CBSE Important Questions for Class 7 Science Forests: Our Lifeline - 2025-26
Important Questions for Chapter 12 of Class 7 Science, "Forests: Our Lifeline," looks at the important role forests play in keeping our environment healthy and supporting many forms of life. It covers different types of forests, their unique features, and how they help sustain life on Earth. By learning about these topics, students can understand why forests are crucial for our planet and the balance within ecosystems.
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The chapter also discusses the challenges forests face due to human actions, such as cutting down trees and destroying habitats. To support your studies, we’ve collected important questions specifically aligned with the CBSE Class 7 Science syllabus. Class 7 Science important questions will help you prepare well for your exams and increase your understanding of how forests impact our lives.
FAQs on CBSE Important Questions for Class 7 Science Forests: Our Lifeline - 2025-26
1. What are some of the most important products we get from forests that are frequently asked about in exams?
As per the CBSE Class 7 syllabus for 2025-26, forests provide us with several essential products. For exams, it's important to remember:
Timber and Wood: Used for making furniture, paper, and for construction.
Medicinal Plants: Many herbs and plants found in forests, like neem and tulsi, are used to make medicines.
Gums and Resins: These are used in making adhesives and paints.
Fruits, Nuts, and Spices: Forests are a source of food for both humans and animals.
Oxygen: Forests release oxygen during photosynthesis, which is vital for all living beings.
2. Explain the different layers of a forest. Why is this an important question for Class 7 Science?
Understanding the structure of a forest is a key concept. A forest is typically divided into four main layers, each with its unique inhabitants:
Emergent Layer: The tallest trees that rise above the rest of the forest.
Canopy: The dense, leafy roof formed by the crowns of most trees. It blocks a lot of sunlight from reaching the layers below.
Understorey: A layer of smaller trees, shrubs, and young trees that can survive in the shade of the canopy.
Forest Floor: The bottom-most layer, covered with fallen leaves, twigs, and decaying organic matter. It is home to insects, fungi, and bacteria.
3. What is deforestation and what are its three main consequences that students must know for their exams?
Deforestation is the large-scale cutting down of trees and clearing of forests. Three major consequences expected in exam answers are:
Climate Change: Fewer trees mean less carbon dioxide is absorbed from the atmosphere, leading to an increase in greenhouse gases and global warming.
Soil Erosion and Floods: Tree roots hold the soil together. Without them, soil is easily washed away by rain, which can lead to landslides and increased flooding downstream.
Loss of Biodiversity: Forests are habitats for countless species of plants and animals. Destroying forests leads to the loss of their homes, threatening their existence.
4. Why are forests often called the 'green lungs' of our planet? Explain the mechanism.
This is a higher-order thinking question. Forests are called 'green lungs' because they perform a function similar to our lungs, but for the entire planet. The mechanism is photosynthesis. Plants and trees take in carbon dioxide (CO₂) from the atmosphere and, in the presence of sunlight, convert it into food. As a crucial byproduct of this process, they release oxygen (O₂), which most living organisms, including humans, need to breathe and survive. This continuous cycle helps maintain the balance of these vital gases in our atmosphere.
5. How do forests play a crucial role in preventing both floods and soil erosion?
Forests act as a natural barrier against floods and soil erosion in two key ways:
Slowing Down Rainwater: The dense canopy of the forest intercepts heavy rainfall, preventing it from hitting the ground directly. The water then drips down slowly, allowing the soil to absorb it gradually. This reduces surface runoff and the risk of flash floods.
Binding the Soil: The extensive root systems of trees and plants act like a net, holding the soil particles firmly in place. This prevents the topsoil from being washed away by rain or blown away by wind, thus controlling soil erosion.
6. What would happen to the nutrient cycle in a forest if all the decomposers were to disappear?
If all decomposers like fungi and bacteria were to disappear, the forest ecosystem would collapse. Here’s why:
Dead organic matter, such as fallen leaves, dead plants, and animals, would pile up on the forest floor without breaking down.
The nutrients locked within this dead matter would not be released back into the soil.
The soil would become infertile and lose its richness. This nutrient-poor soil could no longer support the growth of new plants and trees.
Ultimately, this would disrupt the entire food web, as producers (plants) would die out, affecting all the consumers that depend on them.
7. What is a food chain? Give an example of a simple food chain that might be found in a forest.
A food chain shows how energy is transferred from one living organism to another. It illustrates who eats whom in an ecosystem. A simple example from a forest ecosystem is:
Grass → Deer → Tiger
Here, the Grass is the producer (makes its own food).
The Deer is the primary consumer (eats the producer).
The Tiger is the secondary consumer (eats the primary consumer).
8. Explain the interdependence between plants and animals in a forest ecosystem.
Plants and animals in a forest are highly interdependent, which is a crucial concept for exams. Their survival is linked in many ways:
Food and Shelter: Plants provide food (fruits, leaves, nectar) and shelter for animals. In return, animals help in pollination and seed dispersal, which helps plants reproduce and spread.
Gas Exchange: Plants produce oxygen, which animals need for respiration. Animals release carbon dioxide, which plants need for photosynthesis. This creates a balanced atmospheric cycle within the forest.
Nutrient Cycling: When animals die, decomposers break down their bodies, returning essential nutrients to the soil, which are then used by plants for growth.
9. How do forests help in regulating climate and increasing rainfall?
Forests are critical for climate regulation. They influence local and global climate in two important ways:
Temperature Regulation: Forests absorb a significant amount of sunlight and provide shade, which helps in keeping the surrounding areas cool.
Increasing Rainfall: Trees release a large amount of water vapour into the atmosphere through a process called transpiration. This water vapour rises, cools, and condenses to form clouds, which eventually leads to rainfall, thus playing a vital role in the water cycle.
10. Beyond providing products, how do forests act as a 'lifeline' for tribal communities?
This is a value-based question that connects science with society. For tribal communities, forests are more than just a resource; they are a complete support system. They provide:
Food and Water: They depend on the forest for fruits, roots, and hunting, and forests are often the source of clean rivers and streams.
Shelter: They use materials like wood and leaves from the forest to build their homes.
Traditional Medicine: They possess deep knowledge of medicinal herbs found in the forest to treat illnesses.
Cultural Identity: Their culture, traditions, and spiritual beliefs are often deeply intertwined with the forest ecosystem.
