What did Alexander von Humboldt observe about species richness and explored area in South American jungles?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) - Species richness increased with increasing explored area up to a limit.
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. 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)