PSYC 388 Exam Questions with Correct Answers Latest Update

PSYC 388 Exam Questions with Correct Answers Latest Update Phase - Answers - a point within the cycle - the instantaneous state of the clock - a position within its cycle ** can refer to range of phases (daily active phase or rest phase) Period (tau) - Answers - duration of a complete cycle Wavelength (lambda) - Answers - distance between two acrophases (peaks) - distance a wave travels in one period, or length of one cycle Amplitude (2 definitions) - Answers - the range (peak to trough) OR - half the range (peak to mean/mesor) Acrophase - Answers the peak of the curve (sine wave) What are the four 'circa' rhythms? (and give examples) - Answers 1. Circaannual (approx. 1 year) Ex: summer and winter 2. Circalunar (approx 29.5 days) Ex: determines how much light there is at night 3. Circadian (approx. 24hrs) 4. Circatidal (approx. 12.5 hrs) Ex: high and low tide What two characteristics distinguish these from other rhythms? - Answers 1. the duration of each cycle (its period), matches a major geophysical cycle 2. the rhythms PERSIST in the absence of environmental cycles, with a periodicity that only approximates the geophysical cycle How do you test experimentally whether a daily rest-activity rhythm in an animal is generated by an internal circadian clock, and not by environmental cycles? - Answers - keep the animal in constant conditions attempting to remove all rhythmic stimuli Is the circadian rhythm depicted in this actogram free-running faster or slower than 24h? - Answers - staircase <<24hrs - upside-down staircase >>24hrs What is meant by temperature compensation, and why is this a necessary characteristic of a circadian clock? - Answers - rate of biochemical reactions (basis of all biological processes) varies with temperature - approx. doubles with each 10 degree centigrade increase - must be able to cycle with a stable, ciracadian period across a potentially wide range of temperatures (clock, not thermometer) - runs at same rate regardless of temperature - biochemical reactions cannot violate the rate-temperature principle, so for the clock to tell accurate time across a range of temperatures (compensated) Ex: as tissue temperature rises, clock mechanism speeds up but a second mechanism slows down the clock mechanism --> as temperature rises, the output from this inhibitory mechanism increases, counterbalancing the increase in clock speed caused by the higher temperature (net result that clock speed doesn't change with temperature --> maintained at a stable speed) If a honey bee regularly finds food at a feeder at noon in a lab room in Vancouver, and is then rapidly flown to Montreal [3 time zones east], where the feeder is set up in an identical lab room, what time the next day (in Montreal time) will the bee look for food at the feeder? - Answers - bee will look for food in the feeder at 3pm (3 hours after 12 in Montreal, but 12pm in Vancouver) Why should psychologists (scientists who study or treat behavior) care about circadian rhythms? Give 4 reasons. - Answers 1. understanding motivation: why organisms do what they do - a great deal of variability reflects circadian (and seasonal) regulation (propensity to forage, eat, drink, sleep, etc., vary with the time of day 2. Research Design: circadian rhythms are a non-trivial source of variability in biology and behaviour - if uncontrolled may represent a significant confound variable 3. Understanding how time is represented in the brain - animals can time intervals across a wide range - likely involve different types of clocks which are critical for movement, perception, cognition - circadian time can serve as a model for analysis of neural basis of timing in general 4. Behavioural Ecology: study of ecological and evoluntionary basis of animal behvaiour - analysis of behavior in both place AND time - concept of temporal niches (nocturnal, diurnal, crepuscular) 5. Human performance and the cost of mismatches between biological and social time