IAS Prelims (GS) Preparation 2018
Day # 19 (April 11, 2017)
Topics of the day: Geography 8th NCERT Chapter 3 and 4 key points
Chapter – 3
- A naturally occurring substance that has a definite chemical composition is a mineral.
- A rock is an aggregate of one or more minerals but without definite composition of the constituent of mineral. Rocks from which minerals are mined are known as ores.
- On the basis of composition, minerals are classified mainly as metallic and non-metallic minerals.
- Metallic minerals contain metal in raw form. Metals are hard substances that conduct heat and electricity and have a characteristic lustre or shine. Iron ore, bauxite, manganese ore are some examples.
- Metallic minerals may be ferrous or non-ferrous. Ferrous minerals like iron ore, manganese and chromites contain iron. A non-ferrous mineral does not contain iron but may contain some other metal such as gold, silver, copper or lead.
- Non-metallic minerals do not contain metals. Limestone, mica and gypsum are examples of such minerals.
- The mineral fuels like coal and petroleum are also non-metallic minerals.
- Minerals can be extracted by mining, drilling or quarrying.
-The process of taking out minerals from rocks buried under the earth’s surface is called mining.
- Minerals that lie at shallow depths are taken out by removing the surface layer; this is known asopen-cast mining.
- Deep bores, called shafts, have to be made to reach mineral deposits that lie at great depths. This is called shaft mining. Petroleum and natural gas occur far below the earth’s surface. Deep wells are bored to take them out, this is called drilling.
- Minerals that lie near the surface are simply dug out, by the process known as quarrying.
- If a rock contains copper then the rock looks blue in colour.
- Generally, metallic minerals are found in igneous and metamorphic rock formations that form large plateaus. Iron-ore in north Sweden, copper and nickel deposits in
Ontario, Canada, iron, nickel, chromites and platinum in South Africa are examples of minerals found in igneous and metamorphic rocks.
- Sedimentary rock formations of plains and young fold mountains contain non-metallic minerals like limestone. Limestone deposits of Caucasus region of France, manganese
deposits of Georgia and Ukraine and phosphate beds of Algeria are some examples.
- China and India have large iron ore deposits.
- China, Malaysia and Indonesia are among the world’s leading tin producers.
- China also leads in production of lead, antimony and tungsten.
- Europe is the leading producer of iron-ore in the world.
- The countries with large deposits of iron ore are Russia, Ukraine, Sweden and France.
- Switzerland has no known mineral deposit in it.
- The mineral deposits in North America are located in three zones: the Canadian region north of the Great Lakes, the Appalachian region and the mountain ranges of the
west.
- Iron ore, nickel, gold, uranium and copper are mined in the Canadian Shield Region, coal in the Appalachians region.
- Western Cordilleras have vast deposits of copper, lead, zinc, gold and silver.
- Brazil is the largest producer of high grade iron-ore in the world.
- Chile and Peru are leading producers of copper.
- Brazil and Bolivia are among the world’s largest producers of tin
- Africa is the world’s largest producer of diamonds, gold and platinum.
- South Africa, Zimbabwe and Zaire produce a large portion of the world’s gold.
- Australia is the largest producer of bauxite in the world.
- Kalgoorlie and Coolgardie areas of western Australia have the largest deposits of gold.
- India is the largest producer and exporter of mica in the world.
- Kolar in Karnataka has deposits of gold in India.
- Major limestone producing states in India are Bihar, Jharkhand, Odisha, Madhya Pradesh, Chhattisgarh, Rajasthan, Gujarat and Tamil Nadu
- Silicon, used in the computer industry is obtained from quartz.
- Aluminum obtained from its ore bauxite is used in automobiles and airplanes, bottling industry, buildings and even in kitchen cookware.
- The oldest rocks in the world are in Western Australia.
- A green diamond is the rarest diamond.
- Firewood and fossil fuels are the two main conventional energy sources.
- Electricity from coal is called thermal power.
- Coal is referred to as Buried Sunshine.
- The coal producing areas of India are Raniganj, Jharia, Dhanbad and Bokaro in Jharkhand.
- Petroleum and its derivatives are called Black Gold.
- Compressed natural gas (CNG) is a popular ecofriendly automobile fuel as it causes less pollution than petroleum and diesel.
- Natural gas is found with petroleum deposits and is released when crude oil is brought to the surface.
- Russia, Norway, UK and the Netherlands are the major producers of natural gas.
- In India Jaisalmer, Krishna Godavari delta, Tripura and some areas off shore in Mumbai have natural gas resources.
- Norway was the first country in the world to devlop hydroelectricity.
- Some important hydel power stations in India are Bhakra Nangal, Gandhi Sagar, Nagarjunsagar and Damodar valley projects.
- Non-conventional sources such as solar energy, wind energy, tidal energy are renewable.
- In India Rajasthan and Jharkhand have large deposits of Uranium.
- Thorium is found in large quantities in the Monozite sands of Kerala.
- Heat energy obtained from the earth is called geothermal energy.
- USA has the world’s largest geothermal power plants followed by New Zealand, Iceland, Philippines and Central America.
- In India, geothermal plants are located in Manikaran in Himachal Pradesh and Puga Valley in Ladakh.
- The first tidal energy station was built in France.
- Russia, France and the Gulf of Kachchh in India have huge tidal mill farms.
- Organic waste such as dead plant and animal material, animal dung and kitchen waste can be converted into a gaseous fuel called biogas.
- The organic waste is decomposed by bacteria in biogas digesters to emit biogas which is essentially a mixture of methane and carbon dioxide.
Chapter - 4
- The word agriculture is derived from Latin words ager or agri meaning soil and culture meaning, cultivation.
- Agriculture is a primary activity. It includes growing crops, fruits, vegetables, flowers and rearing of livestock.
- The land on which the crops are grown is known as arable land.
- Agriculture
The science and art of cultivation on the soil, raising crops and rearing livestock.
It is also called farming.
- Sericulture
Commercial rearing of silk worms. It may supplement the income of the farmer.
- Pisciculture
Breeding of fish in specially constructed tanks and ponds.
- Viticulture
Cultivation of grapes.
- Horticulture
Growing vegetables, flowers and fruits for commercial use.
- Organic Farming
In this type of farming, organic manure and natural pesticides are used instead of chemicals. No genetic modification is done to increase the yield of the crop.
- Depending upon the geographical conditions, demand of produce, labour and level of technology, farming can be classified into two main types. These are subsistence farming and commercial farming.
- Subsistence Farming
This type of farming is practiced to meet the needs of the farmer’s family.
Traditionally, low levels of technology and household labour are used to produce
on small output. Subsistence farming can be further classified as intensive subsistence and primitive subsistence farming
- In intensive subsistence agriculture the farmer cultivates a small plot of land using simple tools and more labour.
- Primitive subsistence agriculture includes shifting cultivation and nomadic herding.
- Shifting cultivation is also known as ‘slash and burn’ agriculture.
- Nomadic herding is practiced in the semi-arid and arid regions of Sahara, Central Asia and some parts of India, like Rajasthan and Jammu and Kashmir. In this type of farming, herdsmen move from place to place with their animals for fodder and water, along defined routes.
- Shifting cultivation is known by different names in different parts of the world
Jhumming - North-East India
Milpa –Mexico
Roca - Brazil.
Ladang – Malaysia
- In commercial farming crops are grown and animals are reared for sale in market. The area cultivated and the amount of capital used is large. Most of the work is done by machines.
- Commercial farming includes commercial grain farming, mixed farming and plantation agriculture.
- In commercial grain farming crops are grown for commercial purpose. Wheat and maize are common commercially grown grains.
- In mixed farming the land is used for growing food and fodder crops and rearing livestock.
- Plantations are a type of commercial farming where single crop of tea, coffee, sugarcane, cashew, rubber, banana or cotton are grown. Large amount of labour and capital are required.
- Major plantations are found in the tropical regions of the world. Rubber in Malaysia, coffee in Brazil, tea in India and Sri Lanka are some examples.
- Rice:
Rice is the major food crop of the world.
It is the staple diet of the tropical and sub-tropical regions.
Rice needs high temperature, high humidity and rainfall.
It grows best in alluvial clayey soil, which can retain water.
China leads in the production of rice followed by India, Japan, Sri Lanka and Egypt.
In favourable climatic conditions as in West Bengal and Bangladesh two to three crops are grown in a year.
- Wheat:
Wheat requires moderate temperature and rainfall during growing season and bright sunshine at the time of harvest.
It thrives best in well drained loamy soil.
Wheat is grown extensively in USA, Canada, Argentina, Russia, Ukraine, Australia and India.
In India it is grown in winter.
- Millets:
They are also known as coarse grains and can be grown on less fertile and sandy soils.
It is a hardy crop that needs low rainfall and high to moderate temperature and adequate rainfall.
Jowar, bajra and ragi are grown in India.
Other countries are Nigeria, China and Niger.
- Maize:
Maize requires moderate temperature, rainfall and lots of sunshine.
It needs well-drained fertile soils. Maize is grown in North America, Brazil, China, Russia, Canada, India, and Mexico.
- Cotton:
Cotton requires high temperature, light rainfall, two hundred and ten frost-free days and bright sunshine for its growth.
It grows best on black and alluvial soils.
China, USA, India, Pakistan, Brazil and Egypt are the leading producers of cotton.
It is one of the main raw materials for the cotton textile industry.
- Jute:
Jute was also known as the ‘Golden Fibre’.
It grows well on alluvial soil and requires high temperature, heavy rainfall and humid climate.
This crop is grown in the tropical areas.
India and Bangladesh are the leading producers of jute.
- Coffee:
Coffee requires warm and wet climate and welldrained loamy soil.
Hill slopes are more suitable for growth of this crop.
Brazil is the leading producer followed by Columbia and India.
- Tea:
Tea is a beverage crop grown on plantations.
This requires cool climate and well distributed high rainfall throughout the year for the growth of its tender leaves.
It needs well-drained loamy soils and gentle slopes.
Labour in large number is required to pick the leaves.
Kenya, India, China, Sri Lanka produce the best quality tea in the world.