NCERT Solutions For Class 7 Science Chapter 17

NCERT Solutions Class 7 Science Forests Our Lifeline

Ncert Solutions For Class 7 Science Chapter 17 PDF Download

NCERT solutions class 7 science chapter 17 forests our lifeline is one of the most interesting chapters in class 7 Science. The class 7 science chapter 17 NCERT solutions are provided here so that students can learn the concept of the chapter in an interactive manner. The solutions are prepared by expert teachers in a unique manner so that students can understand the concepts with ease. NCERT solutions will help students to get familiar with the exam pattern and the syllabus of the examination.

NCERT solutions for Science Forests Our Lifeline Class 7 Science specifically deals with the issues of forests. Forests have always been a source of many natural resources over the decades. Man’s ancestors considered forests to be their home for millions of years. It is only with the advent of civilization that we started to move away from forests and start producing our own source of food and resources. Today, the forests are home to many species of plants and animals. They form the ecosystem and each species has a specific role to play.

Q.1. Explain how animals make forest clean and regenerate.

Ans:

Animals help in cleaning forest in many ways. They are also known as cleansing agents. Degeneration is caused by microorganisms. Pollination is caused by animals which help in growing many numbers of plants. Carnivores live by depending on herbivores. Thus, forest has mutual relationships between flora and fauna.

 

Q.2 Explain how floods are prevented by forests.

Ans:

Lots of water are absorbed by forests. Flowing is slowed done mainly done by roots of the trees which majorly help in percolation. Thus, forests help in preventing floods.

 

Q.3. Explain decomposers and their work by giving two examples.

Ans.

Organisms which feed on dead bodies are called as Decomposers. They replenish the nutrients by cleaning the forests off decaying dead bodies. Two examples are beetles and bacteria.

 

Q.4. How do forests maintain the balance between oxygen and carbon dioxide in the atmosphere?

Ans:

During photosynthesis, plants release oxygen and take in carbon dioxide in the atmosphere.The animals inhale oxygen and they release carbon dioxide during respiration. In this way, the cycle goes on. Thus, it maintains balance through this cycle.

 

Q.5. Why  no waste remains in forests?

Ans:

This because of the role of decomposers. They convert the dead remains of plants and animals into humus which naturally adds to the soil. Thus, there is no waste in the forest.

 

Q.6. What are the products that we get from forests?

Ans:

Plant products,  Food, Fodder, Medicines, Description, Animals and animal products, Perfumes and cosmetics, Dying and tanning Utensils,  handicrafts Construction materials, Ornamentals, vegetable foodstuff and beverages provided by fruits, nuts, seeds, roots animal and bee fodder provided by leaves, fruits etc., Medicinal plants (e.g. leaves. bark, roots) used in traditional medicine and/or by pharmaceutical companies, Aromatic plants providing essential (volatile) oils and other products used for cosmetic purposes,Plant material (mainly bark and leaves) providing tannins and other plant parts (especially leaves and fruits) used as colorants, Heterogeneous group of products including thatch, bamboo, and rattan. wrapping leaves, fibers (e.g. Aromas, Buffalo, Silk cotton floss, Screw Pine) thatch, bamboo, fibers’, Entire plants (e.g. orchids, ferns, and philodendron) and parts of the plants (e.g. pots made from roots) used for ornamental purposes, Substances such as gums (water soluble), resins (water insoluble) and latex (milky or clear juice).  Honeybees wax Products are provided by bees. Bush meat Meat is provided by vertebrates, mainly mammals

 

Q.7. Fill in the blanks:

  1. The flowering of plants is done by honeybees, butterflies, insects by the method called________
  2. The basics forest purifier is___________
  3. Animal droppings and leaves decay enriches the________

Ans: 1. By Pollination         2. Through air, water            3. Humus in soil

 

Q.8. Why should we worry about the conditions of forests which are really far away from us?

Ans:

Deforestation leads to forest floods, Soil erosion, global warming which automatically lead to a decrease in animal and plant populations. This affects humans directly or indirectly. Thus we should be more concerned and worried about the condition of our forests.

 

Q.9. Why there is much more variety of animals and plants?

Ans:

Forest life is sustained by animals and plants through the oxygen and carbon dioxide cycle. They convert the decayed matter into humus and thus increase the fertility of the soil. This leads to an increase in the variety of plant and animal species.

 

Q.10. Mark the directions and arrows of the given diagram using the labels given below: 1.watertable 2.oxygen 3.soil 4.atmosphere 5.CO2 6.rain 7.plants.

14

Ans:  

15  

                                 

Q.11.Pick the odd one out. Which is not a product of forests?

  1. Plywood 2. Wax 3. Honey  4. Petrol

Ans: 4. Petrol

 

Q.12. Pick out the incorrect statement.

  1. Soil is being protected by forests from soil erosion.
  2. Animals are not dependent on plants whereas plants are dependent on animals.
  3. The water cycle and climate are influenced by forests.

  Ans: 2. Animals are not dependent on plants whereas plants are dependent on animals.   

 

Q.13. Dead plants are being acted upon by micro-organisms to produce

  1. Wood
  2. Mushrooms
  3. Humus
  4. Sand

Ans:  3.Humus.

Forests are a crucial part of the ecosystem. Therefore, when man encroaches the forests, his action can have disastrous consequences. For instance, when wild animals are being driven out of their ecosystem, they tend to forage for food closer to cities and towns. This means encounters with wild animals are common and might turn out to be fatal. We have heard many reports of big wild cats such as leopards and panthers stalking villages and towns that are near the edge of forests. There are even reports of elephants that trample sugarcane fields in search of food.

Furthermore, destruction to forests can cause many other adverse effects such as floods. Typically, a flood happens when there is excess water in a river and it overflows its banks. Because there is no obstruction present in the path of the flood (such as a forest) it tends to flow unobstructed for long distances and cause harm in its wake.

Destruction of habitat can also lead species to become endangered and go extinct. When this happens, the food chain can become unbalanced and population of other species might go unchecked. Therefore, it is vital and that we do not exploit forests as that might cause an imbalance in the ecosystem and it might adversely affect us.