CBSE Class 10 Science Notes Chapter 15 Our Environment

Class 10 Science chapter 15 notes help students understand how living organisms interact with their physical surroundings to create a balanced system. Many learners struggle with energy flow and waste management. This guide simplifies these ecological cycles, providing a structured approach to help you excel in your Class 10 board exams.

Many students find it difficult to understand how human-made waste or chemical use in one area can lead to global issues like ozone depletion or toxic accumulation in our own food. By focusing on Our Environment Class 10 notes, we provide a structured approach to help you grasp the mechanics of nature and the urgent need for waste management, ensuring you are fully prepared for your Class 10 board exams.

Check out: CBSE Class 10th Books

Our Environment Class 10 Notes

Our Environment Class 10 Notes are given here. These notes align with the CBSE Class 10th syllabus as well as the latest exam pattern: 

What is the Environment?

The environment refers to everything around an organism. It includes both living (biotic) and non-living (abiotic) elements. These factors interact in complex ways. Our actions greatly impact the environment.

Ecosystem

An ecosystem is a community of living organisms interacting with their non-living surroundings. Examples include a pond or a forest. Ecosystems maintain a balance through constant exchange of energy and matter. They can be natural (like grasslands) or human-made (like gardens).

Components of an Ecosystem

Ecosystems have two main parts:

Biotic Components

These are the living organisms within an ecosystem.

• Producers (Autotrophs): Organisms that make their own food. Plants and some bacteria use sunlight through photosynthesis. Phytoplanktons are tiny water plants that float and produce food.

• Consumers (Heterotrophs): Organisms that get food by eating others.

• Herbivores: Eat plants (e.g., deer). Also called primary consumers.

• Carnivores: Eat other animals (e.g., lions). Can be primary, secondary, or tertiary.

• Omnivores: Eat both plants and animals (e.g., humans).

• Decomposers (Saprotrophs): Microorganisms like fungi and bacteria. They break down dead organic matter. Decomposers recycle nutrients back into the soil. They are vital for keeping the environment clean and fertile.

Abiotic Components

These are the non-living physical and chemical parts of an ecosystem.

• Physical Factors: Soil type, water, air, landforms.

• Chemical Factors: Carbon dioxide, oxygen, nitrogen, minerals like phosphorus and calcium.

• Climatic Factors: Sunlight, temperature, rainfall, humidity. These affect how organisms live and spread.

Trophic Levels

Trophic levels are feeding positions in a food chain. Energy transfers from one level to the next.

• First Level: Producers (plants).

• Second Level: Primary Consumers (herbivores).

• Third Level: Secondary Consumers (carnivores that eat herbivores).

• Fourth Level: Tertiary Consumers (carnivores that eat other carnivores).

What is a Food Chain?

A food chain shows how energy flows from one organism to another. Each organism feeds on the one below it. For example, Grass -> Deer -> Lion. Energy moves in one direction. Harmful chemicals can also move up the food chain.

What is a Food Web?

A food web is a network of interconnected food chains. It shows complex feeding relationships in an ecosystem. An organism often has multiple food sources and predators.

Energy Flow

Energy moves through trophic levels. Green plants capture about 1% of solar energy. Only 10% of the energy from one trophic level passes to the next. The remaining 90% is used or lost as heat. This our environment class 10 notes pdf details these energy transfers.

Environmental Problems

Human activities create various environmental challenges. These include pollution and resource depletion.

Ozone Layer Depletion

The ozone layer (O3) in the stratosphere protects Earth from harmful UV radiation. Chlorofluorocarbons (CFCs) from refrigerants and aerosols deplete this layer. Ozone depletion causes skin cancer and other health issues. The Montreal Protocol aimed to reduce CFC use.

Garbage Management

Effective waste management is important. Waste types are:

• Biodegradable Waste: Breaks down naturally (e.g., food scraps, paper).

• Non-Biodegradable Waste: Does not break down naturally (e.g., plastics, metals, DDT). This type causes significant pollution.

Methods for waste disposal include:

• Incineration: Burning waste at high temperatures.

• Landfilling: Burying waste in designated areas.

• Composting: Converting organic waste into manure.

• Recycling: Processing waste materials to make new products.

• Reuse: Using items multiple times.

Biological Magnification

This is the increase in concentration of harmful chemical substances, like pesticides, as they move up the food chain. The highest concentrations appear in top predators. This is an important aspect of Class 10 Science Our Environment Notes.

Check Out: CBSE Class 10 Sample Papers

Class 10 Science Chapter 15 Our Environment Answer Writing Tips 

Class 10 Science Chapter 15 Our Environment answer writing tips help students understand how to present answers clearly and effectively in the CBSE board exam. Following these tips will improve structure, accuracy, and scoring potential.

• Start with a definition or law where applicable

• Use examples or diagrams for 3–5 mark questions

• Mention scientific terms exactly as in NCERT

• Keep answers point-wise and concise

• Avoid mixing unrelated environmental issues

Difference Between Energy Flow and Matter Cycle in Class 10 Science Chapter 15 Notes

One very important concept in CBSE class 10 chapter 15 revision notes is the difference between energy flow and matter cycle.

Energy flow is one-way. It starts from the Sun, moves to producers, then to consumers, and finally is lost as heat to the environment. Energy does not come back to the Sun. Once used, it cannot be reused in the same form.

On the other hand, matter moves in cycles. Nutrients like carbon, oxygen, nitrogen, and water are continuously recycled in nature. For example, plants take carbon dioxide from the air, animals eat plants, and decomposers return nutrients back to the soil and atmosphere.

Food Webs and Biological Magnification

In nature, food chains are rarely isolated. One organism may be eaten by several others. This interconnected network of food chains is known as a food web.

A critical issue discussed in the CBSE Class 10 chapter 15 revision notes is Biological Magnification. When non-biodegradable chemicals (like pesticides) enter a food chain, they cannot be decomposed. Instead, they accumulate and increase in concentration at each higher trophic level. Since humans occupy the top level, these toxins reach their highest concentration in our bodies, leading to long-term health risks.

Check out: CBSE Class 10 Question Bank

Environmental Problems in class 10 science chapter 15 notes

The stratosphere contains the ozone layer which serves as a protective barrier that shields Earth from harmful ultraviolet radiation emitted by the sun. People who experience UV ray exposure face risks of developing skin cancer and eye cataracts as well as suffering from immune system damage. 

How Ozone is Formed

High-energy UV radiation splits oxygen molecules (O2) into free oxygen atoms (O). The atoms combine with molecular oxygen to create ozone (O3) through their bonding process. 

The Decline of Ozone 

The ozone layer started to experience significant thinning during the 1980s. The primary cause was the release of Chlorofluorocarbons (CFCs) used in refrigeration and fire extinguishers. The 1987 UNEP agreement established a CFC production freeze which enabled the ozone layer to initiate its recovery process.

Science chapter 15 Notes on Managing Our Waste

The way we handle waste determines the health of our environment. Waste is generally classified into two types:

1. Biodegradable Waste: Substances like food scraps and paper that are broken down by biological processes (microorganisms).

2. Non-biodegradable Waste: Substances like plastic, glass, and synthetic fibres that are not acted upon by bacteria and persist in the environment for centuries.

Waste Disposal Solutions

To mitigate the impact of human activity, several waste management strategies are used:

• Biogas Plants: Using biodegradable waste to produce fuel and manure.

• Sewage Treatment: Cleaning water before it enters rivers.

• Landfills: Disposing of waste in deep pits covered with soil.

• Recycling: Reusing non-biodegradable materials to reduce fresh production.

Check out:  CBSE Class 10 Previous Year Question Papers

Benefits of CBSE Notes for Class 10 Science Chapter 15 – Our Environment

• Clear your Basics
  The chapter “Our Environment” is important not only for exams but also for higher classes. These notes help you understand the basic ideas properly so you don’t feel confused later.

• Simple and Clear Meanings:
  Science has many difficult words. Good notes explain important terms in easy language so you can understand and remember them without stress.

• Teach you how everything is connected
  These notes help you understand how plants, animals, humans, air, water, and soil are all linked to each other. You also learn how human activities can affect this balance.

• Important Diagrams and Steps:
  This chapter includes diagrams and processes like food chains, energy flow, and ozone formation. CBSE notes explain these step by step so they are easier to learn.

• Supports Your Textbook Learning:
  Sometimes reading the textbook once is not enough. Notes explain the same topic in a simpler way and help you revise quickly before exams.

• Makes You Feel More Confident:
  When your notes are clear and organised, revision becomes easier. This helps you feel more confident and less nervous during tests and exams.

Read More: NCERT Solutions for Class 10 Science Chapter Our Environment

CBSE Class 10 Science Notes Chapter 15 FAQs

1. Where to Find class 10 science chapter 15 notes pdf?

You can search for the pdf online on reliable websites. .

2. Why are decomposers vital for our environment?

Decomposers break down complex organic substances from dead organisms into simple inorganic nutrients, ensuring the soil remains fertile for producers.

3. How does the 10 percent law affect food chain length?

Because only 10% of energy reaches the next level, energy eventually runs out, which is why most food chains in the Our Environment Class 10 notes are limited to 3–4 steps.

4. What causes the depletion of the ozone layer?

The primary cause is the release of synthetic chemicals called Chlorofluorocarbons (CFCs), which are widely used in cooling systems and aerosols.

5. What is the difference between biodegradable and non-biodegradable waste?

Biodegradable waste can be broken down by biological agents like bacteria, whereas non-biodegradable waste remains in the environment and causes pollution.