Ecosystem PYQ — Page 4

Consider the following statements concerning food chains (a) Removal of $80 \%$ tigers from an area resulted in greatly increased growth of vegetation (b) Removal of most of the carnivores resulted in an increased population of deers (c) The length of food chains is generally limited to 3-4 trophic levels due to energy loss (d) The length of food chains may vary from 2 to 8 trophic levels. Which two of the above statements are correct?

A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this (1) Lots of urea and phosphate fertilizer were used in the crops in the vicinity. (2) The area was sprayed with DDT by an aircraft. (3) The lake water turned green and stinky. (4) Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis. Which two of above were the main causes of fish mortality in the lake?

Which one of the following is not used for construction of ecological pyramids?

More than $70 \%$ of world's freshwater is contained in:

At which lattitude, heat gain through insolation approximately equals beat loss through terrestrial radiation?

Prolonged liberal irrigation of agricultural fields is likely to create the problem of:

An ecosystem which can be easily damaged but can recover after some time if damaging effect stops will be having:

Which of the following is expected to have the highest value $\left(\mathrm{gm} / \mathrm{m}^2 / \mathrm{yr}\right)$ in a grassland ecosystem?

In which one of the following habitats does the diurnal temperature of soil surface vary most?

A terrestrial animal must be able to:

If a bamboo plant is growing in a far forest then what will be the trophic level of it?

There is no life on Moon due to the absence of: