Question

The graph shows the rank-abundance relationships for species in three communities, \(P\), \(Q\), and \(R\). \includegraphics[width=0.5\linewidth]{47.png}
Which one of the following statements is true with respect to the evenness of the three communities?

• A. \(P > Q > R\)
• B. \(Q > P > R\)
• C. \(R > Q > P\)
• D. \(R > P > Q\)

Hint:

To interpret rank-abundance curves: 1. Shallow slopes indicate higher evenness.
2. Steep slopes suggest dominance by a few species, leading to lower evenness.
3. Compare slopes visually to rank communities by evenness.

Answer 1

The Correct Option is C

Step 1: Understand rank-abundance relationships. The slope of the rank-abundance curve indicates the evenness of a community: A shallower slope represents greater evenness, as species abundances are more evenly distributed.
A steeper slope indicates lower evenness, as a few species dominate the community.
Step 2: Analyze the graph. Community \(P\): This has the steepest slope, indicating the least evenness. Community \(Q\): This has a moderate slope, indicating intermediate evenness. Community \(R\): This has the shallowest slope, indicating the highest evenness. Step 3: Compare evenness among the communities. The evenness order based on the slopes is: \[ R > Q > P \] Step 4: Evaluate the options. Option (A): Incorrect. It suggests \(P\) has the highest evenness, which contradicts the steep slope of its curve. Option (B): Incorrect. It suggests \(Q\) has the highest evenness, but \(R\) has a shallower slope. Option (C): Correct. This matches the observed order \(R > Q > P\). Option (D): Incorrect. It misplaces \(P\) as having higher evenness than \(Q\).