Class Notes NCERT Solutions for CBSE Students
Question: Explain food web with a suitable example.
Answer: Multiple food chains are interlinked together to form a food web. This happens because the secondary consumer depends on different types of animals (primary consumers). For example- Rat are eaten by snakes and also by eagles, and snakes that eat the rats are eaten by the eagles. This shows the interlinked between different food chains, which together forms the food web.
Question: Explain the uses of forests.
Answer: We completely depend on the forests for our needs.
- Purification of air: Forest makes balance between the amount of oxygen and carbon dioxide in the air. it is therefore called the green lungs of nature.
- Rainfall due to forests: Rainfall is dependent on forests. Excess of water from the trees is released into the atmosphere in the form of water vapour by the process of transpiration. The water released in the form of water vapour from the forests helps in the formation of clouds by the process of condensation. The clouds undergo precipitation to form rain. The water vapour transpired from the forests keep the forests cool. Water evaporates at a faster rate if there are no trees, thereby making the Earth devoid of water.
- Prevention of soil erosion: Soil erosion is the removal of the top layer of soil. This layer is fertile and the removal of this layer makes the land barren. The roots of trees hold the soil together and help the water to infiltrate into the soil. In this way, soil erosion due to the runoff water and wind is prevented by the forests.
- Uses of forests in our daily life: Forests provide us with food, medicinal plants, honey, fire woods, timber, rubber, spices, perfumes, oils, resins, natural dyes, etc. Forests are homes to many animals and provide food and shelter to them. Ecotourism and jungle safaris are very popular these days. This creates awareness about forests and animals and educates people about the importance of forests.
Question: What are the effects of deforestation?
Answer: Effects of deforestation:
- With no plants and trees to hold the soil together, the soil gets washed away by strong winds and flowing water.
- Things like wood, medicine and various other products, which we obtain from forests, would no longer be available if deforestation carries on indiscriminately.
- The most important consequences of deforestation is the change in climate. Without a forest cover, the amount of carbon dioxide will increase in the atmosphere. Being a greenhouse gas, it will aid in global warming, increasing the temperature on the Earth.
- Animals will lose their natural habitat and they might even die. This will eventually lead to extinction of different species.
Question: Suggest some ways to conserve forests.
Answer: Forest conservation is the need of the hour. Even though forests are being destroyed due to human activity, forests should be conserved from further depletion for our own good. Some steps to conserve forest and to create awareness about the hazards of deforestation and preserving the rich resource of forests.
- Trees should be planted in wastelands where the forest cover is disappearing. The plantation of trees in large numbers is called afforestation.
- People and students should be encouraged to plant more trees through programmes like “Vanamahotsava”.
- Awareness and education regarding the importance of forests should be given to people and students.
- Overgrazing by cattle should be prevented by providing sufficient pastures in the areas near forests.
- Illegal logging of trees for timber must be prevented.
- Conversion of forestland for the purpose of industrialization must be stopped.
- People who go for trekking and camping should be cautioned about the hazards of forest fires due to human negligence.
- The personnel in forest departments must be trained and equipped to control forest fires.
- Farmers must be educated to plan cultivation in their lands without cutting down trees.
- Every city should have a green patch reserved for developing parks.
