The slow rate of decomposition of fallen logs in nature is due to their

1. low moisture content

2. poor nitrogen content

3. anaerobic environment around them

4. low cellulose content

Consider the following statements concerning food chains

(i) Removal of 80% tigers from an area resulted in greatly increased growth of

vegetation

(ii) Removal of most of the carnivores resulted in an increased population of deers

(iii) The length of food chains is generally limited to 3-4 trophic levels due to energy loss

(iv) The length of food chains may vary from 2 to 8 trophic levels

Which two of the above statements are correct?

1. ii and iii

2. iii and iv

3. i and iv

4. i and ii

Quercus species are the dominant component in

1. temperate deciduous forests

2. alpine forests

3. scrub forests

4. tropical rain forests

Which of the following ecosystem types has the highest annual net primary productivity ?

1. Tropical rain forest

2. Tropical deciduous forest

3. Temperate evergeen forest

4. Temperate deciduous forest

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

1. Dry weight

2. Number of individuals

3. Rate of energy flow

4. Fresh weight

Photosynthesis is absent in 

1. aphotic layer                 

2. photic layer        

3. benthic layer                 

4. pelagic layer.

The given type of ecological pyramid represents

1. pyramid of numbers in tree ecosystem

2. pyramid of biomass in a fallow land 

3. pyramid of biomass in a lake

4. energy pyramid in a spring

Which of the following zones of a lake is habitat for snails, slugs and microorganisms?

1. Littoral

2. Limnetic

3. Benthic

4. Profundal

Mr. X is eating curd/yoghurt. For this food intake in a food chain he should be considered

as occupying

1. first trophic level

2. second trophic level

3. third trophic level

4. fourth trophic level.

What is PAR range?

(1) 200 nm - 800 nm          

(2) 400 nm - 700 nm

(3) 350 nm - 550 nm         

(4) 600 nm - 100 nm