The following graph shows the species-area relationship. Answer the following questions as directed: (a) Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him. (b) Write the situations as discovered by the ecologists when the value of 'Z' (slope of the line) lies between (i) 0.1 and 0.2 (ii) 0.6 and 1.2. What does 'Z' stand for?

(A) Alexander Von Humboldt was the naturalist who studied the relationship shown in the graph. He observed that within a region, species richness increased with increase in explored area but only upto a limit (B) When the value of z lies between (i) z = 0.1 to 0.2: for small or average area (ii) z = 0.6 to 1.2 : for large area, for example, entire continent. Z stands for slope of line (C) The slope of the line 'b' become steeper when very large areas such as continents are considered for species-area relationship.