zool 5.2

molluscs means what in latin

mollusc in in distribution (everywhere)

what forms the mantle

secrete calcareous spicules

cuticular band of teeth in the esophagus § for feeding, but not present in all groups § mollusc characteristic not found in other groups

develop into a locomotor or muscular foot used for clinging & crawling.

germ layers of molluscs

symmetry of molluscs

segementation of molluscs

all molluscs are cepahlized, and has well developed heads except

outward fold of the body wall; encloses space between mantle & viscera

contains digestive, respiratory (gill ctenidia, lungs) & reproductive organs

– feeding, sensory, locomotory organs

outer organic layer - helps protect underlying calcareous layers from erosion - thicker in freshwater than in marine molluscs

parts of the shell

middle layer composed of densely packed prisms of calcium carbonate (either aragonite or calcite) laid down in protein matrix

- innermost calcareous layer (shiny)

study of molluscan shells

where does gas exchange occur in molluscs

– vascularized in some enabling gas exchange

Lung – has small opening to the environment called

the only molluscs that has closed circulatory system complete with vessels & capillaries, enabling them to be active predators

monitor incoming water & also serves as tactile receptor

margins of bivalves to detect light

squid’s skin enabling the organisms to communicate & camouflage

– kidney that collects liquid waste from the coelom & is pumped out of the shell

the sexual characteristic of most terrestrial gastropod

classes by shell characteristics

- marine with worm-like body; no shell; body covered with calcareous spines embedded on the cuticle

Solenogastres lacks what?

vermiform; mostly borrows - feeds on microorganisms/detritus, has radula, but no shell

- long thought to be extinct; <12 species - collected at depths of 2000 m - unhinged, cap-shaped shell - 3-6 pairs ctenidia (gills) - 3-7 pairs of metanephridia, 1-2 pairs gonads, 10 pairs of pedal nerves in ladder like nervous system; separate sexes

- elongated, dorsoventrally flattened body with reduced head - marine on rocky intertidal substrates

Polyplacophora shell of eight dorsal plates called

Polyplacophora uses radula tipped with

Polyplacophora chitons are surrounded by a structure called a

twisting process in veliger stage) their visceral mass become asymmetrical

Rarest & most expensive in the world; found in the Philippines; stolen in museums due to it value

octopuses, squid, cuttlefish, nautiluses, devilfish - most advanced mollusc (intelligent) - shell reduced or absent - head well-developed with eyes & radula - head with arms or tentacles (prey capture, attachment, locomotion, copulation

Cephalopoda has conical shell except for

Jet propulsion eject water from

largest know eyes in the earth

• Most intelligent invertebrates

has 94 tentacles, shells with many chambers, does not have a conical shell

– delicacy in Palawan; bivalve not a worm; found in mangrove tree barks; 2 shells in anterior ends

- body enclosed in one-piece tubular shell open at both ends - head absent - mouth with radula & tentacles - dioecious

scaphopoda have tentacles surrounding the foot called ______ that latch onto food