1. Environment and Ecology

🤔 Why to study Environment and Ecology ?🌱
● Important for each and every exam conducted in India having subjects related to Global warning and Climate change.
● UPSC Prelims and Mains (GS 1 & 3) Weightage – More than any other topic.
● UPSC Prelims – 15-20 Questions will be definitely asked.
● To the point, scientific basics, easy to grasp – Scoring.

Please click on below links to learn more about them:

TOPICS – Environment and Ecology (E&E).

◆UPSC CSE Prelims & mains And useful for MPSC also◆
● Importance of E&E in prelims and mains – Analysis the Syllabus (Explained Above)
● Fundamentals of Ecology and the associated concepts
● Community, Succession and various types of interaction
● Ecosystem and Food Chain, Food Web, Energy Flow in the Ecosystem
● Environmental Pollution – Air, Soil, Water, Radioactive and various associated concepts
● Biodiversity, Importance and the climate change
● Climate Change and the associated Concepts
● Wetlands, Mangroves and the Coral Reefs
● Extinction of Species and IUCN & the Red List
● Important Flora and Fauna of India
● Conservation of Biodiversity – In-Situ and Ex-Situ Conservation
● Major Conservation Projects in India
● Environment – Conservation, Pollution, Degradation, EIA
● Environmental Laws and Legislations in India
● Earth Summit and the Evolution of various Environmental Organizations
● Conventions and Protocols related to Environment and Ecology
● Environmental Hazards
● Natural Resources
● Types of Renewable Energy Sources and their Importance, Status of progress in India
● Innovation in the field Environment Technology to tackle Climate Change
● Current Issues in Environment and Ecology
● Forestry, the Man and the Environment – Agroforestry, Social Forestry, Integrated Agriculture and Environment Management
● Agriculture and the Environment
● Biomes and the types
● Major Biogeographic Regions of India


Fundamentals of Ecology and the associated concepts

◆ Organism :- Any living system.
Examples- Plant, Animals, Fungus, Reproduction.
• Categorization of Organisms
1) Animalia
2) Plantae
3) Fungi
4) Monera
5) Protista
Definition – Scientific study of relationship of living organism with each other and with their environment.
◆ Ecological Niche The functional Characteristics of a species in its habitat. Niche is unique to a specie in the habitat.
Ex- Lion
◆ Species Largest group of similar populations of organisms who members are capable of interbreeding, and to produce fertile offspring.
◆ Speciation – Process by with new species are formed and evolution is the mechanism by with speciation is brought about Ex- Kaibab Squirrels and Albert squirrels.
◆ Population – A group of freely interbreeding individuals of the same species present in a specific area at a given time. Local population of given are is called Demes.
◆ ECAD of Species – A population of individuals belonging to the same Genetic stock but they have drastic differences in morphological or vegetitive features like size, shape etc.
◆ Ecotype – Is population of individuals of a species, which are genetically different.
◆ Natality – Rate at which new individuals are born and added to a population under given environmental conditions.


Community, Succession and various types of interaction

◆ Community – Group of organism of different species living in a comman area ( includes multiple populations)
◆ Ecological Succession- The process by which communities of plant and animal species in an area are replaced or charged into another over a period of time.
◆ Two types of Ecological Succession
1) Primary Succession
2) Secondary Succession
1) Primary Succession- Take place an over a bare or unoccupied areas such as rocks outcrop, Newly formed deltas and sand dunes, emerging volcano island and lava flow etc. Where no community has existed previously.
◆ Pioneer Community – Community that first inhabits a bare area they will later get replaced by another community with different species combination. This process continues sequentially.
• Succession brought by living inhabitants of that community itself is Autogenic Succession.
• Succession brought by outside force is known as Allogenic Succession.
• Each transitional community that is formed and replaced during succession is called Seral Community.
• The final stage of succession by the community called Climax Community. In reality multiple climaxes take place.
2) Secondary Succession- Development of a community after the existing Community is removed, disturbed or destroyed by hurricane/forest fire / harvesting etc.
◆ Definition- A Secondary Succession is relatively fast as, the soil has the necessary nutrients as well as a large pool of seeds and other dormant stages of organism.
◆ Xerach – succession that occurs on land ( low moisture content ) like bare rock.
◆ Hydrach – Succession that takes place in a water body.
◆ Nudation – Bare area without any life.
◆ Invasion ( Pioneer ) – Successful establishment of a species in a bare area.
A) Migration
B) Ecesis means establishment ( individual come and live )
C) Aggregation : Reproduction.

◆ Competition and Coaction – Inter and intra-specific competition.
◆ Reaction – most important stage, environment modified under influence of living organism.
◆ Stabilisation ( climax ) – final terminal or climax community becomes more or less Stabilised, equilibrium.


Environmental Pollution – Air, Soil, Water, Radioactive and various associated concepts

Definition Pollution is defined as any undesirable change in the physical, chemical or biological characteristics of environmental components i.e. air, water and soil that adversely affects the life forms and life support system of the biosphere directly or indirectly.

POLLUTANT The agent that contaminate the environmental component is called pollutant.
Pollutant can be grouped in two broad categories:

● These remain in an unchanged form in the environment for a very long time such as pesticide, heavy metals, rubber, nuclear waste etc.
● Such substances are not broken down and decomposed by bacteria.
● These pollutants persists for very long time in nature, get accumulated and often biomagnify to a dangerous level when they move in material cycles in the nature and along with the food chain.

● Pollutants such as paper, garden waste, domestic sewage, agro-based residues and fertilizers etc. breakdown into simple product by bacterial decomposition process.
● The simple products are raw material of nature that are utilised in the ecosystem Decomposition of these non-persistent pollutants occur naturally as well as through engineered systems such as sewage treatment plant.
● Such man-made systems enhance nature’s capacity to decompose.
● These biodegradable pollutants pose a threat when their input in the environment exceed the decomposition capacity.

SOURCE OF POLLUTION – Pollutants can enter the environment either through point or nonpoint sources.
● Point sources are distinct and confined sources that discharge the pollutants/effluents through a chimney or through it discharge channel such as pipes or tunnels from industries or municipal areas.
● Nonpoint sources or area sources are diffused sources that discharge pollutants over a large area some of the examples are runoff from construction sites and agricultural fields.

● Uncontrolled growth in human population.
● Rapid industrialization.
● Urbanization.
● Uncontrolled exploitation of nature.
● Forest fires, radioactivity, volcanic eruptions, strong winds etc.

● Air pollution is aggravated because of four developments: increasing traffic, growing cities, rapid economic development, and industrialization.
● The presence in the atmosphere of one or more contaminants in such quality and for such duration as it is injurious, or tends to be injurious, to human health or welfare, animal or plant life.
● It is the contamination of air by the discharge of harmful substances.
● Air pollution can cause health problems, damage the environment, property and climate change.

● Airborne emissions emitted from various industries are a cause of major concern.
● These emissions are of two forms, viz. solid particles (SPM) and gaseous emissions.
● Thus, Air Pollutants can be solid particles, liquid droplets, or gases.
●They can be natural or manmade.
●The pollutants have been classified into primary and secondary categories.
● The primary pollutants are “directly” emitted from the processes such as fossil fuel consumption, Volcanic eruption and factories.
● The major primary pollutants are Oxides of Sulphur, Oxides of Nitrogen, Oxides of Carbon, Particulate Matter, Methane, Ammonia, Chlorofluorocarbons, Toxic metals etc.
● The Secondary pollutants are not emitted directly. The secondary pollutants form when the primary pollutants react with themselves or other components of the atmosphere.
● Most important secondary level Air Pollutants are Ground Level Ozone, Smog and POPs (Persistent Organic Pollutants).

● Persist in the form in which they are added to the environment. DDT, CO, SOx, NOx, Insecticides.

Oxides of Sulphur
● Sulphur Oxides are generally a product of the Volcanoes, Industrial processes, Coal and petroleum, because most of them have Sulphur as a component.
● The Sulphur Dioxide in presence of a catalyst such as NO2 causes Acid Rain, because of the formation of Sulphuric Acid.
● The Indian Coal is though low in sulphur content but still coal consumption is a major danger of acid rain because of the coal based power plants.

Oxides of Nitrogen
● Most of the Nitrogen Oxides are produced due to high temperature combustion.
● In the cities the brown haze dome above the cities is mostly because of the Nitrogen Oxides.
● The most important toxic gas is Nitrogen dioxide which is brown, with sharp odor.

Oxides of Carbon
● Carbon Monoxide, which is colorless, odorless and non irritating but very poisonous gas is the product of incomplete combustion of the natural gas, coal or wood.
● The vehicle exhaust is the major source of CO.
● The Carbon Dioxide is associated with the Ocean Acidification and is emitted from combustion, factories and respiration of living organisms.
● We have primary pollutants such as Volatile Organic Compounds or VOCs which are methane (CH4) and non-methane (NMVOCs).
● Methane is a GHG which contributes to Global Warming.
● The NMVOCs include the aromatic compounds such as Benzene, Toluene, Xylene which are proved or suspected carcinogens.
● Another dangerous compound is the 1,3-butadiene, often associated with industrial uses.

Particulate Matter
● The particulate matters are the fine particles which may be either solid or liquid, suspended in a gas.
● They are different from the Aerosols. Aerosols are particle and gas referred together.
● The aerosols which are created by the Human activities are anthropogenic aerosols. They account for around 10% of the total aerosols in the atmosphere.

Other Primary Pollutants
● Another category of the primary air pollutants is toxic metals such as Cadmium, Lead and Copper, which are products of the Industrial processes.
● The Chlorofluorocarbons (CFCs) are proved to be harmful to the ozone layer emitted from products currently banned from use.
● In agriculture process, Ammonia is emitted which has characteristic pungent odor. It is a precursor to foodstuffs and fertilizers.
● Ammonia is also a building block for the synthesis of many pharmaceuticals.

These are formed by the chemical reactions among Primary Pollutants.

Ground Level Ozone
● The most important secondary pollutant is the Ground Level Ozone or Tropospheric Ozone.
● The most important secondary pollutant is the Ground Level Ozone or Tropospheric Ozone.
● Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapours, and chemical solvents are some of the major sources of Nox and VOC.
● Ground Level Ozone forms due to reactions of the NOx, Carbon Monoxide and VOCs in presence of sunlight.
● In the last 100 years, the emission of Methane (a Volatile Organic Compound) has increased dramatically and it has contributed to the increased concentration of Ground Level Ozone.

● Another most important secondary pollutant is the Smog, which has made up of Smoke and Fog.
● Traditionally, the smog has resulted from large amounts of coal burning in an area caused by a mixture of smoke and sulphur dioxide.
● Now a days, the Vehicle emissions and Industrial emissions that are acted on in the atmosphere by ultraviolet light from the sun to form secondary pollutants that also combine with the primary emissions to form photochemical smog.

Air Pollution and Atmospheric Problems
● Apart from causing damage to materials, plant and animal communities and health problems in humans, air pollution affects the atmospheric processes.
● Acid rain, smog, global warming, ozone depletion etc. are some of the effects of pollution in our atmosphere.

● Addition of certain substances to the water such as organic, inorganic, biological, radiological, heat, which degrades the quality of water so that it becomes unfit for use.
● Water pollution is not only confined to surface water, but it has also spread to groundwater, sea and ocean.

Types of Water Pollutants –
i) Biological Agents
ii) Chemical Agents
iii) Physical Agents

i) Biological Agents

● Pathogenic organisms like viruses, bacteria and protozoans are serious water pollutants as far as human health is concerned.
● Cholera, bacterial and amoebic dysentery, gastroenteritis, typhoid, polio, viral hepatitis, worm infections, flue etc. are important water borne disease.
● Some insect that have aquatic larvae transmit Malaria, dengue, yellow fever and viruses in our country generally onset of rainy season is accompanied by such epidemics.
● Floods, water lodging, pipe bursting, mixing of sewage water with drinking water are some of the common problem we face during rainy season that cause these epidemics.
● Over populated areas, unplanned Industrial and human settlement, lack of proper civic amenities are some of the contributory factors.
● Water gets contaminated due to human wastes, animal wastes, domestic sewage and waste water discharges from tanneries and slaughter houses.

ii) Chemical Agents
● Chemical pollutants can be water- soluble, water insoluble or oxygen demanding wastes.
● These can be inorganic in nature like nitrates, phosphates, acids, salts and toxic heavy metals.
● Organic chemical pollutants include oil, gasoline, pesticides, dyes, paints, plastics, cleaning solvents, detergents and organic wastes like domestic sewage, animal waste etc.
● Radioactive substances that make the third category of chemical pollutants are released into water bodies as a result of processing of uranium ore, wastes from research laboratories etc.
● Organic wastes and inorganic nutrients like phosphates and nitrates enrich the water bodies that may cause eutrophication.

iii) Physical Agents
● Suspended solids, sedimentary solids and temperatures are the physical factors that affect the quality of water.
● These water pollutants adversely affect by silting, clogging the waterways, filling the dams and making water muddy.
● Aquatic animal face problem in breathing through gills in such water.
● Suspended organic and minerals solid absorb toxic substance like heavy metals and pass them in food chain.
● Thermal Pollution occurs when heat-laden water enters the water body.

● Addition of phosphates, nitrates and organic waste from industries like tanneries slaughterhouses, starch factories, paper mills, milk plants, run-offs from agricultural lands over – enrich the water bodies by increasing their nutrient content and so increase their productivity.
● The productivity of an ecosystem reflects the rate at with its producer photosynthesise.
● A lake with high productivity is called an eutrophic lake and it has a dense population of producer often visible as green scum on the surface water.
● The activities of aerobic bacteria, the decomposers, in the presence of oxygen release the nutrients from the organic waste.
● These nutrients act as fertilizers and cause population explosion of water microscopic plants like algae and other like duck beat weed, water hyacinth etc.
● The abundant growth of algae is called algal bloom.
● Bacterial activity consumes lot of dissolved oxygen and so do the algae and other green plants for respiration.
● This leads to decrease in the oxygen available to fishes that ultimately cause the death of the fishes.
● Eutrophication occur only in a stagnant water bodies and not in flowing water because flowing water carries away the wastes and the nutrients and disperses it too larger area.
● An oligotrophic lake has low nutrient content low productivity and clearwater that could be drinkable.

● Soil pollution is defined as the build-up in soils of persistent toxic compounds, chemicals, salts, radioactive materials, or disease causing agents and other xenobiotic (man-made) chemicals or other alteration in the natural soil environment.

Pollution in soil is mainly associated with:
● Indiscriminate use of fertilizers.
● Indiscriminate use of pesticides, insecticides and herbicides.
● Dumping of large quantities of solid waste.
● Deforestation and soil erosion
● The most common chemicals involved in soil pollution are petroleum hydrocarbons, solvents, pesticides, lead, and other heavy metals.
● A soil pollutant is any factor which deteriorates the quality, texture and mineral content of the soil or which disturbs the biological balance of the organisms in the soil.
● Pollution in soil has adverse effect on plant growth.

● Pollutants runs off into rivers and kills the fish, plants and other aquatic life.
● Crops and fodder grown on polluted soil may pass the pollutants on to the consumers.
● Polluted soil may no longer grow crops and fodder.
● Soil structure is damaged (clay ionic structure impaired).
● Corrosion of foundations and pipelines.
● Impairs soil stability.
● May release vapours and hydrocarbon into buildings and cellars.
● May create toxic dusts.
● May poison children playing in the area.

● Radioactivity is a phenomenon of spontaneous emission of proton (Alpha-particles), electrons (Beta-particles) and gamma rays (short wave electromagnetic waves) due to disintegration of atomic nuclei of some elements. These cause radioactive pollution.
● All types of the radiations are the form of energy.
● Radiations that have longer wavelength have low frequency, low energy and less penetrating power.
● Radiations with shorter wavelengths have high frequency, high energy and high penetrating power.

● Alpha particles, can be blocked by a piece of paper and human skin.
● Beta particles can penetrate through skin, while can be blocked by some pieces of glass and metal.
● Gamma rays can penetrate easily to human skin and damage cells on its way through, reaching far, and can only be blocked by a very thick, strong, massive piece of concrete.

● They include cosmic rays from space and terrestrial radiations from radio nuclide present in earth’s crust such as Radium – 224, Uranium-238, Thorium-232, Potassium-40, Carbon-14, etc.

● Nuclear power plants
● Nuclear weapon
● Transportation of nuclear material
● Disposal of nuclear waste
● Uranium mining
● Radiation therapy

The effects of radioactive pollutants depend upon:
● Half-life
● Energy releasing capacity
● Rate of diffusion and rate of deposition of the pollutant
● Various environmental factors such as wind
● Temperature, rainfall also influence their effects.



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