Mollusks Review by LisaB1982

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									MOLLUSK Review

Name one of the three classes of mollusks you learned about.
Gastropods, cephalopods, Bivalves

The free swimming ciliated larva found in most aquatic mollusks is Trochophore called a _________________

The space around the heart is called the _____________ space (cavity). pericardial

In mollusks the heart and organs for digestion, excretion, and reproduction are found in this body region.
Visceral mass

The octopus, squid, and chambered nautilus belong to this group of Mollusks.

This bump on the dorsal surface of a clam near the hinge is umbo the _______

Pigment cells in the outer mantle layer in cephalopods that can change color for camouflage.

Identify the colored structures.
Anterior & posterior adductor muscles

The nervous system in a clam consists of _____________________________ 3 pairs of ganglia
connected by 2 pairs of nerve cords

Type of body cavity found in mollusks.
No coelom pseudocoelom eucoelom


The powerful muscles that open and close a clam shell are the ___________
Adductor muscles
(posterior and anterior)

Identify the body system each organ belongs to: Excretory Kidney __________________ Reproductive Testes/ovary ____________________
Respiratory Gills ___________________

Digestive Digestive gland ___________________ Nervous Ganglia ____________________ Circulatory Heart ____________________

What keeps water moving over the gills in a clam?
Cilia on gills move water

A flexible tongue-like strip of tissue covered with tough, abrasive teeth that point backwards found in some mollusks.

Compare Digestive and Nitrogen waste
DIGESTIVE WASTE Made where? Comes from? Removed by what body system? Leaves body as?
In digestive tract
Left over from undigested food Digestive Feces

By body cells
breakdown of proteins during metabolism Excretory ammonia, urea, OR uric acid

This structure is the _____________ intestine

Only cephalopod with a shell
Chambered nautilus

Name the group of mollusks that does NOT have a radula.

Layer of epidermis lining the shell of a clam

#2 #1 #3

#2 = ________________________ Anterior adductor muscle
gills #3 = _______________________

The process during larval development in which the visceral mass in gastropods twists around 180º bringing the mantle cavity, gills, and anus to the front of the animal. torsion open Clams have a(n)__________ circulatory system.
Open Closed

This part of the clam secretes the shell.

bilateral Mollusks have _________ symmetry.
None radial bilateral

Fertilization in clams is __________ both
internal external both Depends on speciesin freshwater clams its usually internal in marine (ocean) clams its external

Identify this structure

The circulatory fluid (blood) in a mollusk is called _______________ hemolymph

Respiratory organ in clams.

The flaps that wave to move food up toward the mouth are called palps ___________________

The organ that passes through the pericardial cavity and lies under the heart is the __________________ intestine

The space between the mantle and the visceral mass.
Mantle cavity

Which group of mollusks does NOT have a shell?
Bivalves cephalopods gastropods


Organisms that stay in one place and don’t move around are called Sessile ___________________ Tell an advantage of having a coelom compared to a pseudocoelom.
1. Muscles of body wall are separate from those of gut. (Can move and digest at same time) 2. Coelom provides space for circulatory system to transport blood 3. Provides a space for organs

invertebrates Mollusks are _______________
vertebrates invertebrates

This blue structure secretes the shell.

Which group of mollusks is mainly sessile?
Bivalves gastropods cephalopods


T or F Most clams are hermaphrodites like earthworms.
False; most clams have separate sexes

Calcium carbonate ________________ in a mollusk’s shell makes it hard.

An organism with a true coelom is eucoelomate called a ______________.

Identify this structure. foot

Clams and oysters belong to this group of mollusks.
Bivalves gastropods cephalopods


This structure starts digestion and grinds food.

Cephalopods are the only mollusks with a ___________ circulatory system. closed
open closed

Fertilization in cephalopods is internal external
Males use a specialized tentacle to transfer packets of sperm to the mantle cavity of the female

Only mollusk group that develops from egg to juvenile without becoming a trochophore larva.

Snails and slugs belong to this group of mollusks.
bivalves cephalopods gastropods


Name one of the functions of the gills in a clam.
1. Gas exchange (oxygen and carbon dioxide) 2. Trap food particles

Anus This opening is the _________.

Name part that belongs to each body system: kidney Excretory __________________ Digestive ____________________ Palps, Esophagus, stomach, digestive gland, intestine, anus Adductors, foot Muscular ___________________ Ganglia, nerve cords Nervous ___________________

Heart, hemolymph, Circulatory ____________________ hemocoel

This is the Digestive gland ________________________.

Another word that means shell is ___________ . valve

Type of circulatory system in which blood is NOT enclosed in vessels

Tell one body part you might look for if you wanted to tell direction in a clam.
UMBO- it’s on the dorsal side FOOT- triangle points to the anterior end PALPS- at anterior end SIPHONS- at posterior end

Which group of mollusks has chromatophores that can change color to blend in with the surroundings?

Why does the surface of the gills have ridges?
Increases surface area to absorb more oxygen & catch more food

The excretory organ in a clam is the
nephridia kidney flame cells


This is the Incurrent __________ siphon __________

This organ surrounds the stomach and makes digestive enzymes.
Digestive gland

How does a trochophore larva swim? Ring of cilia around middle help it move

Body system that removes nitrogen waste from the body cells
digestive nervous excretory respiratory




#1 = ________________________ foot
mantle #2 = _______________________

In a clam the coelom mainly surrounds the heart and is called pericardial the______________ cavity. Organisms that strain food from the Filter feeders water like clams are called _________.
predators filter feeders scavengers autotrophs

These are located on the surface of the clam’s shell and can Growth rings help tell it’s age.

This part of the clam foot is the ____________

Name a part of the nervous system in a clam
Ganglia OR nerve cord

This opening is located near the excurrent siphon so waste is washed away




#1 = ________________________ Posterior adductor muscle
mantle #3 = _______________________

This is the ____________ Excurrent siphon ____________

Organ in a clam is where nutrients are absorbed.
Digestive gland

Most organisms in this class of mollusks have 1 shell (or none)

PHYLUM that clams, octopus, slugs, and snails belong to

Tell one way the reproductive system in a clam is different from an earthworm
hermaphrodites direct development external fertilization

Tell one way the nervous system in a clam is like that of an earthworm Both have ganglia Both have a nerve cord (clam has 2 pairs)

have 2 sexes (male & female) indirect development (larva) internal/external fertilization

The 3 functions of the digestive gland are to __________________ Make digestive enzymes (bile) Finish digestion Absorb nutrients

The excretory organ in a clam is the ______________ kidney

This space you see when you opened your clam is called the ________________ mantle cavity
Coelom pericardial space mantle cavity

The intestine runs through the space shown and is covered by the _________


The function of the palps is to __________________ Move food to the mouth

anterior The ____________ end of the clam is closest to the umbo.
Anterior Posterior

Identify the body part by its description: bump on dorsal side of shell ______________ umbo
Edge of shell shortest distance from umbo ______________________ anterior

Tissue that lies on top of tube running through pericardial space ___________________ heart Growth rings Lines on clam shell ___________________
Mantle Layer lining shell ____________________

The function of the gills is to __________________ Both A & B are correct
A. B. C. D. remove oxygen from water filter food particles make digestive enzymes excrete nitrogen waste

Clams belong in the Animalia ______________ Kingdom Mollusca (mollusks) ______________ Phylum Bivalvia (bivalves) ______________ Class

Identify the function of each body part: Adductor muscles__________________ Open and close shell Collect and remove digestive waste intestine ____________________
Gills ___________________ food Exchange gases & trap

Digestive gland Make digestive enzymes to break down ___________________
food; finish digestion; absorb nutrients

Move food up from gills Palps ____________________ to mouth Pump hemolymph (blood) Heart ____________________ Makes shell Mantle ________________________

True OR False Clams show cephalization. FALSE
No true head area- Ganglia/sense organs are spread out throughout body not concentrated in head

Tube that connects the mouth and the stomach in a clam

The excretory organ in clams is the __________________ kidney

In Latin the name Mollusca means “soft body” ________________.
soft body two shells filter feeder little rings

Identify the body part by its description: looks like a piece spaghetti inside visceral mass __________________ intestine
Greenish brown area in anterior end ____________________ Digestive gland

White fans in front of gills palps ___________________ Long flat structure with ridges (stripes) that runs along side of clam ___________________ gills

Type of symmetry seen in clams bilateral Clams, oysters, octopus, snails, and squid belong to the PHYLUM _______________ Mollusca

Kind of circulatory system seen in an octopus: Closed open closed
All other mollusks have an open system

Invertebrates (no backbone) Mollusks are _______________



Clams show __________ development indirect
They hatch as trochophore larvae and change into their adult form



In Latin the name Bivalvia means “2 shells” ________________.
soft body two shells filter feeder little rings

What causes oxygen and carbon dioxide to move into and out of a clam?

Diffusion moves molecules from where there is a HIGH concentration to where there is a LOW concentration Why do gills have ridges?
Increases surface area

What is the disadvantage of an OPEN circulatory system?

Less efficient way to transport nutrients and oxygen High and low oxygen blood mix Why is it a good plan for a clam to have its anus near the excurrent siphon?
Washes away digestive waste

TELL WHICH BODY SYSTEM EACH PART BELONGS TO respiratory gills __________________________ Ganglia _________________ nervous circulatory heart___________________ excretory kidney _________________ adductors ____________________ muscular digestive intestine ____________________

protostomes MOLLUSKS are _____________
protostomes deuterostomes

Give an example of a mollusk that is a bivalve
Clams, oysters, scallops

Match the Mollusk with its CLASS
BIVALVIA Clams, oysters, scallops ___________

Squid, octopus, CEPHALOPODA chambered nautilus ______________
Snails, slugs, conchs, GASTROPODA Nudibranchs ______________

With a few exceptions:
2 Bivalves have _____ shell(s) Most Gastropods have _____1shell(s) few 0 0 Cephalopods have ____ shell(s) (Except nautilus)

Name 3 body systems that use the mantle cavity as an exit
Digestive-anus releases feces here Excretory- Kidney releases urea here Reproductivesperm and eggs are released here (external) Or sperm and eggs join here and larva exits (internal) Respiratory also uses this spacegills are located here

Breathe through skin
Aortic arches closed

heart open
3 pr ganglia 2 pr nerve cords

1 pr cerebral ganglia 1 ventral nerve cord

COMPARE: Earthworms COELOM ? Absorbs nutrients? EXCRETORY

True; pericardial cavity


Digestive gland


TELL 3 characteristics of ALL Mollusks
eucoelomates invertebrates protostomes Soft bodies Bilateral symmetry trochophore larvae (if indirect)

Name the colored structure: palps

Give its function:
Move food trapped on gills up to mouth

Name the colored structure: mantle

Give its function:
Secrete shell

Name the colored structure: foot

Give its function:

Name the colored structure: Visceral mass

Give its function:
Contains body organs

Name the colored structure: heart

Give its function:
Pump hemolymph (blood)

Name the colored structure: Pericardial cavity(space)

This could also be called the _____________ coelom

Name the colored structure: Digestive gland

Give its functions:
Make bile, finish digestion, absorb nutrients

Name the colored structure: anus

It is the exit opening for which Body system?

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