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Chapter 9
1. One proposed mechanism for the evolution of multicellularity involves an ancestral
multinucleate cell in which plasma membranes formed between nuclei, resulting in a
multicellular organism. This proposed mechanism is referred to as the __________
hypothesis.
A) colonial
B) syncytial
C) polyphyletic
D) metazoan
E) synthetic
2.
A)
B)
C)
D)
E)
Which of the following items is not found in sponges?
choanocytes
tissues
pinacocytes
porocytes
mesohyl
3.
A)
B)
C)
D)
E)
Contractile pinacocytes that can regulate water circulation in some sponges are called
spongiocytes.
choanocytes.
porocytes.
archeocytes.
amebocytes.
4.
A)
B)
C)
D)
E)
Just underneath the pinacocyte layer of a sponge is a jellylike layer referred to as the
ectoderm.
endoderm.
mesoderm.
mesohyl.
endochyme.
5.
A)
B)
C)
D)
E)
The collar of a choanocyte
regulates the diameter of the osculum.
filters food from the water.
creates currents in the water.
regulates the diameter of the ostia.
secretes digestive enzymes.
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6.
A)
B)
C)
D)
E)
The taxonomy of sponges is determined by
the shape of the choanocytes.
the complexity of the osculum.
the material that composes the skeleton.
the presence or absence of porocytes.
the shape of the body of the sponge.
7.
A)
B)
C)
D)
E)
The __________ is the simplest, but least common body form of sponge.
leucon
sycon
demosponge
ascon
sclerosponge
8.
A)
B)
C)
D)
E)
The porocytes of ascon sponges lead to the outside via openings called
spongocoels.
atriopores.
blastopores.
oscula.
ostia.
9.
A)
B)
C)
D)
E)
The single large opening at the top of the spongocoel is the
osculum.
atriopore.
ostium.
mouth.
anus.
10.
A)
B)
C)
D)
E)
__________ sponges have incurrent canals formed by infoldings of the body wall.
Sclerosponge
Sycon
Leucon
Calcisponge
Ascon
11.
A)
B)
C)
D)
E)
Sponges may gain nutrition by all of the following modes except
filtration.
trapping of food items by the collar.
active transport of nutrients.
phagocytosis.
active predation.
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12.
A)
B)
C)
D)
E)
The unique adhesive cells of ctenophores are
statoblasts.
cnidoblasts.
colloblasts.
pleuroblasts.
statoliths.
13. The most complex sponge body form, the __________, is characterized by multiple
oscula and a complex canal system where choanocytes reside in small chambers.
A) leucon
B) ascon
C) sycon
D) polyp
E) medusa
14.
A)
B)
C)
D)
E)
Excretion and gas exchange in sponges are accomplished by
active transport.
diffusion.
contractile vacuoles.
nephridia.
osmosis.
15.
A)
B)
C)
D)
E)
Eggs and sperm of sponges are commonly formed from
pinacocytes.
porocytes.
choanocytes.
spongiocytes.
sclerocytes.
16.
A)
B)
C)
D)
E)
Ctenophores move via bands of cilia called
lappets.
rhopalia.
comb rows.
acontia.
tentacles.
17. Freshwater (and some marine) sponges form resistant structures which function in
asexual reproduction, called
A) brown bodies.
B) larvae.
C) statoblasts.
D) spores.
E) gemmules.
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18.
A)
B)
C)
D)
E)
Gemmules contain masses of __________ which can survive freezing or drying.
amoeboid cells
porocytes
choanocytes
spongin
pinacocytes
19.
A)
B)
C)
D)
E)
Members of class __________ are those historically used as commercial sponges.
Calcarea
Demospongiae
Hexactinellida
Syconidae
Leuconidae
20. Members of the phylum __________ are characterized by radial (or biradial) symmetry,
diploblastic organization, a gastrovascular cavity, and cnidocytes.
A) Mesozoa
B) Placozoa
C) Cnidaria
D) Porifera
E) Ctenophora
21.
A)
B)
C)
D)
E)
Members of the cnidarian class __________ never have a medusa stage.
Mesozoa
Hydrozoa
Scyphozoa
Anthozoa
Cubozoa
22.
A)
B)
C)
D)
E)
Cnidarians exchange respiratory gases and nitrogenous wastes via
active pumping.
movement of cilia.
active transport.
movement of microvilli.
diffusion.
23. An intracellular structure made of a fluid-filled capsule holding a coiled, hollow tube is
the
A) cnidocyte.
B) choanocyate.
C) cnidocil.
D) nematocyst.
E) pinacocyte.
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24.
A)
B)
C)
D)
E)
The __________ body form of a cnidarian is typically asexual and sessile.
sycon
polyp
ascon
leucon
medusa
25.
A)
B)
C)
D)
E)
The __________ body form of a cnidarian is typically dioecious and free swimming.
sycon
polyp
ascon
leucon
medusa
26. The __________ cavity of cnidarians serves in digestion and as a site for exchange of
respiratory gases and wastes.
A) intestine
B) spongocoel
C) gastrocoel
D) gastrovascular cavity
E) archenteron
27.
A)
B)
C)
D)
E)
The free swimming larva of cnidarians is the
planula.
pilidium.
trochophore.
bipinnaria.
veliger.
28.
A)
B)
C)
D)
E)
The feeding polyps of an Obelia colony are called
hydranths.
gastrozooids.
gonozooids.
statocysts.
statoblasts.
29.
A)
B)
C)
D)
E)
The Portuguese man-of-war is a colonial
scyphozoan.
anthozoan.
mesozoan.
hydrozoan.
cubozoan.
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30.
A)
B)
C)
D)
E)
Members of the cnidarian class __________ are called the “true jellyfish.”
Cubozoa
Anthozoa
Hydrozoa
Scyphozoa
Mesozoa
31.
A)
B)
C)
D)
E)
Sensory structures located in 8 notches around the bell of jellyfish medusae are
statoliths.
colloblasts.
manubri.
nematocysts.
rhopalia.
32.
A)
B)
C)
D)
E)
The main source of nutrient carbohydrates in coral come from
zooxanthellae.
captured prey.
rhopalia.
acontia.
ephyrae.
33.
A)
B)
C)
D)
E)
Members of the phylum Ctenophora are commonly called
jellyfish.
comb jellies.
water bears.
ephyrae.
polyps.
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