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

Download NCERT Notes for Class 10 Science Chapter 13 PDF

Students can download the full PDF notes for the chapter Our Environment to revise all the topics easily. It covers topics like ecosystems, waste management, and how humans affect nature. The NCERT notes for class 10 Science chapter 13 PDF can be used both online and offline for quick revision. The NCERT Notes for Class 10 provide clear explanations of important topics, making learning easier and effective for students.

Our Environment Class 10 Notes

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. Concepts like biodegradable and non-biodegradable waste, and the impact of human activities are also covered in the Our Environment Class 10 Notes.

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.
• Plastic bags, bottles, metals, nylon, pesticides, and chemicals are some examples of non-biodegradable substances.
• These materials contribute to pollution and the 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. Different microorganisms, such as bacteria, fungi, and actinomycetes, are responsible for biodegradation.
• 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.

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 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. A wolf eating upon fox is an example of a 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.

• In the above diagram, the first trophic level is occupied by the producers (green plants).
• The second trophic level is occupied by primary consumers, which are herbivores. In this diagram grasshopper occupies the second trophic level.
• The third trophic level is made up of secondary consumers that are small carnivores, here birds.
• The fourth trophic level is made up of tertiary consumers known as larger carnivores, such as the fox.
• In a food chain, producers form the largest biomass, and energy decreases at higher trophic levels.
• Example: Grass insects, frogs, snakes, and eagles
• Grasshoppers eat grass, and birds eat the grasshoppers, which are then eaten by foxes, 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 are 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 the food web depends upon the diversity of organisms in the system.

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 the 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:

• The ozone layer in the stratosphere protects us from the harmful UV radiation from the sun.
• The depletion of this ozone layer is due to human activities that have serious effects, and this has become a subject of concern over the last few years.
• The ozone layer depletion takes place due to the 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 occurring widely in the stratosphere, the depletion is particularly marked over the Antarctic region. This has resulted in the formation of a large area of the thinned ozone layer, commonly known as the 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, crops, forests, and animals.
• It causes sunburn, skin cancer in humans. It also increased the acid production.

Also Read, NCERT Books and Syllabus

• NCERT Books for Class 10
• NCERT Syllabus for Class 10

Benefits of the Class 10 Science Chapter 13 Notes

Studying this chapter with well-prepared notes offers a lot of benefits to students. Some of them are listed below:

• These Class 10 Science Chapter 13 Notes highlight real-life applications of environmental concepts.

• Well-structured notes help students quickly revise terms like food chains, food webs, and ozone depletion.

• Students can easily remember diagrams that are often asked in exams by using the Class 10 Science Chapter 13 Notes.

• The notes encourage awareness about sustainable living and responsible use of resources.

Our Environment: Previous Year Questions and Answers

The 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. For quick and effective revision, students can refer to the NCERT Class 10 Science Chapter 13 Notes Our Environment.

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 producers, capture the energy present in sunlight and convert it into chemical energy.

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

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