Q26
2 marksVery Short AnswerSection B

Name the term used for the materials which cannot be broken down by biological processes. Give two ways by which they harm various components of an ecosystem.

Our Environment
Biodegradable and non-biodegradable substances
Official Answer

The term used for materials that cannot be broken down by biological processes is non-biodegradable.


Two ways by which they harm various components of an ecosystem are:

  1. Persistence and Accumulation: Since they cannot be broken down by decomposers (like bacteria and fungi), they persist in the environment for a long time, causing soil and water pollution and physical obstruction to organisms.
  2. Harm to Ecosystem Members: They can enter food chains and accumulate in the bodies of living organisms, causing toxicity and leading to biological magnification, which harms various trophic levels.
non-biodegradablepersistharmecosystemdecomposersbiological magnification

Marking Scheme

  • 1Identification of the term 'non-biodegradable' (1 mark)
  • 2First way they harm the ecosystem (e.g., persistence/pollution/inert nature) (0.5 marks)
  • 3Second way they harm the ecosystem (e.g., entering food chains/harming organisms/biological magnification) (0.5 marks)

Hint

Think about materials like plastics that decomposers cannot break down, and how they remain in nature for a long time.

Quick Oral Answer

The term is 'non-biodegradable'. They harm the ecosystem because they are inert and persist in the environment for a long time, causing pollution, and they can enter the food chain, leading to toxic accumulation in organisms.

Analysis & Explanation

According to the NCERT text, substances that are not broken down by biological processes (such as the action of enzymes from bacteria or other saprophytes) are called non-biodegradable. Because decomposers lack specific enzymes to break down these human-made materials (like plastics), these substances remain inert and persist in the environment for a very long time. This persistence leads to accumulation, which can physically choke habitats, pollute soil and water, and enter food webs, causing toxicity and harm to various organisms across different trophic levels.

Common Mistakes

  1. 1Confusing biodegradable with non-biodegradable.
  2. 2Failing to mention that decomposers lack specific enzymes to break them down.
  3. 3Not specifying how they cause harm (e.g., simply writing 'they are bad' instead of explaining persistence or food chain entry).

Interesting Facts

Enzymes are highly specific in their action. Just as our digestive enzymes cannot break down coal to give us energy, decomposers lack the specific enzymes required to break down synthetic materials like plastics, which is why they remain non-biodegradable.

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Frequently Asked Questions

How many marks does this question carry in CBSE Class 10 Science 2024?

This question carries 2 marks in the CBSE Class 10 Science 2024 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 "Biodegradable and non-biodegradable substances" from CBSE Class 10 Science.

What type of question is this in the CBSE Class 10 Science 2024 paper?

This is a Very Short Answer question from Section B in the CBSE Class 10 Science 2024 paper.