NEET Biology Ecosystem Important Questions Set 02

These Class 12 NEET Biology important questions on Ecosystem give 19 questions with step-by-step answers, arranged as very short, short and long answer types, taken from a model test paper. They help NEET aspirants revise the definitions, structures, differences and key terms of the chapter.

Very Short Answer Type Questions

Question 1. Define stratification.
Answer: Vertical distribution of different species occupying different levels is called stratification.

Question 2. Name the two man-made ecosystems.
Answer: (i) Crop field
(ii) Aquarium

Question 3. What is ecosystem?
Answer: An ecosystem is a functional unit of nature and comprises abiotic and biotic components.

Question 4. What is net primary productivity?
Answer: Gross primary productivity minus respiration losses is the net primary productivity.

Question 5. Define detritus.
Answer: Dead remains of plants and animals including fecal matter constitute detritus.

Question 6. Name the dark coloured amorphous substance that is highly resistant to microbial action.
Answer: Humus

Question 7. Give the two most important climatic factors that regulate the decomposition.
Answer: Temperature and soil moisture.

Question 8. What is standing crop?
Answer: Each trophic level has a certain mass of living material at a particular time called the standing crop.

Question 9. Define secondary consumers.
Answer: If the animals eat other animals which inturn eat the plants (or their produce) they are called as secondary consumer.

Question 10. Expand:
(i) GFC,
(ii) DFC.
Answer: (i) GFC – Grazing Food Chain
(ii) DFC – Detritus Food Chain

Short Answer Type Questions

Question 11. Pyramid of energy is always upright, can never be inverted. Explain
Answer: When energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step.

Question 12. What are pioneer species? Name the pioneer species of hydrarch succession.
Answer: The species that invade a bare area are called pioneer species. Small phytoplanktons are pioneer species in hydrarch succession.

Question 13. What is the reservoir for the sedimentary cycle. Give the function of reservoir also.
Answer: The reservoir for the sedimentary cycle is located in earth's crust. The function of the reservoir is to meet with the deficit which occurs due to imbalance in the rate of influx and efflux.

Question 14. Give the role of pioneer species during succession on bare rock.
Answer: Lower plants, like lichens as a pioneer species form a crust over the bare rock and begin to form soil from their organic remains and by stimulating chemical breakdown of the rocks. Lichens are normally followed by mosses, which speed up the process of soil accumulation by trapping wind blown particles.

Question 15. Differentiate between a detrivore and a decomposers giving an example of each.
Answer: Detrivore feeds on dead plants and animals (Detritus) e.g., Earthworm. Decomposers breakdown complex (organic) matter into simpler (inorganic) matter e.g., Bacteria, Fungi.

Question 16. Construct a pyramid of biomass starting with phytoplanktons. Label three trophic levels. Is the pyramid upright or inverted? Why?

Answer:

A well-labelled diagram should show these parts: Fish; Zooplankton; Phytoplankton.

The pyramid of biomass in aquatic ecosystem is generally inverted, because the biomass of fishes, and other aquatic animals far exceeds that of phytoplanktons.

Question 17. Explain the difference between the seral stage and the climax community during succession.
Answer: The different communities or stages represented by combination of mosses, herbs, shrubs and trees replacing one another during succession are referred to as seral stage, while the terminal stage of succession is represented by the climax community. The climax community is stable and does not show changes in species composition.

Long Answer Type Questions

Question 19. (a) Mention one ward for the following :
(i) Name the nutrient cycles in which reservoir pool is lithosphere.
(ii) What does succession in water known as?
(iii) Mention the largest man-made ecosystem.
(iv) Name two detritivores.
(b) Differentiate between food chain and food web. (Any two)
Answer: (a) (i) Sedimentary nutrient cycling
(ii) Hydrosere / Hydrach
(iii) Agro ecosystem
(iv) Earthworm, Termites
(b) Food chain Food web
1. It is a single series of trophic levels. 1. It is a multiple series of trophiclevels.
2. Each food chain is distinct from other 2. A food web consists of a number of food chain. interconnected trophic levels.

Question 20. (a) Fill in the blanks:
(i) Prize tag for soil formation is ________.
(ii) Percent carbon dissolved in oceans is ________.
(iii) ________ percent of PAR is captured by plant.
(iv) Vertical distribution of different species occupying different levels is ________
(b) Differentiate between Grazing food chain and Detritus food chain. (Any two).

Answer:

(a) (i) 50% of 33 trillion US dollars a year
(ii) 71%
(iii) 2 – 10%
(iv) Stratification
(b) Grazing food chain Detritus food chain
1. It extends from producers through 1. It begins with dead organic matter and herbivores to carnivores. passes through detritus feeding organisms in soil to organisms feeding on detritus feeders.
2. It adds energyinto ecosystem. 2. It prevents wastage of energy bound in organic matter.