CBSE Class 8 Geography Chapter 2 Notes Understanding the Lesson
1. There is difference in the quality of land, soil, water, natural vegetation, animal and the usage of technology and the availability of such resources is the main reason why the different places on the earth differ from each other.
- The most important natural resource which covers only about 30% of the total area of the earth’s surface and not all parts of its are habitable.
- The uneven distribution of population in different parts of the world is mainly due to varied characteristics of land and climate.
3. Land use:
- Land is used for different purposes such as agriculture, forestry, mining, building houses, roads, setting up industries. This is commonly termed as Land use.
- The use of land is determined by the physical factors such as topography, soil, climate, minerals and availability of water.
- Human factors such as population and technology are also important determinants of land use pattern.
- On the basis of ownership land can be classified into private land and community land.
- Private land: owned by individuals.
- Community land: owned by the community for common uses.
- The community lands are also called common property resources.
- The vast changes in the land use pattern also reflect the cultural changes in the society.
- Because of expansion of the agriculture and constructive activities the major threats like land degradation, landslides, soil erosion, desertification are created.
- The thin layer of grainy substance covering the surface of the earth is called soil.
- It is made up of organic matter, minerals and weathered rocks found on the earth. This happens through the process of weathering.
5. Factors of soil formation:
- The major factors are the nature of the parent rock and climatic factors.
- Topography, role of organic material and time taken for the composition of soil formation are also some other factors of soil formation. All these differ from place to place.
6. Degradation of soil and conservation measures:
- Soil erosion and depletion are the major threats to soil as a resources.
- Factors that lead to soil degradation are deforestation, overgrazing, overuse of chemical fertilizers or pesticides, rain wash, landslides and floods.
- Methods that are useful for the purpose of soil conservation are:
7. Mulching: The bare ground between plants is covered with a layer of organic matter like straw which helps in retaining the soil moisture.
8. Contour barriers: In this stones, grass, soil are used to build barriers along contours. Trenches are made in front of the barriers for collecting water.
9. Rock dam: Rocks are piled up to slow down the flow of water and this prevents gullies and further soil loss.
10. Terrace farming: In this broad flat steps or terraces are made on the steep slopes so that flat surfaces are available for the growing of crops and this reduces surface run off and soil erosion.
11. Intercropping: Different crops are grown in alternate rows and are sown at different times to protect the soil from rain wash.
12. Contour ploughing: Ploughing parallel to the contours of a hill slope to form a natural barrier for water to flow down the slope.
13. Shelterbelts: In the coastal and dry regions, rows of trees are planted to check the wind movement in order to protect soil cover.
- A vital renewable natural resource.
- Three-fourth’s of the earth surface is covered with water.
- Earth is called the ‘water planet’.
- It is found that the life began almost 3.5 billion years back in primitive oceans.
- Freshwater accounts for only about 2.7 per cent.
15 . Only 1 per cent of freshwater is available and fit for the human use found as ground water, as surface water in rivers and lakes and as water vapour in atmosphere.
16. Water can neither be added nor substrated from the earth. Its total volume remains constant.
17. Water cycle: Cycling through the oceans, the air, the land and back again, through the process of evaporation, precipitation and run-off. This process is referred to as the water cycle.
18. Water shortage may be a consequence of variation in seasonal or annual precipitation or the scarcity caused by overexploitation and the contamination of the water resources.
19. Even though water is been categorised under the renewable resource category, its overuse and pollution make it unfit for use.
20. There is scarcity of water in many regions of the world and shortage of water may be a consequence of variation in seasonable on annual precipitation.
21. The scarcity is caused by over-exploitation and contamination of water resources.
22. In today’s world access to clean and adequate water is the major problem.
23. Discharge of untreated or partially treated sewage, agricultural chemicals and industrial effluents in water bodies are major contaminants which pollutes water with nitrates, metals and pesticides. Most of these chemicals are non-biodegradable and reach human bodies through water.
24. Forest and other vegetation cover slow the surface runoff and replenish underground water. Water harvesting saves water runoff, from the surface.
25. The valuable resources of water can be conserved by using and adopting the different means of irrigation.
26. In the eastern and northeastern humid regions of India bamboo, grows in plenty.
27. Silk is obtained from silk worms that are bred on Mulberry trees.
28. Biosphere is the narrow zone of contact between the lithosphere, hydrosphere and atmosphere where the natural vegetation and wildlife do exist.
29. The life supporting system in the biosphere where the living beings are inter-related and interdependant on each other for survival is known as the ecosystem.
30. Wildlife includes animals, birds, insects as well as aquatic life forms which all are integral for maintaining balance in the ecosystem.
31. The growth of vegetation depends primarily on temperature and moisture. The major vegetation types of the world are grouped as forests, grasslands, scrubs and tundra.
32. The forests are associated with the areas having abundant water supply.
33. Forests are broadly classified as evergreen and deciduous depending on their sheding of leaves because:
- Evergreen forests do not shed their leaves simultaneously in any season of the year.
- Deciduous forests shed their leaves in a particular season to conserve loss of moisture through transpiration.
34. With the increase in the population of the world there is decrease or we can say rapid decrease in the forest cover all over the world which ultimately creates an urgent need to conserve this valuable resource.
35. Forests are known as our wealth in which plants give shelter to the animals and together they maintain the ecosystem.
36. Changes of climate and human interferences can cause the loss of natural habitats for the plants and animals. Many of the species have became vulnerable or endangered and some are on the verge of extinction.
37. Poaching is one of the main reasons behind the shark decline in the number of particular species. Increasing awareness can help in the conservation.
38. National parks, wildlife sanctuaries, biosphere reserves are made to protect our natural vegetation and wildlife.
39. There will be the balance in the environment if the relative number of species is not disturbed.
40. Awareness programmes likes social forestry and Vanamohatasava should be organised in order to appreciate the habitat of varied species and protect extinction or indiscriminate killing of species in the ecosystem.
41. Laws are passed against the trade and killing of birds as well as animals in many countries of the world. In India killing lions, tigers, deers, great Indian bustards and peacocks is illegal.
42. CITES an international convention has been established in order to list several species of animals and birds in which trade is prohibited.
43. It is an ethical duty of every citizen to conserve plants and animals.
Land, Soil, Water, Natural Vegetation and Wildlife Resources Class 8 CBSE Notes Important Terms
Biosphere Reserves: Series of protected areas linked through a global network, intended to demonstrate the relationship between conservation and development.
National Park: A natural area designated to protect the ecological integrity of one or more ecosystems for the present and the future generations.
Weathering: It is the breaking up and decay of exposed rocks, by temperature changes, frost action, plants, animals and human activity.
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.
Landslide: Defined as the mass movement of rock, debris or earth down a slope.