1. What is “jet lag?” Would you expect an animal that does NOT possess an endogenous circadian rhythm to suffer from jet lag if it traveled rapidly across time zones? Why or why not?
2. Describe experimental evidence from house sparrows supporting the hypotheses (a) that the pineal gland is essential for maintaining circadian rhythms of perch-hopping activity, and (b) that a secretion rhythm of melatonin (the main hormone produced by the pineal) is responsible for the effect of the pineal. In your answer, identify a critical “control” treatment that was included in the study and explain why that treatment is important to our ability to draw conclusions from the experiment.
Answer 1:
Our body is under endogenous circadian rhythm, which maintains sleep-wake cycle of our body. It is controlled by hormones in response to changes in external environment. When, external conditions like light and temperature, change slowly, then our body can make adjustments and we do not face any problem in circadian rhythm.
But, when one is exposed to new environmental conditions and time zone, the body cannot adapt immediately and we face sleeping disorder or imbalance. For example, when one travels long distances via jets, many time zones is crossed in a relatively smaller duration.This causes temporary sleep-wake disorder, which is called jet lag. Hence, we can define jet lag as :
| A temporary sleeping disorder caused due to imbalance in endogenous circadian rhythm, when a person travels across many time zones in a quick time is called jet lag. |
An animal that does not possess endogenous circadian rhythm won't be affected by time lag. This is because such animals are under exogenous rhythm, which are directly controlled by external conditions (example : light and temperature).
1. What is “jet lag?” Would you expect an animal that does NOT possess an endogenous...