Biological Rhythms Flashcards
Diurnal animals are active…
During the day
True or False: Crepuscular animals are active only at dawn
False: active at dawn or dusk (or both)
Circadian rhythms refer to…
revolution of the earth
Circatidal rhythms revolve around..
tides
Biological rhythms dictated by the season are called…
circannual
Phase of the moon
circalunar
An example of a rhythm lasting more than one day is
a infradian rhythm: menstrual cycle
True or False: in hamsters LH levels vary by hour, day and yearly
True
What was De Mairans’ isolation experiment?
leaves/petals open/close with the sun (even when in a box) - this indicates and internal or endogenous behavior
Which is NOT evidence for endogenous clocks:
- behavior away from geophysical cues (e.g. spacecraft)
- individual differences in absence of environmental cues
- individuals housed together adopt similar rhythms
- pattern can be transfered by tissue transplants
individuals housed together adopt similar rhythms
Zeitgeber
a potent environmental cue which regulates onset of rhythmic activities
Ex. Temp, rain, light
True or False: when exposed to constant dim lighting, hamsters will wheel run only in the time that would be night
False: constant dim light results in free running with a period of greater than 23 hours representing the endogenous circadian rhythm of the individual
True or False: Sleep is an example of an Ultradian rhythm
True: Ultradian - meaning less than one day
Parental behavior in rabbits is an example of
Circadian rhythms
Locomotor activity in fiddler crabs is an example of circalunar rhythms
False: fiddler crabs are circatidal rhyms while ant lion hunting behavior is circalunar
An exaple of a circannual rhythm is
animal migratory patterns and reproductive patterns/rhythms
Which is Generally NOT true about circadian clocks:
- inherited
- independent of temperature
- independent of chemical influence
- entrain to limited cycle lengths
- independent of species
- independent of behavioral feedback
- found at every level of organization
Independent of species
True or False: the brain is the fundamental level of circadian clocks
False: plants don’t have brains, neither do single cell organisms, all which have circadian rhythms
Which of these is NOT an important gene involving circadian rhythms:
- per
- mat
- time
- cry
mat
Name three examples of circadian oscillators
- eyes of amphibians
- Pineal glands of fish, reptiles and birds
- SCN of mammals
True or false: the activity of SCN neurons peaks about 12 hours after lights are turned off
FALSE: peaks ~ 4 hours after lights are turned ON
The three components of mammalian biological clocks are…
- environmental light transduced via photoreceptors
- oscillators in SCN
- temporal information leaves SCN to synchronize behavior and physiology
True or False: Providing estrogen to hamsters results in the loss of scalloping activity
False: Estrogen induces scalloping activity and can be eliminated by OVX
True or False: Castration lengthen and androgens replacement restores the period of free-running locomotor behavior in male mice
True
Circannual LH surges in ews are stimulated by
photoperiod
True or False: Melatonin is secreted during the day in nocturnal animals
False: melatonin is only secreted at night in all animals
T/F: high concentrations of steroid hormones completely inhibits secretion of GnRH and LH and this suppresses secretion of steroid hormones by gonads in Syrian hamsters and leads to gonadal regression
FALSE: low concentrations of steroid hormones
T/F: Syrian hamsters must emerge into the light in the spring to activate the regrowth of their gonads
FALSE: In the absence of light, the gonads regrow and beging to produce steroid hormones and gametes in the spring - even when day length is much less than what is required to maintain the reproductive systems in the fall
Phase delay when flying
WEST
Phase advance when flying
EAST
