WBBSE Class 9 Life Science Chapter 5 Natural Resources And Its Sustainable Use Long Answer Questions

Chapter 5 Environment And Its Resources Natural Resources And Its Sustainable Use Long Answer Type Questions

WBBSE Life Science And Environment Class 9 Solutions

Question 1. Discuss the environmental and economic importance of a forest.

Answer:

Importance of a forest:

1. Watershed protection:

Afforestation along the slope of the watershed prevents runoff and reduces the deposition of slits in the riverbed. Some plants with mycorrhizal roots absorb heavy and toxic metals from the soil and reduce the chance of water toxicity.

2. Atmospheric regulation:

The scarcity of plants and excessive industrialization in urban areas reduces O2 and increases CO2 content in the atmosphere. Forest regulates O2, and CO2 balance. By respiration, organisms release CO2 and absorb O2 from the atmosphere.

By the process of photosynthesis, green plants of a forest release O2 and absorb CO2. In this way, the balance of O2 and CO2 in the atmosphere is maintained.

3. Erosion control:

Erosion means washing or blowing away of top layer of soil. Forests prevent soil erosion by several methods.

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They are:

1. The branches of roots firmly bind the soil particles with the ground.
2. The dense leaves of the forest prevent raindrops from hitting the soil particles directly and loosening it from the upper layer of soil.
3. The litter formed by the leaves on the forest floor, partly decomposes to form sticky humus. This sticky humus increases the adhering capacity of the soil particles and prevents soil erosion.

WBBSE Class 9 Life Science Chapter 5 Natural Resources And Its Sustainable Use Long Answer Questions

WBBSE Class 9 Natural Resources Long Answer Questions

4. Local use:

Humans exploit forests in different ways. People living in nearby villages collect firewood from the forest. Forests provide honey, timber, resin, honey, cotton, fur, wool, meat (from herbivores), etc. that are collected and marketed.

5. Productive use:

From a productive point of view, the forest has immense importance. Timber is the main economically important product of the forest, used to prepare sleepers, posts, log houses, plywood, laminates, galleries, furniture, etc.

Ecotourism is another productive aspect of the forest, from which the government earns a huge amount of revenue. Honey, rubber, and several medicinally important materials are collected from the forest.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses different typese forest products

Question 2. Briefly discuss the causes of deforestation.

Answer:

Causes of deforestation:

1. Subsistence agriculture:

It is an unscientific method of farming, where farmers concentrate on growing enough food for themselves and their families. They cut trees and burn smaller vegetation to prepare land for cultivation and cattle grazing.

2. Indiscriminate felling of trees:

The growing population has increased the demand for wood products, starting from match-sticks to furniture. Accordingly, the price of wood has also been increased. Due to this high price of wood, traders encourage indiscriminate felling of trees.

3. Urbanisation:

For the development of the state infrastructure, roads, and railway tracks are laid through forestland. Moreover, miners acquired the forestland for oil, coal, and ore mining. This level of human intervention has affected the lifestyle of both animals and plants and led to habitat fragmentation.

4. Forest fire:

In drier seasons, the local farmers and forest communities burn dry grasses to expand grazing areas. A high concentration of oxygen in the forest atmosphere drives this small fire into a firestorm. It goes out of control and destroys hundreds of trees and many smaller and bigger wild animals.

5. Desertification:

Rivers and streams flowing through forestlands often carry industrial pollutants. These toxic materials cause soil pollution, which leads to polluting the forest ecosystem.

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Question 3. Describe the consequences of deforestation.

Answer:

Consequences of deforestation:

1. Global warming: Due to deforestation and the rapid pace of industrialization, the concentration of greenhouse gases like CO, increases in the atmosphere. This results in global warming.

2 Climatic change: Transpiration by trees increases humidity in the atmosphere, which in turn enhances the chance of rainfall. In many parts of the world, the rate of rainfall has dropped significantly due to deforestation.

3 Change of soil character and erosion: The litter, deposited in the forest floor, decomposes to form humus, which keeps the soil healthy and moist in normal situations. Due to deforestation, the soil gets exposed to the sun and dries out. Moreover, soil particles become loose without binding of roots. Due to this, rain and wind wash off and blow away soil particles, reducing the chance of humification and resulting in soil erosion.

4 Flood and drought: The incidence of flood and drought has increased in every part of the world due to deforestation.

WBBSESolutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses soil erosin and flood and drought

5. Wildlife extinction:

Forests provide habitat for millions of species of flora and fauna. Deforestation makes them homeless. As a result, a certain number of species as well as part of wildlife go extinct.

6. Environmental pollution:

Deforestation results in a decrease in atmospheric oxygen levels. At the same time carbon dioxide increases, which is a cause of air pollution. Mycorrhiza. developing in the root system of some trees can remove heavy and toxic metals from the soil. In the case of deforestation, soil becomes polluted.

Important Long Answer Questions for Chapter 5 Life Science

Question 4. Why should we conserve forests? Mention a few methods of forest conservation.

Answer:

Reasons for forest conservation:

Conservation is the protection, augmentation, and scientific management of resources so as to maintain them at their optimum level providing benefit to the present as well as future generations. Forests must be conserved because of their immense economic, protective, and regulative properties.

Forest conservation is important:

1. To maintain the ecosystem of the forest,
2. To maintain O2-CO2 balance in the environment,
3. To maintain the supply of forest products like timber, food, etc.,
4. To maintain the natural beauty and livelihood of the local people.

Methods of forest conservation:

1. Afforestation: It is the growth of forests on unprotected barren lands.

2. Reforestation: It is developing forest cover in the area that has been damaged or cleared during exploitation.

3. Separation of commercial forestry: Useful plants required by industry should be planted separately preferably on waste land.

4. Grazing: Grazing should be regulated according to the availability of pasturage.

5. Social Forestry: It is the growing of useful multipurpose trees and shrubs on common village lands, roadsides, railsides, etc. by cooperative efforts of people of the area. The plants provide fodder, small timber, and firewood to villagers.

6. Agroforestry: Multipurpose trees and shrubs are planted on the sides of crop fields to provide fodder, fuel, and timber.

Both social forestry and agroforestry reduce pressure on the forests. Trees are also planted at all vacant places and along roads in urban areas (urban forestry) to reduce air and noise pollution.

Practice Long Answer Questions on Natural Resources

Question 5. Mention the uses of water. Briefly describe the causes of water scarcity. Uses of water

Answer:

Water is an essential component of life. Water is one of the most vital natural resources on Earth for life to sustain. The availability and the quantity of water have always played a significant part in determining not only where the population can grow but also their quality of life. It is used in several ways.

1. Drinking:

Water is the most essential and universal drink necessary for life.

2. Agriculture and industrial purpose:

A large quantity of water is used for irrigation of crop fields. Different industries, such as metal, paper, chemical, wood, petrochemical, etc., and boilers of power plants require large quantities of water. Water is used as raw material, solvent, coolant, and washing medium.

Causes of water scarcity:

1. Drop in rainfall:

Rainfall has dropped radically in different parts of the world, resulting in moderate to severe water scarcity.

2. Global warming:

Excessive heat dries out surface water. But this loss is not totally replenished by rain.

3. Overutilization of water:

Over-utilization of groundwater is a result of poor water management, which leads to water scarcity and increased chance of arsenic contamination.

4. Pollution: Disposal of sewage water in streams and lakes is a wasteful technique. By this process, sources of freshwater are polluted and wasted. Tomod me

WBBSE Life Science And Environment Class 9 Solutions

Question 6. How is rainwater utilized to counter the scarcity of fresh water? Mention the advantages and disadvantages of rain water harvesting.

Answer:

Utilization of rainwater:

Rainwater is the largest source of fresh water. By scientific harvesting of rainwater, freshwater scarcity can be controlled to a great extent. Rainwater harvesting is a simple and effective method of water management by which rainwater is collected, stored, and used to meet the demand for fresh water.

The easiest and most popular method is rooftop rainwater harvesting. In this process, rainwater pipes of the roof are connected to a ground-level or underground reservoir.

The rainwater is stored in the reservoir and is used according to necessity. This water can be used directly for any non-potable purposes like watering plants, washing and cleaning, bathing, and toilets.

For cooking and drinking, this water must be disinfected and filtered. For using rain water at the community level, reservoirs of all premises are connected to one or more large community reservoirs.

Finally, this water is treated and disinfected centrally and then pumped to the overhead water supply tank or the main well of the village. Advantages and disadvantages of rainwater harvesting

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses rain water harvesting

1. Advantages:

1. Rainwater is generally free from germs and contaminants.
2. It is soft water with a slightly acidic pH and does not contain any salt.
3. Rainwater contains no corrosive substances, so it does not harm water pipes and reservoirs.

2 Disadvantages:

1. Rainwater harvesting is not practiced in areas with excessive suspended particulate matter in the air.
2. Toxic gaseous materials pollute the atmosphere in regions near chemical industries and fertilizer factories.
3. These gaseous pollutants mix with rain water and make it harmful.

Concepts Related to Resource Management for Long Answers

Question 7. Briefly describe different sources of food for human consumption.

Answer:

Different sources of food for human consumption:

1. Crop production:

The maximum quantity of food we consume is plant products. These include cereals (paddy, wheat, maize, millets, etc.), pulses (moong, masur, gram, pea, etc.) and oil seeds. (mustard seed, sunflower seed, groundnut seed, rape seed, etc.)

2. Horticulture:

Horticulture includes the cultivation of fruits, vegetables, nuts, seeds, herbs, etc. We get fruits and vegetables from horticultural farms. The fruits and vegetables which we use in cooking, are also horticultural products.

3. Cattle farming:

This industry is involved in the breeding and rearing of animals like cows, goats, pigs, etc. It provides us with animal products like meat and milk.

4. Poultry:

This industry is involved in breeding and rearing domestic birds like chickens, ducks, etc. This industry provides us with poultry products like meat and eggs.

5. Fishery:

Fisheries are meant for scientific breeding and rearing of fishes. Fisheries supply fish to our platter.

Question 8. Briefly describe the situation of food scarcity on a global basis. Mention the impacts of food scarcity on Earth.

Answer:

Global food scarcity:

During the last century, industrialization and urbanization have reached their peak. This situation has pushed agriculture already to the back row. Now the rate of agricultural production cannot meet the global demand for food crops.

The environmental changes and increasing population have aggravated this problem. All these factors have developed a scarcity of food all over the world. The situation has become more adverse in poorer and developing countries.

Out of 70 billion of the total world population, about 10 billion have been suffering from malnutrition and partial starvation. A few million are dying out of starvation or diseases caused by malnutrition. People from Africa, Latin America, and Asia are the main victims of food scarcity.

Impact of food scarcity:

Food scarcity is not only taking lives due to starvation and malnutrition, besides these, it also has some other impacts on human life and the environment. To increase crop production, a land is cultivated two or three times in a year.

In developing countries, chemical fertilizers are applied indiscriminately to increase yield. By this practice, the natural fertility of soil is lost, also the soil pH changes. Forest lands are encroached upon by farming.

This practice results in deforestation which is followed by soil erosion and flood. Random use of pesticides in the crop fields causes soil and water pollution that may result in many incurable diseases. Irrigation of crop fields by suction of underground water is reducing the underground water reserve and causing arsenic pollution.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses scarcity of food

Study Guide for Class 9 Life Science Natural Resources Questions

Question 9. Refer to a specific incident related to the world food problem. Give examples of different alternative food sources.

Answer:

The special incident related to the world food problem:

Between July 2011 and mid-2012, a severe drought affected the entire East Africa region. The drought caused a severe food crisis across Somalia, Ethiopia, and Kenya that threatened the livelihood of 9.5 million people. The United Nations officially declared famine in two regions in the southern part of Somalia.

Alternative food sources:

To meet the additional demand for food, scientists and nutrition experts have found dietary potentials in some plant products, other than the common food materials.

1. Moringa oleifera has incredible nutritional value. Many edible parts, like fruits, seeds, leaves, and flowers are rich in protein, iron, Vitamin A, and Vitamin C. It also has great medicinal importance.

2. Yam bean contains enough carbohydrates, dietary fibers, and Vitamin C. It can be consumed raw as salad or cooked, baked, and even fried. Yam bean seeds contain oil.

3. Sago is a carbohydrate-rich matter, extracted from the stem of some palm trees. The granular shape is obtained by mechanical processing. It is tasty and has good nutritive value.

4. Gum Arabic is used to prepare chewing gum. Gaur gum is applied as a thickener in confectionary formulations.

5. Green gaur beans are eaten as vegetables and are used as fodder.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses yam bean

WBBSE Life Science And Environment Class 9 Solutions

Question 10. Discuss the causes of the world food problem.

Answer:

Causes of world food problem:

1. Increase in price of food:

For the last three decades, the price of food has been increasing globally. Due to high price rises, people in developing countries are facing serious problems.

2. Old method of farming:

The practice of conventional farming like monoculture (without crop rotation), using of low yielding seed varieties, using of chemical fertilizers, farming without soil testing and lack of coordination between farmers and marketing sectors are the main reasons for food problems in developing countries.

3. Climatic change and natural calamities:

The scarcity of rainfall or excessive rain may affect the production rate. Natural calamities, like floods or droughts, also reduce the productivity of food throughout the world.

4. Erosion of soil and soil pollution:

Soil erosion reduces the land, available for cultivation. Extensive use of chemical fertilizer reduces soil fertility and productivity. This is another cause of food problems.

5. Population explosion:

On average, 80 million people are born every year. But yearly production of food does not always reach that level to feed those new mouths. Therefore, an increase in the total population also increases food scarcity.

Sample Long Answer Questions from WBBSE Class 9 Life Science

Question 11. Classify the resources of energy on the basis of use. Mention the importance of conservation of energy resources.

Answer:

Classification of energy resources:

1. Conventional energy resources:

Conventional energy resources are those which have been traditionally used for many years. These resources are also widely used at present and are likely to be depleted. Examples are petroleum, natural gas, and hydel power.

2. Non-conventional energy resources:

Non-conventional energy resources are alternate energy resources to conventional energy resources which are being considered to be used on a large scale. Conventional energy resources are likely to be depleted in about 50-60 years and non-conventional energy resources should be fully developed by then to meet the energy- requirement.

Examples: Solar energy, wind energy, geothermal energy, tidal power, biogas, etc.

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses hydel and tidal power

Importance of conservation of energy resources:

1. Energy is of the basic needs of life, therefore resources of energy must be conserved.
2. The conventional resources of energy, especially coal and petroleum are non-renewable, therefore they must be conserved for future generations.

Question 12 Mention three basic steps towards the conservation of energy resources. Mention the different uses of energy.

Answer:

Basic steps towards conservation of energy resources

Steps towards conservation of energy resources are as follows:

1. Thermal power generation is to be regulated to conserve coal.
2. Conventional sources of energy are to be replaced by non-conventional energy sources as far as practicable.
3. Misuse and wastage of energy resources must be cut down substantially.

Different uses of energy:

1. Domestic use:

In rural areas, wood, coal, and kerosene oil are utilized for heating and lighting purposes. In urban areas, energy is used for cooking, lighting rooms, heating, cooling, running electronic gadgets, washing machines, dishwashers, vacuum cleaners, water suction pumps, etc.

2. Commercial use:

In commercial buildings, such as shops, malls, hotels, and restaurants, energy is used for lighting, cooling, heating, and running utility gadgets.

3. Industrial use:

In industries, coal, oil, and natural gas are used for heating, burning, and melting purposes. Lighting and running machines depend upon electrical energy.

4. Use in transport:

Most of the vehicles, ranging from motor-bikes to airplanes, motor-boats to huge ships, run on petroleum-based fuels.

Nowadays, atomic energy is used to run huge submarines and aircraft carriers.

Question 13. Mention the methods of energy conservation in daily life.

Answer:

Method of energy conservation in daily life:

1. Lighting:

Walls to be painted in a lighter shade. Lamps should be kept dust-free. Incandescent bulbs need to be replaced with CFL to LED lamps. Electronic chokes be used instead of copper chokes.

2. Fans:

Fans are to be switched off before leaving the room. Electronic regulators be fitted.

3. Electric iron:

Ironing is to be done at the right temperature. The sprayer is to be used for moistening.

4 Kitchen appliances:

Grinders should be used for wet grinding. Machines are not to be run in over or under-load conditions. The door of the microwave-oven is not to be opened frequently to check food. Flat bottom pans are to be used for the induction oven.

5. Gas oven:

Cooking should be done in regulated flame. Pressure cookers are to be used as much as possible. Pans are to be kept covered while cooking. Before cooking items are to be allowed to reach room temperature after taking them out of refrigerator.

6. Water heater:

Solar water heaters are to be used to replace electric water heaters.

7. Electronic devices:

Before leaving the room even for short intervals, TV and audio systems should be turned off.

8. Computers:

Computer monitor to be turned off during long time downloading.

9. Refrigerator:

Star-rated energy-saver models are to be used. Frequent opening of the door should be avoided. Door padding should be air-tight.

10. Washing machines:

Washing machines should be run in full load condition at optimum water level. Perfect water and detergent quantity should be maintained.

11. Air conditioners:

Energy-saving star-rated equipment is to be installed and to be selected according to cooling capacity and room size. The outdoor unit is to be fitted in a shady place. Filters should be cleaned regularly. The doors and windows of the room are to be sealed perfectly.

Understanding Sustainable Development for Long Answers

Question 14. Mention the need for the conservation of natural resources and classify natural resources.

Answer:

Need for conservation of natural resources:

1. To support life by supporting ecological balance.
2. To ensure that the future generation will be able to access the resources.
3. To preserve the biodiversity.
4. To ensure the survival of the human race.

Classification of natural resources:

WBBSE Solutions For Class 9 Life Science And Environment Chapter 5 Environment And Its Resources natural resorces adn its sustainable uses natural resources

 

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