Quick Revision on Environment for Competitive Exam RRB(NTPC)- June 2025

Quick revision on Environment

Quick Revision on Environment for Competitive Exam RRB(NTPC)- June 2025. Here are some one-liner notes for competitive exams, compiled from different websites.

• World Environment Day is celebrated on June 5.
• The term Ecology was coined by Haeckel.
• Ecology is the science that describes the relationship between living things and other elements in the surrounding environment.
• An ecosystem is a Structural and functional unit of nature where living organisms interact among themselves and with the surrounding environment.
• The term ‘ecosystem’ was coined by A.G. Tansley in 1935.
• Two components of an ecosystem are Abiotic and biotic.
• Biotic components are all living organisms.
• Abiotic components are non-living components that influence an ecosystem.
• The lithosphere is the outermost part of the Earth and is made up of rocks and minerals covered by soil.
• The hydrosphere is made up of all the water and watery layers of the Earth, covering 70 percent of the Earth’s surface.
• The atmosphere is a mixture of gases, water vapour and dust particles held near the Earth’s surface by gravity.
• Nitrogen constitutes 78% and Oxygen 21% of the atmosphere’s total composition.
• The percentage of carbon dioxide present in the atmosphere is 0.03%, or approximately 0.0391%.
• Producers are organisms that make their own food through photosynthesis and are also known as autotrophs.
• Consumers, called heterotrophs, consume food synthesized by autotrophs.
• Herbivores, or Primary Consumers, get energy from eating plants.
• Carnivores, or Secondary consumers, eat primary consumers for energy.
• Omnivores are animals that eat on plants and other animals for nutrition.
• Decomposers are organisms that break down dead plants and animals.
• Examples of decomposers are Bacteria and Fungi.
• A food chain is a series of organisms dependent on the next organism as a source of food.
• Food chains Start with producers.
• A food web is an Interlinked arrangement of food chains.
• Energy flows in an Ecosystem is always unidirectional.
• Ecological balance describes the equilibrium between living organisms and their environment.
• An ecological pyramid is a graphical representation of the relationship between different organisms in an ecosystem.
• A pyramid of energy is a graphical representation of the amount of energy at each trophic level.
• The pyramid of energy in an ecosystem is always upright.
• The amount of energy at each trophic level decreases as it moves through an ecosystem.
• A pyramid of biomass indicates the total mass of organisms in each trophic level.
• A pyramid of numbers shows the number of organisms at each trophic level.
• Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil.
• Agents that cause pollution are called pollutants.
• The Environment (Protection) Act was passed by the Government of India in 1986 to protect and improve environmental quality.
• The Air (Prevention and Control of Pollution) Act came into force in India in 1981, and was amended in 1987 to include noise as an air pollutant.
• Air pollution is the contamination of air by unwanted substances with harmful effects.
• One source of air pollution is 50% of vehicle exhaust smoke.
• The major pollutant from automobile exhaust is carbon monoxide.
• Carbon monoxide is produced from incomplete burning of fuels and reduces the oxygen-carrying capacity of the blood.
• Smog is made up of smoke and fog and can cause breathing difficulties.
• Sulphur dioxide is produced by combustion of fuels like coal and can cause respiratory problems, including permanent lung damage.
• Chlorofluorocarbons (CFCs) are used in refrigerators and damage the ozone layer.
• Acid rain corrodes the marble of monuments, also called Marble cancer.
• The Taj Mahal has been affected by atmospheric pollution and excessive Sulphur Dioxide.
• Acid rain occurs when the pH value of rainwater drops below 5.6.
• Acid Rain is caused by emissions of Sulphur dioxide and Nitrogen oxide.
• Acid rain can cause respiratory issues and corrosion of water pipes, leading to leaching of heavy metals.
• Acid rain damages buildings made of stone or metal.
• Acid rain removes basic nutrients like Calcium from the soil.
• Noise pollution is the emission of loud sound that can harmfully impact humans and animals.
• The unit of sound is Decibel (db).
• A sound loudness a person can withstand without discomfort is about 80 db. Noise pollution is created if noise is in excess to 80-99 dB.
• The main source of noise pollution in urban areas is the Transport system.
• The Water (Prevention and Control of Pollution) Act was passed by the Government of India in 1974 to safeguard water resources.
• Disposal of domestic sewage without proper treatment may cause serious diseases like dysentery, typhoid, jaundice, and cholera.
• Eutrophication is when a body of water becomes enriched in dissolved nutrients (like phosphates and nitrates).
• The most common nutrients causing eutrophication are nitrogen and phosphorus .
• Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a water sample.
• A river with a high BOD value is highly polluted.
• Soil pollution is the change in soil conditions through human activities, resulting in degradation of quality and productivity.
• Waste can be categorized into bio-degradable, recyclable, and non-biodegradable.
• Examples of non-biodegradable waste include Polyethylene bags, Glass, Metals, Electronic devices, batteries, and Plastic bags/bottles.
• Electronic wastes (e-wastes) are irreparable computers and other electronic goods.
• Recycling is the only solution for the treatment of e-waste.
• Hospitals generate hazardous wastes that contain disinfectants, chemicals, and pathogenic micro-organisms.
• Solid waste management is important to prevent land pollution.
• The greenhouse effect is a naturally occurring phenomenon responsible for heating Earth’s surface and atmosphere.
• Without the greenhouse effect, the average temperature would be -18°C instead of the present average of 15°C. The Earth’s body temperature is approximately 16.4°C.
• Important Greenhouse gases include Water vapor, Carbon dioxide, Methane, Nitrous oxide (N2O), and Chlorofluorocarbons (CFC).
• Increased levels of greenhouse gases lead to global warming, which has caused Earth’s temperature to increase by 0.6°C over the past century.
• The largest contributing source of greenhouse gas is the burning of fossil fuels.
• Fossil fuels include Natural gas, coal and petroleum.
• Scientists believe global warming is leading to odd climatic changes, increased melting of polar ice caps, and a potential rise in sea level.
• Global warming can be controlled by cutting down fossil fuel use, improving energy efficiency, reducing deforestation, planting trees, and slowing population growth.
• Ozone (O3) is an allotropic form of oxygen that forms a layer in the stratosphere.
• The ozone layer acts as a shield absorbing ultraviolet radiation from the sun.
• The balance of ozone in the stratosphere has been disrupted by chlorofluorocarbons (CFCs), leading to the formation of the ozone hole.
• The thickness of the ozone layer is measured in Dobson units (DU).
• Ozone layer depletion causes aging of skin, skin cancers, immune deficiency disorders, and eye problems like snow-blindness and cataracts.
• UV rays also affect plant growth and reduce agricultural productivity.
• The Montreal Protocol, signed in 1987 (effective 1989), is an international treaty to control the emission of ozone depleting substances.
• The Kyoto Protocol is an international agreement setting targets for industrialized countries to cut their greenhouse gas emissions.
• The Kyoto Protocol was agreed to in 1997 in Kyoto, Japan, and entered into force on February 16, 2005.
• World Wetland Day is celebrated on February 2.
• International Day for biodiversity is observed On May 22.
• The part of the earth where all life is found is called the biosphere.
• Lichens are used as an air pollution indicator.
• Pollution of river water is measured by the dissolved amount of Oxygen.
• In food chain, humans are Primary and secondary consumers.
• Source of geothermal Energy is Earth.
• Gas that traps heat in the atmosphere is called Greenhouse gases.
• Deforestation causes Soil erosion, Loss of biodiversity and Disturbance in hydrological cycle.
• Thunderstorm and lightning converts atmospheric nitrogen into nitrates.
• Volcano is a natural source of pollution.
• A Fish aquarium is an example of an artificial ecosystem.
• Constant flow of energy is from producer to consumer.
• Representation of biomass energy present in different levels of food chain is classified as biological pyramid.
• More than 70% of world’s freshwater is contained in polar ice and glaciers and about 30% is found in ground water.
• Oceans are considered to be the most stable ecosystem in nature.
• Ex-situ conservation is the conservation of plants and animals outside their natural habitat. Examples include botanical gardens, zoological gardens, and germplasm banks.
• In-situ conservation is conservation within natural habitat. Examples include national parks, wildlife sanctuaries, and biospheres reserve.
• The earthworm is referred as a farmers friend.
• A primary pollutant is an air pollutant emitted directly from a source. Examples include Hydrocarbons, Carbon monoxide, Sulfur oxides, Nitrogen oxides, and lead.
• A secondary pollutant forms when other pollutants (primary pollutants) react in the atmosphere. Examples include ozone, nitrogen dioxide, and sulfur trioxide.
• Trophic levels are formed by different organisms linked in a food chain.
• Salim Ali Was an Indian ornithologist and naturalist.
• Earth Day is celebrated on April 22 to demonstrate support for environmental protection.
• The lowest layer of the atmosphere is known as troposphere.
• Photosynthesis is a process used by plants to make food with the help of the Sun.
• The Green Gold revolution is related to the Promotion and trade of Bamboo.
• Savanna grasslands are found between tropical rainforest and desert, mostly located near the equator, with the largest in Africa.
• Percentage of Nitrogen in earth atmosphere is 78%.
• Largest reservoir of Nitrogen is in the Atmosphere.
• Roots of plants contain nitrogen fixing bacteria.
• Percentage of Oxygen in earth atmosphere is 21%.
• Bhopal gas tragedy occurred due to the leakage of Methyl Isocyanate on December 2, 1984.
• Estuary means the tidal mouth of a large river.
• The pH for drinking water should be in the range of 6.5 to 8.5 as per BIS recommendation.
• Compressed Natural Gas (CNG) is considered the best environmentally clean alternative fuel.
• Hydrogen is considered as the energy source of future.
• Most of the hydrogen on Earth is in the form of water.
• Methane is the main component in natural gas. The percentage of methane content of biogas is 50–75 %.
• Biodegradable pollutants are pollutants that are broken down naturally by micro-organisms. Examples include sewage, paper products, vegetables, juice, seeds, and leaves.
• Non-biodegradable pollutants cannot be broken down into smaller, harmless substances.
• The 3R of Energy conservation is reduce, reuse and recycle.