Phylum mollusca molle soft body
This presentation is the property of its rightful owner.
Sponsored Links
1 / 23

PHYLUM MOLLUSCA (Molle= soft body) PowerPoint PPT Presentation


  • 86 Views
  • Uploaded on
  • Presentation posted in: General

PHYLUM MOLLUSCA (Molle= soft body). PHYLUM MOLLUSCA. OVER 100,OOO LIVING SPECIES; MANY 1000’S OF FOSSIL SPECIES FOUND IN ALMOST ALL ENVIRONMENTS: MARINE, FRESHWATER, TERRESTRIAL INCLUDES SNAILS, SLUGS, CLAMS, SQUIDS, OCTOPUSES, . CHARACTERISTICS.

Download Presentation

PHYLUM MOLLUSCA (Molle= soft body)

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Phylum mollusca molle soft body

PHYLUM MOLLUSCA(Molle= soft body)


Phylum mollusca

PHYLUM MOLLUSCA

  • OVER 100,OOO LIVING SPECIES; MANY 1000’S OF FOSSIL SPECIES

  • FOUND IN ALMOST ALL ENVIRONMENTS: MARINE, FRESHWATER, TERRESTRIAL

  • INCLUDES SNAILS, SLUGS, CLAMS, SQUIDS, OCTOPUSES,


Characteristics

CHARACTERISTICS

  • Body Plan: three main parts- head, foot, visceral mass

  • body is unsegmented


Characteristics1

CHARACTERISTICS

  • Mantle - specialized tissue, secretes shell, may be involved in feeding, reproduction and respiration

  • Radula – for rasping; in all but one class

Radula closeup


All organ systems are present

ALL ORGAN SYSTEMS ARE PRESENT

  • Circulation - Open (Hemocoel) - Hemocyanin

  • Respiratory System - gills (Ctenidia), lungs, mantle, epidermis

  • Osmoregulation - Metanephridia also excretion


All organ systems are present1

ALL ORGAN SYSTEMS ARE PRESENT

  • Feeding - Radula (scraping)

    • Bivalves - Filter feed

  • Nervous System - Complex system of Ganglia


All organ systems are present2

ALL ORGAN SYSTEMS ARE PRESENT

  • Reproductive System - usually dioecious, monoecious in some

    • Marine forms have free living trochophore larva

    • Other larval stages may be present


Molluscan classes

MOLLUSCAN CLASSES


Class monoplacophora one plate

Class Monoplacophora“one plate”

  • all known from deep marine waters (>12,000 feet)

  • have a single circular shell

  • with radula


Class polyplacophora many plates chitons

ClassPolyplacophora“many plates”- (chitons)

  • have 8 overlapping plates or shells

    • reduced head, no eyes or tentacles

    • all marine; usually live on rocky shores

    • have radula, gills

    • external fertilization

    • scrape algae


Polyplacophora

Polyplacophora

  • Respiration - Gills in pallial groove

  • Circulation - Heart at posterior end - single Aorta

  • Excretion - Nephridia

  • Nervous System and sense organs - Ganglia and nerves

    • Sub Radular organ - Feeding

    • Esthetes - light sensing

    • Osphradia - Sampling water


Polyplacophora1

Polyplacophora

  • Reproduction - Sexes Separate

    • Usually external fertilization

    • Trochophore larva


Class aplacophora without plates

ClassAplacophora“without plates”

  • Rare; lack shell; wormlike

  • deep marine; burrowing species; predators

  • About 320 species, not much is known of them

  • Your book separates them into two separate classes:

    • !Caudofoveata

    • !Solenogastres


Class gastropoda

Class Gastropoda

  • Largest class of Molluscs

  • Most important feature is Torsion


Torsion

Torsion

  • Twisting of body into loop

  • Perhaps adaptation of veliger larva

  • Disadvantages:

    • Reduction of organs on right side

    • Excretion - Mouth moves near anus

  • Adavntages

    • Allows water to be drawn from the front


Gastropod locomotion

Gastropod - Locomotion

  • Foot

  • Ciliary action below the foot

  • Operculum

  • Swimming


Gastropod nutrition

Gastropod - Nutrition

  • Herbivores - Radula

  • Carnivores

  • Filter feeders

  • NERVOUS SYSTEM

    • Similar to Chiton - but in the shape of “8”


Class bivalvia

Class - Bivalvia

  • Includes Calms, Oysters, Mussels

  • Has two Shells (Valves)

  • Shell held together by Adductor muscle

  • Head is lost

  • Filter feeders

  • Mantle secretes the shell


Molluscan shell structure

MOLLUSCAN SHELL STRUCTURE

  • Periostracum; outer layer

  • Prismatic; middle layer

  • Nacre; inside layer- mother of pearl


Bivalvia

BIVALVIA

  • Locomotion

    • Foot (burrowers)

    • Active swimmers (Scallops)

  • Circulation

    • Open system

  • Excretion

    • Nephridia


Bivalvia1

BIVALVIA

  • Nervous System

    • 2 pairs of ganglia

    • Sense organs (statocysts, ocelli, ospharidia)

  • Reproduction

    • Sexes separate

    • Internal fertilization

    • Larva - Glochidium


Class cephalopoda

Class - Cephalopoda

  • Includes Squid, octopus, Nautilus

  • Most advanced of Molluscs

  • Well developed head and eyes

  • Head has tentacles with suckers

  • Squids are largest of invertebrates

  • Locomotion by jet propulsion


Class scaphopoda tusk shells

Class Scaphopoda(tusk shells)

  • slender, tubular shells open at both ends

  • all marine

  • have tentacles around mouth

  • no defined head

  • no gills, respiration across mantle


  • Login