Deck 7: Cnidarians and Ctenophores

Question 1

Digestion in cnidarians is

A)intracellular only.
B)extracellular only.
C)both extracellular and intracellular.
D)none of these

Answer 1

C

Question 2

Compared to the sponges,the radial animals are much more advanced in their

A)respiratory system.
B)excretory system.
C)nervous system.
D)circulatory system.

Answer 2

C

Question 3

The neuromuscular system first evolved in the cnidarians.

Answer 3

True

Question 4

Nematocysts are expelled when

A)the osmotic pressure reaches 140 atmospheres.
B)the hydrostatic pressure exceeds the osmotic pressure.
C)the internal hydrostatic pressure increases when water enters due to osmotic pressure inside.
D)the cnidocil stimulates the cnidocyte to decrease hydrostatic pressure and increase osmotic pressure.

Question 5

All ctenophores are marine,and most of them are free-swimming forms.

Question 6

Radial symmetry benefits animals that actively move in certain directions because they approach their environment from all sides equally.

Question 7

Some nematocysts do not inject poison.

Question 8

Nematocysts are found in some cells lining the gastrovascular cavity of scyphozoans.

Question 9

The central nervous system of cnidarians includes a brain.

Question 10

Hydra reproduces asexually by means of

A)buds.
B)nematocysts.
C)gland cells.
D)gametes.

Question 11

The freshwater Hydra has a medusa stage in its life cycle.

Question 12

Most of the hydrozoans are colonial marine animals with both an asexual polyp and a sexual medusa stage in their life cycle.

Question 13

The radiate animals represent the tissue-organ level of organization.

Question 14

The class of cnidarians with the most conspicuous medusa stage is

A)HydrozoA.
B)Scyphozoa.
C)Anthozoa.
D)Ctenophora.

Question 15

The anthozoans include the marine sea anemones and corals.

Question 16

A common characteristic of cnidarians is

A)an osculum.
B)dimorphism and often polymorphism.
C)gills.
D)choanocytes.

Question 17

Cnidarians are widespread in marine habitats,but there are a few freshwater forms.

Question 18

The most typical habitat of cnidarians is the shallow,warm ocean.

Question 19

Ctenophores,also known as sea wasps,are responsible for many fatal stings in tropical waters.
Multiple Choice Questions

Question 20

Some fish eat cnidarians,and then use the ingested nematocysts for their own defense.

Question 21

The nematocyst is enclosed within the cell that secreted it,called a ________________.

Question 22

The morphological type adapted to a sedentary or sessile life is the _________,and that adapted for floating or free-swimming existence is the _____________.

Question 23

Zooxanthelae

A)fix carbon dioxide and photosynthesize in a non-symbiotic relationship.
B)recycle phosphorus and nitrogenous waste compounds.
C)are found in river outflows with high turbidity.
D)detract from the ability of coral to deposit calcium carbonate.

Question 24

The structure of the nervous system in cnidarians is referred to as a _________________.

Question 25

Coral reefs are limited to areas

A)of shallow water.
B)of upwelling.
C)near river outflows.
D)of high latitudes.

Question 26

Sea anemones and corals lack

A)a sexual stage.
B)an asexual stage.
C)a polyp stage.
D)a medusa stage.

Question 27

The ciliated larva of the cnidarians is called a ________.

Question 28

Reef-building corals have mutualistic algal cells in their tissues called

A)coralline algae.
B)zooxanthellae.
C)kelp.
D)Euglena.

Question 29

The body wall of a Hydra consists of an outer epidermis and an inner gastrodermis with ______________ between them.

Question 30

The medusa of Obelia is the

A)sexual jellyfish stage.
B)sexual colonial stage.
C)asexual jellyfish stage.
D)asexual colonial stage.

Question 31

The function of the siphonoglyph is

A)to pump water into the gastrovascular cavity.
B)to sting the prey.
C)to aid in swimming.
D)unknown.

Question 32

The ______________ are often bioluminescent.

A)anthozoans
B)ctenophores
C)hydrozoans
D)scyphozoans
Fill in the Blank Questions

Question 33

Ctenophores capture prey by use of

A)nematocysts.
B)collenchyme.
C)colloblasts.
D)statocysts.

Question 34

A pharynx and siphonoglyphs are structures found in

A)HydrA.
B)sea anemones.
C)Aurelia.
D)Obelia.

Question 35

Most of the zooids of Obelia are feeding polyps called ____________________.

Question 36

In Obelia,the feeding polyp is the

A)perisarc.
B)gonangium.
C)manubrium.
D)hydranth.

Question 37

The function of rhopalia is

A)digestive.
B)respiratory.
C)food capture.
D)sensory.

Question 38

The tall secretory cells around the pedal disc and mouth of Hydra are the ___________ cells.

Question 39

In cnidarians,extracellular digestion occurs in the

A)gastrovascular cavity.
B)gastrodermal cells.
C)mesoderm.
D)nematocysts.

Question 40

The correct sequence in the life cycle of the jellyfish Aurelia is

A)planula,ephyra,scyphistomA.
B)scyphistoma,planula,ephyra.
C)planula,scyphistoma,ephyra.
D)ephyra,planula,scyphistoma.

Question 41

Sea anemones may exhibit an unusual form of asexual reproduction by ________________.

Question 42

Ctenophores are propelled by eight plates bearing long,fused ____________.

Question 43

The long threadlike structures that help to overcome prey and provide defense in sea anemones are called _______________.

Question 44

Molecular evidence suggests that hydrozoans,scyphozoans,and cubozoans shared a common ancestor with an anthozoan life cycle and a ___________ form later to the life cycle.

Question 45

A distinguishing characteristic of cubozoan medusae is the presence of a flattened blade called a _________________ at the base of the tentacles.

Question 46

The small organs of equilibrium in scyphozoan jellyfishes are called _____________,and these are borne in more complex sense organs called ________________.

Question 47

The three types of nematocysts in the Hydra are the penetrants,the glutinants,and the ___________.

Question 48

Octocorallian corals include soft corals,sea pansies,sea pens,and sea fans and other gorgonian corals (horny corals).All of these are characterized by strict _________________ symmetry.