Birds have been placed on an artificial light-dark cycle in a laboratory that initially corresponds to the natural lighting conditions outside; the lights are on from 6:00 a.m. to 6 p.m. The light period is then shifted so that the lights come on at 9:00 a.m. In this case, the animal's body time would be set
A) at natural time. Their biological clocks are not fooled by the artificial lighting.
B) 3 hours earlier than real time.
C) 3 hours later than real time.
D) 6 hours later than real time.

Question

Quizplus · Accepted Answer

The birds' biological clocks would adjust to the new lighting schedule, setting their body time 3 hours later than real time, as their day effectively starts later with the lights coming on at 9:00 a.m. instead of 6:00 a.m.

Birds Have Been Placed on an Artificial Light-Dark Cycle in a Laboratory