Transcript worms - Local.brookings.k12.sd.us

WORMS
FLATWORMS
=“Platyhelminthes”
Planaria – free living
Tapeworms - parasitic
Flukes - parasitic
PLANARIA
• Free living/aquatic
• ACOELOMATES
(NO body cavity)
• No TEGUMENT or CUTICLE
DIGESTIVE/CIRCULATORY
• Combined gastrovascular cavity
• Only 1 opening to digestive system
• Mouth at end of tube in middle of body
PLANARIA
NERVOUS
• Cerebral ganglia with 2 nerve cords
• Eyespots can detect light
• Simple learning
EXCRETORY
• FLAME CELLS remove excess water
RESPIRATORY
Exchange gases through skin
PLANARIA
REPRODUCTIVE
• Hermaphrodites
trade sperm with other worms
lay eggs in protective sac on rocks
• Ability to regenerate (regrow lost
parts)
– can be used to reproduce asexually
TAPEWORMS
Parasites that live in
the intestines of all
vertebrates
Scolex with hooks
and suckers
on anterior end help
it hold on
TAPEWORMS
ACOELOMATES
TEGUMENTProtective covering made of cells
Resists digestive enzymes/fools immune system
NO DIGESTIVE SYSTEM/no mouth
absorb nutrients that you digest through
their skin
EXCRETORY/NERVOUS SYSTEM
Similar to Planaria but no eyes
TAPEWORMS
REPRODUCTIVE
• Hermaphroditescan fertilize self or trade
sperm with other worms
• Grow by adding
PROGLOTTIDS
which contain both male
and female reproductive
organs
30 foot worm can
have 2000 proglottids
PARASITIC WORMS
Adult lives and reproduces in
PRIMARY HOST
Larval form lives in
INTERMEDIATE HOST
HOW DO THEY INFECT
HUMANS?
Primary host:
Human
Intermediate
host:
cow
FLUKES
• Parasites
• No coelom
Leaf shaped body
Covered by
TEGUMENT for
protection
FLUKES
DIGESTIVE/CIRCULATORY
• Anterior/Posterior suckers help it hold on
• 1 opening into a gastrovascular cavity
NERVOUS
Cerebral ganglia with 2 nerve cords
but no eyes
FLUKES
REPRODUCTIVE
Most hermaphrodites/some separate sexes
Fertilized eggs leave body
in feces or urine
Complicated life cycle with 2 hosts
Adults- sexual reproduction
Larva – asexual reproduction
HOW DO THEY
INFECT HUMANS?
Primary host:
Human
Larva burrow into skin
Intermediate
host: snail
ROUND WORMS
“NEMATODES”
•
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Ascaris
Trichinella
Hookworms
Pinworms
Filarial worms
ROUND WORMS
“NEMATODES”
• Many free living/some parasites
• PSEUDOCOELOMATES –
body cavity only lined on one side with
mesoderm
• Covered with CUTICLE(non-cellular)
for protection
• 2 separate sexes
ROUND WORMS
“NEMATODES”
REPRODUCTIVE
Separate sexes
DIGESTIVE
Digestive tract with 2 openings like Earthworms
ROUND WORMS
“NEMATODES”
Ascaris – enter by contaminated food/water
live in intestines
only 1 host
Trichinella – enter by eating meat with cysts
live in intestine
Pork host- causes Trichinosis
ROUND WORMS
“NEMATODES”
Hook worms – live in intestine
release eggs in feces
larva burrow into feet
Pinworms – Most common in U.S.A.
live in lower digestive system
females migrate out at night to lay eggs on skin
infected by ingesting eggs
ROUND WORMS
“NEMATODES”
ELEPHANTIASIS
• worms live in lymph system
• blockage causes limbs to swell
• transmitted by mosquitoes
Dog heartworm is also
a filarial worm
SEGMENTED WORMS
“Annelids”
COELOMATES
CUTICLE covers
body for protection
SEGMENTED WORMS
“Annelids”
DIGESTIVE
digestive system with 2 openings
EXCRETORY
NEPHRIDIAremove water/nitrogen waste
RESPIRATORY
Exchange gases through skin
SEGMENTED WORMS
“Annelids”
REPRODUCTIVE
• Hermaphroditesexchange sperm with partner
• Lay eggs in mucous sac left on ground
SEGMENTED WORMS
“Annelids”