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The Worms. The Worms. Phylum Platyhelminthes Phylum Nematoda Phylum Annelida. Characteristics of Worms. Soft-bodied, long, legless Bilateral symmetry Cephalization—having an anterior end with nerve tissue. Phylum Platyhelminthes “the flatworms”. Free-living: planarians
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The Worms The Worms Phylum Platyhelminthes Phylum Nematoda Phylum Annelida
Characteristics of Worms • Soft-bodied, long, legless • Bilateral symmetry • Cephalization—having an anterior end with nerve tissue
Phylum Platyhelminthes“the flatworms” • Free-living: planarians • Parasitic: tapeworms, flukes
Planarians • Epidermis • Gastroderm • Mesoderm
Planarians • Planarians move by-- • Planarians eat by-- • Planarians get rid of soluble waste by--
Planarians • Planarians’ nervous system consists of-- • Planarians reproduce by--
Characteristics of Parasitic Flatworms • Few sensory organs as adults • No external cilia in adults • A thick tegument • Have suckers, hooks, or both for attachment
The Flukes • Sheep liver fluke • Causes liver rot
The Tapeworms • Scolex • the head region • Proglottids • segments that grow from behind the scolex; contain a complete set of reproductive organs
The Tapeworms • Intermediate host • an animal that temporarily harbors the immature form of a parasite
Phylum Nematoda (round & unsegmented) “the roundworms”
Ascaris A typical roundworm
Ascaris ONLY reproduces sexually & is NOT hermaphroditic
Other Roundworms • Hookworm • Incubate in warm soil • Preventing infections: • Proper elimination of wastes • Wear shoes!! • Trichina worm • Pinworm
Phylum Annelida “little rings” Segmented worms (septa)
Annelida • Clitellum • Prostomium • Casts • Setae • Crop • Gizzard • Aortic arches • Nephridia
What does “Annelida” mean? • Flat worm • Segmented worm • Little rings • Two sides
What is the term for the membranes that divide earthworms into segments? • Septa • Nephridia • Setae • Proglottids
Which structures aid the earthworm in movement? • Septa • Setae • Nephridia • Prostomia
What is the muscular organ that grinds soil and breaks it into small pieces? • Prostomium • Gizzard • Crop • Clitellum
The earthworm respires through its • cuticle and epidermis. • nephridia. • aortic arches. • mouth.
Earthworms have an open circulatory system. • True • False
The structures responsible for the removal of soluble wastes • Aortic arches • Kidneys • Nephridia • Blood
Earthworms are hermaphroditic. • True • False