult in human small intestine
Parasitism in platyhelminthes is an ___
apomorphy
relatively new characteristic for this phylum
