Chapter 5 class (exam2)

Question 1

Endogenous Hypothesis:

Answer 1

An internal biological clock

Question 2

Environmental stimulus hypothesis:

Answer 2

environmental cues are used

Question 3

Zeitgebers (time givers)

Answer 3

Cues from periodicities in environmental variables such as light cycle, temperature, tides

Question 4

Long-Term Cycles

Answer 4

1. Epicycle or Ultradian
2. Tidal
3. Lunar
4. Circadian
5. Circannual
6. Intermittent
7. Diapaurse Phase

Question 5

Epicycle or Ultradian

Answer 5

Variable

Ex: Vole Feeding

Question 6

Tidal

Answer 6

12. 4 hours
    ex: Oyster shell opening
13. 8 days
    ex: Grunion egg-laying

Question 7

Lunar

Answer 7

29. 5 days

ex: Kangaroo rat foraging

Question 8

Circadian

Answer 8

24 Hours
Diurnal ————–Active during the day———Squirrel
Nocturnal ———–Active at night————-Owl
Crepuscular——–Active and dusk and dawn—Rabbit

Question 9

Circannual

Answer 9

12 months

ex: Bird reproduction, migratory cycle, etc.

Question 10

Intermittent

Answer 10

Days to years

ex. Desert insect breeding (often in desert)

Question 11

Diapaurse Phase

Answer 11

Dormancy during bad season

ex. Hibernation

Question 12

Humans internal clock gets___if not exposed to ___

Answer 12

off if not exposed to external cues (same for most animals

Question 13

Cricket Clock

Answer 13

o 12 hour light, 12 hour dark cycles produce normal timing of singing, and entrained cycle
o Crickets show a free-running cycle for singing without a day-night cycle
o Continuous light = 25 – 26 hours, continuous dark = 23.5 hours

Question 14

If crickets eyes are ___, you get ___…

Answer 14

o If crickets eyes are disconnected from optic lobes, you get a free running cycle where cricket is continuously in dark, but the clock is still running
 Thus, the eyes simply provide environmental ques

Question 15

Optic lobes disconnected from the brain =

Answer 15

o random singing. This looks like the location of the clock (as brain by itself doesn’t seem to keep the clock running)
 Such light cycles are seen in animals and in plants

Question 16

Sand Crickets

Answer 16

o … show different light cycles depending on long-winged or short-winged morph, based on their environment

Question 17

o The rodent/mammal biological clock seems to be located in …

Answer 17

the suprachiasmatic nucleus

Question 18

Mammal light cycle:

Answer 18

• Light –> Retina –> Suprachiasmatic Nucleus –> SCN pacemaker –> (PER protein, PK2 protein, tau, and CREM Gene (Pineal Gland) –> ICER protein –> Melatonin from Pineal Gland … base of the 24-hour cycle
  o ICER Protein builds up –> Inhibits CREM Gene  Ends ICER production –> Cycle Ends
  o Photoperiod –> Alters CREM sensitivity to inhibition  Adaption to day length

Question 19

o Mice: normal cycle =

Answer 19

23 + hours
 Heterozygous for clock allele = 25 hours
 Homozygous for clock allele = 28 hours, then complete breakdown

Question 20

 Anole (green lizard) Reproduction

Answer 20

o Temp/Light driven clock –> displaying male 
o Pituitary gonadotropins –> Egg development 
o Ovaries releasee estrogen –> Target brain cells  receptivity
o No predator –> Mating –>Proglastaglandin –>Stop receptivity 
 Mating act itself is what elicits the Proglastaglandin
o Egg laying –> ovaries –> Still summer? –> cycle again
 Cycle stops come August, even should the females be injected with hormones. Appears that light cycle determines

Question 21

What elicits Proglastaglandin?

Answer 21

Mating act itself

Question 22

What does Proglastaglandin do?

Answer 22

stop mating receptivity (I think?)

Question 23

The mechanical stimulation associated with mating ends…

Answer 23

sexual receptivity in females. In some species like rabbits, this stimulation causes ovulation- Ovulation on Demand.

Question 24

In temperate and polar regions, day length often …

Answer 24

starts breeding. The time between mating and birth is a factor:
o Short times (birds): Triggered by increasing day length
o Long times (deer): Triggered by decreasing day length
 Second full moon after the fall equinox theory about
when deer mate?
o Full moon seems to also influence reproduction of
 Worms in coral reef
o External factor of rainfall
o Kangaroos in Australia

Question 25

Delayed Implantation:

Answer 25

 Hill kangaroos breed do not implant fertilized eggs in the uterus until rain occurs and the food is abundant
• Mother kangaroo will throw baby out of pouch if there is not enough food. This leads to better chance of success in next reproductive cycle

Question 26

In Pinon Jays, breeding is initiated by…

Answer 26

seeing growing pinecones

Question 27

White crown sparrows:

Answer 27

migrate annually from south to Alaska

Question 28

White Crown Sparrows Circadian Clock:

Answer 28

 Must have well timed departure, and based off length of day. But eyes are not involved in the process
 Not based on vision, but on photoreceptors in the brain, maybe in the pineal gland
 A photosensitive clock is set at dawn. For the next 12 hours, it is insensitive to light. Then sensitivity peaks at 16-20 hours
 A photosensitive period exists at the end of the day. Additional light during that period begins fat deposition and gonadal development (develops by 100x)
• Photoperiod que is effective in spring but not in fall

Question 29

Male Mice

Answer 29

o Take over a territory and mate
o Will kill any pups for the next three weeks
 As these would have been the offspring of previous male
o Then care for pups parentally
o Kill pups again about 7 weeks after mating, when their pups would be gone
o Number of light-dark cycles is the main factor in timing, not number of hours
o Territorial males mate with a harem of females (offspring of previous male). Their presence facilitates sexual maturation in females; inhibits it in males.
 Provides reproduction for these females more rapidly
 Other males take advantage of territory and not appear competition to territorial male

Question 30

Main factor in timing for male mice is:

Answer 30

number of light-dark cycles (not number of hours)

Question 31

Females mice without a male

Answer 31

stop ovulating. Those exposed to urine of strange male resorb embryos or abort (Bruce effect).
 Basically not investing in any offspring at this point, as the offspring could be killed by strange male

Question 32

COMPARISON of mice to humans

Answer 32

Male contact/smell regularizes female cycle
 Female contact/smell increases male testosterone production and beard growth
 Expose men to nursing women/babies – aroused
 Around ovulation: changes in skin tone, pitch of voice increases, dress more provocatively

Question 33

Ring Dove Reproduction

Answer 33

o Males begin courting after placement with female
 But castrated ones don’t (need of testosterone)
o Courtship stimulates female pituitary to release FSH (follicle stimulating hormone), causing ovarian follicle development
o Follicles secrete estrogen, causing uterine growth and development
o Within day or two, nest construction and copulation (mating) begins
o Next, presence stimulates production of progesterone in females (and some in males)
 Progesterone promotes incubation in both sexes after eggs are laid
o Egg laying is activated, in part, by pituitary secretion of LH (lutinizing hormone).
o Incubation, maintained by progesterone secretion, lasts 14 days. Male and female take turns on the nest
 Egg in nest and stimulation from incubation behavior causes both sexes’ pituitary glands to secrete prolactin

Question 34

What role does prolactin play in ring dove reproduction?

Answer 34

 Prolactin inhibits PSH and LH secretion, and all sex behavior ceases. Prolactin stimulates crop development and production of crop milk, may help maintain incubation
o Squabs hatch in 2 weeks, eat crop milk for the next 10-12 days. Feeding wanes toward the end, probably because prolactin secretion decreases
o Prolactin decreases, pituitary secretes FSH and LH, and the sequence recurs.

Question 35

At each stage, a bird’s internal state interact with external variables to produce behavior. The variables are:

Answer 35

 Hormones: Hormonal state of both sexes, including feedback loops
 Behavior: Each dove’s behavior stimulates changes in mate hormone levels and behavior
 Environmental Cues (nest and eggs): Influence hormonal and behavior changes in both

Question 36

Hormonal Mediation

Answer 36

• Organizational Effects
• Activational Effect
• Associated Reproductive Patterns
• Dissociated Reproductive Patterns
• Testosterone
• Stress

Question 37

Organizational Effects

Answer 37

Control brain development – irreversible

Question 38

Activational Effect:

Answer 38

Initiate or regulate behavior – reversal

Question 39

Associated Reproductive Patterns:

Answer 39

Hormones control reproductive patterns

Typically what is thought of with behavior following hormones

Question 40

Dissociated Reproductive Patterns:

Answer 40

Hormones do not control some elements of reproductive patterns

• -> Example of doves: if in area where it is possible to raise second family, this can happen, but hormones are way down – testosterone possibly more associated with territorial claim than reproduction?
• -> Example of red sided garter snake: Males produce testosterone in fall, causing sperm production. Then hibernate. Spring, no big testosterone production, but they still mate without hormone appears to be the temp more than the hormones involved with mating behavior

Question 41

Testosterone:

Answer 41

Promotes sperm production, sexual behavior, aggression, and suppresses the immune system
o Last feature is quite a down-side, and it is reflected in poor health

Question 42

Stress

Answer 42

Environmental factors
 Acute Stressors: like a predator, cause glucocorticoid hormones to be produced as part of the flight or fight response
 Chronic Stressors: (such as low dominance rank, little food, etc.) activates the hypothalamic-pituitary-adrenal (HPA) axis
• Not healthy

Question 43

Acute Stressors:

Answer 43

like a predator, cause glucocorticoid hormones to be produced as part of the flight or fight response

Question 44

Chronic Stressors:

Answer 44

(such as low dominance rank, little food, etc.) activates the hypothalamic-pituitary-adrenal (HPA) axis
• Not healthy