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Environment and Biodiversity MCQs – 01 ( Basics of Ecology )

Basics of Ecology MCQs with answers and explanations for UPSC, State PSCs and Other Examinations.

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1. Which of the following are covered under the definition of environment ?

1. Man
2. Topography of the place
3. Man-made Goods
4. Natural Goods

Select the correct codes:

(a) 1, 2 and 3
(b) 1, 3 and 4
(c) 2 and 4
(d) All of the above

Correct Answer –  (d) All of the above

  • The place, people and the object surrounding them(both man made and natural) are together called an environment. 
  • It is a combination of natural and human made factors. 
  • It includes both biotic and abiotic conditions existing in the area.

2. The term ‘ENVIRONMENT’ originated from which language?

(a) French
(b) German
(c) Sanskrit
(d) English

Correct Answer –  (a) French

  • The term ‘environment’ is derived from the French word ‘Environer’ meaning ‘Neighborhood’ or ‘Surroundings’. 
  • Environment plays an important role in the existence of life on earth.
  • Different living species are dependent on the environment for their food, air, water, and other requirements. Therefore, it is a responsibility of every individual to save and protect our environment.

3. Environment is made up of which among the following :

1. Atmosphere
2. Lithosphere
3. Hydrosphere
4. Living Organisms

Select the correct codes:

(a) 1, 2 and 3
(b) 1, 3 and 4
(c) 2 and 4
(d) All of the above

Correct Answer –  (d) All of the above

  • The environment is made up of the atmosphere, lithosphere, hydrosphere and the living organisms.
  • Atmosphere – Thick layer of gasses surrounding the earth.
  • Lithosphere – Solid outermost layer of the earth.
  • Hydrosphere – Made up of all the water or water vapor existing in the environment.

4. Consider the following statements about ecosystem :

1. Living organisms are part of the ecosystem.
2. Non-living things are not part of any ecosystem.

Select the correct statements from the codes below:

(a) 2 Only
(b) 1 Only
(c) None of the above
(d) All of the above

Correct Answer –  (b) 1 Only

  • An ecosystem includes all the living and nonliving things present in the environment.
  • There are two major types of ecosystems which are as follows:
  • Natural ecosystem – These are created by nature. 
  • Examples of Natural ecosystems:
    • Deserts
    • Forests
    • Grasslands
    • Lakes
    • Mountains
    • Rivers
    • Oceans etc.
  • Artificial ecosystem – These are artificially created by man. 
  • Examples of Artificial ecosystem:
    • Aquarium
    • Crop fields
    • Gardens and parks 
    • Artificial ponds etc.

5. Consider the following statements about the components of ecosystem :

1. Algae is an abiotic component of the ecosystem.
2. Rivers are a biotic component of the ecosystem.

Select the correct statements from the codes below:

(a) 2 Only
(b) 1 Only
(c) None of the above
(d) All of the above

Correct Answer –  (c) None of the above

  • Biotic components of the ecosystem – Includes all living organisms.
  • Examples of Biotic components :
    • All types of animals and birds
    • Forests and Grasslands
    • Insects
    • Reptiles and mammals
    • Microorganisms like algae, bacteria, fungus, viruses etc.
  • Abiotic components of the ecosystem– Consists of all non-living components. 
  • Examples of Abiotic components:
    • Air 
    • Cloud
    • Landforms and mountains
    • Rivers and Lakes
    • Climate related components like temperature, humidity, water vapor
    • Sand and dust etc.

6. Consider the following statements about the components of ecosystem :

1. Autotrophs are part of the abiotic component of the ecosystem.
2. Sunlight is a biotic component of the ecosystem.

Select the correct statements from the codes below:

(a) 2 Only
(b) 1 Only
(c) None of the above
(d) All of the above

Correct Answer –  (c) None of the above

  • Biotic components refer to all living components in an ecosystem
  • Biotic components can be categorized into following :
    • Autotrophs – Plants
    • Heterotrophs – Consumers
    • Saprotrophs – Decomposers

7. Fungi and bacteria are categorized as :

(a) Autotrophs
(b) Heterotrophs
(c) None of the above
(d) Saprotrophs

Correct Answer –  (d) Saprotrophs

  • Fungi and bacteria are categorized as Saprotrophs.
  • They thrive on the dead and decaying organic matter.  
  • Decomposers are an essential part of the ecosystem as they help in recycling nutrients which can be reused by plants.

8. Herbivores are categorized as :

(a) Autotrophs
(b) Heterotrophs
(c) None of the above
(d) Saprotrophs

Correct Answer –  (b) Heterotrophs

  • Plants are categorized as producers or autotrophs as they can produce their own food through the process of photosynthesis. 
  • Consumers or heterotrophs depend on other organisms for food.
  • Consumers are further classified into following categories:
    • Primary consumers or Herbivores – Rely on producers for food.
    • Secondary consumers –  Rely on primary consumers for food. They can either be carnivores or omnivores(like men).
    • Tertiary consumers – Rely on secondary consumers for food.  They can either be carnivores or omnivores(like men).

9. The base of the ecological pyramid is occupied by ?

(a) Autotrophs
(b) Heterotrophs
(c) None of the above
(d) Saprotrophs

Correct Answer –  (a) Autotrophs

  • An ecological pyramid is the graphical representation of the number, energy and biomass of the successive trophic levels of an ecosystem.
  • The base of the ecological pyramid is occupied by the producers or autotrophs, followed by primary and secondary consumers. 
  • The tertiary consumers hold the apex of the pyramid .

10. Which among the following is not a function of the ecosystem ?

(a) Nutrient cycling
(b) Energy flow
(c) Decomposition
(d) Rainfall

Correct Answer –  (d) Rainfall

  • Functions of the ecosystem:
  • Nutrient cycling –  Nutrients are consumed, converted and recycled back.
  • Energy flow – Energy flows from one trophic level to another as the energy captured from the sun by producers flows to consumers and then from consumers to decomposers and finally back to the environment which can be utilized again by the producers.
  • Production – Production of biomass by producers
  • Decomposition – Decomposition of biomass by Saprotrophs.
  • Rainfall as water is an abiotic component of an ecosystem. However rainfall is not caused by the ecosystem itself.

11. Which among the following is not part of 5 Levels of Ecology ?

(a) Organism
(b) Community
(c) Country
(d) Biosphere

Correct Answer –  (c) Country 

  • There are five Levels Ecology which are as following :
    • Level 1 – Organism
    • Level 2 – Population
    • Level 3 – Community
    • Level 4 – Ecosystem
    • Level 5 – Biosphere

12. Consider the following statements about the components of ecosystem :

1. In a food chain, flow of energy is linear.
2. In a food web, flow of energy is non-linear.

Select the correct statements from the codes below:

(a) 2 Only
(b) 1 Only
(c) None of the above
(d) All of the above

Correct Answer –  (d) All of the above

  • In a  food chain, flow of energy is linear and energy flows from one trophic level to another in sequence.
  • In a food web, there are combinations of many different food chains hence  flow of energy may not be linear.

13. Consider the following statements about the Phytoplanktons:

1. Phytoplankton have chlorophyll to capture sunlight and perform photosynthesis.
2. Phytoplankton are the base of several aquatic food webs.

Which of the above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer – (c) Both 1 and 2

  • Phytoplankton, also known as microalgae, are similar to terrestrial plants as they contain chlorophyll and require sunlight to perform photosynthesis.
  • Phytoplanktons are the base of several aquatic food webs and work as producers.
  • They provide food for a wide range of sea organisms including whales, shrimp, snails, and jellyfish.

14. Consider the following statements about the Biotic Interactions:

1. In Amensalism, One species is harmed while the other species is unaffected.
2. In Predation, One species benefits while the second species is harmed.

Which of the above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer – (c) Both 1 and 2

  • In Amensalism, One species is harmed while the other species is unaffected.
  • Example → A large tree shades a small plant, retarding the growth of the small plant. The small plant has no effect on the large tree.
  • In Predation, One species benefits while the second species is harmed.
  • Example → Small animals like deer are killed by predators like leopards, tigers and cheetahs.

15. Consider the following statements about the Biotic Interactions:

1. In Competition, both species are adversely affected.
2. In Commensalism, One species benefits while the other is unaffected.

Which of the above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer – (c) Both 1 and 2

  • In Competition, both species are adversely affected.
  • It generally occurs when vital resources in an area are in short supply and multiple species depend on the same resources.
  • Example → Competition for water in the desert.
  • In Commensalism, One species benefits while the other is unaffected.
  • Example →  Suckerfish often attaches to a shark. This helps the suckerfish get protection and a meal from the leftovers of the shark’s meal however the shark is unaffected due to this.

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