Deck 39: Simple Animals: Sponges to Flatworms

Question 1

Which statement is an accurate description of metazoans?

A) Metazoans are unicellular.
B) Metazoans develop from an embryo.
C) Metazoans do not develop a zygote.
D) Metazoans produce gametes by mitosis.
E) Metazoans never reproduce asexually.

Answer 1

Metazoans develop from an embryo.

Question 2

It is believed that metazoans could have evolved from

A) eumetazoans.
B) colonial protists.
C) flagellated monerans.
D) trichoplax.
E) None of the answers are correct.

Answer 2

colonial protists.

Question 3

Fossil evidence about the origins of metazoans suggests that

A) multicellularity arose about 600 million years ago.
B) multicellularity arose independently on several different continents.
C) early multicellular animals arose from protozoa fusing to form flat worm-like animals.
D) metazoans evolved first in the Ediacara Hills of South Australia.
E) All of the answers are correct.

Answer 3

multicellularity arose about 600 million years ago.

Question 4

Which animal phylum is NOT a member of the subkingdom Eumetazoa?

A) Nemertea
B) Cnidaria
C) Porifera
D) Platyhelminthes
E) All these phyla belong to the Eumetazoa

Question 5

Animal phyla that show protostome development include

A) Arthropoda, Annelida and Platyhelminthes.
B) Platyhelminthes, Arthropoda and Echinodermata.
C) Annelida, Mollusca and Chordata.
D) Mollusca, Annelida, Cordata.
E) Echinodermata, Mollusca and Platyhelminthes.

Question 6

Differences between protostomes and deuterostomes are first evident at

A) coelom formation.
B) gastrulation.
C) cleavage.
D) neurulation.
E) splitting of the mesoderm.

Question 7

With the exception of cnidarians and nematodes, eumetazoans can be divided into the two groups: protostomes and deuterostomes. A feature NOT used to separate these groups is the

A) fate of the blastopore in embryo development.
B) way the coelom forms in the embryo.
C) way the embryonic cells divide.
D) number of germ cell tissues.
E) the way the mesoderm slits.

Question 8

The main difference between eumetazoans and parazoans is that

A) parazoans do not have an embryonic stage.
B) parazoans do not have cell layers.
C) parazoans do not have differentiated cells.
D) parazoans have no tissues or organs.
E) eumetazoans have a complex nervous system.

Question 9

A distinctive feature of phylum Porifera is

A) a gastrovascular cavity with a mouth only for digestion.
B) radial symmetry.
C) an internal cavity lined by flagellated cells.
D) a tubular body with a simple nervous system.
E) an exoskeleton of chitin.

Question 10

Amoebocytes in sponges are described as totipotent because of their ability to

A) protect other cells from disease.
B) divide and give rise to any other cell of the sponge.
C) form a protective coating over the sponge.
D) secrete spicules.
E) contain three layers of cells.

Question 11

The skeleton of a sponge may be composed of

A) spongin fibres.
B) calcium carbonate spicules.
C) silica spicules.
D) collagen fibres.
E) All of answers are correct.

Question 12

Which animal does NOT belong to the phylum Cnidaria?

A) Sea star
B) Coral
C) Sea wasp
D) Jellyfish
E) Sea anemone

Question 13

In cnidarians, the mouth is borne on the

A) manubrium.
B) gastrodermis.
C) hypostome.
D) manubrium and gastrodermis.
E) manubrium and hypostome.

Question 14

Radial symmetry is characteristic of animals that

A) filter feed.
B) are attached to a substrate.
C) are poisonous.
D) have tentacles.
E) All of the answers are correct.

Question 15

Which layer is NOT present in the body wall of a cnidarian?

A) Ectoderm.
B) Endoderm.
C) Mesoglea.
D) Mesoderm.
E) All of the answers are correct.

Question 16

The function of a statolith in a scyphozoan is to

A) maintain balance.
B) maintain the shape of the bell.
C) sense light.
D) facilitate attachment of the polyp stage to the substrate.
E) sense gravity.

Question 17

An independent, free-swimming, young medusa produced by the scyphozoan jellyfish Aurelia is called

A) an ephyra.
B) an actinula.
C) a planula.
D) a scyphistoma.
E) a strobila.

Question 18

An important feature of most corals (Class Anthozoa) not widely found among other cnidarians is

A) a free-swimming larval stage.
B) their ability to live in freshwater and marine habitats.
C) a colonial habit.
D) the presence of symbiotic algae in their tissue.
E) sexual reproduction usually involves external fertilisation.

Question 19

Which class of cnidarians never have a medusa stage in their life cycle?

A) Class Cubozoa
B) Class Scyphozoa
C) Class Anthozoa
D) Class Hydrozoa
E) Class Anthozoa and Class Hydrozoa

Question 20

Ctenophorans are thought to be related to cnidarians because

A) at least one group also possesses nematocysts.
B) they have eight ciliary plates.
C) they look like the medusoid stage of some cnidarians.
D) they have a similar digestive system.
E) they have only a polyp form like some cnidarians.

Question 21

Absence of a coelom in the phylum Platyhelminthes

A) is seen to be a primitive feature.
B) limits the amount of organ specialisation possible.
C) means that there is no perivisceral cavity.
D) means there is no body cavity between the mesoderm and the endoderm.
E) All of the answers are correct.

Question 22

A consequence of the absence of a coelom in platyhelminths is that

A) they are dorsiventrally flattened to facilitate transport of essential substances.
B) they are always parasitic.
C) specialisation of organs is limited.
D) they are dorsiventrally flattened to facilitate transport of essential substances and they are always parasitic.
E) they are dorsiventrally flattened to facilitate transport of essential substances and specialisation of organs is limited.

Question 23

Flatworms have specialised cells for excretion called

A) rhabdites.
B) flame cells.
C) the germ layer.
D) protonephridia.
E) kidneys.

Question 24

Reproduction in flatworms occurs by

A) cross-fertilisation.
B) parthenogenesis.
C) self-fertilisation.
D) cross-fertilisation and parthenogenesis.
E) cross-fertilisation, self-fertilisation and parthenogenesis.

Question 25

Turbellarians are the only

A) free-living flatworms.
B) flatworms to have flame cells for excretion.
C) flatworms that are dioecious.
D) None of the answers are correct.
E) All of the answers are correct.

Question 26

The difference between monogeneans and digeneans is that monogeneans

A) are monoecious.
B) are endoparasites.
C) have one host.
D) are ectoparasites.
E) have proglottids.

Question 27

The following is a description of an animal parasite. The parasite may be found in blood vessels of the human intestine. Eggs pass through into the alimentary canal and are released in the faeces. Larval stages are found in a freshwater snail as a secondary host. Re-infection of humans occurs through the skin. The animal described is most likely to be

A) Ascaris lumbricoides.
B) Wucheria bancrofti.
C) Schistosoma japonicum.
D) Taenia sp.
E) Fasciola hepatica.

Question 28

Which is NOT a feature of the proglottids of cestodes?

A) Proglottids are capable of cross-fertilisation.
B) Proglottids grow from the anterior end.
C) There is an indeterminate number of proglottids in the adult.
D) Proglottids contain an alimentary canal.
E) Proglottids have many body segments produced by strobilisation.

Question 29

Animals in phylum Nemertea are called proboscis worms because they have a distinctive

A) eversible pharynx to suck up food.
B) proboscis that emerges from the mouth.
C) proboscis for chewing food.
D) tube-like structure to attach to the host.
E) retractable proboscis for capturing prey.

Question 30

Which Phylum could be described as acoelomate, bilaterally symmetrical and protostome?

A) Porifera
B) Cnidaria
C) Platyhelminthes
D) Nematoda
E) Cestoda

Question 31

Cestodes are

A) tapeworms.
B) parasites of vertebrates.
C) contain a scolex to attach to the host.
D) have proglottids which are produced by strobilisation.
E) All of the answers are correct.

Question 32

Which of the following statements about cestodes is CORRECT?

A) Some cestodes are tissue parasites of vertebrates but have an intermediate invertebrate host.
B) The tegument of cestodes is highly permeable and is the only means of food uptake.
C) Tapeworms are similar in features to platyhelminths, with suckers to attach to the host and a growth zone that buds off body segments
D) Cestodes are ectoparasitic flukes with a complex life cycle involving two hosts.
E) Cestodes resemble platyhelminths in that they have a flattened body and a ciliated epidermis.

Question 33

The phylogenetic tree of animals shows that

A) Sponges, Phylum Protozoa, are the earliest lineage.
B) Eumetazoans are radially symmetrical.
C) Eumetazoans diverged with one branch becoming protostomes and the other becoming deuterostomes.
D) Protostomes and deuterostomes are distinguished by whether the blastopore becomes the mouth or the anus.
E) The subkingdom Eumetazoa are divided into protostomes and deuterostomes

Question 34

In sponges, the ostium is

A) a pore in the external wall through which water is drawn for feeding.
B) the central cavity of the body.
C) the pore through which the water leaves the body.
D) the vacuole formed for food ingestion.
E) the structure for attachment to the surface.

Question 35

Ctenophores

A) most lack nematocysts.
B) have transparent sac-like bodies.
C) have ciliary plates made up of fused cilia.
D) contain a conspicuous structure, the statocyst, which is a balance organ.
E) All of the answers are correct.

Question 36

In Platyhelminths differ from cnidarian

A) since cnidarians have only two cell layers.
B) because Platyhelminths have a mesoderm which leads to organ formation.
C) because cnidarians have a skeleton of calcium carbonate.
D) as Platyhelminths have an excretory system which opens into the archenteron adjacent to the mouth.
E) since platyhelminths are parasites of vertebrates.

Question 37

In many protostomes, each embryonic cell develops into a predetermined tissue type which is fixed very early in development. This type of development is called

A) ordained.
B) fixed.
C) determinate.
D) settled.
E) certain.

Question 38

What gene family is thought to be responsible for the evolution of different body plans due to their temporal and spatial expression in embryos?

A) bHLH
B) Hox
C) Myb
D) Wrky
E) Myc

Question 39

Based on molecular data, the Platyhelminthes are grouped in which major clade?

A) Protonephridia.
B) Ctenophora.
C) Anthozoa
D) Cubozoa
E) Lophotrochozoa

Question 40

A molecular biologist mutates and silences an unknown gene in a species of turbellarian. The resulting organism appears morphologically the same as the wild-type, but is unable to adhere securely to surfaces. What might this unknown gene have been responsible for the development of?

A) Cyclosporins
B) Feet
C) Lower mucilage
D) Ventral epithelia
E) Rhabdites

Question 41

Despite often living in the bladder, why is the blood fluke, Schistosoma, not easily washed out of its host?

A) They secrete a glue-like substance that attaches them firmly to the walls of the tissues they colonise.
B) Blood flukes grow a rhizoid that secures them to the host tissue.
C) They secrete a protease enzyme that partially degrades host wall tissue, after which the abaxial axis of the fluke effectively 'fuses' with the degraded host tissue, permanently anchoring the fluke in place.
D) They live in blood vessels in the tissue walls.
E) They have a posterior with hooks and barbs.

Question 42

Which of the following organisms does NOT have bilateral symmetry?

A) Box jellyfish
B) Flat worm
C) Slug
D) Star fish
E) Proboscis worm

Question 43

A researcher wants to publish the findings of the discovery of a new animal species and hands a draft manuscript to you to critique. The author lists several basic features of the organism which are listed below; which of the features is incorrect?

A) The animal develops via ontogeny.
B) The animal has a bilateral symmetry.
C) The animal is multicellular.
D) The animal is an autotroph.
E) The animal is diploid.

Question 44

Where does the anus form in deuterostomes?

A) In a split in the mesoderm
B) Within the radial arch of the archenteron.
C) At the gut apex
D) At the site of the blastopore
E) From a budding outcrop that extends from the coelom

Question 45

In the Porifera, which cellular layer is equivalent to the epithelium of other animals?

A) Choanocerm
B) Pinacoderm
C) Mesophyl
D) Porocylum
E) Amoeboderm