1. Weta and cockroach questions

2. The chart below shows the activity of a weta kept in a laboratory at 20OC.
From day 1 to 11 the weta was exposed to
12 hours light followed by 12 hours dark.
From day 12 it was kept in constant dark.

5. Free running period
The time between repeats of behaviour in CONSTANT conditions
In this case the behaviour starts later and later every “day” so it must be slightly longer than 24 hours
Daily rhythm = circadian rhythm

6. Explain the activity pattern shown by the weta over the 30 days
It was regularly active during periods of light during the first 12 days
But it started progressively later when in constant conditions BECAUSE although it has a biological clock that keeps the rhythm, there is no zeitgeber to keep it in time. The endogenous free running period is slightly longer than 24 hours which is why it started activity later each day.

7. Endogenous or exogenous
Endogenous because the rhythmic behaviour continued after being put in constant conditions

8. This actogram was incorrectly labelled
This actogram was incorrectly labelled. (You knew that weta is nocturnal)
This is how it should have looked

9. Light phase

10. Light phase
Day 1

11. Light phase
Day 2

12. Light phase
Day 2
again

13. Light phase
Day 3

14. Light phase
Day 3
again
This makes for easier comparisons

15. cockroaches

16. The diagram above records the spontaneous activity of two species of cockroaches over several days.
The dark phase is shaded.

17. (a) Compare and contrast the behaviour of the two species.
How are they the same?
How are they different?

18. (b) Explain how you could find out if this rhythmic behavior was driven endogenously or exogenously.
Endogenous means …….
Exogenous means …….
I would put them in ___________ conditions.
If the rhythmic behaviour continued it is driven ________________ which means it has a ___________ _________

19. (c) Discuss what you would observe if C
(c) Discuss what you would observe if C. subcorticaria had a biological clock and C. undulivitta did not.
If C. sub had a biological clock I would observe that its behaviour in the constant conditions would … because _ _ _ _. However the rhythm _ _ _ _ _ ___
If C. und did not have a biological clock I would observe that its behaviour in the constant conditions would _ _ _ __ _ __ __. This is because _ _ _ __