Question

Imagine a chain of islands of the same size that are at increasing distances from a mainland. The immigration rate should be highest for islands close to the mainland because they should receive the most colonizers. The extinction rate should be the same for all these islands. Use the equilibrium model of island biogeography to predict how the number of species on an island changes with distance from a mainland. Select the statement below that best represents your prediction.

A. The number of species increases with increasing distance from the mainland.

B. The number of species decreases with increasing distance from the mainland.

C. The number of species remains constant regardless of distance from the mainland.

D. The number of species is unrelated to distance from the mainland.

Answer 1

The number of species decreases with increasing distance from the mainland.

Step-by-step explanation:

According to the equilibrium model of island biogeography, the number of species on an island changes with distance from a mainland. Islands closer to the mainland have higher immigration rates and receive more colonizers, leading to a higher number of species. In contrast, islands farther from the mainland have lower immigration rates, resulting in a lower number of species. The extinction rate is the same for all islands. Therefore, the best prediction is that the number of species decreases with increasing distance from the mainland (option B).