HL2 Biology: E.6d Food, Sleep, Sex

DBQ p.335- Rhythmical Behavior Patterns

1. The bats start flying slightly after sunset, and as the sun sets earlier as winter approaches, they follow the change in the sunset time (i.e. start flying earlier). Bats fly relatively shorter flights during autumn, but the frequency of flights increases.

2. (a) During the summer, the flight of the bats are long and last almost the entire night (especially towards the end of the summer), while in autumn, the flights are very short. During the summer, the length of the flights increase as the season ends, while in autumn, it shortens as winter nears. Lastly, flights during the summer seem more detached (have) gaps in individual flights, while in autumn, the flights are more consistent.
(b) In the summer, the bat flights may be longer because it is warmer during the night and they can afford to fly the entire night, while in autumn, it is too cold to fly at midnight, and hence, only fly immediately after sunset. Another reason might be that in the summer, the nights are shorter and they can fly the entire time, while in autumn, the nights get longer, and thus they cannot afford to fly the entire time (energy waste).

3. One may say that the patterns change with the ups and down of sunset/sunrise times and hence change with seasons. However, this argument may be refuted, because this only shows data for one year, and one cannot be sure whether these are just random fluctuations or actual patterns (data from multiple years or cumulative years must be used).