EVS

 EVS Notes:

 

Q1. Mention few reasons for air pollution.

Ans: Causes of air pollution:

1. Burning of fossil fuels and fibers.

2. Cutting of forests.

3. Eruption of volcanoes.

4. Increase in population.

5. Agricultural activities like use of chemical fertilizers, insecticides, pesticides and burning of husks etc.

Q2. What are renewable and non-renewable resources? Explain with suitable examples.

Ans:

Q3. What is deforestation? Analyze its cause and consequences.

Ans: Deforestation refers to the decrease in forest areas across the world that are lost for other uses such as agricultural croplands, urbanization, or mining activities. Greatly accelerated by human activities since 1960, deforestation has been negatively affecting natural ecosystems, biodiversity, and the climate. The UN’s Food and Agriculture Organization estimates the annual rate of deforestation to be around 1.3 million km2 per decade.

Causes:

·         Forests are being converted to agricultural land to feed the world's rising population.

·         Trees are felled for various reasons, including timber, firewood, and cow ranching.

·         Slash-and-burn agriculture, known in India's north-eastern states as Jhum cultivation, has also contributed to deforestation.

·         Construction of houses and other structures.

·         Forest fires are sparked by lightning and other natural phenomena.

Q4. Differentiate between Ecology and Ecosystem.

Ans: Difference Between Ecology and Ecosystem

₪An ecosystem is a natural unit comprising all living and non living things in the area and how biotic and abiotic components function together while influencing each other. Thus it talks about not just the living organisms but also abiotic factors that affect life inside the system.

₪Ecology is a comprehensive study of organisms and their relation with the environment they live in and interact with one another. It includes the amount and spread of organisms and how and why their distribution is affected by their relationship with the environment. An ecosystem on the other hand is a sub-set of ecology and mean all the complicated interactions that take place among living and non-living things in an area.

₪ Ecology is the study of the relationship between living organisms and their environment. An ecosystem is a place, such as a rotting log, a forest, or even a schoolyard, where interactions between living and non-living things occur. All living organisms and non-living parts within this place are interacting all the time and adjustments must occur if the organisms are to survive. Living organisms make up the biotic components of the ecosystem, while non-living things make up the abiotic parts of the same ecosystem. Ecosystems vary in size and complexity.

Q5. What is food chain? State its importance.

Ans: A food chain explains which organism eats another organism in the environment. The food chain is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. This occurs when one organism consumes another organism. It begins with the producer organism, follows the chain and ends with the decomposer organism. Importance of food chain are:

 

1.      Food chains show the intricate relationships in ecosystems.

2.      Food chains reveal how each organism depends on other organisms for survival.

3.      These display what happens when a producer or consumer is lost.

4.      Food chains help scientists learn more about ecosystems and it also helps them to make them keep the balance of the ecosystems.

5.      The food chains are considered as the living components of the biosphere.

6.      Food chains help to transfer energy from one level to another.

7.      Through the food chains, transfer of materials and nutrients also takes place.

8.      The food chain gives a picture of organisms in an ecological community that are linked to each other through the transfer of energy and nutrients.

9.      A food chain describes the method in which a particular organism collects its food.

10.  Everyone needs the energy transmitted through a food chain in order to survive.

 

 

Explain the various components of ecosystem.

Notes already given.

What is biodiversity? What methods will you use to conserve the biodiversity.

Biodiversity conservation is the protection and management of biodiversity to   obtain   resources for sustainable development.

 

        Biodiversity conservation has three main objectives:

 

·         To preserve the diversity of species.

·         Sustainable utilization of species and ecosystem.

·         To maintain life-supporting systems and essential ecological processes.

Methods to conserve: It is believed that an area with higher species abundance has a more stable environment compared to an area with lower species abundance. We can further claim the necessity of biodiversity by considering our degree of dependency on the environment. We depend directly on various species of plants for our various needs. Similarly, we depend on various species of animals and microbes for different reasons.

Following are the important strategies for biodiversity conservation:

 

1.      All the varieties of food, timber plants, livestock, microbes and agricultural animals should be conserved.

2.      All the economically important organisms should be identified and conserved.

3.      Unique ecosystems should be preserved first.

4.      The resources should be utilized efficiently.

5.      Poaching and hunting of wild animals should be prevented.

6.      The reserves and protected areas should be developed carefully.

7.      The levels of pollutants should be reduced in the environment.

8.      Deforestation should be strictly prohibited.

9.      Environmental laws should be followed strictly.

10.  The useful and endangered species of plants and animals should be conserved in their nature as well as artificial habitats.

11.  Public awareness should be created regarding biodiversity conservation and its importance.

   What is soil pollution? Explain the sources and control measures of soil pollution.

Ans: Soil pollution is defined as the presence of toxic chemicals (pollutants or contaminants) in the soil, in very high concentrations to pose a risk to human health and the ecosystem. Or in simple words Alteration in the natural soil due to human activities is termed Soil Pollution. For example, exposure to soil containing high concentrations of benzene can increase the risk of soil pollution diseases like contracting leukemia.

Types of Soil ​Pollution

 

1.      Agriculture soil pollution is caused due to the excessive use of pesticides and insecticides.

 

2.      Soil Pollution by industrial discharges of chemicals from mining and manufacturing of goods.

 

3.      Solid waste soil pollution/ Poor management or inefficient disposal of waste.

 

4.      Soil Pollution due to urban activities. Etc

 

Causes:

1.      The use of insecticides and pesticides for a long period can cause soil pollution. Repetitive use can cause insects and pests to become resistant to it. Instead of killing pests and insects, it degrades the soil quality. They are full of chemicals that are not produced in nature and cannot be broken down by them. As a result, they seep into the ground after they mix with water and slowly reduce the fertility of the soil. Plants absorb many of these pesticides, and after decomposition cause soil pollution.

2.      Disposal of plastics and other solid waste is a serious issue that causes soil pollution, disposal of electrical items such as batteries causes an adverse effect on the soil due to the presence of harmful chemicals. Eg: lithium present in batteries can cause the leaching of soil. Human waste such as urine, faeces, diapers, etc is dumped directly in the land. It causes both soil and water pollution.

3.      It is caused when pollutants present in the air mix with the rain and fall back on the ground. The polluted water could dissolve away some of the essential nutrients found in soil and change the structure of the soil thus making it unsuitable for agriculture.

 

Discuss the different methods of conservation of water.

Ans: A little water conservation methods that can be practised by individuals to reduce the wastage of water are provided below.

1.      Installing flow-restricting shower heads to save water during showers.

2.      Taking bucket-baths instead of showers.

3.      Turning off the tap while shaving or brushing teeth.

4.      Immediately fixing any leaking taps and pipes in our homes.

5.      Practising rainwater harvesting to reduce the wastage of rainwater.

 

(i) Explain the following conservative methods:

a) In-situ conservation

b) Ex-situ conservation

 

Ans:

(ii) Discuss the effects of global warming. Write about your role to reduce the global

warming.

Ans: Global warming:

Long term rise in temperature of the Earth's surface is called global warming.

Causes:

1. Increase in the atmospheric levels of gases (CO2, CH4, NO2, etc.) due to extensive burning of fossil fuels. 
2. Accumulation of these gases in higher concentration does not allow the Earth's heat to escape in the outer atmosphere, thus leading to increase in its surface temperature.

Effects:

1. Temperature of the lower atmosphere rises.
2. Ocean water gets heated and expands.
3. Low coastal areas will get flooded.
4. Regional patterns or precipitation (rain and snow) will be affected. 
5. Glaciers and polar ice sheets will melt faster.

Measures to be taken to control global warming:

1. Reduce usage of fossil fuels. 
2. Control release fo greenhouse gases in the atmosphere.
3. Reforestation to fix CO2 and NO2. 
4. Control in human population growth.

 

What is sustainable development? Briefly describe the concept and important pillars of

sustainable developments.

 

Ans: The concept of sustainable development aims to encourage the use of products and services in a manner that reduces the impact on the environment and optimizes the resources in order to satisfy human needs. To understand why sustainable development is the need of the hour, take a look at the following key pointers that elucidate upon its importance:

 

1.      Development of non-polluting renewable energy systems

2.      Population stabilization

3.      Integrated land-use planning

4.      Healthy cropland and grassland

5.      Woodland and re-vegetation of marginal lands

6.      Conservation of biological diversity

7.      Control of pollution in water and of the air

8.      Recycling of waste and residues

9.      Ecologically compatible human settlements

10.  Environmental education and awareness at all levels

The three pillars of sustainable development are:

   Q9. Explain the causes, effects and control measures of air pollution.

Ans: Causes of Air Pollution

Following are the important causes of air pollution:

Burning of Fossil Fuels

The combustion of fossil fuels emits a large amount of sulphur dioxide. Carbon monoxide released by incomplete combustion of fossil fuels also results in air pollution.

Automobiles

The gases emitted from vehicles such as jeeps, trucks, cars, buses, etc. pollute the environment. These are the major sources of greenhouse gases and also result in diseases among individuals.

Agricultural Activities

Ammonia is one of the most hazardous gases emitted during agricultural activities. The insecticides, pesticides and fertilisers emit harmful chemicals in the atmosphere and contaminate it.

Factories and Industries

Factories and industries are the main source of carbon monoxide, organic compounds, hydrocarbons and chemicals. These are released into the air, degrading its quality.

Mining Activities

In the mining process, the minerals below the earth are extracted using large pieces of equipment. The dust and chemicals released during the process not only pollute the air, but also deteriorate the health of the workers and people living in the nearby areas.

Domestic Sources

The household cleaning products and paints contain toxic chemicals that are released in the air. The smell from the newly painted walls is the smell of the chemicals present in the paints. It not only pollutes the air but also affects breathing.

Effects of Air Pollution

The hazardous effects of air pollution on the environment include:

Diseases

Air pollution has resulted in several respiratory disorders and heart diseases among humans. The cases of lung cancer have increased in the last few decades. Children living near polluted areas are more prone to pneumonia and asthma. Many people die every year due to the direct or indirect effects of air pollution.

Global Warming

Due to the emission of greenhouse gases, there is an imbalance in the gaseous composition of the air. This has led to an increase in the temperature of the earth. This increase in earth’s temperature is known as global warming. This has resulted in the melting of glaciers and an increase in sea levels. Many areas are submerged underwater.

Acid Rain

The burning of fossil fuels releases harmful gases such as nitrogen oxides and sulphur oxides in the air. The water droplets combine with these pollutants, become acidic and fall as acid rain which damages human, animal and plant life.

Ozone Layer Depletion

The release of chlorofluorocarbons, halons, and hydrochlorofluorocarbons in the atmosphere is the major cause of depletion of the ozone layer. The depleting ozone layer does not prevent the harmful ultraviolet rays coming from the sun and causes skin diseases and eye problems among individuals.

Effect on Animals

The air pollutants suspend in the water bodies and affect aquatic life. Pollution also compels the animals to leave their habitat and shift to a new place. This renders them stray and has also led to the extinction of a large number of animal species.

Air Pollution Control

Following are the measures one should adopt, to control air pollution:

Avoid Using Vehicles

People should avoid using vehicles for shorter distances. Rather, they should prefer public modes of transport to travel from one place to another. This not only prevents pollution, but also conserves energy.

Energy Conservation

A large number of fossil fuels are burnt to generate electricity. Therefore, do not forget to switch off the electrical appliances when not in use. Thus, you can save the environment at the individual level. Use of energy-efficient devices such as CFLs also controls pollution to a greater level.

Use of Clean Energy Resources

The use of solar, wind and geothermal energies reduce air pollution at a larger level. Various countries, including India, have implemented the use of these resources as a step towards a cleaner environment.

Other air pollution control measures include:

1. By minimising and reducing the use of fire and fire products.
2. Since industrial emissions are one of the major causes of air pollution, the pollutants can be controlled or treated at the source itself to reduce its effects. For example, if the reactions of a certain raw material yield a pollutant, then the raw materials can be substituted with other less polluting materials.
3. Fuel substitution is another way of controlling air pollution. In many parts of India, petrol and diesel are being replaced by CNG – Compressed Natural Gas fueled vehicles. These are mostly adopted by vehicles that aren’t fully operating with ideal emission engines.
4. Although there are many practices in India, which focus on repairing the quality of air, most of them are either forgotten or not being enforced properly. There are still a lot of vehicles on roads which haven’t been tested for vehicle emissions.
5. Another way of controlling air pollution caused by industries is to modify and maintain existing pieces of equipment so that the emission of pollutants is minimised.
6. Sometimes controlling pollutants at the source is not possible. In that case, we can have process control equipment to control the pollution.
7. A very effective way of controlling air pollution is by diluting the air pollutants.
8. The last and the best way of reducing the ill effects of air pollution is tree plantation. Plants and trees reduce a large number of pollutants in the air. Ideally, planting trees in areas of high pollution levels will be extremely effective.

 

 

What do you mean by hot spots of biodiversity? Write about the salient features of hot spots in India.

Ans: According to Conservation International, a region must fulfill the following two criteria to qualify as a hotspot:

 

·         The region should have at least 1500 species of vascular plants i.e., it should have a high degree of endemism.

·         It must contain 30% (or less) of its original habitat, i.e. it must be threatened.

·         Following the criteria must for an area to be declared as Biodiversity Hotspot

1.      The Himalayas

2.      Indo-Burma Region

3.      The Western Ghats

4.      Sundaland

 

The Himalayas

 

Considered the highest in the world, the Himalayas (overall) comprises North-East India, Bhutan, Central and Eastern parts of Nepal. This region (NE Himalayas) holds a record of having 163 endangered species which includes the Wild Asian Water Buffalo, One-horned Rhino; and as many as 10,000 plant species, of which 3160 are endemic. This mountain range covers nearly 750,000 km2.

 

Indo – Burma Region

 

The Indo-Burma Region is stretched over a distance of 2,373,000 km². In the last 12 years, 6 large mammal species have been discovered in this region: the Large-antlered Muntjac, the Annamite Muntjac, the Grey-shanked Douc, the Annamite Striped Rabbit, the Leaf Deer, and the Saola.

 

This hotspot is also known for the endemic freshwater turtle species, most of which are threatened with extinction, due to over-harvesting and extensive habitat loss. There are also 1,300 different bird species, including the threatened White-eared Night-heron, the Grey-crowned Crocias, and the Orange-necked Partridge.

 

The Western Ghats

 

The Western Ghats are present along the western edge of peninsular India and covers most of the deciduous forests and rain forests. As per UNESCO, it is home to at least 325 globally threatened flora, fauna, bird, amphibian, reptile and fish species. Originally, the vegetation in this region was spread over 190,000 km2 but has been now reduced to 43,000 km2. The region is also known for the globally threatened flora and fauna represented by 229 plant species, 31 mammal species, 15 bird species, 43 amphibian species, 5 reptile species and 1 fish species. UNESCO mentions that “Of the total 325 globally threatened species in the Western Ghats, 129 are classified as Vulnerable, 145 as Endangered and 51 as Critically Endangered.”