EVIDENCES OF EVOLUTION

        The word “evolution” is derived from the Latin word “evolvere” which means to “unroll” or “unfold”. Thus, the theory of Organic Evolution states that it’s a kind of gradual unfolding or formation of more complex, advanced and present day forms from simple and primitive organisms living in the past,millions of years ago. 

There are various evidences available to prove this point. viz.

(a) Morphological and Anatomical Evidences

(b) Embryological evidences

(c) Paleontological (Fossils) evidences: The study of fossils (paleontology) is the best and most direct conventional type of evidence, e.g., the fossil of Archaeopteryx*. (“Archaeo” means primitive and “ptera” means wings in Latin) is a classical example of evolution of birds from reptiles, because it contains features of both the forms. Similarly, the world famous fossil of “Lucy” (Australopithecus afarensis) shows that “bipedal” locomotion arose for the first time in ancestral man here and finally led to the development of erect “modern” man.

(d) Biogeographical evidences

(e) Biochemical evidences: The most convincing evidence of common ancestry comes from similarities of certain biomolecules viz. composition of protoplasm, enzymes, cytochrome ‘C’ (respiratory pigment present in all eukaryotic cells), blood serum proteins, hemoglobin, insulin, etc. The degree of molecular homology is more in closely related forms and vice versa, e.g.,amino acid sequence for cytochrome ‘C’ of humans and chimpanzee is identical.

(f) Genetic evidences or Molecular evidences: These are the latest observable tools in determining the phylogenetic relationships between organisms and allow molecular comparisons even between very uncommon relatives with no morphological, behavioural, physiological or ecological relationships e.g., bacteria and humans. Some of the molecular tools used to prove evolutionary relationships are:

•         Amino acid analysis or sequencing e.g., Hb, Mb sequencing in para and orthologous species.
•         Nucleotide sequence analysis (data from 5S ribosomal RNA)
•         DNA hybridisation
•         Restriction enzymes: which cleave DNA into fragments at particular sites like ECORI from                          E. coli. They allow comparisons among DNA of different species                                           
•         RFLPs (Restriction Fragment Length Polymorphisms) 

•         Mitochondrial DNA and microsatellites, etc.

 EVOLUTION OF LIFE

        The  theories explained how life must have originated on early primitive earth about 3.5 billion years ago, but it did not give any information about how the biological diversity arose. Again, there were different views about how this must have happened.

    Some of the dominant thoughts were: (i) Greek Theories (ii) Pre-modern Theories and (iii) Modern Theories. 

Among the Modern Theories, the following two are most popular. 

Theory of Inheritance of Acquired Characteristics

This theory was proposed by famous French naturalist Jean Baptiste Lamarck. It propounded that the characters were acquired by the organisms due to an “inner need” or “desire” of the organism and these acquired characters were then inherited. This theory was subsequently rejected.

Theory of Natural Selection

Charles Darwin, who is better known as the “Father of Evolution” was the architect of this world famous theory, which charmed both the scientists as well as laymen. This theory took shape when Darwin was aboard H.M.S. Beagle, the famous ship, for a voyage planned for world exploration.According to him, the struggle for existence, due to limited availability of resources, led to the survival of the fittest or natural selection

 ORIGIN OF LIFE

We salute the spirit of inquisitiveness of man, which gave birth to the discipline of science. The same spirit of questioning also led man to often wonder how life or the first organism came into existence. This quest led him to find answers to how, when and where life originated.

        For centuries, it was believed that life originated de novo. In addition several other scientific and non-scientific theories were also put forward.

Some of them are:

(i) Theory of special creation: (or Biblical Theory) – It was put forward by Father Suarez, a

Spanish Monk.

(ii) Theory of spontaneous generation (or Abiogenesis): (Gr, ‘a’ – absence, “bios” – life,

“genesis” – origin) or origin from non-living matter.

(iii) Theory of Panspermia or Cosmozoic Theory: According to this theory, life came from some

other planet. It’s still believed to be true by some scientists like Wikramsinghe, Francis Crick

and Leslie Orgel.

(iv) Biogenesis: Francesco Redi and Louis Pasteur laid the foundation for the Theory of

Biogenesis, which propounded that living organisms arise from pre-existing ones and not from

non-living matter.

(v) Chemosynthetic Theory or Chemogeny: This theory proposed that first form of life originated

from inorganic chemical elements by formative action of some external physical force viz.

lightening or cosmic rays, etc. It was put forward by A.I. Oparin and J.B.S. Haldane and the

experimental evidence was provided by Stanley Millar & Harold Urey. For example, Mighi

meteorite in Ukraine and analysis of another meteorite content viz. Murchison, Victoria in

Australia by space biologists also revealed similar composition indicating that similar processes

are still occurring elsewhere in space. However, in this case, although the presence of amino

acids and polynucleotide are similar to DNA, these are of chemical origin and therefore have

identical strands instead of complementary strands.

 SAVIOURS OF BIODIVERSITY

Environmental pollution is causing a lot of distress not only to humans but also to animals, driving many animal species to endangerment and even extinction. Methods are being devised to save this precious biodiversity.

GREEN CHEMISTRY

Green Chemistry is a specific type of prevention of pollution. It involves the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. It has been applied to a wide range of industrial and consumer goods, including paints, dyes, fertilizers, pesticides, plastics, medicines, electronics, dry cleaning, energy generation and water purification.

          Hazard is simply another property of a chemical substance. As properties of chemicals are because of their specific molecular structure, they can be modified by changing that structure. Various types of hazards that can be handled by Green Chemistry include physical hazards (being explosive or inflammable), toxicity (being carcinogenic or cancer causing, or lethal) or global hazards (climate change or stratospheric ozone depletion). Like a substance can be designed to have a low melting point or green colour, it can also be designed to be non-toxic.

Tools used in Green Chemistry

By choosing an alternate synthetic design, we focus not on the ultimate molecule but on the synthetic pathway used to create it. Modification of the synthesis can lead to the same final product, yet reduce or eliminate toxic starting materials, by-products and wastes. The following tools can be used to modify a synthesis:

1. Alternative Feedstocks (Starting Materials) The selection of a feedstock, i.e., the starting material used for the manufacture of a product, determines what hazards will be faced while handling this substance. A feedstock must be evaluated to determine whether it possesses chronic toxicity, carcinogenicity, ecotoxicity, etc. Currently, most of the organic chemicals are made from petroleum feedstocks. Petroleum undergoes oxidation during conversion to useful organic chemicals. This oxidation step is one of the most environmentally polluting steps of chemical synthesis. It has contributed to the risk to human health and the environment, mainly through the use of heavy metals, like chromium, as oxidising agents. It is, therefore, important to reduce the use of petroleum-based products. Agricultural and biological feedstocks are excellent alternative starting materials. They are already highly oxygenated. Therefore, their use eliminates the need for the polluting oxygenation step. A raw material or feedstock should be renewable rather than depleting. Petroleum and other fossil-fuel based feedstocks are depleting and feedstocks based on biomass and agricultural wastes are renewable. At present a host of agricultural products like soy, potatoes, corn and molasses are being transformed through a variety of processes into consumer products like textiles, nylon etc.

2. Alternative Reagents Alternative reagents are being increasingly used to carry out synthesis. For example, heavy metals, used in petroleum oxidation processes, are quite toxic and carcinogenic. They are being replaced by light to carry out the required transformation.

3. Alternative Solvents Many solvents commonly used in synthesis are volatile organic compounds (VOCs) that cause smog when released in air. Individuals with respiratory problems suffer great distress because of this environmental effect. Solvents like methylene chloride, chloroform, carbon tetrachloride, benzene, etc. have been identified as suspected human carcinogens. The uses of chlorofluorocarbons (CFCs) range from cleaning solvent, propellant, blowing agent for moulded plastic foams, to refrigeration. CFCs have very low direct toxicity to humans and wildlife, and are both nonflammable and non-explosive. However, CFCs are known culprits of ozone layer depletion. Some of the alternatives to these organic solvents include the use of supercritical or dense phase fluids, such as supercritical carbon dioxide. This system is not harmful from human health and environmental point of view.

            Supercritical fluids are obtained by subjecting small molecules, like carbon dioxide, to the appropriate temperature and pressure to attain the critical point at which the molecules possess the character of a fluid which is a cross between a liquid and a gas. The properties of this fluid (solvent) can be adjusted by adjusting the parameters of temperature and pressure. Supercritical solvent systems are now replacing a variety of other traditional organic solvents.

                Now methods are being developed where the reagents and feedstocks serve as the solvent as well. In some cases the reagents and feedstocks are made to react in the molten state to ensure proper mixing and optimal reaction conditions, or on solid surfaces such as specialised clays. Thus, ways are being designed to carry out reactions in solventless systems. If a solvent is essential for a particular synthesis, then the most innocuous one must be selected. Water is the safest solvent possible. A major problem with many solvents in relation to human health and the environment is their ability to volatilise. The use of immobilised solvents may serve as a solution. Immobilisation can be done by binding the solvent molecule to a solid support (polymer), so that it becomes non-volatile. Some polymers are beingdeveloped which have solvent properties and are not hazardous.

4. Alternative Product (Target Molecule) While designing safer chemicals (target molecules), the object is to maximise the functional benefits of a molecule and minimise or eliminate its toxicity or other hazards. This is done by identifying the part or parts of the molecule that produce toxic effects, and also those that are responsible for its desired function. The part related to the toxic effect can be avoided or suitably changed to reduce or eliminate the toxic effect.

        Another way to reduce hazardous effects of a substance is to minimize its bioavailability. If a toxic substance is not able to reach its target organ (e.g. heart, lungs, liver), where it can manifest its toxicity, then it is rendered innocuous for all purposes. By changing the physical and chemical properties of a molecule, like solubility in water and polarity, the absorption of molecules through biological membranes and tissues can be made difficult or impossible. Elimination of absorption and bioavailability leads to reduction in toxicity.

5. Green Analytical Chemistry The detection, measurement and monitoring of chemicals in the environment is done through Analytical Chemistry. Instead of determining environmental problems after they occur, Green Chemistry seeks to prevent the formation of toxic substances. Even minute amounts of toxic substances are detected with the help of sensors and process controls are adjusted to minimise or stop its formation.

6. Alternative Catalysts Catalysis has increased the level of efficiency of chemical synthesis, and has also brought about environmental benefits. Use of new catalysts has eliminated the need for large quantities of reagents that would have been otherwise required to carry out those syntheses. Such large amounts of regents would have increased the bulk of the waste stream.

7. Minimal Energy Requirements Energy requirements of a synthetic procedure should be minimised because energy generation and consumption bring about a major environmental effect. The advantage of using a catalyst is that it lowers the energy of activation needed to accomplish a reaction, and therefore, minimises the thermal energy required for the transformation.

        Microwave energy is now being utilised in order to effect chemical reactions rapidly, and generally in the solid state. This eliminates prolonged heating necessary to carry out a reaction. Through the use of ultrasonic energy, the conditions of the reactants are considerably changed to promote a chemical transformation.

8. Alternative Methodology Unnecessary use of blocking groups, protecting groups, additional functional groups should be avoided, because this requires use of materials (often hazardous) to make the substance and generates a waste in the regeneration of the original substance.

        Some methods make use of toxic chemicals such as cyanide or chlorine. In addition, these methods at times generate large quantities of hazardous wastes. For example, the pulp and paper industry uses chlorine compounds in processes that generate toxic chlorinated organic waste. Green chemists have developed a new technology that converts wood pulp into paper using oxygen, water, and polyoxometalate salts. Water and carbon dioxide are the only by-products. Substances used in a chemical process should be chosen so as to minimise the chances of chemical accidents, including explosions and fires.

9. Designing for Biodegradability Chemical products should be designed so that after their function is over they do not persist in the environment and do not accumulate in plant or animal systems, but break down into innocuous degradation products. Plastics are known for their durability and long life. That is why they cause environmental concerns in oceans and other aquatic media. Pesticides tend to bioaccumulate in many plant and animal species, thereby causing damage to the species itself, or, to humans if consumed. These products should be designed so that they do not remain in their initial state in the environment after their useful life is over. Their degradation products also should not be toxic or hazardous.

10. Green Chemistry Evaluation Whether dealing with a reagent, solvent, product, starting material or the process itself, the following essential characteristics need to be known to conduct a Green Chemistry evaluation:

(i) Toxicity to humans

(ii) Toxicity to wildlife

(iii) Effects on the local environment

(iv) Global environmental effects 

 ENVIRONMENTAL POLLUTION

Pollution is the introduction of contaminants into the environment that cause harm or discomfort to humans or other living organisms, or that damage the environment. India has been ranked as the seventh most environmentally hazardous country in the world. Brazil is the worst, United States is second worst and China is third. Singapore has been found to be the best.

There are three major types of environmental pollution:

Air Pollution

Water Pollution

Soil Pollution

Air Pollution

Some of the most important air pollutants are Sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone, volatile organic compounds (VOCs) and airborne particles. Radioactive pollutants are the most destructive ones specially when produced by nuclear explosions. Carbon dioxide and water vapour present in the atmosphere, strongly absorb a large fraction of the earth’s emitted radiation. This absorbed radiation is partly re-emitted to the earth’s surface. The net result is that the earth’  surface gets heated up by a phenomenon called the Greenhouse Effect.

Deforestation and combustion of fossil fuels (oil, gas, coal) have a cumulative effect on the net increase in carbon dioxide content. Forests are the areas where a great deal of photosynthesis occurs, which helps in maintaining a balance in the atmospheric carbon dioxide level.

Trees and animals contribute large quantities of hydrocarbons (mainly methane) to the atmosphere. Harmful effects of hydrocarbon pollution are due to the photochemical reactions in which they are involved. Large quantities of automobile exhausts in the atmosphere exposed to intense sunlight leads to the formation of photochemical oxidants. This gives rise to photochemical smog (Characterised by brown, hazy fumes) which irritates the eyes and lungs, leads to the cracking of rubber and extensive damage of plant life. Smog is a combination of smoke and fog. Smog containing high levels of sulphur dioxide is called reducing smog. Peroxyacyl nitrate (PAN) is a potent eye irritant found in photochemical smog.

Oxides of nitrogen and sulphur entering the atmosphere are converted into nitric acid and sulphuric acid respectively. They combine with hydrochloric acid from HCl emission to generate acidic precipitation known as acid rain. Acid rain is now a major pollution problem in some areas. It causes extensive damage to buildings and sculptural materials of marble, limestone, slate, mortar, etc. It is harmful for aquatic plants and animals, and causes soil acidification.

Small solid particles and liquid droplets are collectively called particulates. These are present in large amounts in the atmosphere and sometimes pose a serious air-pollution problem. Examples of processes which inject particulate matter into the atmosphere: volcanic eruptions, blowing of soil and dust by wind, formation of fly ash from power plants, smelters and mining operations, and smoke from incomplete combustion processes. Airborne asbestos (a fibrous silicate mineral) and toxic metals like beryllium are carcinogenic. Fine particles (less than 3 microns) are the worst causes of lung damage. Coal miners’ black-lung disease, and asbestos workers’ pulmonary fibrosis are associated with the accumulation of such small particles. Very fine particulate matter, which is less than 2.5 microns in size, is called PM 2.5 and is known to cause diabetes and cardiovascular diseases. 

Air in Delhi is choking with pollutant PM 2.5. Any kind of combustion, especially of vehicular origin, contains this particle. If PM 2.5 is not regulated it will increase the number of patients suffering from asthma and lung cancer. It brings about lead deposition in the lungs. Particulates accelerate corrosion of metals and cause damage to buildings, sculptures, paints, etc. Particulates in the atmosphere reduce visibility and influence the climate through the formation of clouds, rain and snow.

Burning CNG has the highest rates of potentially hazardous carbonyl emissions. Retrofitted CNG car engines emit 30% more methane than original CNG engines. Almost all CNG car engines in India are retrofitted. Coal pollution kills more than 300,000 people every year. Nitrogen and sulphur oxides emitted by aircrafts, at an altitude of 35,000 ft, combine with other gases in the atmosphere to create harmful pollutants.

Vehicle emission is responsible for 70% of the air pollution in India. Bangalore is called the asthma capital of India. The levels of suspended particulate matter are above permissible limits in Mumbai. 

Bhopal gas tragedy was the greatest industrial disaster in the world that took place at a Union Carbide pesticide plant in the Indian city of Bhopal, Madhya Pradesh. On 3rd December, 1984 (midnight), the plant accidentally released methyl isocyanate (MIC) gas. Within a week about 10,000 people died, 1,000 became blind while more than 1 lakh continued to suffer from various disorders. This was the deadliest man made environmental disaster in history.

On 14 July 2010, chlorine gas leaked from the Sewri industrial area on land owned by the Mumbai Port Trust and approximately 76 people were treated in hospital. Rice crop yields in Southern India are decreasing as brown clouds are increasingly blocking the sunlight. The brilliant white of the famous Taj Mahal is slowly fading to a sickly yellow. The Supreme Court ordered the closure of more than 200 factories to save the Taj Mahal from being polluted by fumes.

There has been a drastic fall in the number of butterflies in the Western Himalayas, famous for their biodiversity. In areas of Himachal Pradesh, and Jammu and Kashmir, the population of 50% of the 288 species has declined more than half in just 10 years. Over 700 million people in India suffer from high levels of indoor air pollution as 75% homes use biomass fuel like wood, crop residue and dung cakes.

Excessive ultraviolet radiation coming from the sun through the ozone layer in the upper atmosphere, which is eroded by some air pollutants, may cause skin cancer in wildlife and damage to trees and plants. Ozone in the lower atmosphere may damage lung tissues of animals, and adversely affect plant respiration and photosynthesis.

Water Pollution

Water pollutants include insecticides and herbicides, food processing waste, pollutants from livestock operations, volatile organic compounds (VOCs), heavy metals, chemical waste, disease causing agents, sewage, Detergents, oil, sediments and radioactive materials. Beryllium, boron, cadmium, chromium, cyanide, lead, mercury, selenium, silver, sulphide, vanadium and zinc are some of the toxic water pollutants.

Waterborne diseases caused by polluted drinking water are typhoid, amoebiasis, giardiasis, ascariasis, hookworm, hepatitis, encephalitis, gastroenteritis and Diarrhoea. Conditions related to water polluted by chemicals are cancer, hormonal problems, and damage to liver, kidney, nervous system and DNA. Water polluted by mercury can lead to Parkinson’s disease, Alzheimer’s disease, heart disease, etc.

According to a United Nations report released on 22 March 2010 on World Water Day, contaminated and polluted water kills more people than all forms of violence including wars. 80% of urban waste in India ends up in rivers.

The river Ganga is dying slowly due to unchecked pollution. Samples taken from the river Ganga near Varanasi showed that levels of fecal coliform, a dangerous bacterium that comes from untreated sewage, were some 3,000 per cent higher than what is considered safe for bathing.

Chemical contamination in water can cause declines in frog biodiversity. Persistent organic pollutants (POPs) may cause declines, deformities and death of fish life. Plants and animals may be killed by too much sodium chloride (ordinary salt) in water. Plants may be killed by herbicides in water. Water pollution may disrupt photosynthesis in aquatic plants.

Soil Pollution

Soil pollutants include hydrocarbons, solvents and heavy metals. Soi contamination causes cancer. Lead in soil damages the brain, and mercury leads to kidney damage. It causes headache, nausea, fatigue, eye irritation, skin rashes, and depression of the central nervous system. It may alter plant metabolism and reduce crop yields. It can alter the metabolism of microorganisms. Trees and plants may absorb soil contaminants and pass them up the food chain. This may lead to increased mortality rates and even animal extinction.

Fossil Fuel Pollution

Fossil fuels (oil, gas, coal) are used in vehicles, power-generating plants, and in the manufacture of products like plastics, solvents, detergents, lubricating oils, etc. Fossil fuels contribute to soil contamination and water pollution.

When oil is transported by pipelines, an oil leak from the pipeline may occur and pollute the soil, and subsequently the groundwater. When oil is transported by tankers in an ocean, an oil spill may occur and pollute ocean water. Transport and power-generating plants are the biggest sources of fossil fuel pollution. Fossil fuel combustion is also a major source of carbon dioxide emissions (air pollution) and perhaps the most important cause of global warming.

 CHEMICAL THREATS TO BIODIVERSITY

Chemistry has brought about a medical revolution which resulted in the average life expectancy rising from 47 in 1900 to 75 in the 1990s. The explosive expansion of world’s food supply has been because of development of chemicals that protect crops and enhance growth. In almost every area (food, clothing, shelter, transportation, communication, etc.) chemistry has brought about an improvement in the quality of life of people.

The Toxics Release Inventory (TRI), USA, established under the Emergency Planning and Community Right-to-Know Act, tracks the release of chemicals by different sectors of industry. Of the top ten industrial sectors tracked by the TRI, the chemical industry releases a greater amount of waste to the environment than the other nine industrial sectors combined.

 CHEMICAL TOXICOLOGY

There are various chemicals in the environment, some of which are toxic.These toxic chemicals are released by industries into air, water and soil. They upset the complex system of chemical reactions occurring in the human body. They can cause discomfort, illness, disability or even death. Chemical Toxicology is the science of the study of toxic chemicals and their modes of action.

Toxic Chemicals in Air Some of the extremely hazardous substances in the atmosphere are acrylonitrile, arsenic, asbestos, benzene, beryllium, cadmium, chlorinated solvents, chlorofluorocarbons, chromates, coke oven emissions, ethylene dibromide, ethylene oxide, lead, mercury, ozone, sulphur dioxide, vinyl chloride and toxic waste disposal emissions.  Toxic Chemicals in Water ,The toxic elements found in natural and waste waters are arsenic, cadmium, beryllium, boron, chromium, copper, fluorine, lead, manganese, mercury, molybdenum, selenium and zinc. The water bodies contain pesticides, mainly from the drainage of agricultural land.

Effect of Toxic Chemicals on Enzymes

Toxic chemicals attack enzymes, inhibiting their essential function. Heavy metal ions like Hg2+, Pb2+ and Cd2+ act as effective enzyme inhibitors.

Classification of Toxic Substances

1. Corrosive Poisons Corrosive poisons are toxic substances which destroy tissues, e.g., strong acids and alkalies, and many oxidants which can destroy tissues. Concentrated mineral acids such as sulphuric acid and bases like sodium hydroxide attack cellular structures. The cell dies because the proteins are hydrolysed by the acid or the base

2. Metabolic Poisons Metabolic poisons cause illness or death by interfering with a vital biochemical mechanism to such an extent that it ceases to function or does not function efficiently.

3. Neurotoxins Some metabolic poisons limit their action to the nervous system. These include poisons such as strychnine and curare. Neurotoxins act at the point where two nerve fibres come together (called a synapse).

Neurotoxins such as atropine and curare occupy the receptor sites on nerve endings of organs that are normally occupied by the impulse carrying acetylcholine. When atropine or curare occupies the receptor site, no stimulus is transmitted to the organ. Neurotoxins of this type are useful in medicines. For example, atropine is used to dilate the pupil of the eye to facilitate examination of its interior. When applied to the skin, atropine salts relieve pain by deactivating sensory nerve endings on the skin. Curare is used as a muscle relaxant. Nicotine is a natural compound that blocks receptor sites as is done by atropine and curare. This powerful poison causes stimulation and then depression of the central nervous system. Nicotine is present in tobacco and insecticides

4. Mutagens Mutagens are chemicals that can change the genes and chromosomes (hereditary pattern) to cause abnormalities in the offspring. They alter the structures of DNA and RNA, which compose the genes that transmit the traits of parent to offspring. Nitrous acid is a potent mutagen in bacteria, viruses, moulds and other organisms. It reacts with nitrogenous bases of DNA to produce new compounds. The result is an alteration in the genetic coding of DNA, so that a different protein is formed. Sodium nitrite is used as a preservative, colour enhancer or colour fixative in meat and fish products. Sodium nitrite is converted to nitrous acid by hydrochloric acid in the human stomach. Some examples of mutagens: Aflatoxin (from mould), Benzo (α) pyrene (from cigarette and coal smoke), Caffeine, Captan (a fungicide), Chloroprene, Dimethyl sulphate (used for methylation), LSD (lysergic acid diethylamide), Maleic hydrazide (plant growth inhibitor), Mustard gas (dichlorodiethyl sulphide), Ozone, solvents in glue (like toluene, acetone, cyclohexane, hexane and ethyl acetate), and TEM (triethylene melamine, an anticancer drug).

5. Teratogens The chemicals which affect reproduction are called teratogens. The study of birth defects produced by chemical agents is called Teratology. There are three known classes of teratogens: radiation, viral agents and chemical substances. Any chemical that can cross the placenta is a potential teratogen. Smoking a cigarette results in higher-than-normal blood levels of such substances as carbon monoxide, hydrogen cyanide, cadmium, nicotine and benzo (α) pyrene. Many of these substances are present in polluted air as well. Other examples of teratogens: Arsenic, Cobalt, Gallium, Lead, Lithium, Mercury,Thallium, Zinc, Caffeine, DES (diethyl stilbestrol) and PCBs (polychlorinated biphenyls).

6. Carcinogens Carcinogens are chemicals that cause cancer in animals and humans. An abnormal growth is classified as cancerous or malignant when examination shows it is invading neighbouring tissue. A growth is said to be benign if it is localised at its original site. Some compounds cause cancer at the point of contact. Other compounds cause cancer in an area remote from the point of contact. The liver, the site at which most toxic chemicals are removed from the blood, is particularly susceptible to such compounds.

7. Hallucinogens Hallucinogens can produce temporary changes in perception, thought and mood. They destroy one’s sense of judgement. LSD has been linked with birth defects.

8. Alcohols Methyl alcohol is highly poisonous and is a cumulative poison in human beings. It has a toxic effect on the optic nerve and large doses can cause blindness. In the body, it gets oxidised first to formaldehyde and then to formic acid, which is eliminated in the urine. The toxic effect on the optic nerve is caused by the oxidative products.

 Ecosystems

A community and its physical environment is called its Ecosystem. An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the non-living (abiotic), physical components of the environment with which the organisms interact, such as air, soil, water and sunlight.

What is an eco system?

Ecosystem is an open system with inputs, internal transfers and outputs of energy and nutrients. Sunlight is the initial energy source for nearly all ecosystems. 

Types of Ecosystem

The different types of ecosystems are

(i) Natural Ecosystem

(a) Terrestrial ecosystem

(b) Aquatic ecosystem

(c) Lentic (lake, pond or swamp)

(d) Lotic (river, stream or spring)

(ii) Artificial Ecosystems

ecological community

The species that live and interact in an area constitute an ecological community. Ecological communities are loose assemblages of organisms.

The organisms in a community can be divided into trophic levels (the position of an organism in food chain) based on the source of their energy.

Primary producers get their energy from sunlight. Herbivores that get their energy by eating primary producers are primary consumers; organisms that get their energy by eating herbivores are secondary consumers; and so on.

 A sequence of interactions in which a plant is eaten by a herbivore, which in turn eaten by a secondary consumer, and so on, is known as food chain. Food chains are usually interconnected to make a food web because most species  in a community eat and are eaten by more than one species. Most communities have three to five trophic levels. 

Energy and biomass decreases as it flows from lower to higher trophic levels and thus can be represented in the form of pyramid. Most of the energy ingested by organisms that is converted to biomass is eventually consumed by decomposers.

Ecological pyramids An important feature of energy flow is that most of the energy going from one trophic level to the next, in a food chain and food web, dissipates into the environment as a result of the second law of thermodynamics. Ecological pyramids often graphically represent the relative energy values of each trophic level. There are three main types of pyramids— a pyramid of numbers, a pyramid of biomass and a pyramid of energy.

Ecosystem productivity The gross primary productivity (GPP) of an ecosystem is the rate at which energy is captured during photosynthesis in a given period of time. In addition, a plant respires to provide energy for its own use; this acts as a drain on photosynthesis. Energy in plant tissues after cellular respiration has occurred is net primary productivity (NPP). 

Both GPP and NPP are expressed as energy per unit area per unit time. Humans consume (32%) far more of earth’s resources than any other of animal species. If we want our planet to operate sustainably, we must share terrestrial photosynthetic product with other organisms.

In environments that show variations in salinity, temperature and other environmental conditions, food webs tend to have short chains. In stable environments, such as parts of the deep ocean, food chains are longer. In addition to energy inputs, primary productivity and ecosystem structure require a cycling of nutrients. Water and minerals move slowly through the physical environment, rapidly through organisms, and back to the environment in biogeochemical cycles. 

Water moves through a hydrological cycle. In land ecosystems, plants stabilise soil and minimise nutrient loss during the cycle as runoff. In atmospheric cycles, a nutrient prevails mainly in gaseous form (such as carbon, in carbon dioxide). 

In the carbon cycle, carbon dioxide is the main gas in the atmosphere. The ocean is carbon’s main reservoir. Burning of fossil fuels, logging and conversion of natural ecosystems for farming disrupt the global carbon budget and may be responsible for global warming.

Nitrogen is a limiting factor in the total net productivity of ecosystem on land. Gaseous nitrogen is abundant in the atmosphere. Nitrogen–fixing bacteria convert N2 to ammonia and nitrates, which producers take up.

Mycorrhizae and root nodules, two symbiotic interactions, enhance the nitrogen uptake. Sedimentary cycles interact with the hydrological cycle to move mineral nutrients to and from ecosystems.

Certain human activities are depleting minerals from ecosystems, as when weathered soil of tropical forests is cleared for agriculture.

Some human activities are accelerating the process of eutrophication. They are adding nutrients such as nitrates and phosphates to aquatic ecosystems.

This promotes growth and decay of destructive algal blooms. The decomposition of these plants leads to the depletion of oxygen in the water, which threatens fish and other animal populations.

ECOLOGY

Ecology is the scientific study of the rich and varied interactions between organisms and their abiotic environment. In ecological studies, the environment encompasses both abiotic (such as water, mineral nutrients,light, temperature) and biotic factors (living organism).  

Interactions between organisms and their environment is a two way process in which organisms influence and are influenced by their environment. There are many reasons to care about ecology. Our lives are enriched by the fascinating interactions between the organisms. 

Watching a butterfly visiting a flower and bringing about pollination is worth seeing. Beyond simple curiosity, information from ecological sciences is needed to solve many practical problems. An understanding of ecology allows us to grow food, control pests and diseases and deal with natural disasters such as flood, drought and earthquake.

BRANCHES OF ECOLOGY

Ecology and Evolution

1. Ecology and Evolution

Ecology and evolution are considered sister disciplines of the life sciences.Natural selection, life history, development, adaptation, populations and inheritance are examples of concepts that correlate equally in to ecological and evolutionary theory.

(a) Behavioural Ecology 

This is the study of animal behavior in the natural environment, also known as ethology. Behavioural ecology also deals with ecological and evolutionary changes, because of the interactions among the organisms. 

Adaptation is the central unifying concept in behavioural ecology.The behaviours evolve and become adapted to the ecosystem because they are subject to the forces of natural selection. 

Consider the edible beetles that direct sprays of poisonous chemicals at their attacker. Predator-prey interactions are an introductory concept in behavioral ecology.

(b) Social Ecology 

This is concerned with the relationships between organisms and their environment. Social ecological behaviours are notable in the social insects, slime molds, social spiders and human society. Individuals that belong to a social group have to face competition for food, mates and other limited resources. They face diseases and parasitic infections. 

A special kind of behavior exists between many groups known as altruism (Behavior that harms the individual who performs it but benefits other individuals).Parenting is also altruism, where the children are benefited. Altruism is extreme among some insect societies, such as honeybee and termite colonies.Groups that are predominantly altruists beat groups that are predominantly selfish.

(c) Co-evolution 

Populations of the other species are part of any organism’s environment. The population having prey-predator interactions exert pressure on each other. If prey evolves, the predator counter develops mechanisms to catch the prey. 

This is the basis of co-evolution in populations. There are many examples where interacting organisms evolve together e.g., Lithops (flowering stone) growing in the open area develop stone like pattern and color to hide from herbivores.

(d) Bio-geography 

This is the comparative study of the geographic distribution of organisms and the corresponding evolution of their traits in space and time. Bio-geographical processes that result in the natural splittingof species explain modern distribution of the earth’s biota (flora and fauna).

2. Molecular Ecology

Molecular ecology is a relatively new field where the important relationship between ecology and genetic inheritance is analysed using modern techniques of molecular analysis. 

Molecular ecological research became more feasible with the development of rapid and accessible genetic technologies, such as the polymerase chain reaction (PCR). The DNA of different organisms is compared and their evolutionary relationships are analysed.

3. Human Ecology

Human ecology is the interdisciplinary investigation into the ecology of our species. It is the discipline that inquires into the patterns and process of interaction of humans with their environment. It studies human values, life styles, resource use, waste etc. The human species is not an external disturbance. It is the keystone species within the system.

4. Landscape Ecology

Landscape ecology is a sub discipline of ecology that studies ecological  processes that operate over large areas. A landscape ecologist examines the connections among ecosystem found in a particular region.

THE HIERARCHICAL STRUCTURE OF ECOLOGICAL SYSTEM

The different levels of biological organisation include:

The characteristics of molecules and their organization in a cell up to speciation are discussed in the biology section. This chapter includes interaction at population and the levels above it.

Population Ecology

Population is a group of organisms of the same species that live in the same area at the same time. Certain principles govern the growth and sustainability of populations over time. Ecological interactions start within and between populations.

Each population has its own gene pool and range of traits. It also has a characteristic size, density, distribution pattern and age structure.Environmental conditions and species interactions influence thesecharacteristics. Population size is generally an outcome of births, deaths, immigration and emigration. As long as the per capita birth rate remains evenslightly above per capita death rate, a population can grow exponentially.

Resources in short supply put limits on the growth of population. The maximum number of individuals of a population that can be sustained indefinitely by the resources in a given environment is referred as carrying capacity. The number may rise or fall with changes in resource availability.

The size of a low-density population may increase gradually; go through a rapid growth phase, then levels off once the carrying capacity for the population is reached. The limiting factors vary in their relative effects and vary over time, so, population size also changes over time. Limiting factor such as competition for resources, disease and predation are densitydependent.

Density-independent factors, such as weather on the rampage,tend to increase the death rate or decrease the birth rate more or less independently of population density.

Community Ecology

Community is a natural association that consists of all populations of different species that live and interact within an area at the same time. These interactions in turn influence the structure of communities.The many ways in which organisms interact with one another are as following:

Symbiosis 

Any intimate relationship or association between members of two or more species. Symbiosis is the result of co-evolution. Flowering plants and their pollinators have a symbiotic relationship.

Parasitism: 

Interactions in which one organism is harmed, but the other is benefited. A parasite may weaken its host; it rarely kills its host. More than 100 parasites live in or on the human species. When it causes a disease and sometimes the death of host, it is known as pathogen.Crown gall disease, caused by a bacterium, occurs in many plants.

Mutualism: 

Interactions in which both participants are benefited. The interdependent association between nitrogen fixing bacteria of the genus Rhizobium and legume, is an example. Another example is the association between reef building coral animals and microscopic algae.The symbiotic alga is called zooxanthellae. Mycorrhizae is such an association between fungi and roots of 80% plants.

Commensalism: 

Interactions in which one participant benefits but the other is unaffected, e.g., relationship between two insects; silverfish and army ants, relationship between a tropical tree and many epiphytes, smaller plants, such as mosses, orchids and ferns that live attached to the bark of the tree’s branches. The epiphytes anchor itself to the tree to obtain adequate light and water and not for obtaining nutrients from the tree.

 Important Scientific Laws and Theories

Archimedes’ Principle

1. Archimedes’ Principle: It states that a body wholly or partially immersed in a liquid experiences an upward thrust, which is equal to the weight of the liquid displaced by it. Thus, the body appears to lose a part of its weight. This loss in weight is equal to the weight of the liquid  displaced by the body.

 Aufbau Principle

2. Aufbau Principle: It states that, in an unexcited atom, electrons reside in the lowest energy orbitals available to them.

Avogadro’s Law

3. Avogadro’s Law: It states that equal volumes of all gases under similar conditions of temperature and pressure contain equal number of molecules.

 Brownian Motion

4. Brownian Motion: It is a zigzag, irregular motion exhibited by small solid particles when suspended in a liquid or gas due to irregular bombardment by the liquid or gas molecules.

Bernoulli’s Principle

5. Bernoulli’s Principle: It states that as the speed of a moving fluid,liquid, or gas increases, the pressure within the fluid decreases. The aerodynamic lift on the wing of an aeroplane is also explained in part by this principle.

Boyle’s Law

6. Boyle’s Law: It states that temperature remaining constant, volume of a given mass of a gas varies inversely with the pressure of the gas.

Thus, PV = K (constant), where, P = Pressure and V = Volume.

Charles’s Law

7. Charles’s Law: It states that pressure remaining constant, the volume of a given mass of gas increases or decreases by 1/273 part of its volume at 0 degree celsius for each degree celsius rise or fall of its temperature.

Coulomb’s Law

8. Coulomb’s Law: It states that force of attraction or repulsion between two charges is proportional to the amount of charge on both charges and inversely proportional to the square of the distance between them.

Heisenberg Principle (Uncertainty principle)

9. Heisenberg Principle (Uncertainty principle): It is impossible to accurately determine with accuracy, both the position and the momentum of a particle such as electron simultaneously.

Gay-Lussac’s Law of Combining Volumes

10. Gay-Lussac’s Law of Combining Volumes: Gases react together in volumes which bear simple whole number ratios to one another and also to the volumes of the products, if gaseous—all the volumes being measured under similar conditions of temperature and pressure.

Graham’s Law of Diffusion

11. Graham’s Law of Diffusion: It states that the rates of diffusion of gases are inversely proportional to the square roots of their densities under similar conditions of temperature and pressure.

Physical Quantity |Science in Everyday Life

Physical Quantity

❖❖ It is the physical property of a body, substance, or of a phenomenon, that can be quantified by measurement.

Measurement of a Physical Quantity

❖❖ It is done by assigning a value to a physical quantity by comparing itwith a standard value (calibrated value) of that physical quantity whichis called unit.

❖❖ To know the value (or magnitude) of a physical quantity, we generally measure it in different systems of units.

System Units

❖❖ Physical quantities are measured in four systems of units:

●● CGS (Centimetre, Gram, Second): In this system of units, Length,

Mass, and Time are measured in Centimetre, Gram, and Second,

respectively. CGS system is also called the Metric or French System

of Units.

●● FPS (Foot, Pound, Second): In this system of units, Length, Mass, and

Time are measured in Foot, Pound, and Second. FPS system is also

called British System of Units.

●● MKS (Metre, Kilogram, Second): In this system of units, Length,

Mass, and Time are measured in Metre, Kilogram, and Second.

●● SI system (International System of Units) of units was adopted and

accepted on the basis of a comprehensive consensus. In fact, the

SI system is an extended and modified form of the MKS system.

Fundamental Quantities in SI System

S. No. Fundamental Quantity Fundamental unit Symbol

1. Length Metre m

2. Mass Kilogram kg

3. Time Second s

4. Electric current Ampere A

5. Temperature Kelvin K

Unit of Length

❖❖ The SI unit of length is metre (m). One metre is the distance travelled by

light in vacuum in 1 /299792458 of a second.

Facts to Know!

❖❖ A vector is a quantity that has magnitude as well as direction, e.g., force, position, etc.

❖❖ A scalar quantity has only magnitude and no direction, e.g., temperature,

mass, etc.

Other Units of Length

❖❖ Light year: The distance travelled by light in one year in vacuum.

1 light year = 9.46 × 1015 m

❖❖ Parsec (Parallactic Second): The distance at which an arc of length equals

to one astronomical unit subtends an angle of one second at a point.

Units of Length or Distance

1 Nautical Mile 1.825 km

1 Mile 1.609 km

1 km 1000 m

1 cm 10–2 m

1 mm 10–3 m

1 mm 10–6 m

1 Nano metre 10–9 m

1 Å 10–10 m

1 pico metre 10–12 m

1 Fermi metre 10–15 m

❖❖ Area is related with square of length; some units of area are:

●● 1 acre = 4047 m2

●● 1 hectare = 104 m2

❖❖ Volume is related with cube of length; some units of volume are:

●● 1 cubic centimetre (cm3) = 1 millilitre (mL)

●● 1 Gallon = 3.7 Litre

●● 1 barrel = 159 Litre

Unit of Mass

❖❖ The SI unit of mass is kilogram. One kilogram is defined as the mass of

5.0188 × 1025 atoms of carbon-12.

Other Units of Mass

❖❖ 1 gram = 10–3 kg

❖❖ 1 ounce-oz = 28.35 gram

❖❖ 1 milligram = 10–6 kg

❖❖ 1 atomic mass unit (amu) = 1.66 × 10–27 kg

❖❖ 1 quintal = 100 kg

❖❖ 1 tonne or metric ton = 1000 kg

❖❖ 1 Chandra Sekhar Limit (CSL) = 1.4 times the mass of sun = 2.8 × 1030 kg

Unit of Time

❖❖ The SI unit of time is second. One second is defined as 1/86400 part of a mean solar day.

Other Units of Time

❖❖ 1 picosecond =10–12 s

❖❖ 1 nanosecond = 10–9 s

❖❖ 1 microsecond = 10–6 s

❖❖ 1 hour = 60 minute = 3600 seconds

❖❖ 1 day = 24 hours = 1440 minute = 86400 seconds

❖❖ 1 solar month = 30 or 31 days

❖❖ 1 lunar month = 29.5 days or 4 weeks

❖❖ 1 year = 13 lunar months and 1 day = 12 solar months = 365.25 days

❖❖ 1 leap year = 366 days

Indian Measurement System

1. System in the Ancient Period: 8 Parmanus = 1 Rajahkan (dust particle

from the wheel of a chariot)

8 Rajahkans = 1 Liksha (egg of lice)

8 Likshas = 1 Yookamadhya

8 Yookamadhyas = 1 Yavamadhya

8 Yavamadhyas = 1 Angul

8 Anguls = 1 Dhanurmushti

2. System in the Medieval Period: Gaz was divided into 24 equal parts, and

each part was called Tassuj.

Motion, Force, and Laws of Motion

❖❖ The change of position or the movement of any object from one position to another position with respect to the observer is called Motion. It can be described in terms of the distance moved or displacement.

❖❖ Motion of any body is defined by its position with respect to its observer.

❖❖ Distance is the actual path travelled by the object from its initial point to

final point, and it is a scalar quantity.

❖❖ Displacement is the shortest straight line path between initial and final positions. If the initial and final positions are the same, then the displacement is zero.

❖❖ Distance depends upon path but displacement does not.

❖❖ Distance is greater than or equal to displacement; they are equal only

when in straight line motion, without taking a U-turn.

❖❖ The SI Unit of both distance and displacement is Metre (m).

Uniform and Non-uniform Motions

❖❖ Uniform motion is the motion in which equal distance is covered in equal

time intervals.

❖❖ Non-uniform motion on the other hand is one in which an unequal distance is covered in equal intervals of time.

Speed and Velocity

❖❖ Speed is the distance travelled by an object per unit of time.

Speed = Distance travelled/Time taken

❖❖ Average speed, the ratio of total distance travelled to the total time taken by the body to cover it, is known as the average speed.

Average speed = Total distance travelled/Total time taken

❖❖ Instantaneous Speed is the speed of the object at a particular moment in time.

❖❖ Velocity is the displacement of the body per unit time.

Velocity = Displacement of object/Time taken

❖❖ Average Velocity: the ratio of the total displacement to the total time taken by the body is the average velocity.

Average Velocity = Total Displacement/Total time taken

❖❖ Instantaneous Velocity is the velocity of an object in motion at a particular point in time.

❖❖ Speed is a scalar quantity, and its SI unit is metre/ sec, while on the other hand, velocity is a vector

quantity, and its SI unit is metre/sec.

Acceleration

❖❖ Acceleration is the measure of change of velocity with respect to time. It is also called the rate of change of velocity.

Acceleration = (Final velocity – Initial velocity)/Total time taken

❖❖ SI unit of acceleration is metre/sec2. It is a vector quantity.

❖❖ Acceleration has the same direction as velocity if the velocity increases.

Whereas it has opposite direction as velocity if velocity decreases, and in this case, the acceleration is negative. Negative acceleration is also known as Retardation or De-acceleration.

Uniform and Non-uniform Acceleration

❖❖ When the velocity of a body changes by equal amounts in equal time intervals, the acceleration is said to be uniform.

❖❖ When the velocity of a body changes by unequal amounts in equal time intervals, the acceleration is said to be non-uniform.

❖❖ Velocity has both magnitude and direction while speed has only magnitude and no direction.

Velocity has the same direction as displacement.

❖❖ Average speed is always greater than the average velocity except in the case of straight line motion without a U-turn, where both are equal.

❖❖ When a body returns to its initial position, the average velocity will be zero but the average speed will not be zero.

❖❖ When the direction of motion changes, the velocity also changes.

 [Set 2] Greenhouse Effect and Climate Change MCQs | RRB JE, ALP, NTPC Environment Previous Questions

41. The concept of ‘carbon credit’ originated from which one of the following?

[Jharkhand PCS (Pre) 2011]

(A) Kyoto Protocol

(B) Earth Summit

(C) Montreal Protocol

(D) G-8 Summit

42. Bio-Carbon Fund Initiative for

Sustainable Forest Landscapes is

managed by the [IAS (Pre) 2015]

(A) Asian Development Bank

(B) International Monetary Fund

(C) United Nations Environment

Programme

(D) World Bank

43. Which of the following is not

related to the astronomical theories

of climate change?

[UPPCS (Pre)(Re. Exam) 2015]

(A) Eccentricity of earth’s orbit

(B) Obliquity of earth’s rotational

axis

(C) Precession of Equinoxes

(D) Solar irradiance

44. Who had suggested that shifting

Earth on its axis is one of the

factors, responsible for the climatic

change? [UPPCS (Mains) 2015]

(A) Robert Hooke

(B) Milutin Milan Kolich

(C) George Simpson

(D) T.C. Chamberlain

45. Which one of the following provides

the cryogenic indicator of climate

change?

[UPPCS (Pre)(Re. Exam) 2015]

(A) Ice core

(B) Fossilized pollen

(C) Tree ring growth

(D) Evaporite Deposit

46. India’s first National Action Plan on

climate change was released in

[UPPCS (Pre) 2016]

(A) 2008 AD (B) 2012 AD

(C) 2014 AD (D) 2015 AD

47. Which of the following is not listed

under eight action of climate action

plan of Government of India?

[UP UDA/LDA (Spl)(Mains) 2010]

(A) Solar Energy

(B) Atomic Energy

(C) Waste Energy Conversion

(D) Afforestation

48. Which one of the following is not

included in Eight Missions under

India’s National Action Plan on

Climate Change?

[UPPCS (Mains) 2016]

(A) Solar Power

(B) Afforestation

(C) Nuclear power

(D) Waste to energy conversion

49. When was Jharkhand Action Plan

on Climate Change published?

[Jharkhand PCS (Pre) 2016]

(A) 2013 (B) 2014

(C) 2015 (D) 2011

50. According to Jharkhand Action

Plan on Climate Change Report

(2014) which is the most sensitive

District? [Jharkhand PCS (Pre) 2016]

(A) E. Singhbhum

(B) Saraikela Kharaswan

(C) Ranchi

(D) Bokaro

51. Scientists of Manchester University

recently suggested controlling

global warming by cloud

brightening over Pacific ocean

through geo-engineering. Which of

the following substances is used for

this? [UPPCS (Mains) 2009]

(A) Silver salt (B) Iron powder

(C) Sea water (D) Gypsum

52. Which of the following statements

is incorrect for ‘Green Climate

Fund’ (GCF)? [UPPCS (Mains) 2013]

(A) It was established in the Durban

Conference on Climate change

(B) It would support programs and

policies in developing nations

(C) The developed nations would

provide the fund

(D) The fund will start operating

from 2014

53. Which one of the following

countries is the first country in the

world to propose a carbon tax for its

people to address global warming?

[IAS (Pre) 2006]

(A) Australia (B) Germany

(C) Japan (D) New Zealand

54. Which of the following represents

the average increase in earth’s

temperature during the last

century? [Mizoram PSC (Pre) 2019

UPPCS (Pre) 2012]

(A) 0.6ºC (B) 0.7ºC

(C) 0.8ºC (D) 0.9ºC

55. The United Nations Framework

Convention on Climate Change

(UNFCCC) is an international

treaty drawn at [IAS (Pre) 2010]

(A) United Nations Conference

on the Human Environment,

Stockholm, 1972

(B) UN Conference on Environment

and Development, Rio-de-

Janeiro, 1992

(C) World Summit on Sustainable

Development, Johannesburg,

2002

(D) UN Climate Change Conference,

Copenhagen, 2009

56. Consider the following statements.

1. Kyoto Protocol came into force

in the year 2005.

2. Kyoto Protocol primarily

deals with reducing overall

greenhouse emissions.

3. Carbon dioxide is five times

more effective as a greenhouse

gas than methane.

Which of the above statements is/

are correct? [RAS/RTS (Pre) 2013]

(A) 1 and 2 (B) 2 and 3

(C) Only 1 (D) Only 3

57. With reference to the Agreement

at the UNFCCC meeting in Paris

in 2015, which of the following

statements is/are correct?

1. The Agreement was signed by

all the member countries of the

UN and it will go into effect in

2017.

2. The Agreement aims to limit

the greenhouse gas emissions

so that the rise in average global

temperature by the end of

this century does not exceed

2ºC or 1.5ºC above pre-industrial

levels.

3. Developed countries acknowledged

their historical responsibility

in global warming and

committed to donate $ 1000

billion a year from 2020 to help

developing countries to cope

with climate change.

Select the correct answer using the

code given below. [IAS (Pre) 2016]

(A) Only 1 and 3

(B) Only 2

(C) Only 2 and 3

(D) 1, 2 and 3

58. Consider the following statements.

1. Clean Development Mechanism

(CDM) is respect of carbon

credits in one of the Kyoto

Protocol Mechanisms.

2. Under the CDM, the projects

handled pertain only to the

Annex-I countries.

Which of the statements given

above is/are correct?

[IAS (Pre) 2008]

(A) Only 1

(B) Only 2

(C) Both 1 and 2

(D) Neither 1 nor 2

59. Consider the following pairs.

Term sometimes Their

seen in the news origin

1. Annex-I - Cartagena

Countries Protocol

2. Certified - Nagoya

Emission Protocol

Reductions

3. Clean - Kyoto

Development Protocol

Mechanism

Which of the pairs given above is/

are correctly matched?

[IAS (Pre) 2016]

(A) Only 1 and 2 (B) Only 2 and 3

(C) Only 3 (D) 1, 2 and 3

60. In the context of mitigating the

impending global warming due to

anthropogenic emissions of carbon

dioxide, which of the following can

be the potential sites for carbon

sequestration?

1. Abandoned and uneconomic

coal seams

2. Depleted oil and gas reservoirs

3. Subterranean deep saline

formations

Select the correct answer using the

code given below. [IAS (Pre) 2017]

(A) Only 1 and 2

(B) Only 3

(C) Only 1 and 3

(D) 1, 2 and 3

61. Consider the following statements.

1. Climate and Clean Air Coalition

(CCAC) to Reduce Short Lived

Climate Pollutants is a unique

initiative of G20 group of

countries.

2. The CCAC focuses on methane

black carbon and hydrofluoro

carbons.

Which of the statements given

above is/are correct?

[IAS (Pre) 2017]

(A) Only 1

(B) Only 2

(C) Both 1 and 2

(D) Neither 1 nor 2

62. Concerning ‘Forest Carbon Partnership

Facility’, which of the following

statements is/are correct?

1. It is global partnership of

Governments, businesses, civil

society and indigenous people.

2. It provides financial aid

to universities, individual

scientists and institutions

involved in scientific forestry

research to develop ecofriendly

and climate adaptation

technologies for sustainable

forest management.

3. It assists the countries in their

‘REDD + (Reducing Emission

from Deforestation and Forest

Degradation+)’ efforts by

providing them with financial

and technical assistance.

Select the correct answer using the

code given below. [IAS (Pre) 2015]

(A) Only 1 (B) Only 2 and 3

(C) Only 1 and 3 (D) 1, 2 and 3

63. The scientific view is that the

increase in global temperature

should not exceed 2ºC above the

pre-industrial level. If the global

temperature increases beyond 3ºC

above the pre-industrial level, what

can be its possible impact/impacts

on the world?

1. Terrestrial biosphere tends

towards a net carbon source.

2. Widespread coral mortality will

occur.

3. All the global wetlands will

permanently disappear.

4. Cultivation of cereals will not

be possible anywhere in the

world.

Select the correct answer using the

code given below. [IAS (Pre) 2014]

(A) Only 1

(B) Only 1 and 2

(C) Only 2, 3 and 4

(D) 1, 2, 3 and 4

64. Human activities in the recent

past have caused the increased

concentration of carbon dioxide in

the atmosphere, but a lot of it does

not remain in the lower atmosphere

because of

1. Its escape into the outer

stratosphere.

2. The photosynthesis by phytoplankton

in the oceans.

3. The trapping of air in the polar

ice caps.

Which of the statements given

above is/are correct?

[Tamil Nadu PSC (Pre) 2016

IAS (Pre) 2011]

(A) 1 and 2 (B) Only 2

(C) 2 and 3 (D) Only 3

65. What would happen if phytoplanton

of an ocean is completely destroyed

for some reason?

1. The ocean as a carbon sink

would be adversely affected.

2. The fond chains in the ocean

would be adversely affected.

3. The density of ocean water

would drastically decrease.

Select the correct answer using the

code given below. [IAS (Pre) 2012]

(A) 1 and 2 (B) Only 2

(C) Only 3 (D) 1, 2 and 3

66. Which of the following are the

primary causes of climate change?

1. Excessive burning of fossil fuels

2. Exploding numbers of automobiles

driven by oil

3. Increasing solar flares

4. Heavy deforestation

Select the correct answer using the

code given below.

[UPPCS (Pre) 2017]

(A) Only 2 and 3

(B) Only 1, 2 and 4

(C) 1, 2, 3 and 4

(D) Only 1 and 4

67. With reference to ‘Global Climate

Change Alliance’, which of the

following statements is/are correct?

1. It is an initiative of the

European Union.

2. It provides technical and

financial support to targeted

developing countries to

integrate climate change into

their development policies and

budgets.

3. It is coordinated by World

Resources Institute (WRI)

and World Business Council

for Sustainable Development

(WBCSD).

Select the correct answer using the

code given below. [IAS (Pre) 2017]

(A) Only 1 and 2

(B) Only 3

(C) Only 2 and 3

(D) 1, 2 and 3

68. Which of the following statements

regarding global warming are

correct? [Uttarakhand PCS (Pre) 2002]

1. Melting of polar ice caps and

subsequent rise in the sea level

is the most important effect of

global warming.

2. The sea level is likely to rise by

one metre by 2070 AD if the

present level of global warming

is not controlled.

3. All the coral islands in the

world will be submerged.

4. By 2044 AD, Fiji is likely to

submerged and the rise in the

sea level by the same year will

pose a grave danger to the

Netherlands.

Code

(A) 1, 2, 3 and 4

(B) 1, 2 and 3

(C) 1, 3 and 4

(D) Only 4

69. Consider the following agricultural

practices.

1. Contour bunding

2. Relay cropping

3. Zero tillage

In the context of global climate

change, which of the above help/

helps in carbon sequestration/

storage in the soil?

[IAS (Pre) 2012]

(A) 1 and 2

(B) Only 3

(C) 1, 2 and 3

(D) None of the above

70. Which of the following statements

regarding ‘Green Climate Fund’ is/

are correct?

1. It is intended to assist the developing

countries in adaptation

and mitigation practices to

counter climate change.

2. It is founded under the

aegis of UNEP, OECD, Asian

Development Bank and World

Bank.

Select the correct answer using the

code given below. [IAS (Pre) 2015]

(A) Only 1

(B) Only 2

(C) Both 1 and 2

(D) Neither 1 nor 2

71. Due to their extensive rice

cultivation, some regions may be

contributing to global warming.

To what possible reason/reasons is

this attributable?

1. The anaerobic conditions

associated with rice cultivation

cause the emission of methane.

2. When nitrogen based fertilizers

are used, nitrous oxide is emitted

from the cultivated soil.

Which of the statements given

above is/are correct?

[Tamil Nadu PSC (Pre) 2018

IAS (Pre) 2010]

(A) Only 1

(B) Only 2

(C) Both 1 and 2

(D) Neither 1 nor 2

72. Which of the following statements

are true regarding the members of

the Asia Pacific Partnership?

1. Their population account to

45% of the world’s population.

2. They consume the world’s 48%

of energy.

3. They contribute nearly 48% of

the world’s greenhouse gases.

4. They intend to support the

Kyoto Protocol.

Select the correct answer from the

code given below.

[UPPCS (Mains) 2005]

(A) Only 1 and 2

(B) Only 1, 2 and 3

(C) Only 2, 3 and 4

(D) All of the above

73. Consider the following statements.

1. Kyoto Protocol came into force

in the year 2005.

2. Kyoto Protocol deals primarily

with the depletion of the ozone

layer.

3. Methane as a greenhouse gas

is more harmful than carbon

dioxide.

Which of the statements given

above is/are correct?

[IAS (Pre) 2005]

(A) 1 and 2 (B) 1 and 3

(C) Only 1 (D) Only 3

74. Which one of the following is not

correctly matched?

[UPPCS (Pre) 2017]

Greenhouse Gas Source

(A) Carbon dioxide - Thermal

Power

Stations

(B) Chlorofluoro - Automobile

carbon

(C) Nitrous Oxide - Waterlogged

Paddy fields

(D) Sulphur - Brick Kilns

dioxide

75. As a result of global warming, there

has been

1. Better global communication

2. Melting of glaciers

3. Flowering of mango trees

before times

4. Adverse impact on health

Select your answer from the code

given below. [UPPCS (Pre) 2003

UP UDA/LDA (Pre) 2002

UPPCS (Pre) 2001]

(A) 1, 2 and 3 are correct

(B) 2, 3 and 4 are correct

(C) 1, 2 and 4 are correct

(D) 1, 3 and 4 are correct

76. Which of the following conditions

indicate the impact of global

warming?

1. Melting of glaciers

2. Rise in sea level

3. Changes in weather conditions

4. Rise in global temperature

Select the correct answer from the

code given below. [IAS (Pre) 2009]

Code

(A) 1 and 2

(B) 1, 2 and 3

(C) 2, 3 and 4

(D) All of the above

77. Consider the following.

1. Rice fields

2. Coal mining

3. Domestic animals

4. Wetlands

Which of the above is a source of

methane, a major greenhouse gas?

[IAS (Pre) 2008]

(A) 1 and 4 (B) 2 and 3

(C) 1, 2 and 3 (D) 1, 2, 3 and 4

78. Consider the following statements

regarding ‘Earth Hour’.

1. It is an intiative of UNEP and

UNESCO.

2. It is a movement in which the

participants switch off the

lights for one hour on a certain

day every year.

3. It is a movement to raise the

awareness about the climate

change and the need to save the

planet.

Which of the statements given

above is/are correct?

[IAS (Pre) 2014]

(A) Only 1 and 3

(B) Only 2

(C) Only 2 and 3

(D) 1, 2 and 3

79. Given below are two statements.

Assertion (A): Climate change is

leading to increase in social tension

in India.

Reason (R): The frequency

and intensity of the extreme

weather events will have serious

repercussions on food security.

Choose the correct answer from the

code given below.

[Tripura PSC (Pre) 2018

UPPCS (Pre) 2017]

Code

(A) Both (A) and (R) are true and

(R) is the correct reason of (A)

(B) Both (A) and (R) are true, but

(R) is not the correct reason of (A)

(C) (A) is true, but (R) is false

(D) (A) is false, but (R) is true

41. (A) 42. (D) 43. (D) 44. (B) 45. (A) 46. (A) 47. (B) 48. (C) 49. (A) 50. (B)

51. (C) 52. (A) 53. (D) 54. (C) 55. (B) 56. (A) 57. (B) 58. (A) 59. (C) 60. (D)

61. (B) 62. (C) 63. (B) 64. (B) 65. (A) 66. (B) 67. (A) 68. (C) 69. (C) 70. (A)

71. (C) 72. (C) 73. (B) 74. (B) 75. (B) 76. (D) 77. (D) 78. (C) 79. (A)

Greenhouse Effect and Climate Change MCQs | RRB JE, ALP, NTPC Environment Previous Questions

Greenhouse Effect and Climate Change

1. Greenhouse effect is the process [RAS/RTS (Pre) 1992]

(A) to obtain suitable temperature for plantation

(B) of heating the atmosphere by absorption of infrared radiations by atmospheric

carbon dioxide

(C) by which barren mountains changes into green

(D) in which deep water seems green

2. Where was the climate change conference held in the year 2015? [Chhattisgarh PCS (Pre) 2015]

(A) Paris (B) Quata

(C) Bon (D) Colombo

3. Which of the following United Nation’s climate change conference was held in Paris?

[UP Lower Sub. (Pre) 2015]

(A) 25th (B) 23rd

(C) 22nd (D) 21st

4. Climate change is caused by [UPPCS (Pre) 2013]

(A) Greenhouse gases

(B) Depletion of ozone layer

(C) Pollution

(D) All of the above

5. What is ‘Greenhouse effect’?[MPPCS (Pre) 1991, 2006]

(A) Increase in temperature of Earth due to concentration of gases in atmosphere

(B) Acid rain

(C) Black rain

(D) None of the above

6. The concept of Greenhouse Gases was postulated by [UPPCS (Mains) 2011]

(A) C.C. Park

(B) J.N.N. Jeffers

(C) Joseph Fourier

(D) L. Zobler

7. ‘Intended Nationally Determind Contribution’ sometime seen in news refers to [IAS (Pre) 2016]

(A) Promise made by European countries for rehabilitation of refugees from middle East

(B) World action plan to deal with climate change

(C) Equity share holding of member countries in AIIB

(D) World action plan for sustainable development goals

8. ‘Kyoto Protocol’ is related to [MPPCS (Pre) 2014]

(A) Air pollution

(B) Greenhouse gas

(C) Climate change

(D) Water pollution

9. Greenhouse effect is enhanced in the environment due to [UPPCS (Pre) 2015]

(A) Carbon monoxide

(B) Carbon dioxide

(C) Oxygen

(D) None of the above

10. Which one of the following gases is not a greenhouse gas? [UPPCS (Pre) 2016]

(A) CO2 (B) CH4

(C) NO2 (D) O2

11. Which of the following group of gases contribute to the ‘Greenhouse Effect’? [UPPCS (Pre) 2013]

(A) Ammonia and Ozone

(B) Carbon monoxide and Sulphur dioxide

(C) Carbon tetrafluoride and Nitrous oxide

(D) Carbon dioxide and Methane

12. Which set of the following gases is most important for greenhouse effect? [Uttarakhand PCS (Pre) 2016]

(A) Carbon dioxide, Methane, Chlorine, Nitric oxide

(B) Nitric oxide, Methane, Ethane, Chlorfluoro carbons

(C) Carbon dioxide, Methane, Nitrous oxide, Water vapour

(D) Carbon Monoxide, Sulphur dioxide, Methane, Water vapour

13. Which one of the following naturally occurring greenhouse

gases causes the highest percentage of Greenhouse effect? [UPPCS (Mains) 2011]

(A) Carbon dioxide

(B) Methane

(C) Ozone

(D) Water vapour

14. Which one of the following is not responsible for global warming? [UPPCS (Mains) 2016]

(A) Methane

(B) Water vapour

(C) Argon

(D) Carbon dioxide

15. Which one of the following statements regarding the Emission Reduction Purchase Agreement

signed with the World Bank in May, 2011 is not correct? [UPPCS (Mains) 2010]

(A) The agreement has been signed between the World Bank and the Government of India

(B) The agreement shall be valid for ten years

(C) The agreement is for securing carbon credits for a project of Himachal Pradesh

(D) As per the agreement, one ton of carbon dioxide will be equivalent to one credit unit

16. Which one of the following gases is both harmful and beneficial to life on Earth?

[UP Lower Sub. (Mains) 2013]

(A) Oxygen

(B) Ozone

(C) Nitrogen

(D) Carbon dioxide

17. Today the largest contributor to carbon dioxide (CO2) emissions is

[UPPCS (Pre) 2010]

(A) China (B) Japan

(C) Russia (D) USA

18. Which of the following countries is the largest emitter of carbon?

[UP Lower Sub. (Pre) 2015]

(A) USA

(B) China

(C) India

(D) European Union

19. Which of the following is known as ‘carbon negative country’ in the world? [UP Lower Sub. (Pre) 2015]

(A) Afghanistan (B) Bahrain

(C) Bhutan (D) Nepal

20. Which one among the following substances does not contribute to global warming? [UPPCS (Pre) 2013]

(A) Oxides of Sulphur and Nitrogen

(B) Methane

(C) Carbon dioxide

(D) Water vapour

21. Which of the following is not Greenhouse Gas?

[UPPCS (Mains) 2007]

(A) Carbon dioxide

(B) Sulphur dioxide

(C) Methane

(D) All of the above 

22. Which one of the following gas is responsible for global warming?

[Uttarakhand PCS (Pre) 2006, 2004]

(A) Only Oxygen

(B) Oxygen and Carbon dioxide

(C) Carbon dioxide and Methane

(D) Only methane

23. Which of the following is responsible for global warming?

[Jharkhand PCS (Pre) 2013]

(A) Methane

(B) Carbon dioxide

(C) Water vapour

(D) All of the above

24. Which of the following is not Greenhouse Gas?

[UPPCS (Mains) 2012]

(A) Methane

(B) Nitrous oxide

(C) Chlorofluoro carbons

(D) Hydrogen

25. Which of the following is not Greenhouse Gas? [UPPCS (Pre) 2012

RAS/RTS (Pre) 1993]

(A) Carbon dioxide

(B) Methane

(C) Nitrous oxide

(D) Nitrogen

26. Global warming is caused due to the emmission of [UPPCS (Mains) 2004]

(A) Nitrogen

(B) Carbon dioxide

(C) Carbon mono-oxide

(D) Hydro carbon

27. Apprehension of Global Warming are aggravated by increased concentration,

in the atmosphere of

[UPPCS (Spl)(Mains) 2008

UPPCS (Pre) 2006

UPPCS (Mains) 2004]

(A) Carbon dioxide

(B) Nitrous oxide

(C) Ozone

(D) Sulphur dioxide

28. The ‘Global Warming’ is due to [UP Lower Sub. (Mains) 2013]

(A) Heavy rainfall

(B) Increase in carbon dioxide

(C) Decrease in carbon dioxide

(D) Increase in forestation

29. Which one of the following is the most fragile ecosystem that will be first affected by global warming?

[Uttarakhand PCS (Pre) 2010]

(A) Arctic and Greenland Ice sheet

(B) Amazon rain forest

(C) Taiga

(D) Indian Monsoon

30. The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere because it absorbs [IAS (Pre) 2012]

(A) the water vapour of the air and retains its heat

(B) the ultraviolet part of the solar radiation

(C) all the solar radiations

(D) the infrared part of the solar radiation

31. Which human activity is most affected by climate? [West Bengal PSC (Pre) 2019

Jharkhand PCS (Pre) 2013]

(A) Fishing

(B) Mining

(C) Manufacturing

(D) Farming

32. The greenhouse gas liberated by cud-chewing animals is [Telangana PSC (Pre) 2018

Uttarakhand PCS (Pre) 2005]

(A) Carbon dioxide

(B) Methane

(C) CFC

(D) Nitrous oxide

33. The United Nations Convention on climate change ratified by more than 50 countries became effective

on [UPPCS (Pre) 2012]

(A) 21st March, 1994

(B) 21st May, 1995

(C) 21st June, 1996

(D) 21st June, 1999

34. Which of the following countries does not have global atmosphere watch station to collect data on

world temperature?

[UPPCS (Pre) 2012]

(A) Algeria (B) Brazil

(C) Kenya (D) India

35. Which of the following statement is not true about CDM?

[Andhra Pradesh PSC (Pre) 2016

UP UDA/LDA (Pre) 2001]

(A) It controls Greenhouse emission

(B) It reduces global warming

(C) Kyoto Protocol suggests for assessment of the sustainable development of it

(D) It prohibits developed countries from investing in projects in developing countries

36. In the context of CO2 Emission and Global Warming. What is the name

of a market driven device under the UNFCC that allows developing countries to get funds/incentives

from the developed countries to adopt better technologies that reduce greenhouse gas emissions?

[Jammu & Kashmir PSC (Pre) 2017 IAS (Pre) 2009]

(A) Carbon Footprint

(B) Carbon Credit Rating

(C) Clean Development Mechanism

(D) Emission Reduction Norm

37. What is ‘Greenhouse Gas Protocol’? [IAS (Pre) 2016]

(A) It is an international accounting tool for government and business leaders to understand

quantify and manage greenhouse gas emissions

(B) It is an initiative of the United Nations to offer financial incentives

to developing countries to reduce greenhouse gas emissions and to adopt eco-friendly

technologies

(C) It is an inter-governmental agreement ratified by all the member countries of the United

Nations to reduce greenhouse gas emissions to specified levels by the year 2022

(D) It is one of the multilateral REDD + initiatives hosted by the World Bank

38. Which of the following is not true for India to combat the adverse impact of Climate Change?

[UPPCS (Pre) 2017]

(A) Establishment of Clean Development Mechanism (CDM)

(B) Investment of `100 crores as an initial corpus under National Adaptation Fund

(C) Not attended the 19th Meeting of BASIC at Sun City, South Africa held recently.

(D) All of the above are true

39. Which of the following is not correctly matched? [MPPCS (Pre) 2017

UPPCS (Pre)(Re. Exam) 2015]

(A) First World Climate Conference -1979

(B) First Earth Summit-Agenda-21

(C) Earth Summit Plus 5-1997

(D) Carbon Trading - Montreal Protocol

40. Regarding ‘carbon credits’ which one of the following statements is not correct? [IAS (Pre) 2011]

(A) The carbon credit system was ratified in conjunction with the Kyoto Protocol

(B) Carbon credits are awarded to countries or groups that have reduced greenhouse gases

below their emission quota 

(C) The goal of the carbon credit system is to limit the increase of carbon dioxide emission

(D) Carbon credits are traded at  price fixed from time-totime by the United Nations Environment Programme

Answers

1. (B) 2. (A) 3. (D) 4. (D) 5. (A) 6. (C) 7. (B) 8. (C) 9. (B) 10. (D)

11. (D) 12. (C) 13. (D) 14. (C) 15. (A) 16. (D) 17. (A) 18. (B) 19. (C) 20. (A)

21. (B) 22. (C) 23. (D) 24. (D) 25. (D) 26. (B) 27. (A) 28. (B) 29. (A) 30. (D)

31. (D) 32. (B) 33. (A) 34. (D) 35. (D) 36. (C) 37. (A) 38. (C) 39. (D) 40. (D)