Table of Contents
Chapter 17- Forests Our Lifeline -Question and Answers -Solved Worksheet
1. Explain the role of forests in maintaining the balance of gases in the atmosphere.
Answer-
- Forests help maintain the atmospheric balance by absorbing carbon dioxide and releasing oxygen through photosynthesis.
- They act as a natural carbon sink, reducing greenhouse gas levels and mitigating climate change.
2. Describe the significance of forests as natural habitats and renewable resources.
Answer-
- Forests provide habitat to over half of the world’s terrestrial species, supporting a diverse array of animals, plants, and microorganisms.
- As renewable resources, forests offer sustainable supplies of wood, fruits, and medicinal plants, crucial for various human needs.
Also Check – Chapter 12 – Forests: Our Lifeline – 4 Worksheets Solved and Unsolved – Class 7
3. How do the different layers of a forest contribute to its ecosystem?
Answer-
- The canopy layer captures sunlight and protects lower layers, hosting birds, insects, and mammals.
- Understorey layers, including the top, shrub, and herb layers, offer habitats for different species, supporting biodiversity.
- The forest floor, enriched with decomposing material, is vital for nutrient cycling, supporting decomposers and small fauna.
Rapid Revision – Class 7 Science -Chapter 17- Forest our Lifeline – Complete Notes
4. What is the importance of humus on the forest floor?
Answer-
- Humus, formed from decomposing organic matter, enriches the soil with essential nutrients.
- It improves soil structure and fertility, supporting plant growth and the overall health of the forest ecosystem.
5. What is humus, and why is it important for forest soil?
Answer- Humus is a dark, organic material in forest soil formed from decaying plant and animal matter. It’s vital because it improves soil structure, making it porous for better water retention and air circulation. Additionally, humus provides essential nutrients to plants and supports soil microorganisms, crucial for nutrient recycling in the forest ecosystem.
6. How do plants function as primary producers in a forest ecosystem?
Answer-
- Plants use sunlight, water, and carbon dioxide to perform photosynthesis.
- They produce their own food, which nourishes them and provides energy to the rest of the ecosystem.
- This process also releases oxygen, essential for the survival of many organisms.
7. Describe the role of decomposers in a forest ecosystem.
Answer- Decomposers in a forest ecosystem, including fungi, bacteria, and some insects, break down dead organic matter into simpler substances. This decomposition process is crucial for recycling nutrients back into the soil, ensuring plant growth and maintaining the health and balance of the forest’s life cycle.
8. Explain the interdependence of different components in a forest ecosystem.
Answer- In a forest ecosystem, the interdependence among various components creates a stable environment where species can thrive. Plants provide food and oxygen; animals, including herbivores, carnivores, and omnivores, contribute to plant pollination and seed dispersal; decomposers recycle essential nutrients; and scavengers help in cleaning the forest. This balanced interaction supports the ecosystem’s health and sustainability.
9. How do forests contribute to balancing oxygen and carbon dioxide in the atmosphere?
Answer- Forests play a critical role in atmospheric balance by absorbing carbon dioxide and releasing oxygen through photosynthesis. This process helps reduce greenhouse gases and mitigate climate change, while providing essential oxygen for living organisms.
10. Describe the role of forests in the water cycle and flood prevention.
Answer- Forests impact the water cycle by absorbing water and releasing it into the atmosphere through transpiration, contributing to cloud formation and rainfall. They also prevent floods by absorbing significant amounts of rainwater, reducing water runoff and the risk of flooding.
11. Explain the importance of forests as habitats supporting biodiversity.
Answer- Forests are vital habitats supporting a vast diversity of plants and animals. They provide shelter, food, and breeding grounds, contributing to ecological balance and the health of our planet. This biodiversity is essential for ecosystem stability and the resilience of natural environments.
12. Why is forest conservation crucial, and what are some effective methods?
Answer-
- Forest conservation is essential for maintaining environmental health and biodiversity. It combats climate change, prevents habitat loss, and controls floods.
- Effective methods include recycling to reduce wood demand, afforestation to restore deforested areas, and sustainable practices like selective logging and replanting.
13.Describe the dynamic nature of forests and their role in ecosystem sustainability.
Answer-
- Forests are dynamic ecosystems, constantly changing and evolving due to interactions among plants, animals, microorganisms, and the environment.
- They undergo cycles of growth and regeneration, with old trees dying and creating space for new growth, ensuring continuous rejuvenation.
- Seasonal changes affect food availability and animal behaviours, contributing to the forest’s adaptability and resilience.
14. How do forests contribute to the earth’s oxygen supply and climate regulation?
Answer-
- Through photosynthesis, forests produce oxygen, which is essential for life, and absorb carbon dioxide, a major greenhouse gas.
- They regulate the climate by storing carbon, cooling the air through transpiration, and influencing rainfall patterns, thus playing a crucial role in maintaining a balanced global climate.
15. Explain the role of decomposers and nutrient cycling in forest ecosystems.
Answer- Decomposers, like fungi and bacteria, break down dead organic matter in forests, returning essential nutrients to the soil. This nutrient cycling is vital for sustaining plant growth and the overall health of the forest, supporting a self-sustaining ecosystem.
16. What is the importance of forests in preventing pollution, and how do they accomplish this?
Answer- Forests are natural filters that play a key role in pollution prevention. They absorb harmful gases and trap dust and smoke particles from the air, while forest soils and roots filter water, removing impurities. This ability helps maintain clean air and water quality, essential for the health of the environment and living organisms.
17. What are the primary uses of wood and timber obtained from forests?
Answer- Wood and timber from forests are primarily used for building homes, making furniture, and creating paper products. Different types of wood, such as oak, pine, and teak, have varied uses due to their unique properties.
18. How do medicinal plants from forests contribute to healthcare?
Answer- Medicinal plants from forests are key ingredients in many traditional and modern medicines. For example, the bark of the willow tree is used to produce aspirin, showcasing how forest-sourced plants play a vital role in medical treatments and pharmaceuticals.
19. Describe the importance of afforestation and the negative impacts of deforestation.
Answer-
- Afforestation, the planting of new forests in areas without previous tree cover, benefits the environment by increasing forest cover, enhancing biodiversity, and aiding in climate regulation.
- Deforestation, on the other hand, leads to loss of biodiversity, increased greenhouse gases, soil erosion, and disruption of the water cycle, contributing to climate change and ecological imbalance.
20. Explain the significance of biodiversity in forests and the role of conservation efforts like biosphere reserves and wildlife conservation projects.
Answer-
- Biodiversity in forests, encompassing a wide range of plants, animals, and microorganisms, is crucial for the stability and health of these ecosystems. Each species plays a unique role, contributing to ecosystem balance and genetic diversity.
- Conservation efforts like biosphere reserves aim to conserve biological and cultural diversity while promoting sustainable development. Wildlife conservation projects focus on protecting endangered species and their habitats, essential for preserving the rich variety of life in forests.
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