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NCERT Class 10th Science Chapter 15 Our Environment Notes- Download PDF Notes

NCERT Class 10th Science Chapter 15 Our Environment Notes- Download PDF Notes

Edited By Irshad Anwar | Updated on Jul 07, 2025 11:42 AM IST

Did you know that the waste we throw away can harm our environment for years? The NCERT notes for class 10, chapter 13 are designed by subject experts in clear language. These notes are easy to read and a great resource for quick revision before exams. This chapter includes important topics like food chains, food webs, energy flow, and types of waste. It also explains how human actions affect nature and the ozone layer. The NCERT notes make all topics simple and useful for board and competitive exam preparation.

This Story also Contains
  1. Download NCERT Notes for Class 10 Chapter 13 PDF
  2. NCERT Notes for Class 10 Chapter 13
  3. Our Environment: Previous Year Questions and Answers
  4. Chapter-Wise NCERT Class 10 Notes Science
NCERT Class 10th Science Chapter 15 Our Environment Notes- Download PDF Notes
NCERT Class 10th Science Chapter 15 Our Environment Notes- Download PDF Notes

The NCERT Notes for Class 10 provide clear explanations of important topics, making learning easier and effective for students. This chapter introduces students to the environment, which consists of biotic (living) components and abiotic (non-living) components. Our environment also includes the ozone layer and its vital role in protecting life on Earth from ultraviolet radiation. The NCERT Notes Class 10 Science cover all concepts, which are useful in competitive exams. Questions from this chapter have been frequently asked in various exams.

Also Read:

Download NCERT Notes for Class 10 Chapter 13 PDF

Students can download the full PDF notes for the chapter Our Environment to revise all the main topics easily. It covers topics like ecosystems, waste management, and how humans affect nature. This PDF is simple to understand and can be used both online and offline for quick revision.

Download PDF

NCERT Notes for Class 10 Chapter 13

To help students with their studies, these notes are prepared in simple language. They explain important topics like food chains, food webs, and energy flow in an easy-to-understand way. Concepts like biodegradable and non-biodegradable waste, ecosystem, and the impact of human activities are also clearly covered.

Biodegradable and Non-biodegradable Substances

Provided below are some of the key points to know the differences between the two different type of substances and their impact on the environment.

Biodegradable substances

  • The substances that can be broken down by natural processes, such as by the action of microorganisms, bacteria, and fungi.
  • Food waste, paper products, wood, cotton fabric, and animal waste are some common examples of biodegradable substances.
  • These materials are less harmful to the environment as they break down naturally.

Non-biodegradable Substances

  • These substances are those that do not break down naturally or take an extremely long time to decompose.
  • Plastics bags, bottles, metals, nylon, pesticides, and chemicals are some examples of non-biodegradable substances.
  • These materials contribute to pollution and degradation of ecosystems. They also harm wildlife and pollute the land and water bodies.
  • Enzymes used in the degradation of substances have a unique effect, and certain enzymes are required for the breakdown of a given substrate. Cyanobacteria can decompose all types of waste.
  • Physical processes such as heat and pressure act on non-biodegradable material.
  • This waste requires recycling or proper waste management systems to prevent environmental damage.

Ecosystem

  • G. Tansley coined the term ecosystem, which, according to him, is the total of interactions between biotic and abiotic components capable of independent existence.
  • Biotic components include plants, animals, and bacteria, and abiotic components include light, temperature, rainfall, wind, and soil.
  • An ecosystem is a self-sufficient unit.
  • It may be a very small example, a freshwater pond, or a very large example, the Sahara desert.
  • In an ecosystem, there is a cyclic exchange of materials between living beings and the environment. The only requirement is a constant input of energy.
  • Desert grassland, forest, crop fields, etc., represent terrestrial ecosystems, whereas ponds, lakes, rivers, sea, etc., are aquatic ecosystems.
  • Most of the ecosystems in the world are natural ones but some of them are man-made ecosystems such as aquariums, parks, etc.

ecosystem


Trophic Level

  • Trophic means feeding, and hence trophic levels are the levels or positions at which species feed.
  • In an ecosystem, producers represent the first trophic level; herbivores, the second trophic level; primary carnivores, the third trophic level; and so on.
  • Mainly, the organisms are classified as producers, consumers, or decomposers depending on how they receive the food from the environment.

Producers-

  • Those organisms that produce food are called producers.
  • The green plants are the ultimate producers organisms in any ecosystem.
  • They can prepare their food by using substances like carbon dioxide, water, and sunlight through the process of photosynthesis.

Consumers-

  1. Those organisms that consume the food prepared by producers are called consumers.
  2. All animals are consumers as they cannot prepare their food from simple inorganic substances.
  3. There are mainly three types of consumers:

Primary consumers- Animals that feed on plants are called primary consumers. Example - cow, buffalo, goat etc.

Secondary consumers- Animals that eat the primary consumers are said to be secondary consumers. Example - Sparrow, crow, etc.

Tertiary consumers- Animals that feed on other carnivores are known as tertiary consumers. Wolf eating upon fox is an example of tertiary consumer.

Decomposers-

  • The materials within the bodies of dead plants and animals are thus acted on by organisms of decay, which are known for the purpose of decomposition.
  • Bacteria and fungi are well-known examples of decomposers.

Food Chains and Food Webs

Some key points of the food chain and food web are explained below, along with clear diagrams.

Food Chain:

  • The sequence of living organisms in an ecosystem in which one organism consumes another organism to transfer food energy is called a food chain.
  • A food chain is made up of a sequence of organisms that participate at distinct biotic levels.
  • A trophic level is formed at each level of the food chain.

food chain

  • In the above diagram, the first trophic level is occupied by the producers (green plants).
  • The second tropic level is occupied by primary consumers which are herbivores . In this diagram grasshopper occupies the second trophic level.
  • The third tropic level is made up of secondary consumers that are small carnivores here bird.
  • The fourth tropic level is made up of tertiary consumers known as larger carnivores such as fox.
  • The number of people employed by producers is the highest.
  • Example: Grass insects, frogs, snakes, and eagles
  • Grasshopper eat grass, and bird eat the grasshopper, which are then eaten by fox, who are then devoured by eagles.

Food web:

  • The interconnected food chains operating in an ecosystem that establish a network of relationships between various species is called a food web.
  • It shows the pattern of energy or nutrient flow throughout an ecosystem.
  • The energy flow in a food chain is one-way, once it reaches the next trophic level, it does not return.
  • The complexity of food web depends upon the diversity of organisms in the system.

food web

Ozone Layer and How it is Getting Depleted

  • Ozone is a highly reactive molecule containing three oxygen atoms(O3).

  • A naturally occurring high altitude layer of ozone is important to life as it absorbs potentially damaging Ultraviolet radiation from sun.

UV rays break up molecular oxygen (O2) into free oxygen (O) atoms, which mix with the molecular oxygen (O2) to generate ozone (O3).

O2 →O + O

O+O2 →O3

Ozone layer depletion:

  • Ozone layer in stratosphere protects us from the harmful Uv radiations from sun.
  • The depletion of this ozone layer is due to human activities that has serious effects and this has become a subject of concern over the last few years.
  • The ozone layer depletion takes place due to reaction between ozone and chlorofluorocarbons(CFCs) which are released from sprays, air conditioners and refrigerators.
  • One molecule of chlorofluorocarbons can damage 10,000 molecules of ozone.
  • Although, ozone depletion is occuring widely in the stratosphere, the depletion is particularly marked over the Antarctic region. This has resulted in formation of large area of thinned ozone layer commonly known as ozone hole.

Effects of Ozone Depletion:

  • Increased UV-radiation reaching the earth's surface due to ozone depletion in the stratosphere is harmful to human health, crop, forests, animals .
  • It causes sunburn, skin cancer in humans. It also increased the acid production, global warming is also increased due to this.

Also Read, NCERT Books and Syllabus

Our Environment: Previous Year Questions and Answers

Previous years’ questions given below help students understand what kind of questions are asked in the exam. They can also check how much they have studied and where they need to improve.

Question 1: _________ is a non-biodegradable substance.

Option 1. Paper

Option 2. Aluminum

Option 3. Plant products

Option 4. None of the above

Answer:

Paper, clipboards, metal containers like aluminium plants and human waste, and several plant products are classified under biodegradable substances. However, an example of a non - non-biodegradable substance could be plastic products.

Hence, the correct answer is option (4), None of the above

Question 2: Primary producers capture about __ of the energy of sunlight that falls on their leaves.

Option 1. 0.1%

Option 2. 1%

Option 3. 10%

Option 4. 0.01%

Answer:

Primary producers that are green plants, also known as autotrophs, capture about 1% of the energy of sunlight that falls on their leaves and convert it into food energy.

Hence, the correct answer is option (2), 1%

Question 3: Every food chain in the ecosystem begins with ____ , which is the primary source of food.

Option 1. Saprophytes

Option 2. Parasites

Option 3. Producers

Option 4. Consumers

Answer:

Primarily, all green plants, which are considered primary producer, capture the energy present in sunlight and convert it into chemical energy.

Hence, the correct answer is option (3), Producers

NCERT Solutions Subject Wise

Chapter-Wise NCERT Class 10 Notes Science

Given below are the notes for each chapter, which are designed to simplify the concepts and help students in doing effective exam preparation.


Frequently Asked Questions (FAQs)

1. What is Producers as per Class 10 Our Environment notes?

Producers are all organisms that can prepare their own food through photosynthesis using the sun's radiant energy received by the chlorophyll in the leaves. 

2. What is consumers and its types?

Consumers are organisms that consume the food produced, either directly or indirectly.
Based on their manner of feeding, consumers can be classed as primary, secondary, or tertiary. 

Primary consumers include all herbivores and some parasites. 

Rabbits, for example, consume grass.
Secondary consumers include many tiny carnivores and parasites. 

A snake that eats rabbits is an example. 

Tertiary consumers include larger carnivores and omnivores. 

An owl, for example, eats snakes. 

3. What is Biodegradable substances ?

Our waste materials are discharged into the environment as a result of our daily activities. Biodegradable compounds are those that can be broken down by biological processes. For example - Plant and animal organic materials.

4. What is Non-biodegradable substances ?

Non-biodegradable compounds are those that are not broken down by bacteria or saprophytes. Plastics are a good example. 

5. What is Decomposers?

Decomposers are creatures that break down the dead remnants and waste products of other organisms.  Decomposers in the soil break down complex organic chemicals into simple inorganic substances that plants can utilise. 

Articles

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

Option 2)

0.16\; J

Option 3)

1.00\; J

Option 4)

0.67\; J

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

Option 2)

 6.45×10−3 kg

Option 3)

 9.89×10−3 kg

Option 4)

12.89×10−3 kg

 

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

Option 2)

200 \, \, J - 500 \, \, J

Option 3)

2\times 10^{5}J-3\times 10^{5}J

Option 4)

20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

Option 2)

\; K\;

Option 3)

zero\;

Option 4)

K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

Option 2)

increase two fold

Option 3)

remain unchanged

Option 4)

be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

Option 2)

Weight fraction of solute

Option 3)

Fraction of solute present in water

Option 4)

Mole fraction.

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

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