Topic: Ecosystem (Test 5)



Topic: Ecosystem
Q.1
Which of the following pyramid/s is/are inverted:
A. pyramid of number in a grassland system
B. pyramid of biomass in a grassland system
C. pyramid of number in an aquatic system
D. pyramid of biomass in an aquatic system
Answer : Option D
Explaination / Solution:

In the aquatic system, the biomass can increase at higher trophic levels. For example, in Oceans, the food chain typically starts with phytoplankton and ends at predatory fish, which has largest biomass. Thus, the pyramid of biomass is inverted in the aquatic systems including marine, ponds etc.

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Q.2
Breakdown of detritus by microbial enzymes into simple forms is called
A. mineralization
B. leaching
C. fragmentation
D. catabolism
Answer : Option D
Explaination / Solution:

Catabolism is the metabolic process due to which mass of the organism reduces. Detritus release microbial enzymes that breakdown the dead or decaying organisms into simpler form.

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Q.3
Conditions favouring decomposition are
A. low temperature and low humidity
B. high temperature and low humidity
C. high temperature and high humidity
D. low temperature and high humidity
Answer : Option C
Explaination / Solution:

Decomposition rate accelerate at high temperature and high humidity. At higher temperature and high humidity number of decomposer increases substantially that accelerate the decomposition.

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Q.4
Available organic matter for herbivores is represented by
A. Respiration
B. NPP
C. Secondary productivity
D. GPP
Answer : Option B
Explaination / Solution:

The organic matter available for herbivores is called net primary productivity (NPP). Total amount of organic matter fix during photosynthesis is called Gross primary productivity (GPP).

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Q.5
Speed of decomposition will be
A. fast if detritus is rich in lignin
B. fast if detritus is rich in simple sugars
C. slow if detritus contains water soluble substances like sugars
D. slow if detritus lacks chitin
Answer : Option B
Explaination / Solution:

In detritus food chain, speed of decomposition will be fast if detritus is rich in simple sugar that can be easily decomposed into glucose by saprophytes that includes bacteria and fungi.

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Q.6
Correct decreasing order for rate of primary productivity on land will be
A. Savannah > Temperate forests > Tropical rainforests > Arid regions
B. Tropical rainforests > Temperate forests > Savannah > Arid regions
C. Temperate forests > Tropical rainforests > Savannah > Arid regions
D. Tropical rainforests >Savannah > Arid regions>Temperate forests
Answer : Option B
Explaination / Solution:

Primary productivity is maximum in tropical rain forests due to availability of sufficient food and water followed by temperate forests. Savannah grasslands have comparatively less productivity and arid regions have limited biotic component and water.

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Q.7
The more fundamental type of ecological pyramid showing the quantitative relationships of the standing crops will be
A. ecological pyramid of number
B. none of these
C. ecological pyramid of biomass
D. ecological pyramid of energy
Answer : Option C
Explaination / Solution:

The pyramid of biomass is more fundamental, they represent the quantitative relationships of the standing crops. In this pyramid there is a gradual decrease in the biomass from the producers to the higher trophic levels. The biomass here the net organisms collected from each feeding level and are then dried and weighed. This dry weight is the biomass and it represents the amount of energy available in the form of organic matter of the organisms. In this pyramid the net dry weight is plotted to that of the producers, herbivores, carnivores, etc. More the number of crop plants higher the biomass.

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Q.8
Humus will never be
A. reservoir of nutrients
B. amorphous substance present at the top of soil surface
C. resistant to microbial action
D. good for plant growth
Answer : Option B
Explaination / Solution:

Humification leads to accumulation of dark coloured amorphous substance called humus that is highly resistance to microbial action and decompose at very slow rate.

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Q.9
Which one of the following is the most important service provided by ecosystems:
A. pollination
B. aesthetic values
C. soil formation
D. water purification
Answer : Option C
Explaination / Solution:

Ecosystem services includes all activities performed by nature to benefits of human beings. The most important ecological service includes soil formation. Soil is essential for growth of plants that provide food to all living forms.

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Q.10
The product of ecosystem processes are called as
A. Ecosystem services.
B. Economic services
C. Biological services
D. Ecological benefits.
Answer : Option A
Explaination / Solution:

The products of ecosystem processes are called as ecosystem services. Ecosystem services includes purification of air and water by forests and soil formation as well as nutrient cycles

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