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Chapter 25 Mollusksand Segmented Worms Segmented Worms
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Phylum Mollusca (“soft”) Includes snails, clams, oysters, squids & octopus
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(Phylum Mollusca) Most live in salt water Most live in salt water Bilateral symmetry Bilateral symmetry Breathe through gills Breathe through gills
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(Phylum Mollusca) Most have … Most have … –paired eyes –3 chambered heart - open circulatory system –1 or 2 shells –separate sexes - reproduce sexually
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All mollusks have a modified foot
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(Phylum Mollusca) Coelum - large central body cavity Coelum - large central body cavity Visceral organs (guts) - complete digestive system Visceral organs (guts) - complete digestive system
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(Phylum Mollusca) Mantle - thin membrane; surrounds internal organs; secretes the shell Mantle - thin membrane; surrounds internal organs; secretes the shell Radula - file-like “teeth” found in the mouth of many Radula - file-like “teeth” found in the mouth of many
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PHYLUM: ANNELIDA “Little rings” / Segmented worms Includes: Includes: –Earthworms –Sandworms –Leeches –Bristleworms Bilateral symmetry Bilateral symmetry Free-living Free-living
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(PHYLUM: ANNELIDA) Some have eyespots Some have eyespots Some have eyes Some have eyes Most are hermaphrodites Most are hermaphrodites
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(PHYLUM: ANNELIDA) Primitive heart - 5 aortic arches Primitive heart - 5 aortic arches Complete Complete digestive system Nephridia - eliminates wastes Nephridia - eliminates wastes
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(ANNELIDS) Simple nervous system Simple nervous system
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(PHYLUM: ANNELIDA) Setae - tiny bristles Setae - tiny bristles Clitellum - Reproductive band on earthworms Clitellum - Reproductive band on earthworms
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Chapter 29 Echinoderms
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Phylum Echinodermata (“spiny skin”) Includes sea urchins, starfish, sand dollars, sea stars, sea cucumbers, brittle stars Includes sea urchins, starfish, sand dollars, sea stars, sea cucumbers, brittle stars Serpent star
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Crown starfish Sand dollar Brittle star Heart urchin Sea urchin All have a hard, spiny, or bumpy exoskeleton
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(Phylum Echinodermata) Aquatic Aquatic Radial symmetry Radial symmetry Sea stars
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Sea cucumber Sea urchin with a worm Sea urchin with feathery tentacles Sea urchins Simple nervous system (no head or brain) Simple nervous system (no head or brain)
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(Phylum Echinodermata) Water vascular system Water vascular system Have a mouth and stomach Have a mouth and stomach Cells that detect light and touch Cells that detect light and touch
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(Phylum Echinodermata) Reproduce: Reproduce: –Sexually - have separate sexes –Asexually - regeneration (replace missing parts)
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