Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the
A) tip of the coleoptile.
B) part of the coleoptile that bends during the response.
C) base of the coleoptile.
D) cotyledon.
E) phytochrome in the leaves.

Answer: A

Charles and Francis Darwin discovered that
A) auxin is responsible for phototropic curvature.
B) auxin can pass through agar.
C) light destroys auxin.
D) light is perceived by the tips of coleoptiles.
E) red light is most effective in shoot phototropism.

Answer: D

Plants growing in a partially dark environment will grow toward light in a response called phototropism. Which of the following statements is true regarding phototropism?
A) It is caused by an electrical signal.
B) One chemical involved is ethylene.
C) Auxin causes a growth increase on one side of the stem.
D) Auxin causes a decrease in growth on the side of the stem exposed to light.
E) Removing the apical meristem enhances phototropism.

Answer: C

We know from the experiments of the past that plants bend toward light because
A) they need sunlight energy for photosynthesis.
B) the sun stimulates stem growth.
C) cell expansion is greater on the dark side of the stem.
D) auxin is inactive on the dark side of the stem.
E) phytochrome stimulates florigen production.

Answer: C

Why do coleoptiles grow toward light?
A) Auxin is destroyed by light.
B) Gibberellins are destroyed by light.
C) Auxin synthesis is stimulated in the dark.
D) Auxin moves away from the light to the shady side.
E) Gibberellins move away from the light to the shady side.

Answer: D

The apical bud of a shoot produces ________, resulting in the inhibition of lateral bud growth.
A) abscisic acid
B) ethylene
C) cytokinin
D) gibberellin
E) auxin

Answer: E

The plant hormone involved in aging and ripening of fruit is
A) auxin.
B) ethylene.
C) florigen.
D) abscisic acid.
E) gibberellin.

Answer: B

Which of the following hormones would never be found in high concentrations in a dormant overwintering flower bud?
A) auxin
B) cytokinins
C) abscisic acid
D) ethylene
E) gibberellins

Answer: D

If a farmer wanted more loosely packed clusters of grapes, he would most likely spray the immature bunches with
A) auxin.
B) gibberellins.
C) cytokinins.
D) abscisic acid.
E) ethylene.

Answer: B

Which of the following plant hormones are most likely to act synergistically if expressed or applied to a drought-stricken plant?
A) auxin and ethylene
B) phytochrome and gibberellins
C) gibberellins and abscisic acid
D) abscisic acid and ethylene
E) brassinosteroids and cytokinins

Answer: D

Which of the following hormones would be most useful in promoting the rooting of plant cuttings?
A) oligosaccharins
B) abscisic acid
C) cytokinins
D) gibberellins
E) auxins

Answer: E

Which of the following plant hormones would most likely be found in high concentrations in a mature, slightly overripe fruit?
A) auxins and cytokinins
B) auxins and abscisic acid
C) gibberellins and cytokinins
D) cytokinins and ethylene
E) abscisic acid and ethylene

Answer: E

The synthesis of which of the following hormones would be a logical first choice in an attempt to produce normal growth in mutant dwarf plants?
A) indoleacetic acid
B) cytokinin
C) gibberellin
D) abscisic acid
E) ethylene

Answer: C

A plant seedling bends toward sunlight because
A) auxin migrates to the lower part of the stem due to gravity.
B) there is more auxin on the light side of the stem.
C) auxin is destroyed more quickly on the dark side of the stem.
D) auxin is found in greatest abundance on the dark side of the stem.
E) gibberellins produced at the stem tip cause phototropism.

Answer: D

When growing plants in culture, IAA is used to stimulate cell enlargement. Which plant growth regulator has to now be added to stimulate cell division?
A) ethylene
B) indoleacetic acid
C) gibberellin
D) cytokinin
E) abscisic acid

Answer: D

The aleurone layer is stimulated to release ________ and ________ as a result of giberrellin release from the embryo.
A) proteins; amino acids
B) carbohydrates; sugars
C) auxins; cytokinins
D) amylase; protease
E) RNAase; DNAase

Answer: D

In individual insects of some species, whole chromosomes that carry larval genes are eliminated from the genomes of somatic cells at the time of metamorphosis. A consequence of this occurrence is that
A) we could not clone a larva from the somatic cells of such an adult insect.
B) such species must reproduce only asexually.
C) the descendents of these adults do not include a larval stage.
D) metamorphosis can no longer occur among the descendents of such adults.
E) Two of these responses are correct.

Answer: A

Both animals and fungi are heterotrophic. What distinguishes animal heterotrophy from fungal heterotrophy is that only animals derive their nutrition by
A) preying on animals.
B) ingesting it.
C) consuming living, rather than dead, prey.
D) using enzymes to digest their food.

Answer: B

Which of the following is (are) unique to animals?
A) cells that have mitochondria
B) the structural carbohydrate, chitin
C) nervous conduction and muscular movement
D) heterotrophy
E) Two of these responses are correct.

Answer: C

Among the characteristics unique to animals is
A) gastrulation.
B) multicellularity.
C) sexual reproduction.
D) flagellated sperm.
E) heterotrophic nutrition.

Answer: A

What do animals as diverse as corals and monkeys have in common?
A) body cavity between body wall and digestive system
B) number of embryonic tissue layers
C) type of body symmetry
D) presence of Hox genes
E) degree of cephalization

Answer: D

The last common ancestor of all animals was probably a
A) unicellular chytrid.
B) unicellular yeast.
C) multicellular algae.
D) multicellular fungus.
E) flagellated protist.

Answer: E

An adult animal that possesses bilateral symmetry is most certainly also
A) triploblastic.
B) a deuterostome.
C) eucoelomate.
D) highly cephalized.

Answer: A

Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?
A) true tissues
B) hard parts
C) bilateral symmetry
D) cephalization
E) embryos

Answer: B

At which developmental stage should one be able to first distinguish a diploblastic embryo from a triploblastic embryo?
A) fertilization
B) cleavage
C) gastrulation
D) coelom formation
E) metamorphosis

Answer: C

At which developmental stage should one be able to first distinguish a protostome embryo from a deuterostome embryo?
A) fertilization
B) cleavage
C) gastrulation
D) coelom formation
E) metamorphosis

Answer: B

The blastopore is a structure that first becomes evident during
A) fertilization.
B) gastrulation.
C) the eight-cell stage of the embryo.
D) coelom formation.
E) cleavage.

Answer: B

Which of the following characteristics generally applies to protostome development?
A) radial cleavage
B) determinate cleavage
C) diploblastic embryo
D) blastopore becomes the anus
E) archenteron absent

Answer: B

Protostome characteristics generally include which of the following?
A) a mouth that develops secondarily, and far away from the blastopore
B) radial body symmetry
C) radial cleavage
D) determinate cleavage
E) absence of a body cavity

Answer: D

Which distinction is given more emphasis by the morphological phylogeny than by the molecular phylogeny?
A) metazoan and eumetazoan
B) radial and bilateral
C) true coelom and pseudocoelom
D) protostome and deuterostome
E) molting and lack of molting

Answer: D

The most ancient branch point in animal phylogeny is that between having
A) radial or bilateral symmetry.
B) a well-defined head or no head.
C) diploblastic or triploblastic embryos.
D) true tissues or no tissues.
E) a body cavity or no body cavity.

Answer: D

Which distinction is given more emphasis by the morphological phylogeny than by the molecular phylogeny?
A) metazoan and eumetazoan
B) radial and bilateral
C) true coelom and pseudocoelom
D) protostome and deuterostome
E) molting and lack of molting

Answer: D

Among the characteristics unique to animals is
A) gastrulation.
B) multicellularity.
C) sexual reproduction.
D) flagellated sperm.
E) heterotrophic nutrition.

Answer: A

Which of the following is (are) unique to animals?
A) cells that have mitochondria
B) the structural carbohydrate, chitin
C) nervous conduction and muscular movement
D) heterotrophy
E) Two of these responses are correct.

Answer: C

What is the probable sequence in which the following clades of animals originated, from earliest to most recent?

1. tetrapods
2. vertebrates
3. deuterostomes
4. amniotes
5. bilaterians

A) 5 → 3 → 2 → 4 → 1
B) 5 → 3 → 2 → 1 → 4
C) 5 → 3 → 4 → 2 → 1
D) 3 → 5 → 4 → 2 → 1
E) 3 → 5 → 2 → 1 → 4

Answer: B

A sponge's structural materials (spicules, spongin) are manufactured by the
A) pore cells.
B) epidermal cells.
C) choanocytes.
D) amoebocytes.

Answer: D

In terms of food capture, which sponge cell is most similar to the cnidocyte of a cnidarian?
A) amoebocyte
B) choanocyte
C) epidermal cell
D) pore cell

Answer: B

Which chemical is synthesized by some sponges and acts as an antibiotic?
A) streptomycin
B) spongin
C) calcium carbonate
D) silica
E) cribrostatin

Answer: E

Sponges are most accurately described as
A) marine predators.
B) marine filter feeders.
C) freshwater scavengers.
D) aquatic filter feeders.
E) aquatic predators.

Answer: D

The excretory organs of annelids are
A) protonephridia.
B) flame bulbs.
C) metanephridia.
D) skin gills.
E) malpighian tubules.

Answer: C

What would be the most effective method of reducing the incidence of blood flukes in a human population?
A) reduce the mosquito population
B) reduce the freshwater snail population
C) purify all drinking water
D) avoid contact with rodent droppings
E) carefully wash all raw fruits and vegetables

Answer: B

The larvae of many common tapeworm species that infect humans are usually found
A) encysted in freshwater snails.
B) encysted in the muscles of an animal, such as a cow or pig.
C) crawling in the abdominal blood vessels of cows and pigs.
D) crawling in the intestines of cows and pigs.

Answer: B

If a lung were to be found in a mollusc, where would it be located?
A) mantle cavity
B) coelom
C) incurrent siphon
D) visceral mass
E) excurrent siphon

Answer: A

Which mollusc clade includes members that undergo embryonic torsion?
A) chitons
B) bivalves
C) gastropods
D) cephalopods

Answer: C

A terrestrial mollusc without a shell belongs to which clade?
A) chitons
B) bivalves
C) gastropods
D) cephalopods

Answer: C

A radula is present in members of which clade(s)?
A) chitons
B) bivalves
C) gastropods
D) cephalopods
E) both chitons and gastropods

Answer: E

Which of the following is a characteristic of nematodes?
A) All species can be characterized as scavengers.
B) They have only longitudinal muscles.
C) They have a true coelom.
D) They have a gastrovascular cavity.
E) Many species are diploblastic.

Answer: B

Humans most frequently acquire trichinosis by
A) having sexual contact with an infected partner.
B) eating undercooked pork.
C) inhaling the eggs of worms.
D) eating undercooked beef.
E) being bitten by tsetse flies.

Answer: B

Among the invertebrate phyla, phylum Arthropoda is unique in possessing members that have
A) a cuticle.
B) a ventral nerve cord.
C) open circulation.
D) wings.
E) segmented bodies.

Answer: D

Chordate pharyngeal slits appear to have functioned first as
A) the digestive system's opening.
B) suspension-feeding devices.
C) components of the jaw.
D) gill slits for respiration.
E) portions of the inner ear.

Answer: B

The earliest known mineralized structures in vertebrates are associated with which function?
A) reproduction
B) feeding
C) locomotion
D) defense
E) respiration

Answer: B

Jaws first occurred in which extant group of fishes?
A) lampreys
B) chondrichthyans
C) ray-finned fishes
D) lungfishes
E) placoderms

Answer: B

Which of these might have been observed in the common ancestor of chondrichthyans and osteichthyans?
A) a mineralized, bony skeleton
B) opercula
C) bony fin rays
D) a spiral valve intestine
E) a swim bladder

Answer: A

Which group's members have had both lungs and gills during their adult lives?
A) sharks, skates, and rays
B) lungfishes
C) lancelets
D) amphibians
E) ichthyosaurs and plesiosaurs

Answer: B

There is evidence that ray-finned fishes evolved
A) in response to a crisis that wiped out the chondrichthyans.
B) directly from lampreys and hagfish.
C) early in the Cambrian period.
D) directly from lancelets.
E) the swim bladder from a lung.

Answer: E

Which of the following belongs to the lobe-fin clade?
A) chondrichthyans
B) ray-finned fishes
C) lampreys
D) hagfishes
E) tetrapods

Answer: E

Which of the following are the most abundant and diverse of the extant vertebrates?
A) ray-finned fishes
B) birds
C) amphibians
D) nonbird reptiles
E) mammals

Answer: A

Which of these are amniotes?
A) amphibians
B) fishes
C) egg-laying mammals
D) placental mammals
E) More than one of these is correct.

Answer: E

Why is the amniotic egg considered an important evolutionary breakthrough?
A) It has a shell that increases gas exchange.
B) It allows deposition of eggs in a terrestrial environment.
C) It prolongs embryonic development.
D) It provides insulation to conserve heat.
E) It permits internal fertilization to be replaced by external fertilization.

Answer: B

Which of the following is characteristic of most extant reptiles and most extant mammals?
A) ectothermy
B) diaphragm
C) shelled eggs
D) keratinized skin
E) conical teeth that are relatively uniform in size

Answer: D

Among extant vertebrates, a sheet of muscle called the diaphragm is found in
A) birds.
B) monotremes.
C) marsupials.
D) placentals.
E) Three of the options listed are correct.

Answer: E

Which of the following are the only extant animals that descended directly from dinosaurs?
A) lizards
B) crocodiles
C) snakes
D) birds
E) tuataras

Answer: D

In which vertebrates is fertilization exclusively internal?
A) chondrichthyans, osteichthyans, and mammals
B) amphibians, mammals, and reptiles
C) chondrichthyans, osteichthyans, and reptiles
D) reptiles and mammals
E) reptiles and amphibians

Answer: D

What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?
A) endothermy
B) feathers
C) an amniotic egg
D) flight
E) a four-chambered heart

Answer: B