Question

Study the graph given below and answer the following questions:

1. Explain the ecological principle represented by the graph and write a mathematical expression for the same.
2. What will happen if the slope of the line ‘b’ becomes steeper?

Answer 1

(i) German naturalist and geographer Alexander Von Humboldt observed that within a region, species richness increases with increasing explored area but only up to a limit.

The relation between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola. On a logarithmic scale, the relationship is a straight line described by the equation:

logs = loge + z logA

Where S = species richness, A = area, Z = slope of the line [regression coefficient] C = Y-axis intercept.

(ii) The slope of the line 'b' becomes steeper when very large areas such as continents are considered for species-area relationship.
[here Z value is in the range of 0.6 to 1.2]