Earth’s atmosphere is different from those of Venus and Mars. The atmosphere of Earth contains a mixture of nitrogen (78.08%), oxygen (20.95%), and a small fraction of carbon dioxide (0.03%), water vapours and other gases. This makes the existence of life possible on Earth. On the other hand, the atmosphere on Venus and Mars mainly contains carbon dioxide, i.e, about 95-97%. It may be the reason that due to this, no life is known to exist in both Venus and Mars.
The atmosphere acts as a blanket by performing the following functions:
(a) Ozone absorbs harmful UV radiations coming from the Sun.
(b) Carbon-dioxide and water vapours trap the heat and regulate the temperature of the Earth by keeping it ambient by absorbing heat rays during the day and by reflecting the heat trapped during the daytime at night.
(c) It slows down the escape of heat from the surface of the Earth into outer space during night time.
Therefore, the atmosphere covers and protects the Earth like a blanket.
Wind is caused by a difference in atmospheric pressure. Around areas of low pressure, air rises upwards in the atmosphere as air rises upwards, more air moves in (sideways) to replace it. As a result, a region of low pressure is created. Then, air from a high pressure region moves to a low pressure region, causing wind.
Clouds are formed when air contains as much water vapour as it can hold. This is called the saturation point and it can be reached in two ways. First, moisture accumulates until it reaches the maximum amount the volume of air can hold. The other method reduces the temperature of the moisture filled air, which in turn lowers the amount of moisture it can contain. Saturation, therefore, is reached through evaporation and condensation, respectively. When the saturation occurs, moisture becomes visible water droplets in the form of fog and clouds.
The following three human activities would lead to air pollution:
(i) Burning of fossil fuels like coal and petroleum.
(ii) Emission of harmful gases and dust particles from vehicles .
(iii) Smoke released from industries containing harmful gases like sulphur dioxide, oxides of nitrogen.
Organisms need water for the following reasons:
(i) All cellular processes need water for their functioning.
(ii) Substances dissolve in water for reactions to take place within the place.
(ii) Since most of the substances are transported in a dissolved form, water is necessary.
(iv) It helps to maintain body temperature.
River is a major source of freshwater.
The discharge of wastewater from homes, dumping of industrial waste, global warming, acid rain and oil pollution in the water body, etc. into the river pollutes this fresh water source.
Soil is the uppermost layer of earth crust formed by weathering of rocks. It is the mixture of living or non-living material. Soil formation is a bidirectional process, i.e from the upper side by decomposition (depends on sunlight, temperature, moisture, water) of detritus and from the lower side by breakdown of large rocks.
The blowing away or washing away of land surface by wind or water is known as soil erosion.
The methods of preventing or reducing soil erosion are:
(i) Afforestation or planting of trees.
(ii) Growth of vegetation.
During the water cycle, water is found in three different states such as solid state (snow, ice), liquid state (rain, ground water), and gaseous state (water vapour).
Two biologically important compounds that contain both oxygen and nitrogen are:
(i) Proteins.
(ii) Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).
The following three human activities would lead to air pollution:
(i) Burning of fossil fuels like coal and petroleum.
(ii) Emission of harmful gases and dust particles from vehicles.
(iii) Smoke released from industries containing harmful gases like sulphur dioxide, oxides of nitrogen.
The greenhouse effect is the way in which heat is trapped close to the surface of the Earth by “greenhouse gases”. These heat - trapping gases can be thought of as a blanket wrapped around the Earth, which keeps it tastier than it without them. Greenhouse gases include carbon dioxide, methane and nitrous oxides. An increase in the content of such gases would lead to a situation of global warming.
The two forms of oxygen found in the atmosphere are:
(i) Diatomic molecular form with chemical formula O2.
(ii) Triatomic molecular form with chemical formula O3 known as ozone.
The atmosphere is essential for life because it is the mixture of gases forming a blanket surrounding the Earth. It maintains an appropriate climate for the sustenance of life by carrying out the following activities :
(i) Atmosphere consists of oxygen. Oxygen is required by living organisms for its survival.
(ii) Atmosphere filters out the harmful ultraviolet rays of the Sun.
(iii) Atmosphere also slows down the escape of heat from the surface of the Earth into outer space during night time.
No living being on Earth can survive without water. Water is essential for life because of the following reasons:
(i) Water is a prerequisite for human health and well being as well as for the preservation of the environment.
(ii) Water is also necessary for agriculture and for many industrial processes.
Almost all living organisms are directly or indirectly dependent on soil. Plants obtain water, minerals from the soil and prepare food for animals.
On the other hand, other organisms that live in water are not totally independent of soil because the microbes growing on the soil in water are the primary producers which start the food chain and even microbes that live in the soil help in the decomposition of dead plants and animals in water to return the nutrients back to the water.
A daily weather forecast is the work of people working for the weather department to collect data on the elements of weather such as maximum and minimum temperatures, maximum and minimum humidity, rainfall, wind speed, etc. Weather satellites are present to take photographs of clouds from space. The maximum and minimum temperature of a day is measured by a thermometer known as the maximum−minimum thermometer. Rainfall is measured by an instrument known as the rain gauge. Wind speed is measured by anemometers. There are various instruments used to measure humidity.
Yes. Isolating human activities to specific areas would help in reducing levels of pollution.
For example ;
(i) Having heavy industries outside the main city will control pollution to some extent.
(ii) The pollution caused by these industries will not contaminate water resources, agriculture land, fertile land, etc.
Forests influence the quality of our air, soil, and water resources in various ways.
Some of them are:
(i) Adds nutrients to the soil due to the lot of vegetation present in the forest getting decomposed . Water : Forest helps in bringing rain and increasing the level of water in the underground and water bodies.
(ii) Forests prevent soil erosion. Roots of plants bind the soil tightly in a way that the surface of the soil cannot be eroded away by wind, water, etc.
(iii) Forests maintain the oxygen level in the atmosphere and also reduce the carbon dioxide level. Forests maintain the temperature of the environment.
Water is capable of dissolving a large number of substances. The soluble minerals contained by the flowing water over the rocks, some of them get dissolved in water. So, rivers carry many nutrients from land to the sea.
Crop rotation; Rotating in high-residue crops-such as corn, hay and small grain-can reduce erosion as the layer of residue protects topsoil from being carried away by wind and water. Conservation Tillage; Conventional tillage produces a smooth surface that leaves soil vulnerable to erosion.
Polluted water with chemicals causes serious effects on animals and human health and ecosystem. The general effects of water pollution are; death of aquatic organisms, disruption of food-chains, spreading various diseases and destruction of ecosystems.
We feel relief from the heat when we visit near the lake. The lake breeze forms during daylight in summer months because water does not warm as quickly as the surrounding land surfaces. Air cooled by contact with the cold lake water is denser than that surrounding the lake and thus forms a zone of relatively high pressure over the lake. When the sun heats land, the air above it warms becoming less dense. With high pressure over the lake and low pressure over land, the regional pressure gradient pushes cool winds towards the land. This is the lake breeze flow because of which we feel better during summer near the lake.
In coastal areas, Air moves from a region of high pressure to a region of low pressure. Air above the land gets heated quickly during the day and starts rising. This creates a region of low pressure as a result of which air above the sea rushes into this area of low pressure. This movement of air from one region to another creates winds. During night, as water cools down slowly, the air above water is warmer than the air on land. So, air moves from land to sea creating winds.
Lichens grow on rocks and release certain enzymes which favour the growth of mosses.
Mosses form clumps of soil from the rock which results in the formation of topsoil.
A biotic factor is a living thing that has an impact on another population of living things or on the environment. e.g; fungi, bacteria, animals, all living things etc. Abiotic factors do the same thing, but they are non-living. e.g; forest fires, water, climate, soil etc. Together, biotic and abiotic factors make up an ecosystem. To survive, biotic factors need abiotic factors. In turn, biotic factors can limit the kinds and amounts of biotic factors in an ecosystem.
All living organisms are basically made up of carbon, nitrogen, sulphur, phosphorus, hydrogen and oxygen. These chemical elements tend to circulate in the biosphere in a characteristic cyclic path, i.e., from environment to living organisms and back to the environment. These more or less circular paths are called biogeochemical cycles or nutrient cycles. In simple ways, these elements are absorbed by the plants from nature and convert them into food. This food passes through different trophic levels of various food chains for utilization by consumers. Finally, the decomposers return the inorganic nutrient to the environment by decomposing the dead bodies and excreta of various consumers.
The percentage of gases like oxygen, nitrogen and carbon dioxide remains almost the same in the atmosphere bcoz the cycling process of all these gases maintains their percentage in the atmosphere at a constant level. Constant recycling replenishes the lost gas in the atmosphere and balance is maintained.
Atmosphere plays a vital role in climate control and acts as a temperature buffer. It prevents the sudden increase in temperature during the day light hour and slows down the escape of heat into the outer space during night thereby preventing the excessive cooling during the night. In this way, the average temperature of earth remains fairly steady. Although the moon is at the same distance from the sun as the earth is, but since moon has no atmosphere, so the temperature on the surface of moon shows large variations. Moon gets heated up as sun’s rays fall on its surface and it cools down drastically when sun’s rays are not falling over it.
Due to the uneven heating of land and sea, there is movement of air leading to wind formation near seashore. Because of the wind created during day time people fly kites near the seashore.
Mathura refinery releases many air pollutants such as sulphur dioxide. SO2 reacts with water in the atmosphere to form sulphuric acid. This sulphuric acid is washed away into the soil by rain (acid rainfall). This acid erodes the stone, surface of buildings, affects salmon reproduction, brickworks, etc. Thus posing a great threat to Taj Mahal as they can destroy the marble quality and its colour, etc.
Lichens occur in those areas where there is substrate stability and low pollution intensity.
Further climatic factors like altitude, relative humidity, temperature etc also contribute to lichen growth.
Water is needed to be conserved because less than 1% of the total water content is freshwater which can be consumed by humans. The rest of the large oceans water is too salty for human consumption.
The following are the reasons for the mass mortality of fishes in a pond:
(i) Addition of hot water.
(ii) Addition of poisonous (mercury) compounds in water.
(iii) Due to blockage of gills of fishes with any pollutant.
Lichens release small quantities of acids which corrode the surface of rocks creating small pores and releasing minerals. With the passage of time the porous surface
changes into a thin layer of soil.
Soil formation takes hundreds to thousands of years, and, provided the site has remained undisturbed for that length of time, the soil profile reflects the natural history of the setting. Soil formation involves two major processes:
(1) slow chemical alteration by water seeping through the weathered rock material after rains.
(2) mixing of the rock material with organic debris produced by the decay of plants.
A fertile soil contains an adequate supply of all the nutrients required for plant growth. The full potential of crops is not realized if a shortage of nutrients occurs at any time during the growth cycle. This is true even though plants are capable of remarkable recovery from short periods of starvation. A fertile soil is not necessarily a productive one. The second major requirement is that the soil must be adequate for plant growth. This soil is based on environmental factors including texture, structure, soil water supply, pH, temperature and aeration.
Step farming is also called contour farming. Normally in hill areas there will be land slides. due tk this soil erosion will occur. Soil erosion will lead to leaching of soil nutrients. To avoid this step farming followed in those areas.
Root nodules are found on roots dicot plants. They contain beneficial bacteria called Rhizobium. Nitrogen is an important plant nutrient and plants have to get nitrogen in plant usable form which is not present in soil or air. What these rhizobium bacteria in the nodules do-is to fix the atmospheric nitrogen and convert it to plant usable form in the form of which plants take up the nitrogen required for them. Hence root nodules are beneficial for plants.
What are the causes of water pollution? Discuss how you can contribute in reducing water pollutionFossil Fuels are Coals,Crude Oil, Natural Gas present under the surface of earth, and all of them have an impact on the Air Quality. Burn a Coal and you will find out black fumes are produced apart from the heat generated. These fumes have very high concentration of Carbon Particles and inhaling it is injurious. Air pollution from coal causes asthma, cancer, heart and lung ailments, acid rain, global warming, and other severe environmental and public health impacts.
The smoke from coal power plants is exceedingly dangerous to human health.
1. Crude Oil: Crude Oil is a mixture of hydrocarbons consisting of alkanes,alkenes and alkynes. It is a very useful product as it provides us different sub products that make our day to day in the form of Diesel,Kerosene,Petrol,Aviation Fuels,Paraffin Wax, Petrochemical Products,etc.
2. The Storage: Transportation and Use of Fossil Fuels should be done with Utmost Care. Apart from being a contributor to pollutants in the air, it is also having a relatively low flash point and can catch fire easily .
First : In case the Fossil Fuel is left open : The volatile organic compounds (VOC)present mixes with the air and since many VOCs are carcinogenic, it would have a negative impact on the person.
Second : Burning of fossil fuels emit pollutants like NOx, Sox ,CO and Specifically Particulate Matters (PM10 and PM2.5) which should be within acceptable limits. Particulate Matters are dust particles where the dust particles are of diameters 10 micrometres for PM 10 and 2.5 micrometers for PM2.5 particles and inhaling them is injurious. PM 2.5 is more harmful compared to PM10 particles as the particles are very minute and get settled in the alveoli of the lungs which has serious long term ill effects on the health of the person.
3. Cleaner burning than other fossil fuels, the combustion of natural gas produces negligible amounts of sulfur, mercury, and particulates. Burning natural gas does produce nitrogen oxides (NOx), which are precursors to smog, but at lower levels than gasoline and diesel used for motor vehicles
Water pollution occurs when harmful substances—often chemicals or microorganisms—contaminate a stream, river, lake, ocean, aquifer, or other body of water, degrading water quality and rendering it toxic to humans or the environment. Some of the main causes of water pollution are:
Sewage: Sewage is another name for waste water from domestic and industrial processes. Despite strict regulatory control, the Environment Agency data shows that the water and sewage industry accounted for almost a quarter of the serious water incidents in England and Wales in 2006.
Agricultural Pollution: The agriculture industry covers 76% of the land area of England and Wales. Agricultural processes such as uncontrolled spreading of slurries and manure, disposal of sheep dip, tillage, ploughing of the land, use of pesticides and fertilisers can cause water pollution. Accidental spills from milk dairies can also affect the quality of water.
Radioactive substance: Radioactive waste is another source of water pollution. Radioactive substances are used in nuclear power plants, industrial, medical and other scientific processes. They can be found in watches, luminous clocks, television sets and x-ray machinery. There are also naturally occurring radioisotopes from organisms and within the environment. If not properly disposed of, radioactive waste can result in serious water pollution incidents.
River Dumping: Lots of people dump supermarket trolleys, bicycles, garden cuttings and electronic waste into rivers or river banks. This is illegal and offenders may be charged for fly-tipping if caught. River dumping not only causes water pollution; it also harms wildlife and increases the risk of flooding. Fly-tipping (this includes river dumping) is a criminal offence. In the most severe cases, it can attract a maximum fine of £50,000 or a 5 year jail term.
Marine Dumping: The Worldwide Fund for Nature (WWF) estimates that a staggering amount of waste enters into the sea every year. Part of this is due to deliberate dumping of waste into coastal waters. Other sources of waste at sea include plastics and other materials blown or washed from land. Marine dumping is illegal under international and UK legislation.
Few tips on preventing water pollution:
A motor car with its glass totally closed is parked directly under the sun. Sunlight emits ultraviolet radiations which pass through the glass and heat the car. The radiations emitted by inner parts of the cannot pass out of the glass, so the heat trapped inside raises the temperature of the interior.
Dust is also considered as a pollutant of air. It is concentrated with the pollen grains which also are considered as dust. Dust is released by constructions, factories,
industries, plants, mining activities etc. Dust mainly constitutes solid particles less than 500 micrometres in size. It is made up of unburnt carbon particles, skin cells, pollen grains, hair, fine grains of minerals, thin fibres, soil particles etc. All these particles of dust make it a pollutant. Dust causes respiratory diseases, skin diseases etc.
Under the influence of solar radiations, the rocks heat up and expand. At night, these cool down and contract. Since all parts of the rocks do not expand and contract at the same rate, cracks appear in the rocks and ultimately the large rocks break up into smaller pieces.
Carbon Dioxide is necessary for Photosynthesis in Plants. Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the sun, into chemical energy that can be later released to fuel the organism's activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water. In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis, and such organisms are called photoautotrophs. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth. Rising carbon dioxide (CO2) levels from burning fossil fuels have been linked to sea level changes, snowmelt, disease, heat stress, severe weather, and ocean acidification.This heats up the atmosphere which further leads to an increase in earth’s average temperature. This phenomenon is called global warming.