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प्रश्न
A species-area curve is drawn by plotting the number of species against the area. How is it that when a very large area is considered the slope is steeper than that for smaller areas?
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उत्तर
Ecologists have discovered that the value of Z (slope of the line) 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). But, if you analyse the species-area relationships among very large areas like the entire continents, you will find that the slope of the line is much steeper (Z values in the range of 0.6 to 1.2). For example, for frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents, the slope is found to be 1.15.
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संबंधित प्रश्न
Give three hypotheses for explaining why tropics show greatest levels of species richness.
Observe the graph and select the correct option:
The 'rivet' in the rivet popper hypothesis is considered to represent the ______.
All are true regarding graph showing species richness - area relationship, EXCEPT ______.
Species richness - area relationship is given by ______.
Select the correct alternative for x and y.
Which of these is true about tropical environments?
Is it true that there is more solar energy available in the tropics? Explain briefly.
Write the inference drawn by Alexander von Humboldt after his extensive explorations of South American jungle.
Study the graph given below:
As per Alexander von Humboldt, what do the symbols S, A, Z and C in the graph stand for, in respect of a species and area relationship?
For frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents, the slope of the species-area relationship is found to be approximately ______.
The relation between species richness and area for a wide variety of taxa appears as ______.
Who observed that within a region, species richness increased with increasing explored area, to a certain limit?
When pre-reproductive and post - reproductive age group is same in structure, the population is______.
Tropical regions show greatest level of species richness because -
- Tropical latitudes have remained relatively undisturbed for millions of years, hence more time was available for species diversification.
- Tropical environments are more seasonal.
- More solar energy is available in tropics.
- Constant environments promote niche specialization.
- Tropical environments are constant and predictable.
Choose the correct answer form the options given below:
Match the scientist in column I with their contribution in column II and choose the correct option.
| Column I | Column II | ||
| i. | Alexander Van Humboldt | a. | Estimated 7 million species round the globe |
| ii. | Robert May | b. | Rivet popper hypothesis |
| iii. | David Tillman | c. | Species Area Relationship |
| iv. | Paul Ehrlich | d. | Productivity stability hypothesis |
Which of the following characteristics are seen in a stable community?
- It is strong enough to withstand environmental disturbance and recovers quickly.
- It is resistant to invasive species.
- It exhibits constant change in biomass production over a period of time.
- It has more species diversity.
