Two ponds were sampled. Pond X contained 50 of species A, 30 of B, 20 of C. Pond Y contained 90 of A, 5 of B, 5 of C. Both have 100 individuals total. Simpson's diversity index D = 1 - sum(pi^2).
Which pond has greater Simpson's diversity, and why?
- Acheck_circle
Pond X, because individuals are spread more evenly across species.
- B
Pond Y, because one species dominates.
- C
Pond Y, because of higher species richness.
- D
Both ponds have equal diversity.
Explanation
D(X) = 1 - (0.25 + 0.09 + 0.04) = 0.62. D(Y) = 1 - (0.81 + 0.0025 + 0.0025) = 0.185. Greater evenness in X yields higher Simpson's diversity.