The amount of energy reaching an upper trophic level is determined by:

1. Net primary production

2. Net primary production and the efficiencies with which food energy is converted to biomass

3. Gross primary production

4. Gross primary production and the efficiencies with which food energy is converted to biomass

Fill in the blanks, in the following simplified model of a nutrient cycle:

           1             2                    3                       4                  5

(1) Producers   Detritus         Soil solution      Decomposition    Weathering

(2) Producers   Detritus         Soil solution      Weathering         Decomposition

(3) Producers   Soil solution   Detritus            Decomposition    Weathering

(4) Producers   Soil solution   Detritus            Weathering         Decomposition

The given figure best represents:

(1) Pyramid of number in parasitic food chain

(2) Pyramid of biomass in forest ecosystem

(3) Pyramid of number in grassland ecosystem

(4) Pyramid of number in forest ecosystem

Which of the following is/are incorrect:

A. All ecosystems are constant in size
B. In nature food chains exist, not food web
C. Flow of energy in ecosystem is unidirectional
D. Gene flow occurs between 2 different population (of 2 species)

(1) A, C

(2) A, D

(3) A, B, D

(4) A, B, C, D

The important step in the process of decomposition in order is:

Which of the following is false?

I. Quantity of biomass in a trophical level at a particular period is called standing crop.
II. The energy content in a trophic level is determined by considering a few individuals of a species         in that trophic level.
III. The succession that occurs in nearly cooled lava is called primary succession.
IV. Rate of succession is faster in the secondary succession
V. Phytoplankton are the pioneers in aquatic succession

(1) Only II

(2) Only III

(3) Only V

(4) Only I and IV

The amount of biomass or organic matter produced per unit area over -a time period by plants during photosynthesis is called primary production, which is expressed as:

(1) g m⁻²

(2) kcal m⁻²

(3) (kcal m⁻²) yr⁻¹

(4) Both (1) and (2)

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

(1) High stability and high resilience

(2) Low stability and high resilience

(3) High stability and low resilience

(4) Low stability and low resilience

During the stages of succession in a given ecosystem the following changes in characteristics may be observed:

Which one of the characteristics, A, B, C, D or E is responsible for the apparent high degree of stability associated with a climax ecosystem?

(1) B

(2) D

(3) A

(4) E

Perturbation of which of the following cycles contributes most to global warming?

(1) The global carbon cycle   

(2) The global water cycle

(3) The global nitrogen cycle 

(4) All of these cycles contribute equally