The following graph shows the species area relationship. Answers the 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 ?
(c ) When would the slope of the line 'b' become steeper ?

Explanation

(a) Alexander Von Humboldt : He observed that within the region species richness increased with increasing explored area but only upto a limit.
(b) i-The slope of regression lines is similar, unaffected by the region or taxa and value of Z lies between 0.1-0.2.
(ii) The slope of regression is steeper when we analyse the species area relationship among very large areas like entire continent. (slope of the line) regression co-efficient between 0.6-1.2. Z-slope of line (regression coefficent).
(c) If species richness is more, the slope of the will become steeper Z values 0.6-1.2 for large areas with rich species diversity, such us mammals in the tropical forests.