Molluscs

radula

radula

unusual ribbon of teeth used for feeding

foot or tentacles

what do molluscs use for movement

mantle

used in molluscs for respiration

lophotrochozoan protostomes

what group do molluscs belong to?

spiral, schizocoelous

molluscs develop via _____ cleavage with _______ coelom

large

are molluscs a large or small animal phyla?

10 cm

molluscs have a large size range but 80% are under ______

marine

habitat of most molluscs

in the sea

where does fossil evidence suggest molluscs evolved?

they are filter feeders

why are bivalves unable to leave aquatic areas?

3

how many germ layers in a mollusc?

snails

molluscs that are often intermediate hosts for parasites that affect humans and domesticated animals

pearls

culturing of ______ from molluscs is an important industry around the world.

bilateral

symmetry in molluscs

dorsal

body wall that forms the mantle

ventral

body wall that forms the muscular foot

ciliated

Surface epithelium usually _______ and bearing mucous glands and sensory nerve endings.

circular, diagonal, longitudinal

types of muscles in mollusc body wall

open

what type of circulatory system do molluscs have?

sexual

type of reproduction in snails

no blood vessels, blood mixes w/ other body fluids

what does an open circulatory system mean?

head-foot

area that contains the feeding, sensory, and locomotory \n organs

Photosensory receptors

range from simple to complex eyes especially in \n cephalopods

odontophores

Complex muscles that move radula and its supportive cartilages in and out of the mouth.

posterior end

where are new rows of teeth secreted in the radula?

pattern and number of teeth

used in the classification of mollusc species

outer surface of the mantle

what secretes the shell in species that have one?

gills or lungs

\n Mantle cavity houses the _________ that develop from the mantle and the exposed surface used in gas exchange

digestive, excretory, reproductive

products of these systems empty into the mantle cavity

mantle

a sheath tissue on each side of the body that protects the soft parts and forms the space called cavity

visceral mass

what is the mantle a part of

Continuous water flow

In aquatic molluscs, ________ brings in oxygen and food, flushes out wastes and reproductive

3

how many layers typically in mollusc shell?

Periostracum

outer horny shell layer

nacreous layer

next to the mantle, secreted continuously by the mantle \n surface so it increases in thickness as the animal grows; the nacre is laid down in thin wavy layers that results in \n iridescent mother-of-pearl layers in abalones and clams.

middle prismatic layer

densely packed prisms of calcium carbonate; grows at the shell margin as the animal grows.

gastropoda

most diverse mollusc class

dextral, sinistral

gastropod shells may be ________ __(__right sided) or \n _______ (left sided) in coiling formation.

apex

smallest and oldest part of whorl

operculum

\n Many snails have _____ covering shell \n aperture (entry).

torsion

developmental process that changes the relative position of the shell, digestive tract and anus, nerves that lie on both sides of the digestive tract, and the mantle cavity \n containing the gills.

coiling

spiral winding of shell and visceral mass

conotoxin

venom used in cone snail radula to capture prey

pneumostome

Pulmonates lack gills but have highly vascular area in the mantle that serves as a lung; it opens to outside by small \n opening called _______

single, nephridium

Most gastropods have a _____ kidney called a _______ and well-developed circulatory and nervous systems.

head and radula

what do bivalves lack?

hinge ligament

\n Bivalves are laterally compressed with two shells or valves that are held together by a ______

umbo

the oldest part of the bivalve shell with growth occurring outward in rings

adductor

what muscles draw bivalve shells together

visceral mass

suspended from the dorsal midline in bivalves

anteroventral

location of muscular foot attachment in bivalves

ctenidia

hang down on each side of a bivalve, covered by fold of the mantle

longitudinal

what muscles shorten to pull bivalves forward

foot swells when blood is pumped in

how do bivalves anchor into the mud for locomocation?

jet propulsion by clapping valves

how do scallops and file shells swim?

respiratory currents

what brings oxygen and organic materials to the gills of bivalves?

mucus

secreted by gland cells to entangle food particles

cilia nad labial palps

direct mucous mass into mouth of bivalves

crystalline style

secreted by style sac and contains enzymes to aid in bivalve digestion

3

how many chambers in bivalve heart

u, nephridial tubes

in bivalves, a pair of ____ shaped kidneys called \n __________ are next to the heart.

2 atria, 1 ventricle

what chambers does a bivalve heart have?

mantle, sinuses, kidney, gills

where can blood be oxygenated in bivalves?

trochophore, veliger, spat larva

stages of embryo development in bivalves

external

what type of fertilization typically occurs in bivalves

internal

freshwater clams have _____ fertilization

Glochidium larvae

specialized veligers that attach to gills of passing fish, \n where they live briefly as parasites to complete their development.

class cephalopoda

marine predators such as squids, octopuses, nautiluses, \n devilfish, and cuttlefish

foot and head

what regions in cephalopods are merged and modified for expelling water

octopus

cephalopod that has completely lost the shell

siphuncle

living chord of tissue that connects cephalopod shell chambers to visceral mass

expell water through ventral funnel/siphon

how do cephalopods swim?

more

Cephalopod nervous and sensory systems are ______ elaborate than other molluscs

cephalopod

largest brain of any invertebrate

color-blind

cephalopods have complex eyes but are typically still ______

contractions of the muscle fibers

how are cephalopod color changes controlled?

spermatophores

package spermatozoa in male cephalopod seminal vesicles

hectocotylus

intromittent organ, made from modified male arm, which is used to remove a spermatophore from the male mantle cavity and insert it into the female oviduct

no

do cephalopods have free-swimming larvae

conchiolin

what is the periostracum made of?