NCERT EVS Questions

1. Which of the following can be example of Ecosystem?

1. Pond
2. Crop field
3. Estuary
4. Forest
5. Aquarium

Select the correct answer using the code given below:
(a) 2 and 4 only
(b) 1 and 5 only
(c) 3 and 4 only
(d) 1, 2, 3, 4 and 5

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Ans. (d)
Explanation : 

• An ecosystem can be thought of as a functional unit of nature in which live species interact with one another as well as the physical surroundings.
• The size of an ecosystem might range from a small pond to a vast forest or a sea. 
  Many ecologists consider the entire biosphere to be a global ecosystem, made up of all of Earth's local ecosystems.
• Because this system is too large and complex to study all at once, it is easier to separate it into two main categories: terrestrial and aquatic.
• Terrestrial ecosystems include forests, grasslands, and deserts, whereas aquatic ecosystems include ponds, lakes, wetlands, rivers, and estuaries.
• Crop fields and aquariums are both examples of man-made ecosystems. 
  As a result, option (d) is the correct answer.

2. Which of the following is/are the limitations of ecological pyramids?

1. It does not take into account the same species belonging to two or more trophic levels.
2. It assumes a simple food chain and does not accommodate a food web.
3. Saprophytes are not given any place in ecological pyramids

Select the correct answer using the code given below:
(a) 1 and 2 only
(b) 2 and 4 only
(c) 1 and 3 only
(d) 1, 2 and 3

Ans. (d)
Explanation : 

• Ecological pyramids have some limitations, such as not accounting for the same species belonging to two or more trophic levels. 
  As a result, statement 1 is true.
  It presupposes a simple food chain, which practically never occurs in nature; a food web is not accommodated. 
  As a result, statement 2 is true.
  Saprophytes, despite playing a critical role in the ecosystem, are not included in ecological pyramids. 
  As a result, statement 3 is true.

3.

1. Temperature
2. Water
3. Light
4. Parasites

Select the correct answer using the code given below:
(a) 1, 2 and 3 only
(b) 1 and 4 only
(c) 3 and 4 only
(d) 1, 2, 3 and 4

Ans. (a)
Explanation : 

• Biotic and abiotic components are important factors that contribute to the wide range of physical and chemical conditions seen in diverse environments.
  Temperature, water, light, and soil are abiotic components that entirely characterise an organism's habitat, as do biotic components such as pathogens, parasites, predators, and competitors, with whom they continually interact.
  Natural selection had produced adaptations to optimise the organism's survival and reproduction in its environment throughout time. As a result, option (a) is the correct answer.

4. Consider the following statements:

1. Mango trees do not and cannot grow in temperate countries like Canada and Germany
2. Snow leopards are not found in Kerala forests

Select the correct answer using the code given below:
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Ans. (c)
Explanation : 

• The most ecologically significant environmental aspect is temperature. On land, the average temperature changes seasonally and falls progressively from the equator to the poles, as well as from plains to mountain peaks.
  Different species' heat tolerance levels determine their geographic spread to a considerable extent.
  Mango trees do not and cannot thrive in temperate regions such as Canada and Germany, snow leopards do not live in Kerala woods, and tuna fish are rarely caught in the ocean beyond tropical elevations. As a result, option (c) is the correct answer.

5. Among the following algae that inhabit the sea, which is likely to be found in the deepest waters?

(a) Green algae
(b) Red algae
(c) Brown algae
(d) All can be found in deepest waters.

Ans. (b)
Explanation : 

• Energy is required for life, and the Sun is the ultimate source of all energy on Earth.
  Only the most intense components of the solar spectrum are able to reach higher depths when the sun's energy goes down the water depths.
  The shortest wavelength and maximum energy are found in the bluish spectrum. As a result, this bluish component can penetrate deep into the ocean depths.
  Because of the pigment phycoerythrin, red algae is now simply referred to as 'red.'
  This phycobilin/phycoerythrin can absorb blue light and use it for photosynthesis, allowing the phycobilin/phycoerythrin to make use of the limited sunlight energy that reaches the ocean's deepest depths. As a result, red algae may thrive in the deepest depths.

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