Question

A graph of species richness vs area on log-log axes is?
A. Linear
B. Sigmoidal
C. Oscillatory
D. Parabolic

Answer 1

Hint:- The variations among living organisms living in different habitats forming a terrestrial, or aquatic ecosystems and the ecological complex is the diversity between them, this includes diversity within species, between species of the ecosystems. It actually represents the totality of genes, species and ecosystems of a region.

Complete answer:- Alexander Von Humboldt was a great German naturalist and geographer who while working on wilderness of South American Jungles observed that within a region, species richness increased with increasing explored area, nut only up to a limit.
The graphical representation of the relationship between species richness and area for a wide variety of taxa is a rectangular hyperbola.
On a logarithmic scale, the relationship can be described by a simple equation given below that gives a straight curve.
Log S = Log C + Z log A where S is species richness, A is rea, Z is slope of the line or regression coefficient and C is the Y-intercept of the linear slope.

Fig: Species-area relationship curve
In any type of taxonomic group or region value of Z comes in between 0.1 to 0.2, regardless of the region. For example, this value is similar for plants in the U.K., birds in California and mollusks in New York.
The value of Z differs when large continents are taken into account for this type of studies e.g., it comes in between 0.6 to 1.2. Even the slope of the line is much steeper. When the z value for frugivorous or fruit eating birds and mammals for tropical forests of different continents is added, it comes equal to 1.15.
Correct option: A. Linear

Note:- Communities with more species are more stable which means it doesn’t show much variations in productivity from year to year and it is resistant or resilient to occasional disturbances by anthropogenic activities or alien species.