Get here Class 7 Science NCERT Text book Answers of Chapter 17. NCERT Solutions Class VII Science includes answers of all the questions of Forests Our Lifeline provided in NCERT Text Book which is prescribed for class 7 in schools
National Council of Educational Research and Training (NCERT) Book Solutions for Class 7th
Chapter: Chapter 17 – Forests Our Lifeline
NCERT Solutions for Class 7th Science Chapter 17 – Forests Our Lifeline
Class 7th Science Chapter 17 Forests Our Lifeline NCERT Solution is given below.
Question 1: Explain how animals dwelling in the forest help it grow and regenerate.
Answer: The animals in forests are of various types. These could be herbivores, carnivores, micro-organisms, etc. These play an important role in maintaining the food chains.
(i) Micro-organisms convert the dead plants and animals to humus. This humus helps in returning the nutrients back to the soil. These are absorbed by plants.
(ii) The animals also help in dispersing the seeds of certain plants.
(iii) The decaying animal dung provides nutrients to various types of seedlings to grow.
All these activities of animals dwelling in the forest help it to grow and regenerate.
Question 2: Explain how forests prevent floods.
Answer: Forest acts as a natural absorber of water. It allows rain water to seep through. In the absence of trees, the rain water would hit the ground directly resulting in flood. However, because of the presence of trees, rain water does not hit the ground directly. It rather hits the ground slowly. Hence, before flooding, all the rain water seeps through ground. In this way, forests prevent floods.
Question 3: What are decomposers? Name any two of them. What do they do in the forest?
Answer: Decomposers are micro-organisms that convert the dead plants and animals to humus. Bacteria and fungi are the two types of decomposers. They help in the process of recycling of nutrients by decomposing various dead organisms such as plants and animals to form humus.
Question 4: Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.
Answer: Forests are called the green lungs. This is because plants in forests release oxygen through the process of photosynthesis and help in providing oxygen to animals for respiration. Plants consume carbon dioxide released by the animals. In this way, plants help in maintaining a balance of oxygen and carbon dioxide in atmosphere.
Question 5: Explain why there is no waste in a forest.
Answer: There is no waste in a forest because micro-organisms act on the wastes and convert them to humus. This humus ensures that the nutrients are returned back to the soil.
Question 6: Fill in the blanks with the appropriate answers:
(a) People obtain groundwater through _______ and ________.
(b) Three forms of water are ________, ________ and ________.
(c) The water bearing layer of the earth is ________.
(d) The process of water seepage into the ground is called ________.
Answer: (a) People obtain groundwater through tube wells and hand pumps.
(b) Three forms of water are ice, water and vapour.
(c) The water bearing layer of the earth is aquifer.
(d) The process of water seepage into the ground is called infiltration.
Question 7: Fill in the blank:
(a) The insects, butterflies, honeybees and birds help flowering plants in _______.
(b) A forest is a purifier of _______ and ________.
(c) Herbs form the ________ layer in the forest.
(d) The decaying leaves and animal droppings in a forest enrich the _______.
Answer: (a) The insects, butterflies, honeybees and birds help flowering plants in pollination.
(b) A forest is a purifier of air and water.
(c) Herbs form the lowest layer in the forest.
(d) The decaying leaves and animal droppings in a forest enrich the soil.
Question 8: Why should we worry about the conditions and issues related to forests far from us?
Answer: There are various reasons for which we should be vigilant about matters related to forests.
(i) A decrease in forest area would lead to an increase in carbon dioxide in air. This will lead to an increase of earth’s temperature.
(ii) Soil erosion would occur if there are no forests.
(iii) Floods would be more frequent in absence of forests.
(iv) Forests provide shelter and food to animals. When forests are adversely affected, the habitats of wild animals are also adversely affected.
Therefore, we need to conserve our forests.
Question 9: Explain why there is a need of variety of animals and plants in a forest.
Answer: A greater variety of plants and animals in the forests helps it to regenerate and grow. Greater variety of plants means more food and habitat for the herbivores. An increase in herbivores means more food for carnivores. Decomposers help to maintain the supply of nutrients to the soil and to the growing plants. This wide variety makes forest a dynamic living entity.
Question 10: In figure, the artist has forgotten to put the labels and directions on the arrows. Mark the directions on the arrows and label the diagram using the following labels:
clouds, rain, atmosphere, carbon dioxide, oxygen, plants, animals, soil, roots, water table
Question 11: Which of the following is not a forest product?
(iii) Sealing wax
Question 12: Which of the following statements is not correct?
(i) Forests protect the soil from erosion.
(ii) Plants and animals in a forest are not dependent on one another.
(iii) Forests influence the climate and water cycle.
(iv) Soil helps forests to grow and regenerate.
Answer: (ii)Plants and animals in a forest are not dependent on one another.
Question 13: Micro-organisms act upon the dead plants to produce
Answer: (iii) humus
Class 7th Science Solutions EnglishHindiMathsSSTSanskrit
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Everything we depend on for our living is from nature. The forests and wildlife that sustain us in multiple ways are made up of complex ecosystems and thousands of diverse species that thrive in it. Yet, they are diminishing at an alarming rate while the world’s population is increasing by many folds.
The Living Planet Report published by World Wide Fund for Nature (WWF) tells us that the populations of birds, mammals, reptiles and amphibians have declined by a whopping 50 per cent since the 1970s.
This equals to the loss of half of the world’s population of vertebrates (animals with backbone)!
Reports like these and the issue of rapid destruction of forests in India have to be taken seriously and conserving our country’s natural heritage should be on the top of our priority list.
Because, there are only less than 5 per cent of forests that are marked as protected areas in India. This tiny section holds around 500 wildlife sanctuaries, national parks and tiger reserves that are fragmented across our country.
Here are a few reasons why we should conserve the protected areas with great diligence.
The forests of the Western Ghats mountains are the source of the rivers that irrigate South India. The glaciers and the adjoining forests in the Himalayas are the source of mighty rivers that sustain north India. The wide range of ecosystems across India is home to an incredible biodiversity of around 5,000 species of vertebrates and 15,000 species of flowering plants. The roles that these species perform are generally invisible to us, but once we understand them, we realise the magic of nature.
For example, the animals that are at the top of the food chain in a forest with tigers are the tigers themselves. Without these apex predators, the population of deer will increase.
They will feed voraciously on the grass cover and small bushes. This will decrease the grasses and the bushes, which in turn affects the numerous animals that depend on it. Scavenging birds of prey like the vultures will disappear from the forest because there would be no carcasses.
Gradually most of the species in the forest will disappear due to ecological imbalance and the forests would be stripped bare. Protecting the tiger in a forest protects hundreds of species that live in it.
We now know that people share an intricate connection with nature for their own survival.
Extracting natural resources at an unsustainable rate by destroying the forests and wildlife puts every one of us at risk.
While we need development, we must ensure that at least the last remaining 5 per cent of protected areas in India must be left alone for our future generations. These are the ones that hold our sustenance on a longer run.
Every one of us must start to practice conservation from our homes and through our career backgrounds. Because, the collective will from all of us will create a positive difference in the protection of India’s priceless but fractured natural heritage.
(The author is an award-winning nature photographer and co-founder of the Youth for Conservation. In this monthly column he talks about his passion for nature, photography and conservation.)