Chapter 5: The Physiological Basis of Behavior

Question 1

One way nervous systems are organized to avoid maladaptive conflicts involves ____ ____ that communicate with one another. EXAMPLE?

Answer 1

One way nervous systems are organized to avoid maladaptive conflicts involves COMMAND CENTERS that communicate with one another Example: the protocerebral ganglion (the mantis brain) that makes sure that a mantis walks or grasps but does not do both at the same time

Question 2

The ability of neural command centers to communicate with and inhibit one another helps set____ ____

Answer 2

BEHAVIORAL PRIORITIES.

Question 3

2 hypothesis as to how animals manage their priorities over time.

Answer 3

1) endogenous clock hypothesis
2) environmental stimulus hypothesis.

Question 4

endogenous clock hypothesis

Answer 4

an endogenous timing mechanisms with a built-in schedule acts independently of any cues from the animal’s surroundings to control how animals change priorities over time.

Question 5

environmental stimulus hypothesis

Answer 5

animals use feedback information from the surrounding environment to change priorities over time.

Question 6

The circadian rhythms in cricket calling behavior falls in line with the ___ ___ hypothesis

Answer 6

endogenous clock hypothesis. male crickets call two hours before night fall, go throughout the night, and stop calling before dawn.

Question 7

The circadian pattern of cricket calling appears to be related to a cyclic production of ____ ____

Answer 7

juvenile hormone.

Question 8

a cycle of activity that is not matched to environmental cycles

Answer 8

a free-running cycle.

Crickets do not simply follow light patterns to control calling

When held under constant light, crickets continue to call

Start calling 25-26 h after last bout. We conclude that cyclical pattern of cricket calling is in part caused by an environment-independent internal circadian rhythm –> THERE IS AN ENDOGENOUS COMPONENT.

Question 9

The cricket nervous system: Visual information from the eyes is relayed to the ___ ____of the cricket brain. If the ___ ___ are surgically disconnected from the rest of the brain, the cricket loses its capacity to maintain a ___ ____.

Answer 9

Visual information from the eyes is relayed to the optic lobes of the cricket brain. If the optic lobes are surgically disconnected from the rest of the brain, the cricket loses its capacity to maintain a circadian rhythm.

Question 10

In mammals, what acts as the pacemaker or master clock that regulates the other mechanisms controlling circadian rhythms within individuals?

Answer 10

the SCN of the hypothalamus may act as a master clock, which allows environmental cues to affect rhythms.

Question 11

Biologists interested in circadian rhythms in vertebrates have focused on the _____ and the_____ _____, a pair of hypothalamic neural clusters that receive inputs from the ____.

SCN clock of hamsters, rats and other mammals appears linked to activity of the ____ gene

Answer 11

Biologists interested in circadian rhythms in vertebrates have focused on the hypothalamus and the suprachiasmatic nucleus (SCN), a pair of hypothalamic neural clusters that receive inputs from the retina

SCN clock of hamsters, rats and other mammals appears linked to activity of the per gene

Question 12

the SCN master clock operates via rhythmic changes in activity of the ___ gene. this gene cods for the ___ protein whose production varies over a 24 hour schedule IN CONCERT WITH ANOTHER GENE CALLED ____.

Answer 12

the SCN master clock operates via rhythmic changes in activity of the PER gene. this gene cods for the PER protein whose production varies over a 24 hour schedule IN CONCERT WITH ANOTHER GENE CALLED TAU.

Question 13

purpose of tau gene? When is it turned on?

Answer 13

tau is a gene that produces Ckle enzyme (clock cycle). Tau is turned on when PER is at beak abundance. the Ckle enzyme degrades PER protein contributing to the 24 hourcycle.

Question 14

what is the fly homologue of tau

Answer 14

dbt gene. double time gene; plays the same role as tau and produces an enzyme that degrades PER protein.

Question 15

In addition to tau and per genes, a third gene, ____ (timing), produces a protein called ____. What is its purpose?

Answer 15

In addition to tau and per genes, a third gene, tim (timing), produces a protein called TIM.

TIM protein complexes with PER and SLOWS THE RATE OF DEGRADATION OF PER BY Ckle (produced by tau)

Question 17

T/F: naked mole rats have circadian rhythms

Answer 17

false. Naked mole rats live in underground environments and do not have to deal with cyclically changing environments: they have apparently lost their circadian rhythm as a result.

they have circannual rhythms that run on a 365-day cycle to deal with predictable annual changes in the environment

Question 18

Explain the circannual rhythm of the golden-manteld ground squirrel

Answer 18

Captive ground-squirrels were held in constant darkness and temperature while supplied with ad lib food. Year after year the squirrels went into hibernation at about the same time as squirrels in the wild. Indicates that they have a rhythym independent of the light and dark cycle.

Question 19

entrain

Answer 19

to reset a biological clock so that an organism’s activities are schedule in keeping with local conditions

Question 20

Environmental cues in nature entrain circadian and circannual clocks that coordinate an animals activities with features of the environment

Answer 20

1) sunset and sunrise
2) lunar cyces
3) rainy season onset
4) increasing day length
5) tidal cycles.

Question 21

explain how kangaroo rats are entrained by the lunar cycle

Answer 21

Kangaroo rats are more likely to stay in their underground retreats when moonlight is available to aid nocturnal predators such as great horned owls. Therefore, they will forage on cloudy nights when there is less moonlight.

In image : Each thin black mark represents a visit to a feeder. From November to March, the rats were active at night only when the moon wasn’t shining. A shortage of seeds late in the year caused them to forage throughout the night even when moon was up, and later still during the day.

Question 22

explain the photosensitivity cycles in a white-crowned sparow

Answer 22

white crowned sparrows possess a clock mechanism that is especially sensitive to light between hours 17 and 19 of each day. at hours 17 and 19, males have marked testicle growth. if sparrows are placed in a dark box during the photosensitive cycle, they will not exhibit testical growth.

Question 23

T/F: Photoperiod is a useful guide for scheduling activites (ex/ breeding) in environments where food resources track the seasons predictably

Answer 23

True. but it is difficult to use photosensitivity in unpredictable environments because day light does not necessarily correlate with favorable conditions all the time.

Question 24

in unpredictable environments, breeding is not goverened by photoperiod, rather, it is goverened by:

Answer 24

favorable weather conditions: rainstorm in the desert, because its the rainfall that drives the flowering plants and seed and food availability in animals rather than the food being predictable.

Question 25

Explain how the roufous winged sparrow of the dessert uses rainfall rather than photosensitivity to regulate breeding periods.

Answer 25

Seasonal changes in the song control regions of the rufous-winged sparrow’s brain (HVC song center). After rain, the HVC is enlarged, and the RA is also larger. There are also more males singing for mates after rain.

Question 26

Outline the neural timing mechanism in house mice

Answer 26

The male house mouse contains a unique neural timing mechanism that protects against being cuckolded

Male house mice are infanticidal and remain so even when they copulate with a female for 21 days, the gestation period of the house mouse.

Three weeks after mating with a female he becomes parental.

He becomes infanticidal again after another 7 weeks.

Question 27

Explain how “day cycles” influence the infanticidal tendencies of male mice.

Answer 27

IN experiments: Male mice were held under artificial ‘slow day’ and ‘fast day’ experimental conditions. Most of the males held under fast-day conditions had stopped being infanticidal by 20 real days (22 fast days) after mating; males experiencing slow days did not decline in infanticidal behaviour until nearly 25 real days had passed.

A dominant male is not ‘fooled’ by a female mouse who gives birth before the 21 day period has elapsed – those are the pups of the previous male to whom the dominant male is unrelated

Question 28

Although infanticidal male house mice are partially regulated by day cycles, as seen in the slow and long day studies, the neural timing mechanism appears to be under hormonal control, and in particular, by _____.

Answer 28

PROGESTERONE.

Knocking out the progesterone receptor eliminated infanticidal behaviour of males.

Progesterone appears to prime infanticidal behaviour.

Question 29

A hormonal effect on infanticidal behaviour in laboratory mice: What hormone strains are seen in infanticidal dads?

Answer 29

Males of the strain C57BL/6 are highly likely to attack their own first or second litters rather than caring for their young.

If, however, the progesterone receptor gene is removed from the genome, the resulting progesterone knockout (PRKO) mice cannot detect progesterone in their bodies and do not exhibit infanticidal behaviour.

Question 30

Organizational vs activational effects of hormones

Answer 30

activational effects: an immediate but temporary effect of a hormone

organizational effect: permanent changes to physiology and behavior due to changes in the nervous system during development.

Question 31

How do hormones have an ACTIVATIONAL (immediate but temporary) effect on male Japanese quails? What brain region is affected?

Answer 31

After copulation, male quail change their behaviour dramatically- a rise in testosterone in the brain results in aromatase converting testosterone into estradiol: the essential hormone for modulating male sexual motivation.

testosterone in male quails cause them to exhibit a staring behavior towards mature female quails. the more testosterone a male quail has, the more interested he is in the female.

This behaviour is induced by the presence of testosterone (which is converted to estrogen) in the preoptic region of the brain.

Question 32

What controls female receptivity in a fruit fly?

Answer 32

Soon after a female fruit fly mates, she becomes completely unreceptive to courting males. She then spends her time laying eggs. This behavioural shift is regulated hormonally, BUT NOT HER HORMONES!

A sex peptide (SP) transferred to females in the male seminal donation appears to be a critical factor in determining female receptivity.

Female fruit flies mated to males unable to supply sex peptide are as likely to copulate with a new male 48 hours after mating with an SP-deficient male as are virgin females to mate on their first sexual encounter.

Question 33

Human example of how male hormones affect female reproductivity.

Answer 33

The risk of pre-eclampsia (high blood pressure during pregnancy) is affected by exposure to seminal fluid

The risk of pre-eclampsia falls with cohabitation and sexual intercourse, but not if condoms are used.

Exposure to paternal antigens appears to prime the maternal immune system to receive the embryo.

Question 34

ASSOCIATED REPRODUCTIVE PATTERN:x

Answer 34

ASSOCIATED REPRODUCTIVE PATTERN: hormonal signals that regulate sexual behaviour lead to increases in both gamete production and sexual activity – e.g., green anoles

Question 35

DISSOCIATED REPRODUCTIVE PATTERN:

Answer 35

mating is dissociated in time from hormonal activity – e.g., red-sided garter snake

Question 36

in species with an asssociated reproductive pattern, ____ ___ trigger internal hormonal changes, which then activate behavioral responses relatively quicklt.

Answer 36

ENVIRONMENTAL CUES

Question 37

in a dissociated reproductive pattern, mating may be dissociated in time from ____ ____.

Answer 37

DISSOCIATED FROM HORMONAL ACTIVTIY (EX/ RED GARTER SNAKE: THE HORMONES RISE AFTER MATING)

Question 38

In an associated reproductive pattern: ___ ____ trigger internal ___changes, which then activate ____ responses within a relatively short time such as in green anoles: at the end of winter, testosterone levels rise, gonads increase in size, males become territorial and court females

Answer 38

Environmental cues trigger internal hormonal changes, which then activate behavioural responses within a relatively short time such as in green anoles: at the end of winter, testosterone levels rise, gonads increase in size, males become territorial and court females

Question 39

Explain the dissociative reproductive pattern of red sided garter snakes in manitoba.

Answer 39

Red-sided garter snakes in Manitoba spend most of the year dormant in a hibernaculum.

In late spring, they emerge en masse from the hibernacula: males focus on females to the exclusion of everything else. Males compete for females but do not fight with one another: circulating levels of testosterone are low.

Then they mate while testosterone levels are low.

After mating, testosterone levels rise again. therefore, mating patterns and reproduction are independent of sex hormone levels.

Question 40

NOTE: In some species, testosterone is NOT essential for male sexual behaviour, but is still important to reproduction via its effects on territorial behaviour: testosterone facilitates aggression instead of sexual behaviour, as occurs in some birds

Question 41

Challenge hypothesis

Answer 41

Testosterone promotes aggression only when it should be most beneficial for reproduction, such as for mate guarding or repelling rival males. Otherwise, males live in harmony with other males.

This is the case in white-crowned sparrows:

testosterone concentrations in the blood of males peak shortly before the FIRST TIME when the males mate with females in their first breeding cycle of the season. in populations that breed twice in one season however, copulation also occurs during the second breeding cucle, but testosterone declines.

Question 42

How does testosterone influence female aggression? Give an example

Answer 42

The challenge hypothesis and the idea that testosterone is linked to aggression during the breeding season leads to another prediction: when competition for mates is a regular feature of a bird’s life history, then aggressive females should possess relatively high testosterone levels.

This is the case in DUNNOCKS. females competing with other females have higher T levels

Question 43

costs of using testosterone in regulation

Answer 43

1) depressed immune system
2) energetic costs
3) increased risk of predation
4) reduced parental care (they are busy out looking for mates)

Question 44

explain how testosterone affects mortality rates in lizards.

Answer 44

The three different forms of side-blotched lizards have different colourr, different behaviours, and different amounts of circulating testosterone. Orange-throated lizards have the highest circulating T, and highest mortality rate. The aggressive orange-throated lizards spend much of their time fighting with rivals when they are vulnerable to predators.

Question 45

how do elevated levels of testosterone affect chimps?

Answer 45

the more testosterone, the more parasites

Question 46

how do elevated levels of testosterone affect male juncos?

Answer 46

the higher the testosterone levels, the less parental investment – dads feed kids less.

Question 47

how do elecated levels of testosterone effects male barn swallows

Answer 47

higher T, more red colouration in males – more red = more attacks from other males

Question 48

T/F: testosterone levels in men influence materialism.

Answer 48

true. Subjects were given a single dose of testosterone vs. placebo and then asked to choose between luxury brand and a cheaper brand of same quality – e.g., Calvin Klein jeans vs. Levis; Rolex watch vs. Swatch; Ferrari vs. Lexus. Testosterone induces men to signal status conspicuously

Question 49

T/F: in dissociative reproduction species like the garter snakes, testosterone is not important because it is seen that they reproduce even at really low levels of testosterone.

Answer 49

False.

Even in the absence of testosterone, male garter snakes have no difficulty mating, but this does not mean that testosterone is not important

T levels are high in the fall when sperm is manufactured

Sperm is stored internally over the winter

Testosterone appears to prime the snake in the fall for mating next spring – and beyond…

Question 50

How does testosterone influence the long term maintenance of mating behavior in garter snakes?

Answer 50

recall; garter snakes are involved in a dissociative reproductive pattern.

Male garter snakes whose testes were removed before breeding in year 1 remained sexually active during the breeding season despite the absence of testosterone. But these males were less likely to court females in years 2 and 3 than males with intact testes.

The retained sexual behaviour in the absence of testes is due to the ORGANIZATIONAL EFFECTS (LONG TERM EFFECTS) of testosterone

Question 51

KEY GLUCOCORTICOIDS

Answer 51

1) cortisol
2) corticosterone.

Question 52

how are glucocorticoids affected by social conditions

Answer 52

repeated territorial intrusions by competitors may raise levels of stress hormones. Chronically elevated glucocorticoids in high density populations may result in depressed immune systems and reduced survival

Question 53

how do glucocorticoid levels vary according to social rank.

Answer 53

if dominant individuals do not have to work hard to maintain dominant status, they may exhibit low levels of stress hormones – if they are constantly challenged by subordinates, the opposite may be true– more dominant individuals may have more corticosteroids.