Class 7 Science Chapter 12 Question Answers - Forests - Our Lifeline

Q1. Where would you find humus in the soil? What significance does it have to the soil?
Ans: Humus is found in the uppermost horizon (A-horizon) and is generally dark in colour as it is rich in humus and minerals. The humus improves soil fertility and gives growing plants nutrients. This layer can hold more water and is typically porous and soft.

Q2. Name a plant from which oil is obtained.
Ans: Sandalwood

Q3. What does a canopy do?
Ans: A canopy is created by the tall tree’s uppermost branches and leaves, which act as a roof over the forest floor.

Q4. Indicate what happens when one food chain in an ecosystem is harmed.
Ans: Since each food chain in a forest is connected to the others, a disturbance in one food chain will have an impact on the others.

Q5. Would every forest have the same kind of trees?
Ans: No, there are variations in the kinds of trees and other plants due to various climatic conditions. Even animal species vary from forest to forest as well.

Q6. It gets darker as you move deeper into a forest. Why?
Ans: Large trees, shrubs, and other plants can be found in a forest. They capture solar radiation for photosynthesis. As a result, the forest floor is dark because the sunlight cannot penetrate it.

Q7. Why are forests called green lungs?
Ans: Plants in the forest produce oxygen through the photosynthesis process. And plants contribute this oxygen to animal respiration. They also keep the atmosphere’s ratio of oxygen to carbon dioxide in check. For this reason, the forests are referred to as green lungs.

Q8. Name a system comprising various plants, animals and microorganisms.
Ans: Forest is a system comprising various plants, animals and microorganisms.

Q9. What do you mean by decomposers?
Ans: Decomposers are microscopic organisms that turn dead plants and animals into humus.

Q10. What is a crown?
Ans: The crown of a tree refers to the branchy portion of the tree that is located above the stem.

Q11. Name the process by which trees emit water vapor into the atmosphere.
Ans: Evaporation is the process by which trees release water vapor into the atmosphere.

Q12. Why should forests be protected?
Ans: Forests supply us with oxygen. They protect the soil and provide habitat for a variety of animals. Forests contribute to good rainfall in neighboring areas. They provide medicinal plants, timber, and a variety of other useful products. Hence, forests must be protected.

Q13. Floods could result from deforestation. Why?
Ans: Floods result from deforestation because there are fewer trees available as a result of deforestation. Floods will result from the soil’s inability to retain water in the absence of trees.

Q14. Why are forests regarded as dynamic living entities?
Ans: The forest offers more opportunities for food and habitat for herbivores by supporting a wider variety of plants. A greater diversity of carnivores can eat more because there are more herbivores. The abundance of animals supports the growth and regeneration of the forest. Decomposers aid in preserving the flow of nutrients to the forest’s expanding plant life. As a result, the forest is a “dynamic living entity”, that is, full of life and vitality.

Q15. How would the water cycle affect if there were fewer trees?
Ans: There would be less evaporation and consequently less water vapor in the air if there were fewer trees. Less cloud cover and a higher temperature will result from this. Consequently, there will be less rain. The water cycle will be impacted in this way.

Q16. How are forests useful in addition to preventing floods?
Ans: Rainwater is naturally absorbed and allowed to seep into the ground by forests. It supports year-round water table maintenance. In order to ensure a consistent supply of water, forests not only assist in reducing floods but also in maintaining the stream’s water flow.

Q17. What occurs if an animal perishes in the forest?
Ans: Vultures, jackals, hyenas, and other scavengers consume the dead animal’s body. These creatures perform cleaning duties in the forest. Furthermore, it demonstrates that in the forests, nothing is wasted.

Q18. Is it possible to build a food chain in the absence of a producer? Give a reason to back up your answer.
Ans: No, producers are always at the beginning of any food chain. All living organisms get their food from the producer. If the producer is not present in a food chain, there will be no flow of energy. As a result, we can say that constructing a food chain without a producer is impossible.