Transcript Worm Phyla - Shah's Aquatic Science

WORM PHYLA
Phylum Nematoda
Phylum Annelida
Phylum Platyhelminthes
Phylum Annelida
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The name means “little rings”
earthworms and leeches
segmented bodies (internal and external)
Bilateral symmetry
Systems – nervous, digestive (gut, mouth, anus), closed circulatory
Sexual Reproduction
Hydrostatic skeleton
 fluid-filled cavity (coelem) surrounded by muscles
 Cephalopods (have a head)
 Concentrated with nerve cells and sensory structures
 Worm Video
Phylum Platyhelminthes
 Flatworms
 un-segmented (no
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http://www.ucmp.berkeley.edu/platyhelminthes/pseudobiceros.jpg
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rings) and appear flat
most no more than a
few millimeters thick.
have tissues and
internal organs
systems
bilateral symmetry,
cephalization (which
means they have a
head!)
Flatworm video
Flatworm Characteristics
 single digestive opening (Mouth/Anus)-food enters and
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undigested waste leaves.
Because they are so thin, most flatworms do not need a
circulatory system to transport materials, but use diffusion.
Respiration also occurs through diffusion
They move to obtain food and escape predators.
They can be both carnivorous or parasitic (this tapeworm
lives inside the human intestines).
Phylum Nematoda
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Roundworms
unsegmented worms
microscopic or a large as a meter in length!
Most roundworms are free living and are found in the
soil, the sea floor, or water.
 Others are parasites that live in plants and animals.