A scientist studying a savanna ecosystem in Tanzania recorded that when the population of zebras increased, the population of lions also increased after a delay. When zebra numbers then decreased, lion numbers also decreased after a delay. This pattern repeated over several years. Which statement best explains this observation?

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Question

A scientist studying a savanna ecosystem in Tanzania recorded that when the population of zebras increased, the population of lions also increased after a delay. When zebra numbers then decreased, lion numbers also decreased after a delay. This pattern repeated over several years. Which statement best explains this observation?

Accepted Answer

The populations show a cyclical predator-prey relationship with time lags — Award 1 mark for identifying the characteristic predator-prey cycle with time lags. Prey population increases provide more food for predators, whose population then increases. This leads to increased predation, reducing prey numbers, followed by predator decline. B is incorrect as the pattern described is characteristic of predation, not disease. C is incorrect as they do not compete (different trophic levels). D does not explain the alternating pattern with time delays.

Answer

Climate change affects both populations identically

Answer

Lions and zebras compete for the same resources

Answer

Both populations are controlled by the same disease

Answer

The populations show a cyclical predator-prey relationship with time lags

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