Question

scientists introduce a small population of reindeer onto a remote island. the reindeer population adapts to the islands ecosystem without the threat of any natural predators by relying on the local lichen (fungi and algae) as a food source. the graph shows the population of reindeer on the island over time. which statement explains a possible cause for the change in the reindeer population over time, as shown in the graph? a the reindeer population never reaches equilibrium. b the reindeer and the lichen share a symbiotic relationship. c the islands resources could not sustain the reindeer population. d the rate of reindeer births on the island was equal to the rate of reindeer deaths.

Explanation:

• Option A: In a real - world ecosystem, populations do reach equilibrium (carrying capacity). So this option is incorrect.
• Option B: A symbiotic relationship implies a mutual benefit. Here, reindeer eat lichen (a predator - prey or consumer - resource relationship, not symbiotic). So this option is incorrect.
• Option C: When the population grows rapidly and then (presumably, as the graph shows a steep rise which might be followed by a crash if not sustained) if the island's resources (like lichen) are limited, the resources could not sustain the reindeer population. This is a valid ecological concept (carrying capacity).
• Option D: If birth rate equals death rate, the population would be stable. But the graph shows a rapid increase, so this option is incorrect.

Answer:

C. The island's resources could not sustain the reindeer population.