CBSE Class 8 Social Science Land Soil Water Natural Vegetation And Wild Life Notes

CBSE Class 8 Social Science Land Soil Water Natural Vegatation and Wild life Notes Learning the important concepts is very important for every student to get better marks in examinations. The concepts should be clear which will help in faster learning. The attached concepts made as per NCERT and CBSE pattern will help the student to understand the chapter and score better marks in the examinations.

LAND, SOIL, WATER, NATURAL VEGETATION & WILD LIFE

LAND RESOURCES

Land is an important component of natural resources. It is not evenly distributed all around the world. Differences are fuuudiu in its use and levels of development, all around the world, depending upon the factors like-relief, climate’and population distribution, etc. Their misuse can endanger survival of humanity.

FACTORS AFFECTING LAND USE

1. Physical Features : Relief features like mountains, plateaus, river, slope of the land etc., influence forest cover, human habitation and hence put a limit on land use.

2. Types of Rocks : Types of rocks like sedimentary, igneous and metamorphic rocks, affect availability of minerals and soils, etc., in an area. Soils are also made from weathering or breakdown of rocks. Therefore, rocks influence the type and degree of land use.

3. Slope : Humans have,generally preferred gentle slopes for habitation as well as agriculture. Steep slopes are not favourable for agriculture or construction of houses as such. Further, on steep slopes soil erosion occurs rapidly.

4. Ciamate : Climate is an important factor determining land use. It affects crop growth, habitation by animals and humans. Cold areas of Tundra region, or extremely hot and and climates of deserts are unsuitable for human habitation.

5. Human Needs : Human needs like construction of roads, railways, ,communication lines, land cultivation, overcoming climate barriers, economic well-being and technology also determine land use. People inhabit in less numbers in the snow bourrcvarea! of Siberia,’or deep inside the deserts, like Sahara.

6. Private vs. Community : Land can also be divided on the basis of Private land an ommunity land. Private land is owned by individuals whereas, community land is owned by the community. Tor common uses like collection of fodder, fruits, nuts, etc. It is also called common group resource.

LAND DEGRADATION
Land degradation takes place due to the following reasons:

1. Change in Landforms: Man has the ability to ground high hills or fill up deep depressions. Dams across rivers, mining and construction of houses, bridges and roads affect landforms directly.

2. Overgrazing : Overgrazing by domestic animals on a large scale has degraded the land, by removing the vegetation. Overgrazing is the main cause of land degradation in states of Gujarat, Rajasthan, Madhya Pradesh and Maharashtra. Overgrazing is the major cause of land degradation.

3. Degradation by Mining and Quarrying: More than 5,500 mines and quarries are operating in India. The dumping of mineral wastes and abandoned mines are degrading and defacing the land.

4. Degradation by industrial vaste : Indiscriminate discharge of effluents has led to land degradation and making the land unfit for cultivation.

5. Degradation by Industrial Dust: Fly ash from thermal power plants and dust generated by cement 1and ceramic industries have also led to land degradation.

HOW CAN WE CONSERVE DEGRADED LAND
The following steps can go a long way in the conservation and reclamation of land :
1. Afforestation and control on overgrazing.
2. Plantation of shelter belts of plants.
3. Growing of thorny bushes to stabilise the sand dunes.
4. Proper discharge and disposal of industrial effluents and wastes.
5. Environmental friendly mining.

SOIL
Soil is the base of terrestrial Iife supporting system. It is a fragile resource which can easily be damaged or destroyed by human activity. It must be conserved and treaeed with care.

DEFINITION OF SOIL
According to Geologists, soil is 'the mixture of disintegrated rock material comprising mineral product together with decayed organic material. and living organisms'.

FACTORS AFFECTING SOIL FORMATION

1. Weathering : Weathering is the bracking up of rocks and the agents of gradation carry this load over the large areas of the land. The colour, structure, mineral content in soil is formed due to it.

2. Climate : Without climate, weathering cannot take place. Climate has different effects on different types of rocks. Through temperature and precipitation, it affects rate of weathering, decomposition of organic material as well as the type and kind of vegetation in the area. Climate can be regarded as the most
dominant factor in soil formation.

3. Biota or Biomass : The decomposition of organic matter gives humus and bacteria to do the activity of mixing and shifting of soil materials. The decayed matter also increases chemical action and lends colour and texture to soil.

4. Topography : It includes relief, slope as well as the direction with respect to sunshine and winds. Gentle slopes favour soil formation, while steep slopes lead to soil erosion.

Soil Erosion
Removal of soil by running water, winds and glaciers is called soil erosion. soil erosion is of various types:

1. Sheet Erosion : When a sheet or layer of soil is removed over a large area by running water, it is called sheet erosion.

2. Rill Erosion : If rills appear, they increase in number over a period of time. It is called rill erosion.

3. Gully Erosion : If the water flows regularly along a definite path down the slope, it cuts a channel called gully and this type of erosion is called gully erosion. The land degraded by gully erosion is called badland or ravine.

HOW CAN WE CONSERVE SOIL?
Chief types of soil conservation methods are as follows :

1. Afforestation : The humus in soil is a substance obtained from plant and animal remains. Therefore, planting of trees, shrubs and grasses provides base for forming humus.

2. Farming Techniques : Soil conservation friendly farming techniques include – contour ploughing, strip cropping, terracing and other techniques. Strip cropping means, planting of alternate rows of different kinds of crops instead of leaving the land fallow. In Contour ploughing farmers plough across a slope along the line of the field in circular manner. In terracing, wide flat rows are made in step-like manner. The terraces hold rain water and prevent soil from getting washed down the slope. The other techniques include mulching, contour barriers, rock dam, intercropping and shelter belts.

* Mulching : It is the covering of bare ground between plants, with a layer of organic matter like straw, to retain soil moisture.
* Contour Barriers: It is the using of stone, grass, soil to build barriers along contours.
* In Rock Dam : Rocks are piled up to slow down flow of water. It prevents gullies and further soil erosion.
* In Intercropping : Different crops are grown in alternate rows and are sown at different times to protect the soil from rain wash.
* In Shelter Belts : Rows of trees are planted in coastal and dry regions, to check the wind movement and to protect soil cover.

HYDROLOGICAL CYCLE
The three atmospheric processes evaporation, condensation and precipitation, involved in the hydrological cycle cause water to be made available globally. For this reason, water is even called a renewable resource, The distribution of water on Earth is as follows :

*  Freshwater : The water made available on Earth by the operation of hydrological cycle is termed as fresh water. It accounts for just 1 percent of the total water available on Earth.
* Ice Caps : Total water made available on Earth, in the process of hydrological cycle is 2% of this.
* Water in Atmosphere : Only tiny fraction (0.001 per cent) of water is found in gaseous form (vapour) in atmosphere.
*  Water in Oceans : 97 per cent of water is found in oceans, seas and salt water lakes. It covers about 71 per cent of Earth’s surface. On planet Earth, water is found in all three gaseous, liquid and solid forms.

Do You Know?
97 Percent of all water is found in oceans, 2 percent is in the form of ice caps, glaciers and 1 percent (fresh water) in lakes, river, etc.

FRESH WATER
Since water came to be found on Earth, its total volume has remained the same. The quantity of water only change in its three states. For example, during the Ice Ages more water was found in solid state in the form of glaciers and ice caps. Fresh water, as we have seen above.

DISTRIBUTION OF FRESH WATER
Like all other natural resources, water is also unevenly distributed over Earth. This distribution is generally governed by climate. Hence, the areas of more precipitation have surplus water, whereas the areas of deficit rainfall have water shortages.
As a result, world’s hottest deserts exist in this region. These hot deserts include Sahara and Arabian desert along with Sind, of which Thar in India is its eastern extension.

RECYCLING
Water is a renewable resource. Recycling of water, if done at the source of contamination, is the best way of removing impurities, according to needs

HOW CAN WE CONSERVE WATER?
* Efficient Use of Water : Efficient and economical use of water, specially to prevent wastage is the best way of conserving water.
* Sprinkler Irrigation : In place of canals or irrigation through open channels sprinkler irrigation should be adopted in developing countries.
* Recycling and Treatment of Effluents at its sources is also an ‘important method of conservation.
* Water Harvesting : It involves artificial recharge of underground water by allowing rainwater to seep into the soil.
* Vegetation Cover : Is essential forwater harvesting described above. It can also control the surface flow of rain water and soil erosion.

NATURAL VEGETATION
The only planet in our solar system where life exists is Earth. Life on Earth, is categorised into animal and plant kingdoms. The third type of living organisms is called bacteria. The organisms have overtime diversified into several different species. This diversity of species is called biodiversity.

WHY DO WE NEED TO PROTECT BIODIVERSITY?
The great distribution of animal and plant species known as biodiversity is quite essential for survival of life on Earth. Plants produce their own food and get energy from the Sun. When animals eat plants, energy is transferred from plants to plant-eating animals. The plant-eating animals may then be eaten by the flesh-eating animals including man: This way, energy travels from one organism to anothev, organism. This feeding transfer is known as food chain. It is imperative to protect this biodiversity in the ecosystem.

ECOSYSTEMS
Life is found in two types of ecosystems — marine and terrestrial.

MARINE ECOSYSTEM
Oceans occupy 71% of Earth’s surface. The marine ecosystems are larger than terrestrial ecosystems. Life emerged first in the oceans. It then got diversified into several species. Life in marine is also very complicated and is found even in the deepest parts of the oceans.

TERRESTRIAL ECOSYSTEM
On land, life is not easier as compared to oceans. There are three types of terrestrial ecosystem—Forests; Grasslands; and Semi-deserts and Deserts.

1. FORESTS
The vegetation of the world is divided on the basis of types of forests.

Chief Characteristics of Forest Ecosystem are:
1. The most productive parts of tress in forests are leaves. Leaves of green plants produce food through photosynthesis. The plant food contains sun’s energy, which travels to other species of life on land.
2. The forest is influenced by and adopted to particular physical conditions and climate.
3. Forests are home to animals and plants. This great variety of animals and trees in forests is called Biodiversity.
4. Forests are generally located where water supply is adequate with optimum temperature for tree growth.

TYPES OF FORESTS
Forests can be divided into two main types : evergreen and deciduous.

(A) EVERGREEN FORESTS
These forests are called evergreen as their trees. do not shed their leaves. These are of two types — tropical rainforests and Coniferous forest. The tropical rainforests are located low altitude Souch East Asia in the subtropical region. Trees have broad leaves they grow tall to reach the sunlight. The coniferous forests on the other hand, are found in higher latitudes and higher altitude area of mountairls, like Himalayas and Andes. Both these ecosystems and are repositories of largest variety of plant and animal species.

(B) DECIDUOUS FORESTS
The deciduous trees shed their leaves in a particular season. There is also a great variety of animals in. these forests. These forests provide habitat to a variety of plant and animals species. Human settlements are also found more around deciduous forests than the evergreen forests.

2. GRASSLANDS
Grasslands are significant habitats of a great variety and a grate diversity of animal life. The grassland are located in main latitudinal zones-tropical and temperate.

3. SEMI-DESERTS AND DESERTS
There are two types of deserts : Semi-deserts and deserts. Both categories include hot and cold deserts.
(a) Semi-Deserts : These have thorny bushes and shrubs and are found in hot semi-deserts or semi-arid areas.
(b) Deserts : As mentioned earlier there are no absolute deserts.. Hot deserts like that of Sahara and Arabia and cold deserts like that of Gobi and Ladakh are characterised by plants of low growth and organisms living below the ground.

HOW CAN WE CONSERVE THE ECOSYSTM?

CONSERVATION
The government and the United Nations have passed laws against deforestation and killing of animals. Laws have also been passed to control pollution. Biosphere reserves, national parks and wildlife sanctuaries have also been set up. All these efforts are still very inadequate. Human impact on natural environment is felt through a number of ways.
To prevent alternations and modifications of ecosystem, many-more, measures are needed. Otherwise, disturbances in balances would have serious consequences.

Do You Know?
Forests account for only 22% land, while the required land is 33% for survival of flora and founa and mankind.

FORESTS AND WILDLIFE RESOURCES
Earth's natural environment is different from the natural environment of other planets due to the presence, of forests and wildlife on it. One unique feature of the Earth is the structure and functioning of forest ecosystems, which is broadly uniform throughout the world.

Do You Know?
Biodiversity is the variety of flora and fanna found in an area. India has nearly 8 per cent of the total number of species, in the world. India is one of the 17 mega diverse countries which possess about 70 percent of the world's diversity.

DECLINING WILDLIFE
There was an abundance of wildlife in India before British established their rule here. With coming of the British rule and increase in the number of firearms, indiscriminate hunting. Due to the rise of population, there has been a demand for land, leading to a clash between wildlife and humans. The wildlife was the obvious loser and some wild animals even became extinct. Today 77 mammals, 21 reptiles, 40 species of birds and 3 amphibians are threatened with extinction. Tiger, lion, thamin of Manipur and hangul of Jammu and Kashmir, wildass of Kachchh, snow leopard, etc., are in the endangered list of wild animals. Not only wild animals, but wild plants are also facing the threat of extinction. About 450 plant species are known to be endangered, threatened or rate.

PROJECT TIGER
A country which boasted of more than 40,000 tigers, just a century ago, is today searching for tigers in its 29 tiger reserves. The first ever effort to save tigers was made by Mrs. Indira Gandhi by imposing a ban on tiger hunting in 1970.
Another step was the implementation of the Wildlife Protection Act in 1972. Afterwards the project Tiger was launched in 1973-74, with a Tiger Reserve covering 16,339 sq. km. of area, that has now been increased to 37,761 sq. km in 28 Tiger Reserves.
Initially the project Tiger yielded encouraging results. Till 1989, the Project Tiger was lauded as the most successful conservation effort in the world.

WHY ARE FLORA AND FAUNA DEPLETING?
In the past couple of centuries, flora and fauna are depleting due to following reasons :
1. Destruction of Habitats : Forests and grasslands are being destroyed by man’s activities and his expanding needs.
2. Rapidly rising Population : Expansion of agriculture, industrialisation as well as human habitation, has led to the depletion of vegetative cover.
3. Diseases and Pest : Cause like pollution, contact with exotic flora and, fauna, use of fertilizers and chemicals in agriculture, acid rain, damage to soil resources and changes in climate, have led to the decline of flora and fauna.
4. Depleting Food Resource : Most animals and even plants are facing extinction on account of depleting food resources.

CONSERVATION OF FLORA AND FAUNA
The steps taken for the protection and preservation of our wildlife are the following :
1. Campaigns : The National Environment Awareness campaign is being organised every year under different categories to create awareness to save our forests and wildlife.
2. Blosphere Reserves : National parks and wildlife sanctuaries have been started to preserve the genetic diversity in representative ecosystems. The major aim of biosphere reserves are : (i) to conserve diversity of flora and fauna, (ii) to promote research on ecology and (iii) to provide facilities for education awareness and training.
3. Legislation : The Wildlife (protection) Act, 1972 and the Forest Conservation Act, 1980, have been enacted to protect forests.
4. Other Measures : Individual schemes like Project Tiger, Project Rhino, National Natural Resource Management System are also in operation or being undertaken from time to time.

COMMUNITY AND CONSERVATION
Forests are considered only a collection oftrees-by people. But in reality, forest is a community of plants and trees, medicinal herbs and other life sustaining vegetation. Life of human race, animals and even insects is possible due to the vegetation. Planting of trees and their protection is encouraged by saying that, it is the greatest virtuous dew’ Some examples of observation by communities are :
1. Bishnois saved the trees some 275 years ago. Amrita Devi sacrificed her life to save the trees.
2. Van Panchayat and Pani Panchyats, of many villages of different states are regularly held for environmental protection.

LAND, SOIL, WATER, NATURAL VEGETATION AND WILDLIFE

Q1. Why life is different in different parts of the world?

A1. The life is different in different parts of the world because of the differences in the quality of land, soil, water, natural vegetation, animals and the usage of technology.

Q2. How land can be conserved ?

A2. Land can be conserved by the following way:-

1) Afforestation.

2) Land reclamation

3) Regulated use of chemical pesticide and fertilizers.

4) Checks on overgrazing.

Q3. What is soil?

A3. The thin layer of grainy substance covering the surface of the earth is called soil. Soil is made up of organic matter, minerals and weathered rocks found on the earth. This happens through the process of weathering. The right mix of minerals and organic matter make the soil fertile.

Q4. Name the factors that leads to soil degradation?

A4. Factors which lead to soil degradation are:-

1) Deforestation

2) Overgrazing

3) Overuse of chemical feritilisers or pesticides.

4) Rain wash.

5) Landslides.

6) Floods.

Q5. Define –1) National park 2) Biosphere reserve.

A5. 1) National park - A natural area designated to protect the ecological integrity of one or more ecosystems for present and future generations.

2) Biosphere reserve - Series of protected areas linked through a global network, intended to demonstrate the relationship between conservation and development.

Q6. What are the natural and human factors that are leading to forest and wildlife depletion?

A6. The natural and human factors that are leading to forest and wildlife resources are:-

1) Deforestation

2) Soil erosion

3) Constructional activities.

4) Forest fires.

5) Tsunami.

6) Landslides.

Q7. Why animals are poached?

A7. The animals are poached for collection and illegal trade of hides, skins, nails, teeth, horns as well as feathers.

Q8. How do we get water back through water recycle?

A8. Water can neither be added nor subtracted from the earth. Its total volume remains constant. Its abundance only seems to vary because it is inconstant motion, cycling through the oceans, the air, the land and back again, through the processes of evaporation, precipitation and run-off. This is how we get water back through water recycle.

Q9. Name the physical and human factors that determine land use?

A9. The use of land is determined by:-

1) Physical factors such as topography, soil, climate, minerals and availability of water.

2) Human factors such as population and technology are also important determinants of land use pattern.

Q10. Why land use pattern is changing?

A10. Land use pattern is changing because of following reasons:-

1) People started encroaching the common lands to build up commercial areas, housing complexes in the urban areas and to expand the agricultural land in the rural areas.

2) Cultural changes which are taking place in our society.

Q11. Name the regions of the world which are facing water scarcity?

A11. The regions of the water scarcity are Africa, West Asia, South Asia, parts of western USA, north-west Mexico, parts of South America and entire Australia are facing shortages in fresh water supply.

Q12. What are the reasons for the water scarcity/?

A12. Water shortage may be a consequence of variation in seasonal or annual precipitation or the scarcity is caused by over exploitation and contamination of water sources.

Q13. How is vegetation useful to us?

A13. Vegetation is useful to us in the following way:-

1) Plants provide us with timber

2) Give shelter to animals,

3) Produce oxygen we breathe,

4) Protects soils so essential for growing crops,

5) Act as shelter belts,

6) Help in storage of underground water,

7) Give us fruits, nuts, latex, turpentine oil, gum, medicinal plants

8) Provide the paper that is so essential for your studies.

Q14. Give the soil profile?

A14. The soil is made up of different layers as follows:-

1) Top soil with humus and vegetation.

2) Sub soil with sand, silt and clay.

3) Weathered rock material.

4) Parent rock.

Q15. Why there is uneven distribution of population?

A15. The uneven distribution of population in different parts of the world is mainly due to varied characteristics of land and climate.

1) Sparsely populated regions:- The rugged topography, steep slopes of the mountains, low lying areas suspectible to water logging, desert areas thick forested areas are normally sparsely populated or uninhabited.

2) Densely populated regions:- Plains and river valleys offer suitable land for agriculture. Hence, these are the densely populated areas of the world.

Q16. Define the following :

1) Land Use

2) Common property resource.

3) Biosphere.

4) Ecosystem.

A16. 1) Land use - Land is used for different purposes such as agriculture, forestry, mining, building houses, roads and setting up of industries. This is commonly termed as Land use.

2) Common property resource - Privateland is owned by individuals whereas, community land is owned by the community for common uses like collection of fodder, fruits, nuts or medicinal herbs. These community lands are also called common property resources.

3) Biosphere - Natural vegetation and wildlife exist only in the narrow zone of contact between the lithosphere, hydrosphere and atmosphere that we call biosphere.

4) Ecosystem - In the biosphere living beings are inter-related and interdependent on each other for survival. This life supporting system is known as the ecosystem.

Q17. Explain the factors that help in soil formation?

A17. The major factors that help in the soil formation are as follows:-

1) Parent Rock - Determines colour, texture, chemical properties,mineral, content, permeability.

2) Climate -Temperature ,Rainfall influence rate of weathering and humus.

3) Relief - Altitude and slope, determine accumulation of soil

4) Flora, Fauna and Micro-organism - Affect the rate of humus formation

5) Time - Determines thickness of soil profile.

Q18. Explain the methods that help in the conservation of soil?

A18. Some methods of soil conservation are:-

1) Mulching: The bare ground between plants is covered with a layer of organic matter like straw. It helps to retain soil moisture.

2) Contour barriers: Stones, grass, soil are used to build barriers along contours. Trenches are made in front of the barriers to collect water.

3) Rock dam: Rocks are piled up to slow down the flow of water. This prevents gullies and further soil loss.

4) Terrace farming: These are made on the steep slopes so that flat surfaces are available to grow crops. They can reduce surface run-off and soil erosion

5) Intercropping: Different crops are grown in alternate rows and are sown at different times to protect the soil from rain wash.

6) Contour ploughing:-Ploughing parallel to the contours of a hill slope to form a natural barrier for water to flow down the slope

7) Shelter belts: In the coastal and dry regions, rows of trees are planted to check the wind movement to protect soil cover.

Q19. Give the distribution of water?

A19. The oceans covers two-thirds of the earth’s surface and support a rich variety of plant and animal life. The ocean water is however saline and not fit for human consumption. Fresh water accounts for only about 2.7 per cent. Nearly 70 per cent of this occurs as ice sheets and glaciers in Antarctica, Greenland and mountain regions. Due to their location they are inaccessible. Only 1 per cent of Fresh water is available and fit for human use. It is found as ground water, as surface water in rivers and lakes and as water vapour in the atmosphere.

Q20. Explain the factors leading to water scarcity?

A20. The factors leading to water scarcity are:-

1) Increasing population- The population is increasing therefore there is rising demands for food and cash crops ,increasing urbanisation and rising standards of living causes water scarcity.

2) Decreasing water resource - Drying up of water sources, over usage of water, lowering of water table and water pollution due to untreated chemical and industrial waste causes water shortage.

Q21. How we can conserve water resource?

A21. We can conserve water resource by the following way:-

1) Water pollution can be controlled by treating these effluents suitably before releasing them in water bodies.

2) Forest and other vegetation cover slow the surface runoff and replenish under groundwater.

3) Water harvesting is another method to save surface runoff.

4) The canals should be properly lined to minimise losses by water seepage.

5) Sprinklers effectively irrigate the area by checking water losses through seepage and evaporation.

6) In dry regions with high rates of evaporation, drip or trickle irrigation is very useful.

7) Treatment of effluents-Discharge of untreated or partially treated sewage, agricultural chemicals and industrial effluents in water bodies are major contaminants which should be treated before discharging it in the river.

Q22. Animals big or small, all are integral in maintaining balance in the ecosystem’ Eleborate the statement with the help of examples.

A22. Wildlife includes animals , birds, insects as well as the aquatic life forms.

1) Animals provide us milk, meat, hides and wool.

2) Insects like bees provide us honey, help in pollination of flowers and have an important role to play as decomposers in the ecosystem.

3) The birds feed on insects and act as decomposers as well.

4) Vulture due to its ability to feed on dead livestock is a scavenger and considered a vital cleanser of the environment. So animals big or small, all are integral in maintaining balance in the ecosystem.

Q23. What are the features of vegetation found in the regions of heavy, moderate and low rainfall regions of the world ?

A23. 1) In areas of heavy rainfall, huge trees may thrive.

2) In the regions of moderate rainfall short stunted trees and grasses grow forming the grasslands of the world.

3) In dry areas of low rainfall, thorny shrubs and scrubs grow. In such areas plants have deep roots and leaves have thorny and waxy surface to reduce

loss of moisture by transpiration. Tundra vegetation of cold Polar Regions comprise of mosses and lichens.

Q24. Differentiate between Evergreen and Deciduous forest?

A24.

Q25. List the steps that can be adopted to conserve the forest and wildlife resource.

A25. The steps that can be adopted to conserve forest and wildlife resource are-

1)National parks, wildlife sanctuaries, biosphere reserves are made to protect our natural vegetation and wildlife.

2) Conservation of creeks, lakes, and wetlands is necessary to save the precious resource from depletion.

3) Awareness programmes- like social forestry and Vanamohatasavashould be encouraged at the regional and community level. School children should be encouraged for bird watching and visiting nature camps so that they appreciate thehabitat of varied species.

4) Laws- Many countries have passed laws declaring that the trades as well as killing of birds and animals are illegal. In India, killing of lions, tigers, deers, great Indian bustards and peacocks have been banned.

5) CITES- An international convention CITES has been established that lists several species of animals and birds in which trade is prohibited.