C and Z in the species-area relationship log S = log C + Z log A repr…

The correct answer is Option (2) → Y- intercept and slope of the line (regression coefficient), respectively

Option (1) Slope of the line (regression coefficient) and Y- intercept, respectively — Incorrect. Both terms are right, but the order is reversed. C is the Y-intercept and Z is the slope, not the other way round.

Option (2) Y- intercept and slope of the line (regression coefficient), respectively — Correct. On a log-log graph the relation is a straight line. Z, the slope, tells how fast species richness rises with area. For most taxa and regions Z lies between 0.1 and 0.2, but over very large areas, such as whole continents, it is much steeper (0.6 to 1.2).

Option (3) Area and species richness, respectively — Incorrect. Area and species richness are the two variables of the equation, A and S. C and Z are the constants of the line.

Option (4) Species richness and slope of the line (regression coefficient), respectively — Incorrect. Z is right, but species richness is S, not C. C is the point where the line cuts the Y-axis.

NCERT Extract:
Patterns of Biodiversity – “… (ii) Species-Area relationships : During his pioneering and extensive explorations in the wilderness of South American jungles, the great German naturalist and geographer Alexander von Humboldt observed that within a region species richness increased with increasing explored area, but only up to a limit. In fact, the relation between species richness and area for a wide variety of taxa (angiosperm plants, birds, bats, freshwater fishes) turns out to be a rectangular hyperbola (Figure13.2). On a logarithmic scale, the relationship is a straight line described by the equation
log S = log C + Z log A
where
S= Species richness   A= Area
Z = slope of the line (regression coefficient)
C = Y-intercept
Ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2, regardless of the taxonomic group or the region (whether it is the plants in Britain, birds in California or molluscs in New York state, the slopes of the regression line are amazingly similar).”

Figure 13.2 Showing species area relationship. Note that on log scale the relationship becomes linear