CBSE Class 10 Science Chapter 15: Our Environment NCERT Solutions

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NCERT Solutions PDF Class 10 PDF

This chapter delves into the fundamental concepts of our environment, exploring the intricate relationships within ecosystems. The NCERT Solutions for Class 10 Science, Chapter 15, provide clear explanations and answers to key questions. Students will learn about different trophic levels, the flow of energy through food chains and food webs, and the consequences of disrupting these natural processes. The solutions also address crucial environmental issues like pollution and the concept of biological magnification, explaining how harmful substances accumulate in the environment. These solutions are designed to help students understand the ecological balance and the importance of sustainable practices, making them an invaluable resource for exam preparation and a deeper understanding of environmental science.

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Quick info

BoardCBSE
ClassClass 10
SubjectScience
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 15: Our Environment

Chapter summary

Chapter 15 of the NCERT Class 10 Science textbook focuses on 'Our Environment'. The provided solutions cover essential topics such as identifying biodegradable and non-biodegradable items, understanding the structure of food chains, and recognizing environment-friendly practices. It also explains the critical concept of trophic levels and the impact of removing organisms from any level, along with the phenomenon of biological magnification. These solutions aim to clarify ecological principles and their real-world implications.

Learning outcomes

  • Identify biodegradable and non-biodegradable items.
  • Explain the formation and components of a food chain.
  • Analyze the impact of removing organisms from different trophic levels.
  • Define and explain biological magnification.
  • Recognize environmentally friendly practices.

Topics covered

Paper topics

  • Ecosystems
  • Trophic Levels
  • Food Chains
  • Food Webs
  • Producers
  • Consumers
  • Decomposers
  • Biodegradable Items
  • Non-biodegradable Items
  • Biological Magnification
  • Environmental Imbalance
  • Environment-friendly Practices

Important topics

  • Food Chains and Trophic Levels
  • Impact of removing organisms from trophic levels
  • Biological Magnification
  • Biodegradable vs. Non-biodegradable substances
  • Environment-friendly Practices

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Questions and Solutions

Question 1

Which of the following groups contain only biodegradable items?

(a) Grass, flowers and leather

(b) Grass, wood and plastic

(c) Fruit-peels, cake and lime-juice

(d) Cake, wood and grass

Solution: The correct option is (c) Fruit-peels, cake and lime-juice. Biodegradable items are those that can be decomposed by natural processes, such as the action of microorganisms. Fruit-peels, cake, and lime-juice are organic materials that break down easily. Options (a), (b), and (d) contain plastic or leather, which are generally non-biodegradable or decompose very slowly.

Question 2

Which of the following constitute a food-chain?

(a) Grass, wheat and mango

(b) Grass, goat and human

(c) Goat, cow and elephant

(d) Grass, fish and goat

Solution: The correct option is (b) Grass, goat and human. A food chain illustrates the flow of energy from one organism to another. It starts with a producer (like grass), followed by a primary consumer (like a goat that eats grass), and then a secondary consumer (like a human that eats the goat). Options (a), (c), and (d) do not represent a typical sequential flow of energy in a food chain.

Question 3

Which of the following are environment-friendly practices?

(a) Carrying cloth-bags to put purchases in while shopping

(b) Switching off unnecessary lights and fans

(c) Walking to school instead of getting your mother to drop you on her scooter

(d) All of the above

Solution: The correct option is (d) All of the above. All the listed practices contribute to environmental protection. Using cloth bags reduces plastic waste. Switching off lights and fans conserves energy, reducing the demand for electricity generation which often relies on fossil fuels. Walking or cycling instead of using a motor vehicle reduces air pollution and fuel consumption. Therefore, all these actions are considered environment-friendly.

Question 4

What will happen if we kill all the organisms in one trophic level?
Solution: If all the organisms in a particular trophic level are eliminated, it will disrupt the flow of energy through the ecosystem. The organisms in the next higher trophic level will lose their food source, potentially leading to their starvation or migration. Simultaneously, the population of organisms in the trophic level below the removed one might experience unchecked growth, as their natural predators are gone. This imbalance can lead to a collapse of the food chain and significant ecological disruption.

Question 5

Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Solution: Yes, the impact of removing all organisms from a trophic level will differ depending on which level is affected. Removing producers (like plants) would have a drastic effect, leading to the starvation of all herbivores and subsequently carnivores. Removing primary consumers (herbivores) would cause a decline in carnivore populations and an overgrowth of producers. Removing top carnivores might lead to an increase in the populations of their prey. It is not possible to remove organisms from any trophic level without causing some damage to the ecosystem, as all levels are interconnected and essential for maintaining ecological balance.

Question 6

What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Solution: Biological magnification is the process by which the concentration of certain non-biodegradable substances, such as pesticides and heavy metals, increases as they move up through successive trophic levels in a food chain. Yes, the levels of magnification will be different and progressively higher at each subsequent trophic level. For instance, if a pollutant is present in low concentrations in producers, it will be present in much higher concentrations in primary consumers, even higher in secondary consumers, and reach the highest concentration in top predators.

Common mistakes

  • Confusing biodegradable and non-biodegradable items.
  • Not understanding the interconnectedness of trophic levels in a food chain.
  • Underestimating the impact of biological magnification on higher trophic levels.

Revision tips

  • Create flashcards for biodegradable vs. non-biodegradable items.
  • Draw out different food chains to visualize energy flow.
  • Explain the concept of biological magnification in your own words.
  • List and explain at least three environment-friendly practices.

Practice MCQs

Q1. Which of the following groups consists entirely of biodegradable items?

Q2. Which of the following represents a complete food chain?

Q3. What is the primary consequence of removing all organisms from a specific trophic level?

Q4. Biological magnification refers to:

Q5. Which practice is considered environment-friendly?

Frequently asked questions

What is the main focus of Chapter 15, 'Our Environment', in Class 10 Science?

Chapter 15 focuses on understanding ecosystems, the flow of energy through food chains and food webs, the roles of different organisms in trophic levels, and the impact of human activities on the environment, including pollution and biological magnification.

How do these NCERT Solutions help students prepare for exams?

These solutions provide clear, step-by-step answers to all exercise questions, helping students grasp complex ecological concepts, understand the consequences of environmental disruptions, and identify key terms and processes like biological magnification.

What are biodegradable items?

Biodegradable items are materials that can be broken down naturally by microorganisms into simpler substances. Examples include fruit peels, cake, wood, and grass.

What is the significance of trophic levels in an ecosystem?

Trophic levels represent the position an organism occupies in a food chain. They are crucial for understanding the flow of energy and the interdependence of organisms within an ecosystem.

Can removing organisms from any trophic level be done without damaging the ecosystem?

No, removing organisms from any trophic level can cause significant damage and imbalance to the ecosystem because all trophic levels are interconnected through food chains and webs.

What is biological magnification, and why is it a concern?

Biological magnification is the increasing concentration of non-biodegradable substances in organisms at successively higher levels in a food chain. It is a concern because these substances can reach toxic levels in top predators, including humans.

Important links

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