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a diverse group of invertebrates such as clams,slugs,squids,and octupuses

Phylum Mollusca

mollusk are


what does the latin term of mollusks mean


most aquatic mollusk and annelids have a larvae stage called a


wat contains the heart organs of digestion,excretion, and reproduction

visceral mass

the head foot consist of what

the head, which contains the mouth and sensory structures; the foot- a large muscular organ for locomation

a layer of epidermis that covers the visceral mass and is protective


the gills are protected within the

mantle cavity

the nervous system consist of paired clusters of nerve cells called


the main feeding adaption of many mollusk is the


what does gastro mean


what does poda mean


what group consist of snails abalones conchs


gastropods undergo the process of _______ during larvael stage


do gatropods have a open or closed circulator system


the heart pumps hemolymph from gills or lungs into the what


_____ live in moist and aquatic enviroments


most _____________ have soft bodies and some hard shells


the ________ is limited space around the mollusks heart


the disadvantage of a shell is offset by

having gills

most mollusks are

billaterally symmetrical

In most mollusk, the mantle secretes one or more hard shells containing

calcium carbonate

what is the largest and most diverse class of mollusks

Gastropoda ( called gastropods)

most gastropods, including snails, abalones, and conchs have

a single shell

during larval development gastropods undergo the process of


gastropods have an open circulatory system in which the heart pumps _____________ from gills or lungs into the hemocoel.


Gastropods are most active

at night

snails live

in moist and aquatic enviroments

most snails locate food using eyes at the end of

their tentacles

how do snails survive dry periods

by retreating into their shells and sealing the opening with their mucus plug

Nudibranch gastropods are

marine and lack shells

slugs are

terrestial and lack shells

Pteropods or "sea butterflies"

have a foot that is modified into a winglike flap and used for swimming rather than crawling


means two

the class Bivalvia includes mollusks such as

clams, oysters, and scallops

Bivalves are called that because

their shell is divided into two valves connected by a hinge

each valve consist of

three layers,

most bivalves are what type of feeders

sessile filter feeders

Bivalves lack

a distinct head and have three pairs of nerve ganglia

clams are bivalves

that live buried in mud or sand

the mantle cavity of a clam is sealed except for a pair of hollow, fleshy tubes called


water enters through the

incurrent siphon

water leaves through the

excurrent siphon

when do oysters become attached to a hard surface

early in their development

How do scallops move through the water

by repeatedly opening their valves and snapping them shut

The class Cephalopoda includes;

octopuses, squids, cuttlefish, and chambered nautiluses

cephalopds means


Cephalopods are specialized

as free- swimming predators

Cephalopods have

tentacles, bear like jaws on the head, a very advanced nervous sysytem, and a closed circulatory system

what do many cephalopods use to disquise and hide themselves


Cephalopods with ten tentacles


squids propel themselves by

pumping jets of water with the mantle through an excurrent siphon

Cephalopods with eight tentacles and are similiar to squid


what is the only existing cephalopod that has retained its external shell

chambered nautilus

the chambered nautilus shell is

coiled and divided into a series of chambers, the body is confined to the outer most chamber

The phylum of Annelids is

made up of bilaterally symmetrical segmented worms

Annelids phylum include

common earthworms, featherduster worms, and bloodsucking leeches.

Annelid means

little rings and refers to the many body segemnts

Annelids have a true coelom that is

divided into seperate compartments by partitions

Most annelids have external bristles called

setae( singular; seta)

Some annelids have fleshy protrusions called


Oligochaeta means

few bristles

Annelids of the class Oligochaeta generally live

in the soil or in fresh water and have no parapodia

the most familiar member of the Oligochaeta class is the


An _____________ has over 100 nearly identical segments

earthworms body

_____________ and ________________ muscles line the earthworms interior body wall

circular and longitudinal

________________ is made possible by segmentation



are in the intestines

Earthworms ingest soil as they

burrow through it

Soil moves through these structure;

mouth, pharynx,esophagus,crop,gizzard intsetine(includes the typhosole) and anus

what plays an important role in the condition of the soil


the nervous system of an earthworm consist of

a chain og ganglia connected by a ventrl nerve cord

____________________ are found in all segments but are concentrated at the anterior end

sensory structures

cellular waste and excess water are excreted through

nephridia ( ls a simple kidney)

____________and _________ diffuse through the skin, which contains many small blood vessels and must be kept moist.

Oxygen and Carbon dioxide

Contractions of the ________________ and the dorsal blood vessels force blood through the closed circulatory system

aortic arches


runs on the top


runs on the bottom

Earthworms are _______________________

hermaphrodites, but an individual worm cannot fertilixe its own eggs

during________________, earthworms press their ventral surfaces together


during mating thay are held together by their setae and a film of mucus secreted by each worm's


The _________________ from each worm move through the mucus to the seminal receptacle of the other.


The clitellum secretes a tube of mucus and


______________________ occurs inside the tube, which forms a protective case for the young worms


Polychaeta means

many bristles

Poly means


Polychaetes differ from annelids in that they have

an antennae and specialized mouth parts

Polychaetes are the only annelids that have a

trochophore stage

what is the smallest class of annelids


Hirudinea consist of

500 species of leeches, which have no setae or parapodia

Many leeches are ___________________ but some are parasites that suck blood from animals


key characteristics of mollusks

sedentary filter feeders,

the body plan of mollusk include;

the viceral mass, the head- foot and the mantle

what is advantage of true coelom over pseudocoelom

with a coelom the muscles of the body wall are seperated from those of the gut, therefore the body wall muscles can contract without hindering the movement of food through the gut. A coelom also provides a space where the circulatory system can transport blood without interference of internal organs

In which phyla of animals is the larva trochophore stage found


For what purpose is a radula used


why are land snails more active when the air around them is moist

the thin membrane lining the mantle cavity must be kept moist to allow gases to diffuse through it

name three major classes of mollusk

Gastropoda, Bivalvia, and Cephalopoda

describe the key characteristics of mollusks

external shell, head. radula, locomaotion

Compare circulatory system of 3 major classes of mollusk

gastropods have open circulatory system meaning the circulatory fluid called hemolymph does not remain entirely within the vessels; Cephalopoda have a closed circulatory system, it transports fluid more rapidly than an open circulatory system, thus nutrients, oxygen, and carbon dioxide are carried quickly through the body;Bivalva have

identify the structure that provides the basis for dividing annelids into three classes;

the number of setae and the presence or absence of parapodia

Advantages of body segmentation

if one segment becomes disabled, the others can still function; movement is possible by segmentation; segmentation enables different parts of the body to carry out variuos functions independently;

describe structural adaptations of earthworms

look up

compare three classes of annelids

Oligochaeta- Polychaeta- Hirudinea

how are an earthworms circular and longitudinal muscles used in locomation

the worm anchors some of the middle segments by their setea & the ability to contract the circular muscles in front of the middle segments allows the worm to move

why does an earthworm require a moist environment to survive

an earthworm requires a moist environment to survive because it diffuses oxygen and carbon dioxide through the skin, which contains many small blood vessels- this exchange of gases can only take place if the skin is moist, secretions of mucus and the presence of a thin cuticle also help keep the worms skin moist

to which phylum do leeches belong


To which phylum do cuttlefish, octopus, squid & chambered nautiluses belong


what is the largest and most diverse class of mollusks



from the greek gaster, meaning stomach amd "pous" meaninf foot

which class of mollusk undergo torsion during the larva development


nudibranch means

naked gill, which refers to the fact that gas exchange occurs during the entire body surface of these animals


is a larve that develops from the fertilized egg of most mollusk and annelids

Parapodia are a distinguishing characteristics of which class of annelids


Annelids are divided into three classes based partly on the number of which of the following


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