Photoperiodism

Question 1

Photoperiodism definition

Answer 1

The use of changes in day length on an annual basis to regulate seasonal behaviour of physiological processes

Question 2

Methods of measuring seasonal changes

Answer 2

Interval timer
External coincidence
Internal coincidecne

Question 3

Interval timer mechanism - greenfly

Answer 3

Measured by period of product generation. For example increases in light, break down in dark. Reaches a critical point in the year when enough can accummulate

Question 4

External coincidence - birds and insects

Answer 4

Window of selectivity controlled by the clock, that needs to overlap with sunlight. This only happens at certain times of day

Question 5

interna coincidence

Answer 5

Two or more circaidan controlled genes need to combine to produce the effect. One will start when suns comes up, one at certain times of day, this only overlaps at short days