CBSE Class 10 Science Notes Chapter 15 Our Environment

CBSE Class 10 Science Chapter 15: Our Environment – Notes

Ecosystem: It consists of biotic (living) and abiotic (non-living) components. Energy flow in an ecosystem follows a food chain or web. Producers (plants) are eaten by consumers (herbivores, carnivores), and decomposers break down dead organisms.
Environmental Pollution: Air, water, and land pollution are critical concerns. Human activities like industrialization, deforestation, and overuse of resources lead to imbalances.
Waste Management: Proper disposal and recycling of waste help in conserving the environment. Reducing, reusing, and recycling are the 3Rs to manage waste.
Biodiversity and Conservation: Conservation is essential to maintain biodiversity. The loss of species and habitats leads to ecosystem instability.
Ozone Layer: The ozone layer protects Earth from harmful ultraviolet rays. Depletion of this layer due to chlorofluorocarbons (CFCs) is a significant environmental issue.

This chapter emphasizes understanding ecosystems, pollution, and conservation efforts to sustain the environment.

Most Important Science Class 10 Questions Answers For Board Examination

Here are some of the most frequently asked questions from the last five CBSE Class 10 board exams for Chapter 15: Our Environment:

What is an ecosystem?
An ecosystem includes all living organisms and their physical environment interacting as a system. It can be natural or man-made.
What is the significance of the ozone layer?
The ozone layer protects life on Earth by absorbing harmful ultraviolet (UV) radiation from the sun.
Explain the food chain and energy flow in an ecosystem.
In a food chain, energy is transferred from producers (plants) to consumers (herbivores, carnivores), and decomposers break down dead matter, completing the cycle.
What are the causes and effects of air pollution?
Air pollution is caused by industrial emissions, vehicle exhaust, and deforestation, leading to respiratory diseases and environmental damage.
What are biodegradable and non-biodegradable wastes?
Biodegradable wastes can be broken down by natural processes, while non-biodegradable wastes do not decompose easily and can cause environmental harm.

Here are some MCQs based on Chapter 15: Our Environment:

What is the primary source of energy in an ecosystem?
- a) Sunlight
- b) Water
- c) Air
- d) Soil
Which of the following is a non-biodegradable waste?
- a) Fruit peel
- b) Plastic bag
- c) Paper
- d) Leaves
What does the ozone layer protect the Earth from?
- a) UV radiation
- b) X-rays
- c) Gamma rays
- d) Infrared radiation
Which of the following is a component of the food chain?
- a) Primary producers
- b) Decomposers
- c) Herbivores
- d) All of the above
Which gas contributes to global warming?
- a) Oxygen
- b) Carbon dioxide
- c) Nitrogen
- d) Hydrogen