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M O L L U S C A , A N N E L I DA , A RT H RO P O DA
THE PROTOSTOMES
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Parazoa no true tissues
Eumetazoa
Multicellularity
Radiata Bilateria
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PROTOSTOMES
“mouth first”
DEUTEROSTOMES “mouth second”
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COMMON FEATURES
Features Mollusca Annelida Arthropoda
# of germ
layers triploblasts
type of
symmetry bilaterally-symmetric
body cavity coelom present
fate of
blastopore mouth develops first
type of
digestive
system
complete digestive system
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DISTINGUISHING FEATURES
Features Mollusca Annelida Arthropoda
Etymology molluscus, “soft” annellus
“little ring”
arthron + podos
“joint foot”
General
description
soft-bodied
animals with an
external or
internal shell
soft, segmented
worms
segmented
body, tough
exoskeleton,
jointed
appendages
# of species ~100,000 spp. ~15,000 sp.
~750,000 sp.
(highest sp.
diversity)
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MOLLUSK BODY
PLAN
• muscular foot
• mantle
• calcium carbonate shell
• visceral mass
http://www.bio.miami.edu/dana/pix/ham.jpg, http://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpg, ,
http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T010708A.gif
http://www.bio.miami.edu/dana/pix/ham.jpghttp://www.bio.miami.edu/dana/pix/ham.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://kentsimmons.uwinnipeg.ca/16cm05/1116/33-21-ClamAnatomy-L.jpghttp://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T010708A.gifhttp://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T010708A.gif
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ANNELID BODY PLAN
• metameres
or segments
• septa
• setae or
chaetae
• sense
organs
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ARTHROPOD
BODY PLAN
•body segments
•exoskeleton of
protein + chitin
•appendages that
extend from the
body wall
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Phylum Mollusca (L. molluscus, “soft”)
Feeding • herbivores, carnivores, filter feeders, detritivores, parasites
• filter feeders: incurrent/excurrent siphon, mucus & cilia on gills
• radula
Respiration • aquatic: gills inside mantle cavity • terrestrial: constantly moist & highly vascularized mantle cavity
Circulation • open circulatory system (snails, clams): sinus
• closed circulatory system (squid, octopuses)
Excretion • nephridia
Response • simple nervous system (bivalves)
• highly-developed nervous system (squid, octopuses)
Movement • foot + mucus (snails)
• jet propulsion (octopuses)
Reproduction • external fertilization (snails, bivalves)
• internal fertilization (cephalopods, some snails)
• hermaphroditic, cross-fertilization
• trochophore larvae
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Phyl
um
Mollu
sca Gastropoda snails and slugs
Cephalopoda octopuses,squids, cuttlefish, Nautilus
Bivalvia clams, oysters, mussels,
scallops
Scaphopoda tusk shells
Aplacophora, Monoplacophora, Polyplacophora
chiton
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Feeding • herbivores, carnivores, filter feeders, detritivores, parasites
• filter feeders: incurrent/excurrent siphon, mucus & cilia on
gills in bivalves
• radula in gastropods
• jaws in cephalopods
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Respiration • aquatic: gills inside mantle cavity
• terrestrial: constantly moist & highly vascularized
lung in mantle cavity
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Circulation • open circulatory system (snails, clams): sinus
• closed circulatory system (squid, octopuses) http://chsweb.lr.k12.nj.us/mstanley/outlines/circulation/Circulation_files/image013.gif
http://chsweb.lr.k12.nj.us/mstanley/outlines/circulation/Circulation_files/image013.gifhttp://chsweb.lr.k12.nj.us/mstanley/outlines/circulation/Circulation_files/image013.gif
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Excretion • nephridia
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Response • simple nervous system (bivalves)
• highly-developed nervous system (squid,
octopuses) http://classconnection.s3.amazonaws.com/754/flashcards/566754/png/49.21320629922544.png
http://classconnection.s3.amazonaws.com/754/flashcards/566754/png/49.21320629922544.pnghttp://classconnection.s3.amazonaws.com/754/flashcards/566754/png/49.21320629922544.png
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Movement • foot + mucus (snails)
• jet propulsion (octopuses)
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Reproduction • external fertilization (snails, bivalves)
• internal fertilization (cephalopods, some snails)
• hermaphroditic, cross-fertilization
• trochophore larvae
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Phylum Annelida (L. annellus, “ring”)
Feeding • herbivores, carnivores, detritivores
• pharynx
Respiration • aquatic: through gills in their chaetae
• terrestrial: diffusion through moist skin
Circulation • closed circulatory system (blood vessels and multiple
hearts)
Excretion • nephridia in each segment
Response • highly-developed nervous system
Movement • terrestrial: contraction of longitudinal and circular
muscles against the hydrostatic skeleton
• aquatic: paddling of the parapodia
Reproduction • asexual: fragmentation, budding in aquatic forms
• some hermaphroditic, cross-fertilization
• internal fertilization in most
• trochophore larvae in marine forms
• eggs in cocoons in terrestrial forms
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Respiration • aquatic: through gills in their chaetae
• terrestrial: diffusion through moist skin
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Circulation • closed circulatory system (blood vessels and
multiple hearts)
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Reproduction • asexual: fragmentation, budding in aquatic forms
• some hermaphroditic, cross-fertilization
• internal fertilization in most
• trochophore larvae in marine forms
• eggs in cocoons in terrestrial forms
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Phyl
um
Annelid
a
Oligochaeta earthworms, Tubifex
Polychaeta bristle worms,
sandworm, clamworm
Hirudinea leeches
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Phylum Arthropoda (G. arthron + podos, “joint foot”)
Feeding • herbivores, carnivores, omnivores, bloodsuckers, filter
feeders, detritivores, parasites
• fangs, proboscis, sickle-shaped jaws, pincers
Respiration • terrestrial: spiracles and tracheal tubes or book lungs in
spiders
• aquatic: feather-like gills in lobsters, crabs and book gills
in horseshoe crabs
Circulation • open circulatory system (heart blood vessels
sinuses heart)
Excretion • aquatic: diffusion
• terrestrial: Malpighian tubules
Response • highly-developed nervous system with brain, nerve
cords, ganglia, and sense organs
Movement • well-developed muscle groups
• exoskeleton
Reproduction • aquatic: internal/external fertilization
• terrestrial: internal fertilization
• metamorphosis: complete/incomplete
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Phyl
um
Art
hro
poda
Crustaceans crabs, crayfish, lobsters,
barnacles, shrimps
Chelicerates horseshoe crab, ticks,
spiders, mites, scorpions
Uniramia centipedes, millipedes,
insects
Trilobita trilobites (extinct)
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Feeding • herbivores, carnivores, omnivores, bloodsuckers,
filter feeders, detritivores, parasites
• fangs, proboscis, sickle-shaped jaws, pincers
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Respiration • terrestrial: spiracles and tracheal tubes or book
lungs in spiders
• aquatic: feather-like gills in lobsters, crabs and
book gills in horseshoe crabs
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Circulation • open circulatory system (heart blood vessels
sinuses heart)
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Excretion • aquatic: diffusion
• terrestrial: Malpighian tubules
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Response • highly-developed nervous system with brain,
nerve cords, ganglia, and sense organs
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http://www.arthursclipart.org/biologya/biology/crustaceans%204.gif
• 2 pairs of antennae,
• pair of mandibles
• pair of compound eyes
• pair of many-branched appendages per segment
http://www.arthursclipart.org/biologya/biology/crustaceans 4.gifhttp://www.arthursclipart.org/biologya/biology/crustaceans 4.gif
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• Pair of chelicerae
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• Single-branching appendages • 2 pairs per segment in millipedes
• 1 pair per segment in centipedes
• Pair of antennae
• Mandibles and maxillae
• *insects are the only invertebrates to have developed flight