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Our Environment

“Taking care of the Environment is not an obligation. Our Environment is our Life”

- Sadhguru


Environment refers to the surrounding of an organism where it thrives. It constitutes both living and non-living things, i.e., physical, chemical and biotic factors.

It is a dynamic interaction of climatic factors, living things and natural resources. All of these elements have a direct impact on human survival and economic activities. The environment in totality is responsible for life on Earth.

Ecosystems – What are its components?

  • All organisms such as plants, animals, microorganisms and human beings as well as the physical surroundings interact with each other and maintain a balance in nature. All the interacting organisms in an area together with the non-living constituents of the environment form an ecosystem.

  • The various components of an ecosystem are interdependent.

  • The ecosystem comprises all the biotic and abiotic factors interacting with one another in a given area.

  • Biotic components: It include all living organisms such as plants, animals, microorganisms and humans, etc. and

  • Abiotic components: It include physical factors like sunlight, temperature, air, wind, rainfall, soil and minerals, etc. E.g., forest, pond, grassland, lake, gardens and crop-fields ecosystems.

Types of Ecosystems

  • The forest, pond, grassland ecosystem etc, are natural ecosystems while gardens and crop-fields are humanmade (artificial) ecosystems.

Food chain and Food Web

  • A series of organisms feeding on one another is known as Food Chain.

  • On the basis of choice of habitat, the food-chains are of two types:

A. Terrestrial food-chain: The habitat is on land.

E.g., Grazing food chain: green plants (or grass) – Insects – Snake – Hawks.

E.g., Detritus food chain: dead organic matter – detritus species(woodlouse) – birds.

B. Aquatic food-chain: the habitat can be different water bodies

E.g., Phytoplankton – Zooplanktons – Fish – Shark.

  • Each step or level of the food chain forms a trophic level.

Trophic level

Source of energy



Solar energy

Green plants, blue green bacteria.



Grasshoppers, antelopes. Termites.

Primary carnivores


Wolves, spiders, some snakes, warblers.

Secondary carnivores

Primary carnivores

Killer whales, tuna, falcons.


Both on plants (producers) and animals (herbivores and carnivores)

Humans, rats, opossums, bears, racoons, crabs.

Detritivores or Decomposers

Wastes and dead organic matter

Fungi, many bacteria, earthworm, vultures.

Each organism is generally eaten by two or more other kinds of organisms which in turn are eaten by several other organisms. So instead of a straight-line food chain, the relationship can be shown as a series of branching lines called a food web.

Pyramid of trophic levels

  • Is a graphical representation.

  • Can be the pyramid of numbers, the pyramid of biomass or the pyramid of energy.

  • All the pyramids start with producers.

a. Pyramid of numbers: gives the number of organisms present at each trophic level. It can be upright or inverted.

b. Pyramid of biomass: gives the biomass of each trophic level and could be upright or inverted.

c. Pyramid of energy: The flow of energy is unidirectional and it is always upright

(The energy that is captured by the autotrophs does not revert back to the solar input and the energy which passes to the herbivores does not come back to autotrophs. As it moves progressively through the various trophic levels it is no longer available to the previous level.)

  • The energy available at each trophic level gets diminished progressively due to loss of energy at each level (in the form of heat).

  • In a food chain, unknowingly some harmful chemicals enter bodies of animals at each trophic level. One of the reasons is the use of several pesticides and other chemicals to protect our crops from diseases and pests.

  • These chemicals are either washed down into the soil or into the water bodies. From the soil, these are absorbed by the plants along with water and minerals, and from the water bodies these are taken up by aquatic plants and animals. This is one of the ways in which they enter the food chain.

  • These chemicals are non-degradable and gets accumulated progressively at each trophic level. As human beings occupy the top level in any food chain, the maximum concentration of these chemicals get accumulated in our bodies.

  • Bioaccumulation: refers to how pollutants enter food chain; there is an increase in concentration of pollutants from environment to first organism in food chain.

  • Biomagnification-refers to tendency of pollutants to concentrate as they move from one trophic level to next level.

How do our activities affect the Environment?

We are an integral part of the environment. Changes in the environment affect us and our activities change the environment around us.

Some of the environmental problems are, deforestation, depletion of the ozone layer and waste disposal etc.

Ozone Layer and How it is getting Depleted?

  • Ozone (O3) – an allotrope of Oxygen – three atoms of oxygen bound in non-linear fashion.

  • Ozone in troposphere = degrade air and helps to form smog

  • Ozone in stratosphere = protects life on earth by absorbing UV radiations.

This radiation is highly damaging to organisms, for example, it is known to cause skin cancer in human beings.

  • Formation of Ozone: The higher energy UV radiations split apart some molecular oxygen (O2) into free oxygen (O) atoms. These atoms then combine with the molecular oxygen to form ozone as shown—

Reason for Ozone Depletion:

i. Excessive use of CFCs (Chloro Fluoro Carbon) in refrigerators, jet planes, spray canes, fire extinguishers, etc.

ii. Nuclear explosion.

iii. Naturally occurring Ozone Depleting Substances (ODS):

a. Hydrogen oxide

b. Methane

c. Hydrogen

d. Nitrogen oxide

e. Chlorine monoxide.

Measures to mitigate Ozone Depletion:

i. Montreal Protocol, 1987

The Montreal protocol on substances that deplete Ozone layer was designed to reduce production and consumption of Ozone depleting substances such as CFCs in order to reduce their abundance in atmosphere, there by protect earth’s fragile ozone layer.

ii. Kigali Amendment 2016

Amendment to the Montreal Protocol to eliminate planet – warming HFC gases.

Garbage Management

- In our daily activities, we generate a lot of material that are thrown away. The disposal of the waste we generate is causing serious environmental problems.

- Many human-made materials like plastics will not be broken down by the action of bacteria or other saprophytes. These materials will be acted upon by physical processes like heat and pressure, but under the ambient conditions found in our environment, these persist for a long time.

- Management of waste disposal ensures best practices of environment to be followed along with proper monitoring and regulation.

Steps involved: 1. Segregation of waste 2. Collection 3. Transport 4. Treatment 5. Processing & Recycling 6. Disposal


Solid waste dumped into low lying area and covered with the soil.


It is burning of substances at high temperature. It is commonly used to dispose hospital waste.


Vermi Composting

Compost: The process in which waste material like livestock excreta (cow dung, etc.), kitchen waste, plant remains, etc, is decomposed in pits is known as composting.

Vermi-compost: Compost is also prepared by using earthworms to hasten the process of decomposition of plant and animal refuse. This is called vermi-composting.

Biogas generation

Sewage is decomposed anaerobically to yield biogas and manure.

What really happens to plastic you throw?

Waste management model, Indore, India


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