Read the Species–Area Relationship
As sampled area increases, more species are found; the pattern has a standard equation and a scale-sensitive slope.
Species–Area Relationship is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Use the equation
Z is the regression slope; the ordinary curve rises like a rectangular hyperbola.
Notice scale
For local areas, Z is often about 0.1–0.2. Across very large areas such as continents the slope is steeper, commonly about 0.6–1.2.
Calculate richness loss from a graph
Read scale and geographic curves
The slope Z is often similar across taxa and regions at ordinary scales, but is steeper for very large areas. A graph with the lowest richness curve represents the least species-rich setting among the choices.
OlympIQ exam lens
- ✓S = C A^Z.
- ✓Log form: log S = log C + Z log A.
- ✓Humboldt’s ordinary curve is a rectangular hyperbola.
- ✓Large-scale Z is higher than local-scale Z.
- ✓Use the area ratio raised to Z to calculate relative richness.
- ✓Expect steeper Z values at very large spatial scales.
- ✓Compare species-area curves at the same area before ranking locations.
Do not confuse the original curved plot with its straight-line log transformation.
Ready to try the pattern?
100% coverage across the 6 linked questions.
Practise 6 linked questions