MOLLUSCS

Výukový materiál OR 03 - 69Tvůrce: Mgr. Alena VýbornáTvůrce anglické verze: ThMgr. Ing. Jiří FollerProjekt: S anglickým jazykem do dalších předmětůRegistrační číslo: CZ.1.07/1.1.36/03.0005Tento projekt je spolufinancován ESF a SR ČR

MOLLUSCS

•A very diverse group•They live mostly in the sea but also in the fresh

water and on the mainland•Skin fold of the body = mantle ▫It excretes calcareous substances from which

their mantles are formed•Mantle protects the soft body

MOLLUSCS

MOLLUSCS

•Orientation in the habitat at a different level according to their lifestyle:▫touch cells (slowly moving)▫smell cells▫cells checking the location▫sight organs

simple eyes chamber eye

MOLLUSCS

•GASTROPODA•BIVALVIA•CEPHALOPODA

GASTROPODA (SNAILS)•marine, freshwater, terrestrial• they move slowly muscular foot•muscular foot contains glands which excrete

mucus; it makes the movement of terrestrial gastropoda easier

•most body is covered by a solid conch•mostly gonochorists•some of them hermaphrodites

GASTROPODA

GASTROPODA•They consume both plant and animal food•A few species predators•Breathing:▫water

oxygen dissolved in the water (river snail) air oxygen – they swim to the water level (great

pond nail, great ramshorn snail)▫terrestrial

air oxygen

GASTROPODA•burgundy Snail•white lipped banded snail•slug•large red slug•great pond snail•river snail•great ranshorn snail

BIVALVIA (MUSSELS)•water molluscs (freshwater, saltwater)• the body is covered by a shell consisting of

two parts• the inner side of the shell is made of a nacre

layer•some bivalvia live attached to hard surfaces• they feed with phytoplankton

BIVALVIA•oyster•scallop•mussel•cockle•pearl oyster•clam

CEPHALOPODA•marine•predators• foot modified into arms (tentacles; 8 – 10) with

suckers• the rest of arm transformed into a funnel•eyes – perfectly evolved• there is no mantle▫the relic – cuttlebone (sepia)▫nautilus - mantle

CEPHALOPODA•cuttlefish•squid•octopus•nautilus

REVISION:•1) The body of bivalvia is protected by?▫Shell

•2) The body of gastropoda is protected by?▫Conch

•3) Individual with both the sexual organs is called?▫Hermaphrodite

•4) A gonochorist is?▫An individual that has either male or female

sexual organs.•5) Squid belongs to?▫Cephalopoda

SOURCE:• DOBRORUKA, Luděk J. Přírodopis pro 7. ročník základní školy. 1.

vyd. Praha: Scientia, 1998, 152 s. ISBN 80-718-3134-4