NCERT Revision Notes for Chapter 17 Forests: Our Lifeline Class 7 Science
CBSE NCERT Revision Notes1
Answer
- Forest
- Deforestation
- Effect of deforestation
- Independence of plants and animals in forest
- Canopy
- Food chain
- Food web
- Importance of forests
- Conservation of forests
2
Answer
→ It is a large area of land thickly covered with trees, bushes etc.
→ It is a system comprising various plants, animals and micro-organisms.
→ It is also protect the soil from erosion.
→ It influences climate, water cycle and air quality.
→ The uppermost layer of forest is trees followed by shrubs, the herbs to the lowest layer of vegetation.
→ Different layers of vegetation provide shelter and food for birds, animals and insects.
→ The components of forest are interdependent on one another.
→ Forest keeps on growing and changing. Also forest can regenerate.
3
Answer
Effect of deforestation
→ Due to deforestation the amount of carbon dioxide in air will increase, which increase the temperature of earth.
→ Deforestation cause floods because soil lost the capacity to hold water.
→ Insects, animals, birds will not get food and shelter.
→ It cause endanger lives and environment.
4
Answer
→ Animals and plants depend on each other to remain alive.
→ Organisms interact with each other and their physical environment to derive energy and survive.
5
Answer
→ It is the aboveground portion of a plant community or crop, formed by plant crowns.
→ In terms of forest canopy refers to the upper layer formed by mature tree crowns and including other biological organisms.
6
Answer
→ It is an interdependence of organisms which shows that who eats whom is known as food chain.
→ Interdependence of producer to consumer and form of various linkages that appears as a chain is known as food chain.
Food web
→ It is a system of interdependent food chain used to represent various relationships in organisms is called food web.
7
Answer
→ It purify air
→ It prevent soil erosion
→ Forest is noise absorbers
→ It provide timber
→ It provide shelter to the animals
→ It helps in to control floods
8
Answer
→ Control forest fires
→ Promote afforestation
→ Do not allow overgrazing
→ Protect wildlife
→ Social forestry
→ Establishment of national parks and bio-reserves.