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IB Biology SL C4.1.9 Competition Vs Cooperation Questions

Interpret elephant feeding experiments to explain how shared versus scarce food changes cooperation, monopoly and fighting in IB Biology SL C4.1.9.

Syllabus
First assessment 2025
Course
Biology SL
Level
SL

Exam points

  • Explain how resource distribution changes intraspecific behaviour: shared food can promote cooperation, while scarcity promotes monopoly or fighting and changes competitive frequency.
  • Interpret behavioural frequency or probability data to compare cooperation and competition under different resource arrangements, dominance ranks or food availability.

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Study C4.1.9—Competition vs. cooperation conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB Biology SL C4.1.9 Competition Vs Cooperation Questions question 1

[Maximum number: 10]

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.

Figure for Question IB Biology SL C4.1.9 Competition Vs Cooperation Questions question 1 — IB Biology SL

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.

Question (a)

(a)
Figure for Question (a) — IB Biology SL

Using the graph, describe how the elephants cooperated when two food trays were available.

[ 2 ]

Question (b)

(b)

Outline the reason that the one-tray experiment was carried out for fewer sessions than the two-trays experiment.

[ 1 ]

Question (c)

(c)

Suggest a reason for the difference in the response of the elephants between the two-tray and one-tray experiments.

[ 1 ]

Question (d)

(d)

Compare and contrast the frequency of monopoly and fighting when there is a change from two trays to one tray of food.

[ 2 ]

Question (e)

(e)

Suggest a reason for the observed changes in competition.

[ 1 ]

Question (f)

(f)

The probability of a fight occurring between two elephants depends on differences in their dominance rank in the group. Rank difference was calculated using the rank of the elephant starting the fight minus the rank of the target elephant. The researchers modelled a graph of the probability of elephants fighting back when another elephant attempted to start a fight if presented with two trays or one tray of food.

Figure for Question (f) — IB Biology SL

Estimate the probability of a fight occurring when an elephant of rank 5 initiates a fight with an elephant of rank 2 if they are presented with two trays of food.

[ 1 ]

Question (g)

(g)

Compare and contrast the chances of a fight occurring with two trays and one tray of food.

[ 2 ]
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