ch21

Question 1

largest group of water animals

Answer 1

Mollusks

Question 2

3 parts of Mollusks

Answer 2

Foot
Visceral hump
Mantle

Question 3

two-shelled mollusks

Answer 3

Bival

Question 4

edible mollusk

Answer 4

Shellfish

Question 5

the substance from which the pearly layer is formed

Answer 5

Nacre

Question 6

formed by nacre. Sometimes valuable.

Answer 6

Pearl

Question 7

hold the two shells of a bivalve

Answer 7

Adductor muscles

Question 8

A clam uses its foot for burrowing very quickly into the sand

Answer 8

Locomotion

Question 9

mollusks have an ____ circulatory system

Answer 9

Open

Question 10

snails, slugs, whelks, abalones, conchs, cowries, and murexes

Answer 10

Gastropods

Question 11

another name for gastropods because of their single shell

Answer 11

Univalves

Question 12

“right-handed” shells

Answer 12

Dextral

Question 13

“left-handed” shells

Answer 13

Sinistral

Question 14

Gastropods without shells

Answer 14

Slugs
Nudibranchs

Question 15

Economic importance of gastropods

Answer 15

clean up organic debris and because they commonly serve as food for man, fish, and birds

Question 16

Operculum function (for shell)

Answer 16

covers shell

Question 17

scrapes food and carries it into the digestive tract

Answer 17

Radula

Question 18

Head-Foot Mollusks

Answer 18

Cephalopods

Question 19

Cephalopod noted for its ability to move by “jet propulsion”

Answer 19

Squid

Question 20

gives squids jet propulsion

Answer 20

Siphon

Question 21

Cephalopods have a _____ circulatory system

Answer 21

closed

Question 22

Cephalopods

Answer 22

squids
octopus
nautilus

Question 23

only cephalopod with an external shell

Answer 23

Nautilus

Question 24

the angles of a nautilus chamber form what is referred to as a _______ spiral

Answer 24

Logarithmic spiral

Question 25

Spiny-skinned invertebrates

Answer 25

Echinoderms

Question 26

Arms of starfish that extend from center

Answer 26

Rays

Question 26

Echinoderms

Answer 26

starfish

Question 27

light-sensitive at end of ray

Answer 27

Eyespot

Question 28

water goes through them and allows them to hold onto things; used by starfish

Answer 28

Tube feet

Question 29

sieve plate; takes water to tube feet

Answer 29

Madreporite

Question 30

smallest multicellular animals; microscopic invertebrates found in freshwater lakes and ponds

Answer 30

Rotifers

Question 31

discovered rotifers

Answer 31

Anton van Leeuwenhoek

Question 32

Hollow-intestined invertebrates

Answer 32

Coelenterates

Question 33

stinging cells of Coelenterates

Answer 33

Cnidocytes

Question 34

Coelenterates with opening on top

Answer 34

Polyp

Question 35

Coelenterates with opening on bottom

Answer 35

Medusa

Question 36

move about by sliding along on its base or by turning “somersaults”

Answer 36

Hydra

Question 37

Coelenterates that go through alterations of generations

Answer 37

Jellyfish

Question 38

goes through stages of sexual and asexual reproduction

Answer 38

Alterations of generations (jellyfish does this)

Question 39

Coelenterates

Answer 39

Polyp Medusa Hydra Jellyfish Sea anemones Coral

Question 40

produce a limestone cup at the base of their bodies

Answer 40

Coral

Question 41

collection of trillions of corals

Answer 41

Coral reefs

Question 42

sponges

Answer 42

Porifera

Question 43

Lack a nervous system

Answer 43

Porifera

Question 44

body opening, or mouth, of a sponge

Answer 44

Osculum

Question 45

located in the sides of sponges and allows water to enter it

Answer 45

Ostia

Question 46

inner layer of cells of sponges

Answer 46

Collar cells

Question 47

the crystalline support structures of the sponge

Answer 47

Spicules

Question 48

reproduction of sponges

Answer 48

Sponges may reproduce sexually or asexually