The putative ancestor of animals was:
A. choanoflagellates
B. chytrids
C. gnetophytes
D. stramenopiles
E. euglenozoa

A. choanoflagellates

Which of the following was NOT a major morphological criterion on which traditional classification of animals was based?
A. presence or absence of a true body cavity
B. type of symmetry
C. pattern of embryonic development
D. presence or absence of certain types of tissue
E. basic pattern of cell division

E. basic pattern of cell division

The comparison between Parazoa and Eumetazoa is best described by which of the following statements?
A. Parazoa have only one kind of cell whereas Eumetazoa have many kinds.
B. The various kinds of cells of Parazoa do not form permanent associations into tissues or organs whereas Eumetazoa possess true, stable tissues.
C. Parazoans are only haploid, whereas eumetazoans are diploid with haploid sex cells.
D. Parazoans invert during their development whereas eumetazoans do not.
E. All of the choices provided are correct.

B. The various kinds of cells of Parazoa do not form permanent associations into tissues or organs whereas Eumetazoa possess true, stable tissues.

Bilateria are characterized by:
A. a plane of symmetry that forms mirror images around a vertical plane in the midline
B. a plane of symmetry that forms mirror images around a horizontal plane in the midline
C. a plane of symmetry around a transverse plane across the center of the body so that the front and back halves are mirror images
D. a plane of symmetry that forms mirror images around an oblique plane in the midline
E. a plane of symmetry that forms mirror images around any plane through the longitudinal midline of the body

A. a plane of symmetry that forms mirror images around a vertical plane in the midline

. Cephalization is:
A. embryonic development of the head in advance of the rest of the body
B. concentration of the sensory organs on the posterior end of the body
C. concentration of the sensory organs on the anterior end of the body
D. an evolutionary degeneration of the head as seen in some parasites
E. a malformation of the head

C. concentration of the sensory organs on the anterior end of the body

Germ layers are:
A. layers infected with bacteria
B. embryonic layers with different developmental potentials
C. layers of cells surrounding the egg prior to fertilization
D. colonial protists arranged in layers
E. none of the choices provided

B. embryonic layers with different developmental potentials

The fate of the embryonic germ layers is:
A. The endoderm forms the gut, the ectoderm forms the epidermis and parts of the nervous system, and the mesoderm forms muscles and most internal organs.
B. The endoderm forms the gut, the ectoderm forms the reproductive tract and endocrine system, and the mesoderm forms muscles and most internal organs.
C. The endoderm forms the inner part of all internal organs, the mesoderm forms the middle parts, and the ectoderm forms the outer coverings.
D. The layers are sequential structures that all disappear during development, with the endoderm appearing first and then is replaced by the mesoderm, which in turn is supplanted by the ectoderm.
E. The endoderm is an embryonic structure that disappears early, whereas the ectoderm persists as the skin and the mesoderm as the internal organs.

A. The endoderm forms the gut, the ectoderm forms the epidermis and parts of the nervous system, and the mesoderm forms muscles and most internal organs.

Triploblastic are animals that:
A. form three separate blastulas from a single embryo
B. produce three eggs, each of which forms a single blastula
C. form three blastopores in each blastula
D. have a blastula composed of three cells
E. have three germ layers

E. have three germ layers

Coelomates are:
A. two embryos that develop in the same coelom
B. animals that have a true coelom
C. animals that have two coeloms
D. animals that have no coelom
E. animals in which the coelom disappears at gastrulation

B. animals that have a true coelom

When division of the zygote reaches the eight-cell stage and the planes of cleavage of the upper four cells line up with those of the bottom four cells so that two tiers of cells result, one directly above the other, the type of cleavage is called:
A. direct cleavage
B. spiral cleavage
C. indirect cleavage
D. protostome cleavage
E. radial cleavage

E. radial cleavage

You are given an embryo with eight cells and you carefully separate them and allow them to develop in separate containers. Each of the cells forms a complete embryo that develops normally into an adult animal. How would you categorize your animal?
A. It has indeterminate cleavage.
B. It has determinate cleavage.
C. It is a protostome.
D. It is an annelid, mollusk, or arthropod.
E. It has spiral cleavage.

A. It has indeterminate cleavage.

Which of the following statements is NOT true of the blastopore?
A. It is the opening from the blastocoel to the outside.
B. It is the opening from the archenteron to the outside.
C. It can develop into the mouth of the adult in some animals.
D. It can develop into the anus of the adult in some animals.
E. It occurs in both protostomes and deuterostomes

A. It is the opening from the blastocoel to the outside.

Metamerism is a characteristic feature of:
A. Annelida
B. Arthropoda
C. Chordata
D. all of the three phyla listed
E. none of the three phyla listed

D. all of the three phyla listed

Forelimbs form at the junction of the neck and thoracic vertebrae, the position of which is controlled by HoxC-6 genes. Several kinds of vertebrates from different Classes are legless, including legless lizards, and amphibians known as caecilians. All descended from legged forms. On the basis of recent research in genetics what would you predict about the functioning of their HoxC-6 genes?
A. The site of expression of their HoxC-6 genes may have moved anteriorly until the level of expression has eliminated the neck region.
B. The site of expression of their HoxC-6 genes would be the same as that of legged vertebrates but is simply turned off early in development.
C. Their HoxC-6 gene has mutated and serves a different function than in legged vertebrates.
D. The effect of the HoxC-6 gene is masked by another gene that is dominant to it.
E. None of the other choices provided offer an adequate explanation and other reasons must be sought.

A. The site of expression of their HoxC-6 genes may have moved anteriorly until the level of expression has eliminated the neck region.

A reinterpretation of animal phylogeny (differing from morphologically based phylogeny) that was made possible by molecular techniques, was:
A. designation of the Ecdysozoa and Lophotrochozoa as clades
B. designation of the Bilateria as a monophyletic group
C. designation of annelids and arthropods as closely related
D. designation of rotifers and nematodes as closely related
E. placement of echinoderms and chordates in entirely different clades

A. designation of the Ecdysozoa and Lophotrochozoa as clades

Traditional and molecular phylogenies disagree on which one of the following issues?
A. whether or not the Eumetazoa are monophyletic
B. whether the Bilateria and Radiata split early into separate monophyletic clades
C. whether the split between Parazoa and Eumetazoa occurred at a very early stage in animal evolution
D. whether Echinodermata and Chordata are both deuterostomes
E. whether the appearance and type of coelom is important in interpreting phylogeny

E. whether the appearance and type of coelom is important in interpreting phylogeny

Which of the following phyla are NOT lophotrochozoans?
A. Platyhelminthes
B. Mollusca
C. Annelida
D. Rotifera
E. Nematoda

E. Nematoda

A horseshoe-shaped crown of tentacles used by many invertebrates for feeding is called a:
A. protostome
B. fimbrium
C. lophophore
D. trochophore
E. rhizophore

C. lophophore

A distinctive type of larva shared by several phyla of invertebrates and considered to be important in phylogeny is the:
A. trochophore
B. paedomorph
C. gastrula
D. metamere
E. tadpole

A. trochophore

What is the primary characteristic that groups phyla within the Ecdysozoa?
A. They all have tropchophore larvae.
B. They all shed their exoskeletons.
C. They all have radial cleavage.
D. They all have lophophores.
E. All of the choices provided are correct.

B. They all shed their exoskeletons.

The polymerase chain reaction (PCR) is used as a tool for:
A. breaking down DNA for analysis
B. amplifying the amount of DNA to provide a large sample
C. fragmenting DNA into smaller pieces
D. rearranging the gene sequences in isolated fragments of DNA
E. extracting DNA from nuclei

B. amplifying the amount of DNA to provide a large sample

If two otherwise dissimilar organisms share similar genomic DNA, it suggests which of the following conclusions?
A. The shared genes are ancient and probably no longer function within the altered physiological states of modern organisms.
B. The shared genes have evolved a number of times and have no phylogenetic significance.
C. The two taxa are more closely related than formerly believed.
D. The shared genes developed early in evolution and are likely to be applicable to a wide diversity of organisms.
E. DNA is not a reliable basis for phylogenetic decisions.

C. The two taxa are more closely related than formerly believed.

Ecdysis is:
A. development of the ectoderm layer in the gastrula
B. development of the epidermis from the ectoderm
C. disintegration of the ectoderm
D. molting
E. the feeding tentacles of the Ecdysozoa

D. molting

The coelom forms in two different ways. Which of the following statements best compares those ways?
A. In schizocoelous development a solid mass of mesoderm splits to form the coelom whereas in enterocoelous development a layer of mesoderm cells forms a pocket off of the developing gut to form the coelom.
B. In enterocoelous development a solid mass of mesoderm splits to form the coelom whereas in schizocoelous development a layer of mesoderm cells forms a pocket off of the developing gut to form the coelom.
C. In enterocoelous development the coelom forms inside the mesoderm whereas in schizocoelous development the coelom forms on the outside of the mesoderm.
D. In schizocoelous development the coelom forms within the mesoderm whereas in enterocoelous development, no coelom is formed at all.
E. Schizocoelous and enterocoelous both form the coelom in identical ways, the difference merely being that the term schizocoelous is used only for deuterostomes and enterocoelous is used only for protostomes.

A. In schizocoelous development a solid mass of mesoderm splits to form the coelom whereas in enterocoelous development a layer of mesoderm cells forms a pocket off of the developing gut to form the coelom.

The placement of the phylum Platyhelminthes in the phylogenetic tree differs between a morphologically based phylogeny and a molecular based phylogeny. Which of the following statements best describes the interpretation based on molecular phylogeny?
A. Modern Platyhelminthes do not have a coelom but did originate from an ancestor that had one.
B. The Platyhelminthes clade separated from other clades before coeloms evolved and consequently Platyhelminthes have never had a coelom.
C. Platyhelminthes originated from ancestors with a coelom and have retained it to the present time.
D. Platyhelminthes evolved from an ancestor without a coelom but developed one during the course of their evolution.
E. Some Platyhelminthes have a coelom but others do not and it is difficult to conclude anything about its evolution within the clade.

A. Modern Platyhelminthes do not have a coelom but did originate from an ancestor that had one.

The relevance of the pseudocoelom to phylogeny has been questioned. Rotifera and Nematoda both have a pseudocoelom. The molecular evidence suggests which of the following conclusions?
A. Molecular evidence confirms that rotifers and nematodes are closely related and that both participate in the same monophyletic clade.
B. Rotifers are more closely related to Lophotrochozoa than to nematodes.
C. Rotifers are more closely related to echinoderms than to nematodes.
D. Rotifers are more closely related to chordates than to nematodes.
E. Rotifers are more closely related to nematodes than to mollusks

B. Rotifers are more closely related to Lophotrochozoa than to nematodes.

Which of the following statements best compares a pseudocoelom and a coelom?
A. A coelom is completely enclosed by mesoderm whereas a pseudocoelom has an outer covering of mesoderm and an inner one of endoderm.
B. A pseudocoelom is completely enclosed by mesoderm whereas a coelom has an outer covering of mesoderm and an inner one of endoderm.
C. The coelom is enclosed by ectoderm and the pseudocoelom is enclosed by endoderm.
D. The pseudocoelom is enclosed by ectoderm and the coelom is enclosed by endoderm.
E. The coelom is enclosed by ectoderm and the pseudocoelom is enclosed by mesoderm.

A. A coelom is completely enclosed by mesoderm whereas a pseudocoelom has an outer covering of mesoderm and an inner one of endoderm.

The aboral side of a radially symmetrical animal is:
A. the side containing the mouth
B. the side opposite the side containing the mouth
C. its outside
D. its inside
E. All of the other choices provided are incorrect

B. the side opposite the side containing the mouth

An acoelomate is an animal that:
A. has a coelom
B. has a pseudocoelom
C. has both a coelom and a pseudocoelom
D. has neither a coelom nor a pseudocoelom
E. has a coelom during early development but later loses it

D. has neither a coelom nor a pseudocoelom

Metamerism is:
A. the division of the body into segments
B. the fusion of body parts
C. shedding of the skin
D. formation of the germ layers in early development
E. the first cellular division following fertilization

A. the division of the body into segments

If it were found that all animals except the Parazoa had a particular set of genes, one could conclude:
A. that those genes are not useful in interpreting phylogeny
B. that Darwin was incorrect in his idea about descent with modification
C. that the Parazoa are not animals
D. that those genes probably are related to the embryonic formation of tissues
E. None of the other choices offered are realistic

D. that those genes probably are related to the embryonic formation of tissues

Which of the phyla of animals has the greatest number of species?
A. Arthropoda
B. Chordata
C. Mollusca
D. Annelida
E. Nematoda

A. Arthropoda

Echinoderms are classified as Bilateria and they start out as bilateral larvae, yet as they develop they change into radially symmetrical adults. Would you expect their genes controlling the development of radial symmetry to be:
A. different from those controlling development of symmetry in all other radially symmetrical animals
B. similar to genes controlling body form in Porifera
C. similar to genes controlling body form in Ctenophora
D. similar to genes controlling body form in the lophophorates
E. similar to a common set of genes controlling body form in Ctenohora, and lophophorates

A. different from those controlling development of symmetry in all other radially symmetrical animals

If you were to discover a new species of animal that did not have body segments, but shed its exoskeleton and was a protostome, under the molecular phylogenetic scheme, you would allocate it to which of the following phyla?
A. Mollusca
B. Echinodermata
C. Nematoda
D. Platyhelminthes
E. Arthropoda

C. Nematoda

If you conducted an experiment in which you took a complete animal and strained it through a fine-mesh cloth so that all its cells separated, then you placed all the cells together and they reunited to form a new animal, to which phylum would that animal likely belong? (This was an actual experiment.)

A. Platyhelminthes
B. Porifera
C. Ctenophora
D. Nematoda
E. All of the choices provided are correct.

B. Porifera

Which of the following is NOT a valid distinction between a blastocoel, an archenteron, and a coelom?
A. During development these cavities appear in the sequence blastocoel, archenteron, coelom.
B. The blastocoel forms the cavity of the digestive tract, the archenteron forms the chest cavity, and the coelom forms the cavity of the digestive tract.
C. The blastocoel is bounded only by an external germ layer, the archenteron is bounded by inner and outer layers of germ cells, and the coelom is a cavity within the mesoderm.
D. The archenteron has a direct opening to the outside of the embryo whereas the other two cavities do not.
E. None of the other choices are correct.

B. The blastocoel forms the cavity of the digestive tract, the archenteron forms the chest cavity, and the coelom forms the cavity of the digestive tract.