Deck 8: Acoelomorpha, Platyzoa, and Mesozoa: Flatworms, Gastrotrichs, Gnathiferans, and Mesozoans

Question 1

Flatworms and cnidarians may have evolved from a common planuloid ancestor.

Answer 1

True

Question 2

The acoelomates are the simplest animals with three germ layers,bilateral symmetry,and an organ-system level of organization.

Answer 2

True

Question 3

The pseudocoelomates include the cnidarians,the rotifers and the gnathostomulids.

Answer 3

False

Question 4

Adult tapeworms live in the digestive tract of vertebrates.

Question 5

Humans become infected with Taenia solium by eating insufficiently cooked beef.

Question 6

Most turbellarian flatworms are free-living,but the flukes and tapeworms are all parasitic.

Question 7

The flatworms are more derived (or advanced)than the cnidarians because of their

A)circulatory and digestive systems.
B)circulatory and respiratory systems.
C)excretory and nervous systems.
D)respiratory and digestive systems.

Question 8

Radial symmetry and cephalization evolved together in the acoelomate animals.

Question 9

All pseudocoelomate organisms have a complete digestive tract.

Question 10

The term tegument is most appropriate for reference to the living outer layer of flatworms.

Question 11

The main ill effects in schistosomiasis result from damage done by the adult worms.

Question 12

The Acanthocephala are nonparasitic,freshwater worms.

Question 13

Flatworms have three germ layers: ectoderm,mesoderm,and endoderm.

Question 14

Many rotifers can reproduce parthenogenetically.

Question 15

Gastrotrichs are large,wormlike animals.

Question 16

Flame cells are the primary excretory structures in rotifers.
Multiple Choice Questions

Question 17

The nervous system in planaria is

A)absent.
B)a nerve net.
C)a single ventral cord.
D)a ladder type.

Question 18

Some characteristics of flatworms and ribbon worms are

A)bilateral symmetry,triploblastic,acoelomate.
B)acoelomate,diploblastic,bilateral symmetry.
C)radial symmetry,triploblastic,acoelomate.
D)diploblastic,radial symmetry,acoelomate.

Question 19

Digenetic trematodes typically have a vertebrate as the definitive host and a mollusc as the intermediate host.

Question 20

A number of Digenea are parasites of domestic animals and humans.

Question 21

The posterior attachment organ of monogeneans is the ________________.

Question 22

Humans become infected with liver flukes by

A)eating infected raw fish.
B)eating infected snails.
C)drinking water contaminated with eggs.
D)swimming in infected waters.

Question 23

Structures found in tapeworms but not in other flatworms are

A)proglottids.
B)scolex.
C)strobila.
D)all of these

Question 24

Most individual turbellarians contain organs of both sexes and are thus termed _____________.

Question 25

The intermediate host of the blood fluke Schistosoma is a

A)fish.
B)human.
C)snail.
D)dog.

Question 26

In flame cells

A)flagella drive fluid through tubules.
B)digestion of proteins takes place.
C)excretion of proteins is one important function.
D)the heat is intense.

Question 27

A pseudocoelom allows for which of the following?

A)Greater freedom of movement
B)Space for development and differentiation of digestive,excretory and reproductive systems
C)A simple means of circulation
D)A storage place for waste products to be discharged to the outside
E)All of the above are true.
Fill in the Blank Questions

Question 28

An organism with three distinct germ layers is termed _______________.

Question 29

"Ectolecithal" describes a situation in which

A)there is no yolk.
B)yolk is contained in separate cells outside the zygote.
C)yolk is concentrated at one end of the zygote.
D)yolk is found around the perimeter of the zygote.

Question 30

Humans become infected with Taenia saginatus when they

A)eat poorly cooked fish.
B)eat poorly cooked pork.
C)eat poorly cooked beef.
D)all of these

Question 31

Gnathostomulids might most typically be found

A)between sand grains in the ocean bottom.
B)living symbiotically with coral.
C)as a parasite in the respiratory system of vertebrates.
D)in wet moss.

Question 32

Acanthocephalans

A)parasitize fish,birds,and mammals.
B)are monoecious.
C)have a well-developed digestive tract.
D)are found in the host's liver.

Question 33

Since flatworms and ribbon worms lack a coelom or a pseudocoel,they are termed ____________ animals.

Question 34

The monogenetic flukes

A)are mostly ectoparasites of fish.
B)are usually found in rabbits.
C)require an intermediate and a definitive host.
D)all of these

Question 35

Rotifers

A)are primarily marine.
B)are dioecious.
C)lack an excretory system.
D)lack a digestive tract.

Question 36

Trematodes have a body covering known as a _________________.

Question 37

The mastax of a rotifer is used for

A)respiration.
B)grinding food.
C)swimming.
D)pumping blooD.

Question 38

Turbellarians have light-sensitive organs called _________________.

Question 39

Free-living flatworms have

A)ocelli.
B)tactile cells.
C)chemoreceptors.
D)all of these

Question 40

Most monogeneans are external parasites of ______________.

Question 41

The free-swimming,ciliated stage that hatches from a digenetic trematode egg is the ____________.

Question 42

Turbellarians have rod-shaped ____________ in the epidermis which produce mucous.

Question 43

The repeated reproductive units of tapeworms are known as ________________.

Question 44

Asexually reproducing stages of digeneans in their snail hosts are the _______________ and ___________________.

Question 45

The main body of the cestode is the ______________.

Question 46

Two distinctive features of Acanthocephala are a spiny proboscis and a _______________ system.

Question 47

The pseudocoel is derived from the embryonic _______________.

Question 48

Because of their body shape and metabolic requirements,early flatworms must have been well predisposed toward _______________.

Question 49

Rotifers have a unique ciliated crown known as the _________________.

Question 50

The traditionally accepted class Turbellaria is ___________ because some ectolecithal turbellarians should be allied with tematodes,monogeneans,and cestodes in a sister group.

Question 51

Eggs of rotifers that are unfertilized and develop parthenogenetically only into females are described as _________,while those that undergo meiosis and are haploid are ___________.

Question 52

In contrast to other flatworms,tapeworms lack a ___________________.

Question 53

Several pseudocoelomate groups have a constant number of cells or nuclei in the adults of a given species.This condition is known as ________.

Question 54

Mesodermal cells,known as ___________ cells,fill the space between muscles and visceral organs in flatworms.

Question 55

The holdfast of a tapeworm is its ______________.

Question 56

People become infected with Schisitosoma when ___________ penetrate the skin.