Animal Behavior

Front 1

In one set of experiments pinealectomized, enucleated American Tree Sparrows were first exposed to long days for
an extended period of time, then exposed to short days for several weeks, and then re-exposed to long days again.
This experiment tested the hypothesis that:
a) Neither the eyes nor the pineal are needed for a normal reproductive response to changing photoperiod.
b) Neither the eyes nor the pineal are needed for long days to induce reproductive development.
c) Neither the eyes nor the pineal are needed for long days to induce photorefractoriness.
d) Neither the eyes nor the pineal are needed for short days to dissipate photorefractoriness.
e) The experiment actually successfully tested all of the above hypotheses.

Back 1

e) The experiment actually successfully tested all of the above hypotheses.

Front 2

Which of the following is a proximate hypothesis regarding the mechanism responsible for hibernators knowing
when to emerge from hibernation?
a) Increasing temperature in the spring acts as a driving cue that stimulates hibernators to terminate hibernation and
emerge.
b) Hibernators possess an endogenous “circannual clock” in the brain that spontaneously signals an increase in
metabolism and motivation to come above ground in spring.
c) Hibernators use a “circa-lunar” clock that causes them to arouse monthly from torpor, actively check conditions
above ground, and to return below ground and re-enter torpor for another month if conditions are not yet suitable
for emergence.
d) All of the above.
e) None of the above.

Back 2

d) All of the above.

Front 3

3) The best evidence that stonechats possess circannual rhythms is:
a) Their reproductive physiology and plumage molt changes cyclically under constant photoperiod.
b) They show cycles of reproductive physiology and plumage molt on constant photoperiod that drift out of phase
with the real world.
c) Their cycles of reproductive physiology and plumage molt on constant conditions remain perfectly synchronized
with the real world.
d) Their reproductive physiology and plumage molt on constant conditions become arrhythmic.
e) Their reproductive physiology and plumage molt become static (unchanging) under constant conditions.

Back 3

b) They show cycles of reproductive physiology and plumage molt on constant photoperiod that drift out of phase
with the real world.

Front 4

One problem with a resonance experiment as a means of testing for a circadian cycle of photo-inducibility underlying
birds’ reproductive response to long days is:
a) The “circadian hypothesis” and the “hour glass hypothesis” both predict the same outcome for a resonance
experiment using short (8 hours or less) light pulses presented as part of a resonance experiment.
b) The “circadian hypothesis” and the “hourglass hypothesis” both predict the same outcome for birds’ responses to
an abrupt increase in photoperiod to long days.
c) Under resonance photocycles, the “light” period will periodically fall during the period of photo-inducibility.
d) Resonance photocycles expose the animal to conflicting entraining stimuli.
e) All of the above are problems with using resonance experiments for this purpose.

Back 4

d) Resonance photocycles expose the animal to conflicting entraining stimuli.

Front 5

Two alternative hypotheses for how birds measure day length are (a) that they use a circadian cycle of
photoinducibility or (b) that they use an “hour glass” mechanism. Which of the following are accurate statements
regarding the predictions that follow from these hypotheses?
a) Both hypotheses predict that a long day of 16 hours of light, 8 hours of dark (16L:8D) will induce reproductive
development.
b) Both hypotheses predict that a short day of 8L:16D will not stimulate reproductive development.
c) The circadian hypothesis predicts that a relatively short pulse of light (e.g., 6 or 8 hours duration) will be able to
induce reproductive development if it is presented at the appropriate circadian time, whereas the hourglass
hypothesis predicts that such short pulses of light will never lead to reproductive development.
d) All of the above.
e) None of the above.

Back 5

c) The circadian hypothesis predicts that a relatively short pulse of light (e.g., 6 or 8 hours duration) will be able to
induce reproductive development if it is presented at the appropriate circadian time, whereas the hourglass
hypothesis predicts that such short pulses of light will never lead to reproductive development.

Front 6

6) Natural activity patterns of free-living kangaroo rats reveal evidence for:
a) Seasonal changes in the duration of nocturnal activity.
3
b) Direct inhibition of night activity by moonlight.
c) Ability to express arrhythmic foraging activity under some circumstances.
d) All of the above.
e) None of the above.

Back 6

d) All of the above.

Front 7

Two major opposing effects that long days have on many species of birds are:
a) Induce growth of the gonads and induce increased luteinizing hormone secretion.
b) Induce increased luteinizing hormone secretion and induce immediate early gene activity in the hypothalamus.
c) Suppress reproductive development initially, but then eventually enhance reproductive development.
d) Induce reproductive development and eventually also induce photorefractoriness.
e) Induce spontaneous gonadal collapse and cause the bird to become completely unresponsive to the long day
stimulus.

Back 7

d) Induce reproductive development and eventually also induce photorefractoriness.

Front 8

The “command center” role of the protocerebral ganglion in praying mantises is best revealed by which of the
following experiments?
a) Comparing the behavior of intact mantises with that of others that have had the connections between the
subesophogeal ganglion and the thoracic and abdominal ganglia severed.
b) Comparing the behavior of mantises with the connections between the protocerebral ganglion and the
subesophogeal ganglion severed with others that have had the connections between the subesophogeal ganglion
and the thoracic and abdominal ganglia severed.
c) Comparing the behavior of intact mantises with others that have had the connections between the protocerebral
ganglion and the subesophogeal ganglion severed.
d) Comparing the behavior of intact mantises with that of others that have had several of the abdominal ganglia
ablated (destroyed).
e) None of the above comparisons is useful in evaluating the “command center” role of the protocerebral ganglion.

Back 8

c) Comparing the behavior of intact mantises with others that have had the connections between the protocerebral
ganglion and the subesophogeal ganglion severed.

Front 9

The molecular basis of circadian rhythms involves:
a) Cyclic transcription of the per gene within circadian pacemaker cells.
b) Enzymatic degradation of the PER protein outside the cell nucleus.
c) Protection of the PER protein from enzymatic degradation through formation of a complex with other clock
proteins.
d) All of the above.
e) None of the above.

Back 9

d) All of the above.

Front 10

In light of the experimental evidence presented regarding crossbills’ responses to different environmental factors, the
fact that crossbills can breed on both the shortest and longest days of the year in the wild suggests that:
a) Their reproductive physiology must be unaffected by both temperature and photoperiod.
b) They must use only food to time changes in reproductive physiology.
c) They must be integrating inputs from multiple types of environmental cues to time reproduction.
d) All of the above.
e) None of the above.

Back 10

c) They must be integrating inputs from multiple types of environmental cues to time reproduction.

Front 11

Crossbills placed on long days under mild food restriction:
a) Grow the gonads at about the same rate as others on long days with unlimited food.
b) Show a very modest reduction in initial luteinizing hormone secretion compared with others on long days with
unlimited food.
c) Show a rapid increase in the size of the gonads when eventually given unlimited food.
d) All of the above.
e) None of the above.

Back 11

d) All of the above.

Front 12

a) The duration of the active phase of the free-running cycle.
b) The duration of the active phase of the entrained cycle.
c) The duration of one complete free-running cycle, e.g., from beginning of one active phase to the beginning of the
next active phase.
d) All of the above.

Back 12

c) The duration of one complete free-running cycle, e.g., from beginning of one active phase to the beginning of the
next active phase.

Front 13

13) Point mutations within the per gene of fruit flies can lead to:
a) Unusually long-period circadian rhythms.
b) Unusually short-period circadian rhythms.
c) Arrhythmicity.
d) All of the above.
e) None of the above.

Back 13

d) All of the above.

Front 14

14) Extension of the proboscis for feeding in blowflies:
a) Normally ceases after a fixed period of time irrespective of how rich the food source is or how full the foregut is.
b) Can be inhibited by sensory impulses transmitted from stretch receptors in the foregut back to the central nervous
system.
c) Is activated initially by excitatory impulses transmitted along the recurrent nerve.
d) All of the above.
e) None of the above.

Back 14

b) Can be inhibited by sensory impulses transmitted from stretch receptors in the foregut back to the central nervous
system.

Front 15

Temporal flexibility of breeding in crossbills is believed to have been selectively favored because:
a) Crossbills live and breed very near the equator, where conditions are conducive to successful breeding at any
time of year.
b) Crossbills feed primarily on conifer seeds, which are unpredictably-distributed in space and time.
c) The specialized bill morphology of crossbills requires them to be able to breed whenever they find a food supply
they can actually exploit.
d) All of the above.
e) None of the above.

Back 15

b) Crossbills feed primarily on conifer seeds, which are unpredictably-distributed in space and time.

Front 16

15) “Circa-tidal” activity rhythms of fiddler crabs have been demonstrated by observing that:
a) Activity of crabs held on constant dim light sometimes occurs during high tide and sometimes occurs during low
tide.
b) Crabs held on natural tidal cycles show activity patterns that exactly track the times of high and low tide.
c) Crabs held on natural tidal cycles but constant dim light “free-run” in terms of activity rhythms.
d) Crabs observed in the field retreat into their burrows as the tide rises.
e) Crabs held on constant conditions in the laboratory (constant darkness and no tidal cycle) show bimodal activity
peaks that correspond approximately with when natural tides would occur.

Back 16

e) Crabs held on constant conditions in the laboratory (constant darkness and no tidal cycle) show bimodal activity
peaks that correspond approximately with when natural tides would occur.

Front 17

The effect of different temperatures on long-day-induced reproductive development of Puget Sound white-crowned
sparrows is best summarized as:
a) Temperature had no effect on long-day-induced reproductive development in either sex.
b) High temperatures tended to enhance the early stages of male reproductive development, and had a dramatic
enhancing effect on late stages of female reproductive development.
c) The only obvious effect of temperature was a profound inhibition of reproductive temperature by the very lowest
temperatures; intermediate and high temperature groups showed similar patterns of reproductive development.
d) Only females were affected by different temperatures.
e) Only males were affected by different temperatures.

Back 17

b) High temperatures tended to enhance the early stages of male reproductive development, and had a dramatic
enhancing effect on late stages of female reproductive development.

Front 18

An important difference in the circadian systems of mammals and birds is:
a) That the circadian rhythms of motor activity (e.g., perch-hopping, wheel-running) produce exclusively nocturnal
activity in mammals and diurnal activity in birds.
b) That the circadian rhythms in mammals free-run on about a 12 month cycle, whereas those in birds closely match
the 24 hour day-night cycle.
c) That the entraining effects of light are mediated through retinal photoreceptors in mammals but by encephalic
(inside the brain) photoreceptors in birds.
d) All of the above.
e) None of the above.

Back 18

c) That the entraining effects of light are mediated through retinal photoreceptors in mammals but by encephalic
(inside the brain) photoreceptors in birds.

Front 19

Name the three definitive attributes of endogenous biological rhythms and briefly describe how one would test
for each attribute.

Back 19

persist, entrained, temperature compensated.

Front 20

persist

Back 20

They persist under constant conditions. To test for this, put the animals in an environment
lacking environmental timing information (constant conditions). The animals on constant conditions
should continue to show cyclic activity, with a period close to but not exactly the same as the real-world
schedule, so they’ll drift out of phase with the real world (i.e., they should free run).

Front 21

Entrained

Back 21

They can be entrained by external cues so that they are precisely synchronized with the cycle
in the real-world environment. To test for this, put the animals in a phase-shifted environment (an
environment where the external changes occur at different times than before, but with the same period
as before. If the animals can entrain, then their activity (or whatever) cycle will, within a few cycles,
come into phase with (entrain to) the new pattern of external cues.

Front 22

Temperature Compensated

Back 22

They are temperature compensated. To test for this it would be easiest to use some kind of
ectothermic animal who’s body temperature will track closely the external temperature. Put several
individuals on one temperature, and several individuals on another temperature, both under otherwise
identical constant conditions, and see whether the free-running period of the endogenous rhythm of
whatever you’re studying remains very similar in the two groups despite the difference in body
temperature in the two groups.

Front 23

Explain how seasonal changes in the GnRH system of the hypothalamus relate to (a) differences in
responsiveness to photoperiod

Back 23

There is lots of GnRH present (could say lots of GnRH immunoreactivity) in the hypothalamus
(OK to just say in the brain) when birds are photosensitive, but it essentially goes away when birds
become photorefractory (it’s actually when they become “absolutely photorefractory” that GnRH
goes away, but it’s sufficient for you just to say “photorefractory”).

Front 24

Explain how seasonal changes in the GnRH system of the hypothalamus relate to (b) differences among species in
degree of temporal reproductive flexibility (i.e., highly seasonal versus very temporally flexible).

Back 24

(b) Species that are highly seasonal (not very flexible about the timing of reproduction) show the most
dramatic seasonal changes in how much GnRH is present in the hypothalamus (brain), whereas
those that are super-flexible about timing of reproduction show little or no seasonal change in the
amount of GnRH present in the brain.

Front 25

Naïve baby inland garter snakes show relatively little interest in slugs as food. Which of the following is a proximate
immediate-causal hypothesis to explain this fact?
a) Inland populations of garter snakes encounter large numbers of leaches, which are dangerous to eat, and
consequently they have been selected to avoid slimy creatures such as leaches and slugs.
b) In-utero exposure to chemicals from foods consumed by pregnant females determines what prey newborn garter
snakes recognize.
c) Naïve baby inland garter snakes lack chemoreceptors that respond to slug chemicals on their tongues.
d) All of the above.
e) None of the above.

Back 25

c) Naïve baby inland garter snakes lack chemoreceptors that respond to slug chemicals on their tongues.

Front 26

Variation in gene activity patterns among individual worker bees is most closely related to:
a) The age of the bees.
b) Which specific task the newly-metamorphosed workers first happened to do.
c) The task the bees currently do, irrespective of age.
d) Individual variation in genetic makeup.
e) None of the above: Gene activity patterns do not vary systematically among individual worker bees.

Back 26

c) The task the bees currently do, irrespective of age.

Front 27

The swimming behavior of Tritonia diomedia corresponds most closely to which of the following?
a) A Fixed Action Pattern
b) A Sign Stimulus
c) A Releaser
d) An Innate Releasing Mechanism
e) A stereotyped learned behavior

Back 27

a) A Fixed Action Pattern

Front 28

The “ramp depolarization” in a DSI of Tritonia diomedia:
a) Influences the rate of action potentials during bursts in the DSI.
b) Influences whether or not the firing rate in the DSI is sufficient to induced a burst of action potentials in C2.
c) Is responsible for the eventual termination of the swim sequence.
d) All of the above.
e) None of the above.

Back 28

d) All of the above.

Front 29

“Cortical magnification” refers to:
a) The microscope power used to visualize brain slices in studies of neuroanatomy.
b) The relative size of different parts of the cerebral cortex.
c) The increase in size of different parts of the brain during development of the central nervous system.
d) The relative degree to which particular sensory areas are represented in the cortex of the brain.
e) The cartoon drawings showing some body parts unnaturally magnified.

Back 29

d) The relative degree to which particular sensory areas are represented in the cortex of the brain.

Front 30

Sensory feedback from the periphery (e.g., through skin stretch receptors):
a) Provides the alternating inhibitory stimuli that generate the alternating dorsal and ventral bending movements
during Tritonia swimming behavior.
b) Is responsible for the eventual termination of the swim sequence, through inhibition of the DRIs.
c) Is responsible for the inhibitory effects of the VSIs on the DSIs and C2s.
d) All of the above.
e) None of the above.

Back 30

e) None of the above.

Front 31

7) Support for the nutritional stress hypothesis comes from:
a) The positive relationship between nestling feather growth and yearling song repertoire size in male reed
warblers.
b) The fact that only a small portion of the variation in yearling male reed warbler song repertoire can be explained
based on nestling feather growth rate.
c) The fact that some HVC neurons of male songbirds respond selectively to the males’ own songs.
d) All of the above.
e) None of the above.

Back 31

a) The positive relationship between nestling feather growth and yearling song repertoire size in male reed
warblers.

Front 32

The C2 cells of the Tritonia diomedia central pattern generator:
a) Are recruited into the neural activity pattern only if the spike rate in the DSIs is sufficiently high.
b) Stimulate the VSIs, and thereby are indirectly responsible for whether a ventral flexion occurs.
c) Are inhibited from firing when the VSIs are firing.
d) All of the above.
e) None of the above.

Back 32

d) All of the above.

Front 33

The “time compensated sun compass” that homing pigeons possess causes them to:
a) Fly at a constant angle relative to the sun’s position in the sky, whether they are “clock-shifted” or not.
b) Fly at a constant angle relative to the sun’s position in the sky only if they are “clock-shifted.”
c) Adjust the angle they fly relative to the sun’s position as a function of the time of day only if they are “clockshifted.”
d) Adjust the angle they fly relative to the sun’s position as a function of the time of day only if they are NOT
“clock-shifted.”
e) Adjust the angle they fly relative to the sun’s position as a function of the time of day, whether they are “clockshifted”
or not.

Back 33

e) Adjust the angle they fly relative to the sun’s position as a function of the time of day, whether they are “clockshifted”
or not.

Front 34

10) Alpha fetoprotein is:
a) A molecule in the blood of pregnant rats and mice that prevents maternal estrogens from getting into the blood of
their developing embryos.
b) A molecule in the blood of pregnant rats and mice that prevents testosterone produced by their male embryos
from influencing the development of their female embryos.
c) A molecule in the blood of rat and mouse embryos that prevents testosterone from masculinizing the brains of
the female embryos.
d) A molecule in the blood of rat and mouse embryos that prevents circulating estradiol from getting from the blood
into target tissues such as the brain.

Back 34

d) A molecule in the blood of rat and mouse embryos that prevents circulating estradiol from getting from the blood
into target tissues such as the brain.

Front 35

11) A good definition of a tuning curve is:
a) A graph of how an animal’s sensitivity to a particular stimulus type varies across a range of stimulus values.
b) A graph of the way stimulus intensity changes across a range of stimulus values.
c) A graph showing the threshold stimulus intensity required for a behavioral response at one particular stimulus
value.
d) All of the above are good definitions of a tuning curve.
e) None of the above is a good definition of a tuning curve.

Back 35

a) A graph of how an animal’s sensitivity to a particular stimulus type varies across a range of stimulus values.

Front 36

Explain how the response characteristics of the A1 auditory receptors allow noctuid moths to determine the
direction a hunting bat is approaching from. A complete answer will make it clear what the A1 response
characteristics are,

Back 36

Response characteristics: A1 receptors fire action potentials sooner and more frequently in response to loud ultrasonic
pulses than they do in response to softer ultrasonic pulse (you did not need to discuss effects of pulse durations to get
full credit on this one).

Front 37

(10 pts) Explain how the response characteristics of the A1 auditory receptors allow noctuid moths to determine the
direction a hunting bat is approaching from. A complete answer will make it clear how the moth can use A1 responses to distinguish between bats above, below, to the right, to
the left, or directly behind, and whether the moth could readily tell a bat directly in front from one directly behind.

Back 37

Implications of these response characteristics: These characteristics mean that the A1 on the side closer to an approaching
bat will start firing sooner and fire a more rapid burst of action potentials than the A1 on the side away from the bat
because the bat call will be softer and arrive slightly later on the off-side of the moth. This allows the moth to
determine whether a bat is to the left or to the right. If the A1s both respond identically to a sound pulse then this
means the bat is either directly behind or directly in front of the moth – the moth can’t tell which. Moth can tell
whether a bat is above or below by comparing the difference between firing activity when wings are up versus down
because when wings are in the down position the ears are more shielded from sounds coming from above the moth
than they are when the ultrasounds come from below the moth. Consequently there will be a greater discrepancy in
the A1 firing rate between wing-up versus wing-down positions if the bat is above the moth than when the bat is
below the moth.

Front 38

Explain why song learning in critical period learners such as white-crowned sparrows is often referred to as
an “imprinting-like” phenomenon.

Back 38

Song learning in critical period learners shares all 3 key characteristics with imprinting: (1) the learning happens only
during an early critical period of life, (2) what is learned is irreversible, and (3) no positive reinforcement is required
for the learning to take place.

Front 39

1) Infanticide is a common behavior of adult male lions. With regard to this behavior, which of the following is
an ultimate hypothesis that would specifically address Tinbergen’s question “How did the behavior evolve?”
a) Male lions that practice infanticide reduce the overall food demands of the pride, leading to more food
for remaining offspring, which therefore grow more quickly and become stronger, healthier adults.
b) Lions belong to a lineage of big cats that all inherited a tendency for infanticidal behavior from a
common ancestor.
c) Individual males that practice infanticide can begin siring their own young sooner if they remove the
young that are present when they first join a pride.
d) All of the above.
e) None of the above.

Back 39

b) Lions belong to a lineage of big cats that all inherited a tendency for infanticidal behavior from a
common ancestor

Front 40

A proximate explanation for the difference in mating system (i.e., monogamy versus polygyny) between
meadow and prairie voles is:
a) Males of the two species possess different forms of the receptor for AVP in specific regions of their
brains.
b) Meadow voles evolved under conditions of high density, favoring a polygynous lifestyle, while prairie
voles evolved under conditions of low density, favoring a monogamous lifestyle.
c) Meadow and prairie voles are relatively distantly-related taxa and consequently are unlikely to share
such traits as mating system.
d) All of the above.
e) None of the above.

Back 40

Males of the two species possess different forms of the receptor for AVP in specific regions of their
brains.

Front 41

through a loudspeaker placed in the middle of his territory:
a) Other males intrude more frequently onto his territory than they would if no song was broadcast.
b) Other males intrude less frequently onto his territory than they would if no song was broadcast.
c) Other males immediately begin fighting over who gets the now-abandoned territory.
d) Other males take no notice because they already have their own territories.
e) There is no effect on the behavior of other males, but females are attracted to the song broadcast.

Back 41

b) Other males intrude less frequently onto his territory than they would if no song was broadcast.

Front 42

Mapping the behavioral trait of song learning onto a phylogenetic tree of all bird orders would be most
useful if you wanted to evaluate the validity of which of the following hypotheses?
a) Song learning was the ancestral trait at the point when parrots diverged from other orders, and has
simply been retained in the more recently-diverged lineages that display it.
b) Song learning enhances male reproductive success under circumstances of high environmental variation.
c) Song learning is facilitated by a particularly well-developed Area X within songbirds.
d) Song learning is a “critical period” phenomenon that depends on experience early in life.
e) Song learning is guided by a “neural template.”

Back 42

a) Song learning was the ancestral trait at the point when parrots diverged from other orders, and has
simply been retained in the more recently-diverged lineages that display it.

Front 43

Brains of male and female zebra finches differ in a number of important ways, including that HVCs of adult
males have dramatically more neurons than do HVCs of females. Which of the following accurately
describes how this pattern is generated through development?
a) Both sexes begin life with very few HVC neurons, and females remain unchanged while males add many
new neurons as they grow and develop.
b) Both sexes begin life with a large number of HVC neurons, and males remain this way while females
lose many of theirs during development.
c) Both sexes begin with about equal numbers of HVC neurons, and females show a gradual decline and
males an increase in the number of HVC neurons over the course of development.
d) All of the above are accurate descriptions.
e) None of the above are accurate descriptions.

Back 43

c) Both sexes begin with about equal numbers of HVC neurons, and females show a gradual decline and
males an increase in the number of HVC neurons over the course of development.

Front 44

Females of some songbirds species:
a) Engage in more copulation solicitation displays when they hear song of their own species than when
they hear song of a different species.
b) Engage in more copulation solicitation displays when they hear songs that are good copies of tutor songs
than when they hear songs that are poor copies of tutor songs.
c) Are able to discriminate between the “real” songs of males of their own species and good copies of their
own species’ song produced by things like mockingbirds.
d) All of the above.
e) None of the above.

Back 44

d) All of the above.

Front 45

The most compelling evidence indicating that eastern phoebes (a species of sub-oscine songbird) do not
learn their songs is:
a) Young birds deafened before they have an opportunity to practice their songs still develop essentially
normal song.
b) The song of the eastern phoebe is relatively simple compared with that of oscine songbirds.
c) Phoebes are more closely related to several other orders of birds than are the rest of the songbirds (the
oscines).
d) Phoebes have a simpler syrinx than do oscine songbirds.
e) All of the above provide compelling evidence that phoebes do not learn their songs.

Back 45

a) Young birds deafened before they have an opportunity to practice their songs still develop essentially
normal song.

Front 46

Which of the following most accurately describes gene expression patterns in the song system of developing
male songbirds?
a) All of the genes related to song memorization begin to be transcribed throughout the song control nuclei
at about the same time during development.
b) Gene transcription begins at one developmental stage in the motor pathway, and at another
developmental stage in the learning circuit.
c) The developmental stage when gene transcription begins varies among different genes, and among
different song control nuclei.
d) Gene transcription in the song system is complete by the time young males leave the nest.
e) Gene transcription in the song system does not begin until males begin to crystallize their songs.

Back 46

c) The developmental stage when gene transcription begins varies among different genes, and among
different song control nuclei.

Front 47

Male white-crowned sparrows typically only hear a single song type (the local dialect) when they are
young.

Back 47

Proximate Development

Front 48

Male white-crowned sparrows possess an innate predisposition to settle on only a single song type,
regardless of how many different song types they hear early in life.

Back 48

PD

Front 49

The male white-crowned sparrow brain typically stores instructions for only a single song type.

Back 49

PC

Front 50

4. Female white-crowned sparrows find males that repeat the same song over and over more attractive
than those that rotate through a set of 2 or more song types.

Back 50

UF

Front 51

Single song types are more effective at keeping rival males out of a male’s territory than are multisong
repertoires.

Back 51

UF

Front 52

Zebra finches belong to a group of closely-related species all of which have females that do not sing
as adults.

Back 52

UE

Front 53

The ancestral condition in the finch group to which zebra finches belong is for adult females to sing,
but this trait was lost in the lineage leading to modern zebra finches.

Back 53

UE

Front 54

3. Female zebra finches that do not sing are consistently preferred by males over those that do sing.

Back 54

UF

Front 55

Adult female zebra finches lack the neural machinery required to generate song.

Back 55

PC

Front 56

Adult female zebra finches have such low testosterone levels that they are never motivated to sing.

Back 56

PC

Front 57

Brain components that are necessary for song production are lost during development in female zebra
finches.

Back 57

PD

Front 58

7. Brain components that are necessary for song production never appear during development of female
zebra finches.

Back 58

PD

Front 59

8. Song costs time and energy with no reproductive benefit for female zebra finches that do it.

Back 59

UF

Front 60

Describe how social experience (e.g., with neighbor males) around the time of song crystallization can
affect what song is crystallized in a repertoire species like a song sparrow. A complete answer will address
the concept of overproduction, and whether or not the sensory phase is affected in this case.

Back 60

The social environment around the time a young male crystallizes his song affects which song types
from his overproduced repertoire he will select to crystallize. Specifically, he will select some songs
that are good matches to some of the song types sung by the neighboring males. This would not require
that the sensitive period for song memorization be affected, since he would be simply deciding which of
the song types he had heard during the normal sensitive phase he was going to practice and perfect.
He would not need to be memorizing new song types.