The wiggly world of wild and
wonderful worms
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Kingdom: Animalia
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Phylum : Platyhelminthes (Flatworms)
Class: Turbellaria (Turbellarians)
 Class: Cestoda (Tapeworms)
 Class: Trematoda (Flukes)
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Phylum: Nematoda (Roudworms)
Family: Oxyuridae (Pinworms)
 Family: Ancylostomatidae (Hookworms)
 Family: Filariidae (Filarial Worms)
 Family: Ascaridae (Ascarids)
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only a few cells thick
bilateral symmetry
muscles to move
no circulatory or
respiratory system
have 3 tissue layers
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ectoderm
mesoderm
endoderm
free-living or parasitic
p.663
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cephalization – nerve
bundling at one end
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acoelomate – lack of a
true body cavity
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primitive “head”
two main nerves
one body opening
“head”
hermaphrodite – have
both male and female
reproductive cells
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sexual reproduction
(don’t self-fertilize)
asexual reproduction (by
fragmentation)
Planarian (Turbellarian)
p.664
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marine
most are predators
some move with cilia
in addition to muscles
p.665
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endoparasites in
intestine of host
1mm – 10m long
hooks and suckers for
attachment to host
absorb nutrients
through their skin
proglottid – body
segment with
reproductive organs that
break off when mature
p.665
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endoparasites in
intestine or
ectoparasites on fishes
tegument – protective
outer layer
hooks and suckers for
attachment to host
p.666
Schistosoma - blood fluke
4-stage life cycle
 eggs are found in water
(Africa, Asia, S.America)
 first larval stage enter
intermediate host (snails)
 second larval stage can
reproduce asexually
 larvae enter human host
through skin or ingestion
and cause damage to liver
and intestine
(schistosomiasis)
 eggs are shed in urine and
feces

Kingdom: Animalia

Phylum : Platyhelminthes (Flatworms)
Class: Turbellaria (Turbellarians)
 Class: Cestoda (Tapeworms)
 Class: Trematoda (Flukes)


Phylum: Nematoda (Roudworms)
Family: Oxyuridae (Pinworms)
 Family: Ancylostomatidae (Hookworms)
 Family: Filariidae (Filarial Worms)
 Family: Ascaridae (Ascarids)
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round in cross-section
bilateral symmetry
better muscle
movement than
flatworms
has 3 tissue layers
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

ectoderm
mesoderm
endoderm
free-living or parasitic

cephelization – nerve
bundling at one end
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pseudocoelom
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primitive “head”
two main nerves
two body openings
acts as circulatory
system (nutrients and
oxygen)
separate sexes
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sexual reproduction
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1 cm long
50% of school age kids
have had it
itching around anus
fecal- oral
transmission (from
feces to mouth)
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1/5 of world population
affected
can cause mild
diarrhea/ cramps/
anemia
larvae enter through
bare feet
move through
bloodstream, into lungs,
into intestine
attach and suck blood
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live in blood or
lymphatic system
mosquito vector
some cause
elephantiasis
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lymphatic fluid collects
in tissues
some cause
heartworm in dogs
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weakness and fatigue,
can lead to death
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most common human
worm infection
contracted through
contaminated food/water
lives in intestine of
pigs/horses/humans
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can cause blockage
feed on host’s food
eggs shed through feces
and can live in soil for
many years