Question 1

Estradiol is

Accepted Answer

Estradiol, while commonly associated with female reproductive functions, is actually derived from testosterone in specific brain regions and is responsible for masculinizing the brain in rats. Its chemical structure is very similar to that of testosterone, making all the provided statements correct.

Question 2

Alpha-fetoprotein

Accepted Answer

The answer of Alpha-fetoprotein
...

Question 3

An adult female rat whose ovaries have been removed will not copulate unless she receives injections of estrogen and progesterone. Similarly, removal of the testes in an adult male rat eventually eliminates copulatory behavior, unless he is given injections of testosterone. This suggests that the effects of these steroid hormones in these situations is

Accepted Answer

The effects of steroid hormones like estrogen, progesterone, and testosterone in restoring copulatory behavior in adult rats after the removal of their ovaries or testes are activational. This means the hormones activate or trigger specific behaviors in the adult animals, rather than organizing or structurally changing the brain during development (organizational effects).

Question 4

Male and female rats that have had their testes or ovaries removed in adulthood generally

Accepted Answer

The correct answer is D because male and female rats that have had their testes or ovaries removed in adulthood generally possess a thoroughly differentiated male or female nervous system, which means their brains are mature and no longer capable of significantly changing in response to the hormonal signals of the opposite sex. This differentiation limits their ability to exhibit behaviors typical of the opposite sex, even when administered the appropriate hormones.

Question 5

Some male tree lizards (Urosaurus ornatus) are aggressive while others are nonaggressive. They are one phenotype or the other and remain so for life. These alternative phenotypes are said to be

Accepted Answer

The term "developmentally fixed" means that once an organism develops a particular trait or phenotype, it remains fixed for life. Since the male tree lizards remain either aggressive or nonaggressive throughout their lives, their phenotypes are considered developmentally fixed.

Question 6

Male tree lizards (Urosaurus ornatus) of the nonaggressive phenotype are flexible in their territorial behavior, switching between territorial and nomadic behavior in response to environmental conditions. When conditions become stressful, levels of the hormone corticosterone rise, eventually triggering the switch to nomadic behavior.

Accepted Answer

The switch to nomadic behavior in male tree lizards is triggered by changes in corticosterone levels in response to environmental stress in adulthood, indicating an activational effect of hormones, not an organizational effect which typically refers to permanent changes caused by hormones during early development.

Question 7

Arnold and Breedlove (1985) questioned the usefulness of the distinction between organizational and activational effects of steroid hormones on behavior.

Accepted Answer

Arnold and Breedlove (1985) raised concerns about the distinction between organizational and activational effects of steroid hormones, suggesting it might be too restrictive and lacking clear biochemical or anatomical evidence. Despite these concerns, the distinction is still considered useful for categorizing hormonal effects in the field.

Question 8

When male marine toads (Bufo marinus) were allowed to clasp females for either zero, one, two, or three hours, concentrations of androgens increased with the number of hours spent in amplexus. The rise in androgens during amplexus suggests that

Accepted Answer

The increase in androgens with the number of hours spent in amplexus (the mating embrace) suggests that the act of mating behavior itself induced the hormonal response, rather than the hormones initiating the mating behavior.

Question 9

When researchers administered corticosterone to amplexing male roughskin newts (Taricha granulosa) or exposed them to stressful conditions known to prompt corticosterone secretion

Accepted Answer

Corticosterone, a stress hormone, when administered to or induced in amplexing male roughskin newts, suppresses their amplectic-clasping behavior, which is crucial for mating.

Question 10

The effect of corticosterone on neurons and on amplectic-clasping behavior in the roughskin newt occurred within minutes of its administration, indicating that the corticosterone

Accepted Answer

Corticosterone's rapid effect on neurons and behavior suggests it acts via membrane receptors, as intracellular receptor binding and altering gene expression would take longer.

Question 11

Crews and colleagues (1984, 1987) examined patterns of reproduction with regard to (1) gamete production, (2) secretion of sex steroids, and (3) timing of mating behavior in a wide variety of vertebrates and found that three general patterns of reproduction emerged. In the Norway rat, for example, it has been found that gonadal growth and an increase in circulating levels of sex steroids activate mating behavior. This pattern would be an example of a(n)

Accepted Answer

This pattern is an example of an associated reproductive pattern because it describes a scenario where gonadal growth and an increase in circulating levels of sex steroids directly activate mating behavior, indicating that these physiological changes are closely associated with the timing of reproductive behavior.

Question 12

Crews and colleagues (1984, 1987) examined patterns of reproduction with regard to (1) gamete production, (2) secretion of sex steroids, and (3) timing of mating behavior in a wide variety of vertebrates and found that three general patterns of reproduction emerged. In the red-sided garter snake, for example, the window of mating opportunity is from 1 to 4 weeks, and courtship behavior of adult male snakes is activated by an increase in ambient temperature following winter dormancy, rather than by a surge in testicular hormones. Sperm produced 5 to 10 weeks later are stored for use during the next spring. This pattern would be an example of a(n)

Accepted Answer

The red-sided garter snake's mating behavior, which is activated by an increase in ambient temperature rather than by a surge in testicular hormones, and the storage of sperm for use in the next mating season, exemplify a dissociated reproductive pattern. This pattern is characterized by a decoupling of mating behavior from the immediate influence of sex hormones, contrasting with associated patterns where such behaviors are closely linked.

Question 13

Crews and colleagues (1984, 1987) examined patterns of reproduction with regard to (1) gamete production, (2) secretion of sex steroids, and (3) timing of mating behavior in a wide variety of vertebrates and found that three general patterns of reproduction emerged. The zebra finch, for example, which lives in the deserts of Australia where rainfall occurs rarely and unpredictably, court, copulate, and build nests within hours of a significant rainfall. This pattern would be an example of a(n)

Accepted Answer

The zebra finch's reproductive behavior, which is closely tied to the occurrence of rainfall, exemplifies an opportunistic reproductive pattern. This pattern is characterized by taking immediate advantage of favorable environmental conditions, such as rainfall, to engage in reproductive activities.

Question 14

Dzieweczynski et al. (2005, 2006) found that aggressive behavior and levels of the hormone 11 KT (an androgen that mediates aggression) in male Siamese fighting fish (Betta splendens) were influenced by male territory status and the presence of an audience. Levels of aggressive behavior and 11 KT tended to be highest when

Accepted Answer

The answer of Dzieweczynski et al. (2005, 2006) found that...

Question 15

The Florida scrub jay (Aphelocoma coerulescens) is a species in which nonbreeding birds (most often offspring of the breeding pair from a previous year) remain on the territory of the breeding pair and help raise their own siblings. Is there evidence that helpers remain and help because they are physiologically incapable of breeding themselves?

Accepted Answer

The answer of The Florida scrub jay (Aphelocoma coerulescens) is...

Question 16

The hormone that is believed to underlie parental behaviors in Florida scrub jays, such as feeding young at the nest, is

Accepted Answer

Prolactin is known to play a significant role in promoting parental behaviors across a wide range of species, including birds. It is associated with nurturing behaviors such as feeding the young, making it the hormone that underlies such parental behaviors in Florida scrub jays.

Question 17

Scent marking, or strategically placing a chemical mark in the environment, is accomplished by means of special scent glands. These glands are

Accepted Answer

Scent glands are exocrine glands because they have ducts that release their products to the body surface, allowing the scent to be deposited in the environment for communication purposes.

Question 18

Among domestic dogs (Canis lupus), adult males

Accepted Answer

Adult male dogs tend to urine mark more frequently than females as a way to establish territory and communicate with other dogs.

Question 19

As Atlantic salmon (Salmo salar) make the developmental transition from parr to smolt, a number of hormones, such as prolactin, growth hormone, cortisol, and thyroid hormones, interact with a variety of environmental cues to produce changes in

Accepted Answer

As Atlantic salmon transition from parr to smolt, they undergo changes in body coloration and markings, osmoregulation to adapt from freshwater to saltwater environments, and in their territoriality and feeding styles. Hormones and environmental cues drive these adaptations to prepare the salmon for their oceanic phase.

Quiz 7: Physiological Analysis of Behavior- the Endocrine System