NCERT Class 10 Science Chapter 13 – Our Environment

NCERT Class 10 Science Chapter 13 explains the structure and functioning of ecosystems and the impact of human activities on the environment. In NCERT Class 10 Science Chapter 13, students study ecosystem components, food chains, ozone depletion and waste management. NCERT Class 10 Science Chapter 13 is an important environmental science chapter for CBSE board exams.

NCERT Class 10 Science Chapter 13 begins with the concept of an Ecosystem, which includes Biotic Components (living organisms) and Abiotic Components (air, water, soil, sunlight and temperature). Biotic components are further classified into Producers, Consumers and Decomposers.

A major part of NCERT Class 10 Science Chapter 13 focuses on Food Chains and Food Webs. Energy flows from producers to consumers through different Trophic Levels. According to the 10% Law, only 10% of energy is transferred from one trophic level to the next. Because of this energy loss, food chains generally consist of only three to four trophic levels.

NCERT Class 10 Science Chapter 13 also explains how human activities affect the environment. The use of pesticides such as DDT leads to Biological Magnification, where harmful substances accumulate at higher trophic levels.

Another important topic in NCERT Class 10 Science Chapter 13 is the Ozone Layer. The ozone layer protects Earth from harmful Ultraviolet (UV) Radiation. Chemicals such as Chlorofluorocarbons (CFCs) damage the ozone layer. The Montreal Protocol (1987) was introduced to reduce ozone-depleting substances.

NCERT Class 10 Science Chapter 13 concludes with Waste Management. Waste is classified into Biodegradable and Non-biodegradable. The principle of Reduce, Reuse and Recycle (3Rs) helps in managing waste effectively.

NCERT Class 10 Science Chapter 13 is highly important for CBSE board exams because conceptual questions from food chains, ozone depletion and environmental impact are frequently asked.

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13.1 Eco-system — what are its components?

• An Ecosystem is a functional unit of nature where Living (Biotic) and Non-living (Abiotic) components interact with each other.
• Abiotic Components include air, water, soil, temperature, light and minerals.
• Biotic Components include all living organisms such as plants, animals and microorganisms.
• Biotic components are classified as Producers, Consumers and Decomposers.
• Producers (Green Plants) prepare food through Photosynthesis using sunlight, carbon dioxide and water.
• Consumers depend directly or indirectly on producers for food; they may be Herbivores, Carnivores or Omnivores.
• Decomposers such as bacteria and fungi break down dead organisms into simpler substances, returning nutrients to the environment.
• Energy flows through the ecosystem from the Sun → Producers → Consumers → Decomposers.

13.1.1 Food Chains and Webs

• A Food Chain is a linear sequence of organisms through which energy flows from one level to another.
• It begins with Producers, followed by Primary Consumers (Herbivores), then Secondary and Tertiary Consumers (Carnivores).
• Each step in a food chain is called a Trophic Level.
• Only about 10% of Energy is transferred from one trophic level to the next, known as the 10% Law.
• Due to loss of energy at each level, food chains generally have 3–4 Trophic Levels.
• A Food Web is a network of interconnected food chains that provides stability to an ecosystem.
• Disruption of one link in a food chain can affect the entire ecosystem.

13.2 How do out activities affect the environment?

• Human activities such as Industrialisation, Urbanisation and Deforestation disturb the natural balance of ecosystems.
• Excessive use of natural resources leads to Depletion of Resources and environmental degradation.
• The introduction of harmful chemicals into the environment results in Pollution of Air, Water and Soil.
• Non-biodegradable substances accumulate in food chains, causing Biological Magnification at higher trophic levels.
• Use of pesticides such as DDT increases concentration of toxic substances in top consumers.
• Rapid increase in human population increases demand for food, energy and land resources.
• Improper waste disposal contributes to environmental contamination.

13.2.1 Ozone Layer and How it is Getting Depleted

• The Ozone Layer is a region in the upper atmosphere that contains a high concentration of Ozone (O₃).
• It protects living organisms by absorbing harmful Ultraviolet (UV) Radiation from the Sun.
• Ozone is formed when UV radiation splits oxygen molecules (O₂) into atoms, which then combine to form O₃.
• Certain human-made chemicals such as Chlorofluorocarbons (CFCs) damage the ozone layer.
• CFCs release chlorine atoms in the atmosphere, which break down ozone molecules.
• Depletion of ozone layer leads to increased exposure to UV Rays, causing skin cancer and eye damage.
• International efforts such as the Montreal Protocol (1987) were initiated to reduce use of ozone-depleting substances.

13.2.2 Managing the Garbage we Produce

• Rapid increase in population and urbanisation has led to a rise in Solid Waste Generation.
• Garbage consists of Biodegradable and Non-biodegradable materials.
• Biodegradable Waste such as vegetable peels and paper can be decomposed by microorganisms.
• Non-biodegradable Waste such as plastics and metals persists in the environment for a long time.
• The practice of Reduce, Reuse and Recycle (3Rs) helps in minimising waste generation.
• Segregation of waste at source into biodegradable and non-biodegradable components is essential for proper disposal.
• Methods such as Composting convert biodegradable waste into manure.
• Proper waste management reduces pollution and protects the environment.

Exam Oriented Facts

• An Ecosystem consists of Biotic and Abiotic Components interacting together.
• Abiotic Components: Air, Water, Soil, Temperature, Sunlight, Minerals.
• Biotic Components: Producers, Consumers and Decomposers.
• Producers prepare food through Photosynthesis.
• Consumers depend on producers directly or indirectly.
• Decomposers recycle nutrients by breaking down dead organisms.
• A Food Chain represents energy flow from one organism to another.
• Each step is called a Trophic Level.
• Only 10% of Energy is transferred to the next trophic level (10% Law).
• Due to energy loss, food chains usually have 3–4 Trophic Levels.
• A Food Web is a network of interconnected food chains.
• Higher trophic levels receive less energy.
• Activities like Deforestation and Industrialisation disturb ecosystem balance.
• Non-biodegradable substances cause Biological Magnification.
• Toxic chemicals like DDT accumulate at higher trophic levels.
• Excessive resource use leads to environmental degradation.
• Ozone (O₃) protects Earth from harmful UV Radiation.
• CFCs (Chlorofluorocarbons) cause ozone depletion.
• Ozone depletion increases risk of Skin Cancer and Cataract.
• Montreal Protocol (1987) aimed to phase out ozone-depleting substances.
• Waste types: Biodegradable and Non-biodegradable.
• 3Rs Principle: Reduce, Reuse, Recycle.
• Composting converts biodegradable waste into manure.

Proper waste segregation reduces pollution and environmental harm

NCERT Class 10 Science Chapter 13 – Our Environment builds awareness about ecosystem balance and sustainable development. A strong understanding of NCERT Class 10 Science Chapter 13 helps students grasp environmental concepts required for board exams and competitive exams.

NCERT Class 10 Science Chapter 13 connects biology with environmental science and strengthens conceptual clarity on ecological balance.

FAQs

Q1. What is NCERT Class 10 Science Chapter 13 about?
NCERT Class 10 Science Chapter 13 explains ecosystems, food chains, ozone depletion and waste management.

Q2. What is the 10% law in NCERT Class 10 Science Chapter 13?
Only 10% of energy is transferred from one trophic level to the next.

Q3. What causes ozone depletion in NCERT Class 10 Science Chapter 13?
Chlorofluorocarbons (CFCs).

Q4. What is biological magnification in NCERT Class 10 Science Chapter 13?
Increase in concentration of harmful chemicals at higher trophic levels.

Q5. Why is NCERT Class 10 Science Chapter 13 important for exams?
Because ecosystem, energy flow and ozone-related questions are frequently asked in CBSE exams.

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