CBSE Class 10 Science Revision Notes Chapter 15

CBSE Class 10 Science Revision Notes Chapter 15 – Our Environment

Chapter 15 – Our Environment of CBSE Class 10 Science is one of the important chapters. It covers the environment, living beings, natural resources etc. The environment is made up of both living and nonliving entities that coexist naturally. It results from a dynamic interaction between climatic variables, living beings and natural resources. These factors have an immediate influence on human survival and economic activity. 

The chapter is vast and it requires thorough practice and revision. Hence, Extramarks has provided CBSE Class 10 Science Revision Notes Chapter 15 – Our Environment on its website which can be accessed and referred to by students. The notes have been prepared to keep the CBSE curriculum and NCERT guidelines in mind. Apart from revision notes, students can also find important questions, CBSE sample papers, CBSE previous year question papers, answer keys, etc. Students can easily access the entire Class 10 study material and plan their study routine.

CBSE Class 10 Science Revision Notes for the Year 2022-23

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1. What Happens to the Environment When We Add Waste to it?

• The physical and biological settings in which an organism lives are called the organism’s environment. 
• Physical conditions include aspects such as soil, temperature, light, and so on. 
• Biological conditions include the plants, animals, and bacteria that surround it. 
• A minor adjustment in any of these factors can impact the organism.
• When garbage is released into the ecosystem, it disrupts the natural equilibrium. Waste is roughly classified into two groups:
  • Biodegradable substances are those that can be broken down by biological processes. 
  • Non-biodegradable compounds, on the other hand, are those that cannot be broken down by biological processes. 

These compounds can be inert and linger in the environment for extended periods of time, causing harm to the various ecosystem components.

2. What are the Components of the Ecosystem?

To preserve equilibrium in our environment, all creatures, including plants, animals, microbes, and humans, interact with their physical surroundings as well as with one another.

An ecosystem is a collection of creatures that interact with each other as an ecological unit, resulting in the movement of energy. An ecosystem comprises biotic components such as live species and abiotic components such as temperature, rainfall, wind, soil, and minerals.

There are two types of ecosystems: Natural and Artificial. \

All living species interact with each other in both of the aforementioned ecosystems, and the abiotic components of the ecosystem influence their development, reproduction, and some of their other activities.

Organisms in the ecosystem can be further classified as producers, consumers, or decomposers based on how they receive their sustenance from the environment.

Producers are creatures that can produce their own nourishment without the assistance of another organism. They are also known as autotrophs. Photosynthesis is the mechanism by which they create nourishment from inorganic elements. Green plants, phytoplankton, and blue-green algae are all autotrophs.

Consumers are creatures that do not create food but rely on producers for their food needs, either directly or indirectly. These are known as heterotrophs. Herbivores, carnivores, omnivores, and parasites are the four types of consumers. Humans and snakes are two examples. Decomposers are creatures that feed on dead and decaying materials and break down complex organic compounds into simple inorganic compounds. These simpler compounds are absorbed by the soil and utilised by the plants. Bacteria and fungi are two examples.

2.1 Food Chains and Webs:

A food chain is a collection of creatures participating at several biotic levels. The feeding connection between creatures in an environment is represented by food chains. The energy transmission from one species to another happens in the food chain. Every food chain starts with producers.

Trophic levels are the successive levels found in a community’s food chains. Energy is transferred from autotrophs to heterotrophs and decomposers. When energy is transported from one level to the next, part of it is lost to the environment in forms that cannot be reused.

There are up to three or four trophic levels in the food chain. Because the energy loss at each stage is so significant, just a limited quantity of sound energy remains when it reaches the fourth trophic level. The number of people in the lowest trophic levels of an ecosystem is often more significant. Therefore, the producers have the most significant number.

Food chains vary in length and intricacy. In general, every creature is eaten by two or more other kinds of organisms, which are then devoured by several additional species of a higher level. The food web is a set of branching lines that depict the link between species. The food web is made up of several interconnected food chains.

In any ecosystem, the movement of energy between trophic levels is unidirectional. The energy acquired by autotrophs is transferred to higher trophic levels and does not return to the lower level. Some toxic substances make their way into our systems via the food chain. For example, some pesticides and other chemicals used to protect crops from diseases and pests drain into the field water, where they are consumed by fish and enter the food chain.

Biological magnification is the accumulation of hazardous compounds or chemicals from a lower trophic level to a higher one. Because humans are at the top of any food chain, they have the highest concentration of these hazardous substances.

3. How Does the Environment Affect Our Activities?

• Ozone Layer and its depletion: 

The ozone molecule is made up of three oxygen atoms. The ozone layer exists in the top layer of the atmosphere, known as the stratosphere. It is a lethal toxin. It is responsible for the development of skin cancer in humans. 

At higher layers of the atmosphere, it shields humans from harmful UV radiation from the sun, which is hazardous to living creatures. Ozone depletion is the significant decrease in ozone molecules in the stratosphere caused by using chlorofluorocarbons (CFCs) in refrigerants and other coolants. 

When exposed to UV radiation, oxygen is broken down into nascent oxygen molecules. This nascent oxygen then combines with the oxygen already present in the atmosphere to generate ozone molecules.

To prevent harm to the ozone layer, the emission of CFCs into the atmosphere should be limited, and alternatives should be adopted instead.

• Garbage management 

Improvements in living must result in increased garbage creation. Changes in product packaging have resulted in massive volumes of garbage that are no longer biodegradable. The increased usage of non-biodegradable things has degraded the environment. 

To manage this waste, we can do the following:

• Application of the 3Rs idea (reduce, reuse and recycle).
• Waste separation into biodegradable and nonbiodegradable components.

Ch 15 Class 10 Science Notes: Details of Ecosystem

• An ecosystem is made up of both biotic and abiotic components of a particular location. For example, as described in Science Chapter 15 Class 10 Notes, forest ecosystems, lake ecosystems, and marine ecosystems.
• Every living organism in a certain geographical location is interconnected with one another. Their reproduction, development, and all other behaviours are all dependent on abiotic ecosystem components.
• Since green plants can make food through photosynthesis, they are referred to as producers.
• Herbivores, carnivores, and omnivores are creatures that rely directly or indirectly on organisms.
• Herbivores are animals that eat plants and are also known as primary consumers. For example, cows, goats, and deer.
• Omnivores are animals that consume both.
• Decomposers are microorganisms such as fungus and bacteria that break down all dead remnants.

Class 10 Science Chapter 15 Notes: Food Chain

Plastic Production

The creation of plastics has caused concern for the environment. Plastic waste may be found throughout the world, including in the ocean. The usage of plastics has a long-term impact on the environment. The yearly production of plastics is projected to be 5.2 trillion. The presence of plastics in the water devastates the ecology and alters animal reproduction patterns.

Emission of Carbon Dioxide and Greenhouse Gases

Humans cause the release of carbon dioxide and greenhouse gases only through the usage of manufactured goods and the burning of fossil fuels. The world’s population has relied heavily on carbon-rich fossil fuels such as oil, coal, and gas to create electricity. Carbon dioxide levels are growing more rapidly than ever before. This has resulted in an increase in global temperature and sea level.

Overexploitation and Overhunting

Plants and animals are declining as a result of overexploitation and overhunting of natural resources through activities such as mining and fishing. Overexploitation and overhunting have had an impact on the survival of plants and animals. These actions do not allow for replenishment, growth, or development. Overhunting is the cause of extinction and disaster.

Class 10th Ch 15 Science Notes: Manage the Environment Impact of Your Work

As per the NCERT Books, Science Chapter 15 Class 10 Notes are prepared and focus on the following dimensions: 

• Risks that are beyond one’s control should be identified and disclosed.
• People should be encouraged to play their part in environmental improvement.
• Work activities and resource utilisation should be structured to be effective and efficient. 
• In addition, environmental rules and regulatory criteria must be followed.
• The environmental impact of one’s activity should be assessed and responsibly utilised.