Correct Option
The correct option is 1.15
Explanation
The question pertains to the Species-Area, a concept popularized by Alexander von Humboldt. It describes how species richness increases with increasing explored area, but only up to a limit. This relationship is mathematically expressed as:
log S = log C + Z log A
Where:
- S = Species richness
- A = Area
- Z = Slope of the line (regression coefficient)
- C = Y-intercept
Detailed Analysis
The value of Z (the slope) indicates how rapidly species richness changes with area. Ecologists have observed distinct patterns in the value of Z depending on the scale of the area analyzed:
- Small to Medium Areas: For most taxonomic groups (e.g., plants in Britain, birds in California) analyzed over smaller regions, the value of Z typically lies in the range of 0.1 to 0.2.
- Large Areas (Continents): When the species-area relationship is analyzed among very large areas, such as entire continents, the slope of the line becomes much steeper. In these cases, Z values generally range from 0.6 to 1.2.
- Specific Case (Frugivorous Birds and Mammals): Specifically, for frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents, the slope (Z) is found to be approximately 1.15. This indicates a very steep increase in species richness as the area expands across continents.
Key Takeaway: While the slope of the species-area line (Z) is generally shallow (0.1-0.2) for smaller regions, it becomes significantly steeper (0.6-1.2) when analyzing biodiversity across very large scales like entire continents.