Analyzing the Graphs

Let’s examine the four options in the image:

1. Option 1: This graph shows a rapid increase in species with area, then a decline, which is not typical for species-area relationships.

2. Option 2: This graph shows a rapid initial increase, then the curve levels off, forming a plateau. This reflects the classic species-area relationship—a rectangular hyperbola.

3. Option 3: This is a straight line, suggesting a constant rate of new species with area, which is not observed in nature.

4. Option 4: This is a sigmoid (S-shaped) curve, which is not typical for species-area relationships.

The Correct Graph

Option 2 is the correct representation of the species-area relationship.

• At first, each increase in area brings many new species.

• As more area is studied, most species are already encountered, so the rate of new discoveries slows, and the curve flattens.

Conclusion

The graph that best represents the relationship between area studied and the number of species encountered is Option 2.

Correct answer:
Option 2 (top right graph)