Q46 - Cost-Benefit Optimization of Animal Territory Size

Theoretical 1 Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Aggression, Territoriality & Social Structure

An animal’s territory is an exclusive area defended by an individual to keep resources, such as food, and mates. Territory is different from home range, because home range simply represents an area over which an animal regularly moves and may overlap with those of neighboring animals of the same species. The size of the territory is determined by the cost and benefit obtained from the area, in a way that maximizes the net benefit gain of individual animals. The graph below shows how cost and benefit change with the size of the territory.

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. The benefit curve shows saturation at a large territory size due to the depletion of resources.

B. The optimal territory size is the intersection point between the cost line and the benefit curve.

C. When resources become scarcer while the cost line is unchanged, the optimal territory size becomes larger.

D. When the population density increases and intraspecific competition becomes intense, territorial behavior could disappear.

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Question reproduced from IBO 2020, Theoretical Exam 1, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)