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Kingdom Animalia:
Phylum Platyhelminthes (flatworms)
Phylum Annelida (segmented worms)
Phylum Nematoda (roundworms)
Platyhelminthes, Annelida, and Nematoda:
what traits do they have in common? _______________________________
what traits are different between them? _____________________________
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Phylum Platyhelminthes : flatworms
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Worms flat, unsegmented body
First animals to exhibit bilateral symmetry, three tissue layers
Flatworms can be free living or parasitic
The have a nervous system with cephalization
They have sac like gut
Lack respiratory, how do they exchange gases?
• Lack circulatory systems,
how do they get food and O2
to all the cells?
Procedure 3. Planaria
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Sketch live planaria and label: head, auricle, eyespots, gastrovascular
cavity, mouth and pharynx
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Tapeworms, page 126
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Parasites of vertebrates, in the digestive system
Lack a mouth and digestive tract
Anterior end with hooks and suckers (scolex)
Body has repeating units (proglottids)
On bottom of page
126, sketch the
tapeworm and label
a proglottid
Phylum Nematoda: Roundworms
Cylindrical worms with unsegmented body
Body covered by a collagen cuticle (elastic but restricts growth),
molted 4 times during growth
Body wall has only longitudinal muscles
Found in virtually all habitats (poles, deserts, hot springs)
Handful of soil contains thousands of nematodes
Nematode parasites exist in nearly all animal and plant species
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Procedure 4: Ascaris
Ascaris lumbricoides is one of the largest and most common parasites found in humans.
It is estimated that 25% of the world's population is infected with this nematode.
Host swallows embryonated eggs, juveniles hatch, and burrow through intestinal wall
Carried through the heart to the lungs, coughed up and swallowed, they mature in the
intestine after two months
They feed on intestinal contents and may block or perforate the intestines
Procedure 4: Vinegar eel
Vinegar eels
Feed on bacteria and fungi found in
nonpasteurized vinegar.
They are raised by aquarists,
who use them to feed newly hatched fish.
Make your own mount with slowing agent
Sketch and describe
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Phylum Annelida: segmented worms
Cylindrical worms with segmented body
Ventral nervous system
Closed circulatory system
Hydrostatic skeleton
Circular and longitudinal muscle layers
Setae (bristles)
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Procedure 6: earthworms
Feed of dead organic matter breaking it down,
Their castings are rich in nutrients for plant growth
Burrow through the soil, aerating it
Sketch earthworm
Setae
And label: mouth, clitellum, setae, anus, prostomium
Parapodia
Leech
Mostly freshwater,
Predators adapted for fluid feeding
Anterior and posterior suckers
Setae absent
Setae
Parapodia
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