Question

According to the MacArthur – Wilson equilibrium model of island biogeography, which one (or more) of the following factors affect(s) extinction rate on an island?

• A. Interspecific competition
• B. Island area
• C. Intraguild predation
• D. Species identity

Hint:

In the MacArthur-Wilson equilibrium model, larger islands have lower extinction rates, and interspecific competition influences the survival of species.

Answer 1

The Correct Option is B

Step 1: Understanding the MacArthur – Wilson Equilibrium Model.
The MacArthur – Wilson equilibrium model of island biogeography suggests that the number of species on an island is determined by a balance between immigration rates and extinction rates. Factors influencing extinction rates include island size and the interactions between species.

Step 2: Analysis of the Options.
- (A) Interspecific competition: This factor influences extinction rates as species competing for limited resources can lead to the extinction of less competitive species.
- (B) Island area: According to the model, larger islands tend to have lower extinction rates because they provide more resources and habitat for species.
- (C) Intraguild predation: This factor may influence species dynamics but is not the primary determinant in the MacArthur – Wilson model.
- (D) Species identity: While the species identity can influence interactions, it does not directly affect the extinction rate as per the model.

Step 3: Conclusion.
The correct factors that affect the extinction rate, according to the model, are island area and interspecific competition.

Final Answer: \boxed{(A) Interspecific competition, (B) Island area}