Ecosystem - Online Test
Q1. Correct sequence for decomposition process is:
Answer : Option B
Explaination / Solution:
Decomposition process involves fragmentation, leaching, catabolism and mineralization in sequence. Decomposition is essential form nutrient cycles in the ecosystem.
Q2. When the main pool is located in the soil and rocks, that nutrient cycle is called
Answer : Option D
Explaination / Solution:
The nutrient cycle in which reservoir is located in earth crust is called sedimentary nutrient cycle. So, soil and rock based nutrient cycles are example of sedimentary nutrient cycle.
Q3. The concept of ecological pyramids was developed by :
Answer : Option B
Explaination / Solution:
The concept of ecological pyramid was developed by Charles Elton; these pyramids are also known as Eltonian pyramids. The pyramids are a graphical representation which depicts the number of organisms, biomass and productivity at each trophic level.
Q4. Which of the following pyramid/s is/are inverted:
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.
Q5. Breakdown of detritus by microbial enzymes into simple forms is called
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.
Q6. Conditions favouring decomposition are
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.
Q7. Available organic matter for herbivores is represented by
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).
Q8. Speed of decomposition will be
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.
Q9. Correct decreasing order for rate of primary productivity on land will be
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.
Q10. The more fundamental type of ecological pyramid showing the quantitative relationships of the standing crops will be
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.
