According to island biogeography, what is the relationship between an island's distance from the mainland and the number of species present on the island?

According to the theory of island biogeography, the relationship between an island's distance from the mainland and the number of species present on the island is generally inverse. Here are the steps explaining this relationship:

1. Isolation: Islands that are farther away from the mainland are more isolated. This means that they are less likely to receive new species from the mainland, either through migration or accidental transport.

2. Colonization: The rate of colonization decreases as the distance from the mainland increases. This is because the probability of species reaching the island decreases with distance.

3. Extinction: The rate of extinction on an island is not directly related to its distance from the mainland. However, it is influenced by the island's size and the number of species present.

4. Equilibrium: Over time, the number of species on an island reaches an equilibrium between the rates of colonization and extinction. This equilibrium number of species is lower for islands that are farther from the mainland, due to the lower rate of colonization.

So, in summary, according to the theory of island biogeography, an island's distance from the mainland is inversely related to the number of species present on the island. The farther the island is from the mainland, the fewer species it tends to have.