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 ?
In very large areas, the number of species is much more that is why the curve is much steeper. This is because the larger area has more, food availability and other resources, so obviously more species may thrive.
Is it possible that productivity and diversity of a natural community remain constant over a time period of, say one hundred years?
No, it is not possible that productivity and diversity of a natural community remain constant over a certain time period.
This is because
(i) The natural habitat is never maintained in real.
(ii) Abundant resources are never available, they are always in short supply or just enough.
(ii) Environmental conditions for survival and reproduction are continuously changing.
There is greater biodiversity in tropical/subtropical regions than in temperate region. Explain.
The tropical/subtropical region exhibit maximum biological diversity because these region remain undisturbed due to less variable climatic conditions. So, tropics had a longer evolutionary time for species diversification. The temperate environment are more seasonal, less constant and unpredictable, therefore less niche specialisation and lesser species diversity are observed.
Why are the conventional methods not suitable for the assessment of biodiversity of bacteria?
Many bacteria cannot be cultured under normal conditions in vitro, which creates a problem in studying their morphological and biochemical characteristics.
Morphology and biochemistry along with some other characteristics are used for the assessment of biodiversity of bacteria. Thus, conventional methods are not suitable for the assessment of biodiversity of bacteria.
What criteria should one use in categorising a species as threatened?
The criteria that should be used in categorising a species as threatened are
(i) Number of the members of the species are declining at an alarming rate.
(ii) Their habitat is being modified or destroyed.
(iii) Predator or poacher activities are increasing.