Practice MCQ Questions for Class 12 Biology with Answers on a day-by-day basis and rating well in exams. Refer to the Ecosystem Class 12 MCQ Questions with Answers right here together with an in-depth explanation. Understand the idea honestly via way of means of continuously practicing the MCQ Questions in your higher education and score nicely in your exams.

Important class 12 MCQ Questions to research your knowledge of the topic. The detailed solutions also are given for your reference. Check the given below Multiple-Choice Questions in your higher education. We have compiled the Class 12 Biology MCQ Questions of Ecosystem with Answers overlaying the complete syllabus. You will discover a list of Biology MCQ Questions in keeping with the trendy prescribed syllabus. 

Practice MCQ Question for Class 12 Biology chapter-wise

1. Submerged Rooted Hydrophyte are:

(a) Uticularia
(b) Prapa
(c) Nymphea
(d) Vallisnaria

2. An ecosystem is a

(a) group of components that interact with one another
(b) group of interacting species in one place at one time
(c) biological community and component of the physical environment with which the community interacts
(d) group of interacting chemicals and their cycles

3. Two main structural features of an ecosystem are

(a) species composition and stratification
(b) species composition and productivity
(c) productivity and energy flow
(d) nutrient cycling and stratification

4. Primary productivity

(a) is equal to the standing crop of an ecosystem.
(b) is greatest in freshwater ecosystems.
(c) is the rate of conversion of light to chemical energy in an ecosystem
(d) is inverted in some aquatic ecosystems

5. The rate at which light energy is converted into chemical energy of organic molecules is the ecosystem’s

(a) net primary productivity
(b) gross secondary productivity
(c) net secondary productivity
(d) gross primary productivity

6. An inverted pyramid of biomass can be found in which ecosystem?

(a) Marine
(b) Forest
(c) Grass land
(d) Tundra

7. Which of the following is not a producer?

(a) Agaricus
(b) Nostoc
(c) Volvox
(d) Spirogyra

8. Which of the following ecosystems is most productive in terms of net primary production?

(a) Tropical rain forests
(b) Deserts
(c) Oceans
(d) Estuaries

9. Energy flow in ecosystem is

(a) Unidirectional
(b) Multidirectional
(c) Bidirectional
(d) None of these

10. Which one of the following is one of the characteristics of a biological community?

(a) Stratification
(b) Natality
(c) Mortality
(d) None of these

11. Which of the following is an example of man-made ecosystem?

(a) Aquarium
(b) Herbarium
(c) Tissue culture
(d) All of these

12. How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

(a) 10%
(b) 1%
(c) 40%
(d) 90%

13. During the process of ecological succession the changes that take place in communities are

(a) Orderly and sequential
(b) Random
(c) Very quick
(d) Not influenced by the physical environment

14. Climax community is in a state of

(a) equilibrium
(b) disorder
(c) constant change
(d) non-equilibrium

15. If the carbon atoms fixed by producers already have passed through three species, the trophic level of the last species would be

(a) tertiary consumer
(b) secondary consumer
(c) tertiary producer
(d) scavenger

16. Which of the following type of ecosystem is expected in an area where evaporation exceeds precipitation, and mean annual rainfall is below 100mm 

(a) Desert
(b) Mangrove
(c) Grassland
(d) Shrubby forest

17. The zone at the edge of a lake or ocean which is alternatively exposed to air and immersed in water is called 

(a) Littoral zone
(b) Lentic one
(c) Benthic zone
(d) Pelagic zone

18. Edaphic factor refers to 

(a) Soil
(b) Relative humidity
(c) Altitude
(d) Water

19. Secondary Succession takes place on/in 

(a) Degraded forest
(b) Bare rock
(c) Newly cooled lava
(d) None of these

20. At the trophic level of consumers, the rate at which food energy is assimilated, is called:

(a) Secondary productivity
(b) Gross primary productivity
(c) Net primary productivity
(d) None of these

21. The term "detritivore" includes

(a) decomposers
(b) primary consumers
(c) secondary consumers
(d) autotrophs

22. The major reservoir for phosphorous is 

(a) Aquifers
(b) Soil and rocks
(c) The atmosphere
(d) Clouds

23. Which of the following pyramids can never be inverted in a natural ecosystem?

(a) pyramid of numbers
(b) pyramid of energy
(c) pyramid of biomass
(d) all can be inverted 

24. The earth is an open system with respect to

(a) organisms
(b) chemicals
(c) energy 
(d) all of the above

25. Both hydrach and xerarch successions:

(a) Take same time
(b) Have similar sere
(c) Lead to mesic conditions
(d) Have same pioneer species

Answer:

1. Answer : (d) Vallisnaria

Explanation: Submerged rooted hydrophytes are the plants that are completely immersed in water and their roots are embedded in the mud. Example – Hydrilla, Vallisneria, Potamogeton, etc.

2. Answer : (c) biological community and component of the physical environment with which the community interacts

Explanation: An ecosystem is a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. Ecosystems contain biotic or living, parts, as well as abiotic factors, or nonliving parts. Abiotic factors include rocks, temperature, and humidity.

3. Answer : (a) species composition and stratification

Explanation: Species composition and stratification are the two main structural features of an ecosystem

4. Answer : (c) is the rate of conversion of light to chemical energy in an ecosystem.

Explanation: Primary productivity is the process by which organisms make their own food from inorganic sources. The majority of primary producers are terrestrial plants and microbial life, such as algae. Primary productivity due to photosynthesis is commonly measured by quantifying oxygen production or CO₂ assimilation.

5. Answer : (d) gross primary productivity

Explanation: Gross primary productivity is the rate of photosynthesis. In other words, it is the rate of conversion of light energy into chemical energy of organic molecules in an ecosystem.

6. Answer : (a) Marine

Explanation: Therefore, the inverted pyramid of biomass can be easily found in the marine ecosystem.

7. Answer : (a) Agaricus

Explanation: Spirogyra (Green alga), Volvox and Nostoc (BGA) are chlorophyll containing organisms and thus prepare their own food. Agaricus is a fungus (Basidiomycetes). It is achlorophyllus and not a producer.

8. Answer : (a) Tropical rain forests

Explanation: Tropical rainforest has high soil moisture , high availability of nutrients so it has high net primary productivity. Hence, they are the most stable ecosystem. Our required answer is tropical rainforest.

9. Answer : (a) Unidirectional

Explanation: Energy flow is the flow of energy through living things within an ecosystem. All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain. Each of the levels within the food chain is a trophic level.

10. Answer : (a) Stratification

Explanation: Stratification means arranging something, or something that has been arranged, into categories. Stratification is a system or formation of layers, classes, or categories. Stratification is used to describe a particular way of arranging seeds while planting, as well as the geological layers of rocks.

11. Answer : (a) Aquarium 

Explanation: The aquarium is a man-made ecosystem where a suitable environment is made with all the plants, aquatic animals, and non- living things.

12. Answer : (a) 10%

Explanation: Only 10% of harbivore productivity is utilized for raising productivity of next tropic level(primary carnivores), while the rest 90% is eaten and used up, in process like respiration, maintenance of body heat and other activities.

13. Answer : (a) Orderly and sequential

Explanation: During the process of ecological succession the changes that take place in communities are orderly and sequential .

14. Answer : (a) equilibrium

Explanation: Climax community is a term for a biological community of plants, animals, and fungi which, through the process of ecological succession in the development of vegetation in an area over time, had reached a steady state or equilibrium.

15. Answer : (a) tertiary consumer

Explanation: If the carbon atoms fixed by producer already have passed through three species then the trophic level of the last species (i.e. third species) would be tertiary consumer.

16. Answer : (a) Desert

Explanation: Deserts have been variously classified as true deserts, having less than 120mm annual rainfall, or extreme deserts showing less that 70 mmyr⁻¹ rainfall. In desert biomes, evaporation from soil always exceeds rainfall by 7 to 50 times.

17. Answer : (a) Littoral zone

Explanation: The littoral zone is the zone at the edge of a lake or ocean or in aquatic habitat which is alternatively exposed to air, hence, light is also available and immersed in water.

18. Answer : (a) Soil

Explanation: Edaphic factors are classified under the abiotic factors affecting an ecosystem. Edaphic factors include factors of soil, e.g., soil texture, substratum, topography, mineral composition, pH, etc. These factors can influence the distribution and interrelationships of organisms, as well as rate of decomposition.

19. Answer :(a) Degraded forest

Explanation: Bare rock is also an example of an ecosystem with primary succession since life is yet to be formed by utilizing the organic materials on it. Thus by considering the given options, the most appropriate one was found to be D, that is, secondary succession takes place in a degraded forest.

20.Answer : (a) Secondary productivity

Explanation: The rate at which food energy is assimilated at the trophic level of consumers is called secondary productivity. In other words, the rate of synthesis of organic matter by consumers is called as secondary productivity.

21. Answer : (a) decomposers

Explanation: A detritivore is an organism that eats dead or decaying plants or animals as food. Detritivores include microorganisms such as bacteria and larger organisms such as fungi, insects, worms, and some crustaceans.

22. Answer : (b) Soil and rocks

Explanation: The largest reservoir of phosphorus is in sedimentary rock. It is in these rocks where the phosphorus cycle begins. When it rains, phosphates are removed from the rocks (via weathering) and are distributed throughout both soils and water. Plants take up the phosphate ions from the soil.

23. Answer : (b) pyramid of energy

Explanation: Pyramid of energy is the only pyramid that can never be inverted and is always upright. This is because some amount of energy in the form of heat is always lost to the environment at every trophic level of the food chain.

24. Answer : (c) energy 

Explanation: Matter does not enter or leave. With respect to energy, Earth is an open system. Sunlight energy flows in and heat energy escapes.

25. Answer : (c) Lead to mesic conditions

Explanation: Xerach succession takes place in dry areas and the series progress from xeric to mesic condition. Hence, both hydrach and xerach succession leads to medium water conditions (mesic).

Click here to practice  MCQ Question for Ecosystem Class 12