Practise IB Biology SL 4.1.9 by using feeding-experiment graphs to compare cooperation, monopoly and fighting when food access changes.
A group of nine semi-wild Asian elephants (Elephas maximus) from an elephant camp in Myanmar were trained to pull two ends of a single rope to get access to food in food trays located on a table behind a barrier. When both elephants pulled the rope, the table moved towards them making the food trays accessible. The task required two elephants to work together in cooperation for mutual benefit to obtain food.
The graph shows the rate of cooperation between pairs of elephants in pulling the rope when there were two food trays, one at each end of the table (as shown in the diagram), or when there was one food tray placed in the centre of the table. The cooperation rate was the number of successful cooperative attempts divided by the number of all attempts in one session. The experiment was repeated for many sessions on successive days.
Using the graph, describe how the elephants cooperated when two food trays were available.
Outline the reason that the one-tray experiment was carried out for fewer sessions than the two-trays experiment.
Suggest a reason for the difference in the response of the elephants between the two-tray and one-tray experiments.
Compare and contrast the frequency of monopoly and fighting when there is a change from two trays to one tray of food.
Suggest a reason for the observed changes in competition.