M O L L U S C A , A N N E L I DA , A RT H RO P O DA

THE PROTOSTOMES

Parazoa no true tissues

Eumetazoa

Multicellularity

Radiata Bilateria

PROTOSTOMES

“mouth first”

DEUTEROSTOMES “mouth second”

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

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)

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

ANNELID BODY PLAN

• metameres

or segments

• septa

• setae or

chaetae

• sense

organs

ARTHROPOD

BODY PLAN

•body segments

•exoskeleton of

protein + chitin

•appendages that

extend from the

body wall

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

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

Feeding • herbivores, carnivores, filter feeders, detritivores, parasites

• filter feeders: incurrent/excurrent siphon, mucus & cilia on

gills in bivalves

• radula in gastropods

• jaws in cephalopods

Respiration • aquatic: gills inside mantle cavity

• terrestrial: constantly moist & highly vascularized

lung in mantle cavity

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

Excretion • nephridia

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

Movement • foot + mucus (snails)

• jet propulsion (octopuses)

Reproduction • external fertilization (snails, bivalves)

• internal fertilization (cephalopods, some snails)

• hermaphroditic, cross-fertilization

• trochophore larvae

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

Respiration • aquatic: through gills in their chaetae

• terrestrial: diffusion through moist skin

Circulation • closed circulatory system (blood vessels and

multiple hearts)

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

Phyl

um

Annelid

a

Oligochaeta earthworms, Tubifex

Polychaeta bristle worms,

sandworm, clamworm

Hirudinea leeches

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

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)

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

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

• Pair of chelicerae

• 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