Chapter 16 Conservation of Other Natural Resources

NIOS Class 12 Environmental Science Chapter 16

INTEXT QUESTIONS 16.1

1. Define resources and natural resources.

Ans: A Resource is anything useful or that can be made useful to humans to meet their needs. A resource that is directly available for use from nature is called a natural resource.

2. Give five examples of natural resources.

Ans: Examples of natural resources are – fresh air, fresh water, soil, forest, minerals and fossil fuels.

4. Name the top petroleum-producing region of India.

Ans: Our primary energy sources are crude oil (petroleum), natural gas and coal. They are formed in nature when plants and planktons get compressed under hard rocks for millions of years.

5. What are lignite and anthracite? How do they differ?

Ans: Lignite is brown coal with low heat content, and anthracite is hard coal with high heat content.

INTEXT QUESTIONS 16.2

1. How do you classify minerals?

Ans: Minerals are classified into metallic and non-metallic minerals. Non-metallic minerals include limestone, Dolomite, Mica, Gypsum, Phosphate, and Kyanite. Metallic minerals are further subdivided into Ferrous metallic minerals (Iron, Manganese, Chromite) and Non-ferrous metallic minerals such as Gold, Silver, Copper, Tin, Zinc, and Aluminium (Bauxite ore).

2. What are haematite, magnetite and limonite?

Ans: Most iron ores found in the country are of three types – Haematite, magnetite and limonite. Haematite is red in colour, called ‘red ore’ and has 68% iron. Magnetite is dark brown in colour, called ‘black ore’, and has 60% iron. Limonite is yellow in colour and has 35% iron.

3. What is limestone? What are its uses?

Ans: Limestone is a non-metallic mineral. It is used in the cement industry, the iron and steel industry, the sugar, paper, fertiliser and ferro manganese industries.

4. Which is the most important mica-producing region of India?

Ans: Bihar and Jharkhand are the most important mica-producing states of India.

5. How can you check the depletion of mineral resources?

Ans: Depletion of minerals can be checked by reuse, recycling of existing supplies, wasteless, useless, and finding a substitute.

INTEXT QUESTIONS 16.3

1. Write the difference between perpetual or unconditional natural resources and conditional natural resource?

Ans: Perpetual or unconditional renewable natural resources last forever on the human time scale. Conditional renewable natural resources must reproduce or regenerate to last forever.

2. How can soil become a non-renewable resource?

Ans: Soil formation is a natural process, so soil is a renewable resource. But formation of an inch of soil layer generally takes 200 to 1000 years, and soil erosion occurs much faster compared to the rate of soil formation, so it can become a non-renewable resource as the topsoil may be lost forever.

3. How is biodiversity of great significance in modern agriculture?

Ans: Biodiversity is of great use to modern agriculture in three ways:

As a source of new crops
As a source of material for breeding improved varieties.
As a source of new biodegradable pesticides.

4. Name the major ecosystems where species live and evolve.

Ans: The major ecosystems where species live and evolve are forest, ocean and grassland ecosystems.

TERMINAL EXERCISE

1. Define natural resources. Name two unconditionally renewable natural resources.

Ans: The resource that is directly available for use from nature is called a natural resource, which includes air, water from rainfall in lakes, rivers and wells, soil, land, forest, biodiversity, minerals, fossil fuels, etc. Solar energy and wind are the two unconditionally renewable natural resources.

2. How do you reduce the use of lead and steel in communication?

Ans: The amount of lead and steel used in telecommunication has decreased with the use of plastic.

3. What is the advantage of having a synthetic substitute for mica?

Ans: Synthetic substitutes of mica have reduced its export as well as production.

4. The ocean floor is rich in manganese nodules, but people are kept away from mining them. Give two reasons.

Ans: Manganese-rich nodules present on the deep ocean floor may be a future source of manganese and other important metals. They can be sucked up by giant vacuum pipes by a mining ship. But because of the high cost involved in the process and who owns them, the ocean has kept people away from this project.

5. When does a mineral element become economically depleted?

Ans: A mineral becomes “economically depleted” when it costs more to find, extract, transport and process the remaining deposit than its worth.

6. Suggest any four ways to check and reduce the depletion of minerals.

Ans: Ways to check and reduce depletion of minerals are as follows.

To check and reduce depletion of minerals, five choices are recycle or reuse existing supplies, wasteless, useless, find a substitute or do without.
When a resource (mineral) becomes scarce, its price rises. This can encourage exploration of new deposits, stimulate development of better mining technology and make it profitable to mine lower-grade ores.
It can also encourage a search for substitutes and promote resource conservation.
Substitution of more abundant materials like plastic and glass for scarce minerals is an important way to check depletion. The amount of lead and steel used in telecommunication has decreased with the use of plastic. Glass fibres have replaced copper wiring in telephone cables. Synthetic substitute of mica has reduced its export as well as production.
One way to improve mining technology is to use microorganisms to extract metals from their ores, known as “biomining” or ‘ecological engineering, which may be an economical and environmentally preferable way to mine metals.
The science of nanotechnology has immense potential in using atoms in producing or manufacturing everything from medicines to solar cells to automobile bodies. Thus, the job of many metals can be taken over by new materials produced by nanotechnology.

7. What is biomining, and what is its advantage?

Ans: The use of microorganisms to extract metals from their ores is known as “biomining” or ‘ecological engineering’, which may be an economical and environmentally preferable way to mine metals. Presently, 30% of all copper produced worldwide comes from such biomining. Biomining is economically feasible, especially with low-grade ores.

8. What are the main causes of land degradation? (Any three). Why should land degradation be checked? (Any three suggestions)

Ans: Human exploitation of land for various activities like agriculture, industry, housing, entertainment, etc., ultimately results in the degradation of land. The degraded lands have reduced capacity to sustain the healthy growth of crops and plants. Land and soil degradation must be checked for the following reasons –

To prevent soil erosion and landslides;
To maintain soil fertility;
For increasing biodiversity;
For maintaining economic growth.

9. Which is an unconditionally renewable resource. Give two examples.

Ans: An Unconditional renewable resource will last forever on the human time scale. Solar, wind and tidal energy are virtually inexhaustible resources on the human time scale.

Solar energy in the form of heat and light is delivered to the earth every day, whether we use it or not. Solar energy can be used in a regulated manner for space and water heating, or it can be converted into electricity by producing steam. The greater heating of the Earth by the sun at the equator than at the poles and the rotation of the Earth set up flows of air called wind. Thus, wind is an indirect form of solar energy and can be captured by wind turbines to generate electricity.

10. State any two methods to check the depletion of fresh water resources.

Ans: Fast depletion of fresh water resources must be checked, and the availability of water may be increased by:

Prevention of water wastage.
Increasing water use efficiency.
Recycling of water.
Capturing and storing more flood runoff.
Harvesting rainwater.
Desalinating seawater.

11. Which are the three levels at which biodiversity occurs?

Ans: These three levels of biodiversity that are interrelated include

(i) Genetic diversity

(ii) Species diversity

(iii) Ecosystem diversity.

12. What is the major cause of biodiversity loss?Ans: The increasing growth of the human population adversely affects rich and unique habitats and their biodiversity. Over-exploitation of ecosystems (forest, grasslands, oceans), habitat destruction and pollution are major causes of biodiversity loss. Over-exploitation of plants and animals may lead to extinction, thus a renewable resource may be lost forever. The overexploitation of living resources must be checked and stopped to conserve and maintain healthy biodiversity for the overall benefit of present and future generations.