1 Phylum Mollusca BIO 2215 Oklahoma City Community College Dennis Anderson.

1

Phylum Mollusca

BIO 2215

Oklahoma City Community College

Dennis Anderson

2

Phylum Mollusca

3

Numbers of speciesNumbers of species

Echinodermata

Ciliophora

Chordata

Mollusca

Platyhelminthes

Nematoda

PoriferaAnnelida

Other

Apicomplex

Sarcomastigophora

Arthropoda

4

Molluscs

• 50,000 -100,000 living species

• 35,000 extinct species• Largest = 1000 pounds• 80% less than 5 cm• Soft body• Most have a shell• Most marine• Snails terrestrial

– Most habitat

5

Phylum Mollusca

• Ventral Foot– Locomotion

• Mantle– Encloses mantle cavity

• Shell• Radula• Coelom

(eucoelomate)• Metanephridia• Open circulatory

system– Closed in cephalopods

6

Economics

• Pearls• Burrowing shipworms • Snails & slugs

– Garden pests– Food– Intermediate hosts for

parasites

7

Trochophore Larva• Same type as Phylum

Annelida

8

MyxozoaMyxozoa

ArthropodaArthropoda AnnelidaAnnelida

MolluscaMollusca

LophophoresLophophores

HemichordataHemichordata

VertebrataVertebrata

Other pseudocoelomates

Other pseudocoelomates

NematodaNematoda

PoriferaPorifera

CtenophoraCtenophoraCnidariaCnidaria

PlacozoaPlacozoa

PlatyhelminthesPlatyhelminthes

NemerteaNemertea

CiliophoraCiliophoraSarcomastigophoraSarcomastigophora

MicrosporaMicrosporaApicomplexaApicomplexa

MesozoaMesozoa

EchinodermataEchinodermata

CrustaceaCrustaceaChelicerataChelicerata

UniramiaUniramia

Other ChordataOther Chordata

9

Generalized Mollusc

10

Body PlanBody Plan

Mantle cavityMantle cavity

CtenidiumCtenidium

Pericardial cavityPericardial cavity MetanephridiumMetanephridium

RadulaRadula

GonadGonad

Stomach and digestive glandStomach and digestive gland FootFoot

11

Dorsal mantle covers the visceral mass.

Dorsal mantle covers the visceral mass.

12

Secretes the shellSecretes the shell

13

Ctenidium (Respiration)Ctenidium (Respiration)

14

Complete digestive systemComplete digestive system

15

Paired ventral nerve cordsPaired ventral nerve cords

16

RadulaRadula

17

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Source: From A Life of Invertebrates, Copyright © 1979 W. D. Russell-Hunter.

Radular Structure

18

Coelom - metanephridiaCoelom - metanephridia

19

Class PolyplacophoraChitons

20

Class PolyplacophoraClass Polyplacophora

• Eight dorsal plates• Reduced head• Radula reinforced

with iron– Scrape algae from

rocks

21

Class Polyplacophora

Mantle cavityMantle cavityMouthMouth

CtenidiumCtenidium

FootFoot

AnusAnus

22

Class PolyplacophoraClass Polyplacophora

MouthMouth

Digestivegland

Digestivegland

StomachStomach GonadGonadPericardial cavityPericardial cavity

NephridiumNephridium

AnusAnus

23

Class BivalviaClams, Oysters, Shipworms

Class BivalviaClams, Oysters, Shipworms

24

Class Bivalvia

• Two shells• Most are filter feeders• No head or radula• Burrow

– Sand, wood, rocks

27

Giant Clam & Burrowing Clam

Siphon

28

Zebra Mussel

• Environmental Pest• Ballast water of ships

from Europe in 1986• Attack be secreting

adhesive byssal threads– Each other– Other mussels– Man made objects

• Pipes, plumbing

29

Zebra Mussel

• Live in high densities• Feed on

phytoplankton• Reproduce rapidly

30

Zebra Mussel

• Attach to native mussels

• Killed all native mussels in Lake Erie

31

Distribution of Zebra Mussel

32

Bivalve structuresBivalve structures

IncurrentsiphonIncurrentsiphon

CtenidiumCtenidium

ExcurrentsiphonExcurrentsiphon

HingeHinge

FootFoot

Labial palpLabial palp

33

Clam anatomyClam anatomyPericardial cavityPericardial cavity

HeartHeart

GonadGonadIntestineIntestine

StomachStomach IncurrentIncurrent

ExcurrentExcurrent

IntestineIntestine

MetanephridiumMetanephridium

34

Clam anatomyClam anatomy

GonadGonadIntestineIntestine

StomachStomachIncurrentIncurrent

ExcurrentExcurrent

Digestivegland

Digestivegland

35


HeartHeart

IncurrentIncurrent

ExcurrentExcurrent

IntestineIntestine

36


HeartHeart

GonadGonad

IncurrentIncurrent

ExcurrentExcurrent

IntestineIntestine

MetanephridiumMetanephridium

37

Oysters

38

Pearl formation

Developing pearlDeveloping pearl

EpitheliumEpithelium

ShellShell

Irritant lodged between shell and mantle

Layers of nacre secreted around foreign material

39

Scallops

40

Shipworms

41

Class GastropodaSnails, Slugs, Conchs, Limpets

Class GastropodaSnails, Slugs, Conchs, Limpets

42

Class Gastropoda

• One shell (if present)• Torsion of body

44

Snail

• Terrestrail• Mantle cavity

functions as lung

45

Snail

Tentacle(Eye stalks)Tentacle(Eye stalks)

TentacleTentacle

PneumostomePneumostome

AnusAnus

FootFootMouthMouth

Genital poreGenital pore

ShellShell

46


Internal Structure of a Generalized Gastropod

47

Nudibranch

• No shell• Dorsal projections

– Gills– Nematocyst discharge

48

AbaloneAbalone

• Several holes in top of shell– Excrete waste

• Food for man

49

Slug

• No shell• Garden pests

50

Limpet

• Herbivores• Cling to rocks or other surfaces

51

Conch

• Large shell• Marine• Many are predators

52

Class CephalopodaSquids, Octopuses, Nautiluses

Class CephalopodaSquids, Octopuses, Nautiluses

53

Class Cephalopoda

• Shell in squid and octopus absent or vestigial

• Jet propulsion• Ink sac• Foot modified into

arms and tentacles• Marine• All predators

54

SquidSquid

DorsalVentral

Posterior surface

Right

Left

55

SquidSquid

FinFin

ArmArm

Funnel (siphon)Funnel (siphon)

EyeEye

TentacleTentacle

CollarCollar

56

SquidSquidShell (Pen)Shell (Pen)

CtenidiumCtenidium

FunnelFunnel

SystemicheartSystemicheart

Branchial heartBranchial heart

57

Squid MaleSquid MaleTestisTestis

Hectocotylous armHectocotylous arm

PenisPenis

58

Squid FemaleSquid Female

Ovary with eggsOvary with eggs

Nidamental glandsNidamental glands

Oviducal glandOviducal gland

Oviducal openingOviducal opening

59


Cephalopod Eye

60

Octopus

• Eight arms with suckers

• Crawl or eject water from siphon

• Change skin color– chromatophores

• Most intelligent invertebrate

61

Nautilus

• Up to 94 tentacles– No suckers

• Shell with many chambers– Lives in outermost

chamber

62

Ammonoids

• Extinct• Devonian to

Cretaceous– 400 to 65 MYA

• Died out with dinosaurs

63

Class Scaphopoda

• Tooth shells• Shell opens on both

ends• Burrow into mud• No gills

– Mantle for gas exchange

• Feed on detritus and protozoa

64

Class ScaphododaClass Scaphododa

65

The End

1 Phylum Mollusca BIO 2215 Oklahoma City Community College Dennis Anderson.

Documents

Transcript of 1 Phylum Mollusca BIO 2215 Oklahoma City Community College Dennis Anderson.