More Invertebrates Chapter 30. More Invertebrates 2Outline The coelom Molluscs Bivalves Cephalopods Gastropods AnnelidsArthropods Crustaceans

More Invertebrates

Chapter 30

More More InvertebratesInvertebrates 2

OutlineOutline

The coelomThe coelomMolluscsMolluscs

BivalvesBivalvesCephalopodsCephalopodsGastropodsGastropods

AnnelidsAnnelidsArthropodsArthropods

CrustaceansCrustaceansUniramiansUniramiansCheliceratesChelicerates

EchinodermsEchinoderms


Advantages of Coelom Advantages of Coelom

Protostomes vs. deuterostomesProtostomes vs. deuterostomes

Differentiated according to three Differentiated according to three major events in embryological major events in embryological developmentdevelopment

1 Cleavage1 Cleavage

Spiral cleavage in protostomesSpiral cleavage in protostomes

Radial cleavage in deuterostomesRadial cleavage in deuterostomes

4Protostomes Compared to Deuterostomes


Advantages of Coelom Advantages of Coelom

2 Fate of blastopore2 Fate of blastopore

Mouth appears near blastopore in Mouth appears near blastopore in protostomesprotostomes

Anus appears near blastopore in Anus appears near blastopore in deuterstomesdeuterstomes

3 Coelom Formation3 Coelom Formation

Schizocoelom forms in protostomesSchizocoelom forms in protostomes

Enterocoelom forms in deuterstomesEnterocoelom forms in deuterstomes


MollusksMollusks

Mollusks (phylum Mollusca)Mollusks (phylum Mollusca)

Have three-part body planHave three-part body plan

Visceral MassVisceral Mass Contains internal organsContains internal organs

Mantle Mantle May secrete shell and/or contribute to May secrete shell and/or contribute to development of gills or lungsdevelopment of gills or lungs

FootFoot Muscle adapted for locomotion, Muscle adapted for locomotion, attachment, or food captureattachment, or food capture

7Body Plan of Mollusks


MollusksMollusks

Mollusks (cont.)Mollusks (cont.)

Nervous system consists of several Nervous system consists of several ganglia connected by nerve cordsganglia connected by nerve cords

Coelom is reduced, and largely limited Coelom is reduced, and largely limited to the region around the heartto the region around the heart

Heart pumps hemolymph through Heart pumps hemolymph through vessels into hemocoelvessels into hemocoel


BivalvesBivalvesClams, oysters, mussels, and scallopsClams, oysters, mussels, and scallopsShell of two hinged parts, closed by Shell of two hinged parts, closed by powerful musclespowerful muscles

No head, no radulaNo head, no radulaCirculatory system open Circulatory system open Sexes are separateSexes are separateCiliated gills hang down within mantle Ciliated gills hang down within mantle cavity on either side of visceral masscavity on either side of visceral massBeating of cilia causes water to enter Beating of cilia causes water to enter cavitycavity

Filter Feeders – capture tiny food Filter Feeders – capture tiny food particles suspended in waterparticles suspended in water

10Bivalve Diversity


CephalopodsCephalopods

Head FootedHead FootedForce water out mantle cavityForce water out mantle cavity

Tentacles and arms capture prey by Tentacles and arms capture prey by adhesive secretions or suckersadhesive secretions or suckers

Beak used to tear prey apartBeak used to tear prey apart

Well-developed sense organsWell-developed sense organs

Closed circulatory systemClosed circulatory system

Spermatophore packets passed from Spermatophore packets passed from males to femalesmales to females

12Cephalopod Diversity


Gastropods, cont.Gastropods, cont.

Have elongated, flattened footHave elongated, flattened foot

Well-developed head regionWell-developed head region

Eyes and tentacles project from coiled Eyes and tentacles project from coiled shellshell

Gills are found in mantle cavity in Gills are found in mantle cavity in aquatic gastropodsaquatic gastropods

Mantle functions as lung in terrestrial Mantle functions as lung in terrestrial gastropodsgastropods

14Gastropod Diversity


AnnelidsAnnelids

Phylum Annelida arePhylum Annelida are

Segmented partitions (septa) divide the Segmented partitions (septa) divide the well-developed, fluid-filled coelom, well-developed, fluid-filled coelom, which acts as hydrostatic skeletonwhich acts as hydrostatic skeleton

Specialized digestive tractSpecialized digestive tract

Closed circulatory systemClosed circulatory system

Ventral solid nerve cordVentral solid nerve cord

Most are marineMost are marine

Setae (bristles) help in movementSetae (bristles) help in movement

16Polychaete Diversity


EarthwormsEarthworms

Do not have well-developed head or Do not have well-developed head or parapodiaparapodia

Setae protrude in pairs directly from Setae protrude in pairs directly from surface of bodysurface of body

Food drawn into mouth by action of Food drawn into mouth by action of muscular pharynxmuscular pharynx

Digestion and absorption occur in long Digestion and absorption occur in long internal intestineinternal intestine

Typhlosole increases surface for Typhlosole increases surface for absorptionabsorption

18Earthworm, Lumbricus terrestris



Segmentaion evidenced by:Segmentaion evidenced by:

Body ringsBody rings

Coelom divided by septaCoelom divided by septa

Setae on most segmentsSetae on most segments

Gangli and lateral nerves in each Gangli and lateral nerves in each segmentsegment

Nephridia in most segmentsNephridia in most segments

Branch blood vessels in each segmentBranch blood vessels in each segment



ReproductionReproduction

HermaphroditicHermaphroditic

Two worms lie in parallel to each other Two worms lie in parallel to each other facing in opposite directionsfacing in opposite directions

Fused midbody segment (clitellum) Fused midbody segment (clitellum) secretes mucus, protecting sperm from secretes mucus, protecting sperm from dessicationdessication


LeechesLeeches

Usually found in fresh waterUsually found in fresh water

Same body plan as other annelidsSame body plan as other annelids

No setae No setae

Two additional suckersTwo additional suckers

Some parasiticSome parasitic

Keep blood flowing and prevent clotting Keep blood flowing and prevent clotting by means of hirudin, a powerful by means of hirudin, a powerful anticoagulantanticoagulant

22Medicinal Leeches, Hirudo medicinalis


ArthropodsArthropodsArthropods (phylum Arthropoda) have Arthropods (phylum Arthropoda) have freely movable jointed appendagesfreely movable jointed appendages

Very successful due to many Very successful due to many characteristicscharacteristics

Rigid, jointed exoskeletonRigid, jointed exoskeleton

Must molt as they growMust molt as they grow

Segmented, but some segments are Segmented, but some segments are fused into regionsfused into regions

Head, thorax, abdomenHead, thorax, abdomen

Well-developed nervous systemWell-developed nervous system

24Arthropod Skeleton and Eye


ArthropodsArthropods

Variety of respiratory organsVariety of respiratory organs

Occurrence of metamorphosisOccurrence of metamorphosis

Three major arthropod subphylaThree major arthropod subphylaCrustaceansCrustaceans

CrayfishCrayfish

UniramiansUniramians

CentipedesCentipedes

CheliceratesChelicerates

SpidersSpiders


CrustaceansCrustaceans

Decapods are the most familiar and Decapods are the most familiar and numerous of crustaceansnumerous of crustaceans

Shrimp, lobsters, crayfish, and crabsShrimp, lobsters, crayfish, and crabs

Thorax bears five pairs of walking legsThorax bears five pairs of walking legs

Head and thorax fused into cephalothoraxHead and thorax fused into cephalothorax

Covered by nonsegmented carapaceCovered by nonsegmented carapace

Abdominal segments equipped with Abdominal segments equipped with swimmeretsswimmerets

Respiratory system consists of gillsRespiratory system consists of gills

27Crustacean Diversity

28Male crayfish, Cambarus


UniramiansUniramiansInclude insects, millipedes, and Include insects, millipedes, and centipedescentipedes

Appendages attached to the thorax Appendages attached to the thorax and abdomen only have one branchand abdomen only have one branch

Head appendages include:Head appendages include:

Only one pair of antennaeOnly one pair of antennae

One pair of mandibles, andOne pair of mandibles, and

One or two pairs of maxillaeOne or two pairs of maxillae

Live on land and breathe by tracheaeLive on land and breathe by tracheae

30Insect Diversity

31Two Types of Insect Mouthparts

32Female Grasshopper, Romalea

33Centipede and Millipede


CheliceratesChelicerates

Include terrestrial spiders, scorpions, Include terrestrial spiders, scorpions, ticks, mites, horseshoe crabs and sea ticks, mites, horseshoe crabs and sea spidersspiders

All appendages attached to All appendages attached to cephalothorax; none on headcephalothorax; none on head

First pair (chelicerae) are feeding First pair (chelicerae) are feeding organsorgans

Second pair (pedipalps) function in Second pair (pedipalps) function in feeding or sensoryfeeding or sensory

35Chelicerate Diversity


EchinodermsEchinodermsSea stars, sea urchins, sea cucumbers, Sea stars, sea urchins, sea cucumbers, and sea liliesand sea lilies

Radial symmetry as adults (not as Radial symmetry as adults (not as larvae) larvae)

Internal calcium-rich plates with Internal calcium-rich plates with spinesspines

Central nerve ring with branchesCentral nerve ring with branches

Water vascular system for locomotionWater vascular system for locomotion

37Echinoderms


ReviewReview

The coelomThe coelomMollusksMollusks

BivalvesBivalvesCephalopodsCephalopodsGastropodsGastropods

AnnelidsAnnelidsArthropodsArthropods

CrustaceansCrustaceansUniramiansUniramiansCheliceratesChelicerates

EchinodermsEchinoderms

More Invertebrates

Ending Slide Chapter 30

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More Invertebrates Chapter 30. More Invertebrates 2Outline The coelom Molluscs Bivalves Cephalopods Gastropods AnnelidsArthropods Crustaceans