Q3
1 markVery Short AnswerSection A

In a food chain of frog, grass, insect and snake, assign trophic level to frog.

Our Environment
Food Chains and Webs
Official Answer

In the given food chain, the frog occupies the third trophic level (as a secondary consumer).


Food Chain:

Grass (Producer)→Insect (Primary Consumer)→Frog (Secondary Consumer)→Snake (Tertiary Consumer)\text{Grass (Producer)} \rightarrow \text{Insect (Primary Consumer)} \rightarrow \text{Frog (Secondary Consumer)} \rightarrow \text{Snake (Tertiary Consumer)}


  • First Trophic Level (T1T_1): Grass (Producer)
  • Second Trophic Level (T2T_2): Insect (Herbivore / Primary Consumer)
  • Third Trophic Level (T3T_3): Frog (Small Carnivore / Secondary Consumer)
  • Fourth Trophic Level (T4T_4): Snake (Larger Carnivore / Tertiary Consumer)
third trophic levelsecondary consumerGrass -> Insect -> Frog -> Snake

Marking Scheme

  • 1Identifying the correct food chain sequence: 0.5 marks
  • 2Assigning the correct trophic level (third trophic level / secondary consumer) to the frog: 0.5 marks

Hint

Identify who eats whom to construct the food chain first: Grass →\rightarrow Insect →\rightarrow Frog →\rightarrow Snake. Then count the steps starting from the producer.

Quick Oral Answer

In the food chain Grass →\rightarrow Insect →\rightarrow Frog →\rightarrow Snake, the frog is at the third trophic level because it is a secondary consumer that feeds on the primary consumer (insect).

Analysis & Explanation

According to the NCERT text, the autotrophs or producers are at the first trophic level. They fix solar energy and make it available to heterotrophs. Herbivores (primary consumers) come at the second trophic level, and small carnivores (secondary consumers) come at the third trophic level. In this specific food chain, grass is the producer (T1T_1), the insect is the herbivore that eats grass (T2T_2), and the frog is the small carnivore that eats the insect (T3T_3). Therefore, the frog is assigned to the third trophic level.

Common Mistakes

  1. 1Confusing the trophic level with the consumer level (e.g., calling the frog a second trophic level organism because it is a secondary consumer).
  2. 2Writing the food chain in the wrong order, such as placing the frog before the insect.

Interesting Facts

Frogs are excellent ecological indicators because their highly permeable skin makes them extremely sensitive to environmental changes and pollution in both aquatic and terrestrial habitats.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2016?

This question carries 1 mark in the CBSE Class 10 Science 2016 examination.

Which chapter does this question come from in Science?

This question is from the chapter "Our Environment" in the CBSE Class 10 Science syllabus.

What topic does this question cover in Science?

This question covers the topic "Food Chains and Webs" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2016 paper?

This is a Very Short Answer question from Section A in the CBSE Class 10 Science 2016 paper.