The environment can be defined as the surrounding in which an organism can survive.  Every living organism gets affected by the environment and organisms also affect the environment.

The term environmentderived from the word “Environia” means to surround. It refers to both the Abiotic (physical or non-living) and the Biotic (living) environment.

some important facts

  • world environment day is celebrated on 5 June every year
  • Environmental conservation– It is a practice to prevent collapsing or loss of species.
  • Environment Protection Act – 1986
  • The Montreal Protocol-1987- is a global agreement to protect the level of ozone in the stratosphere

Ecosystem(The term ecosystem was first used in 1935, by British ecologist Arthur Tansley. )

Interaction of living and non-living of an area with each other, is interacting organisms of an area together with the non-living constituents of the environment form an ecosystem. This shows the relation between organism and their environment. the sum of all these living and non-living in an area is termed an ecosystem.

Types of the ecosystem

Artificial crop-fields, aquariums are human-made.

Natural– forests, ponds, and lakes.

Ecosystem consists of

  1. biotic components -comprising living including plants and animals.Ex – trees, humans, another living organism.
  2. abiotic components– comprising physical factors like temperature, rainfall, wind, soil, and minerals

Biotic components of living organisms having several categories-

Producers – All green plants and certain bacteria which produce food by photosynthesis come under this category and are called the producers.

ConsumersThose organisms which consume the food produced directly or indirectly by the producer or feeding on other consumers are termed as the consumers.

Consumers can be classified as –

Herbivores- Herbivores are animals having plants as a source of food. For ex- deer, koalas.

Carnivorescarnivore is an organism that predates and mostly eats meat, or the flesh of animals.

Omnivores–  An omnivore is an animal that can eat and survive on both plant and animal matter both.

Parasites – A parasite is an organism that lives on or inside the host body and gets benefits by harming one.

Decomposers These are microorganisms, like bacteria and fungi, they break down the complex organic substances into simpler inorganic substances that go into the soil and those simple organic substances reused by the plants. The decomposers obtain energy mostly from dead and decaying consumers. These are also called cleaning agents of the ecosystem. Decomposers also help in recycling the nutrients.

Functions of the ecosystem :

Ecosystems show complex dynamic systems. They perform certain functions as:
(i) Energy flow through the food chain
(ii) Nutrient cycling also termed biogeochemical cycles
(iii) Ecological succession or ecosystem development
(iv) Homeostasis (or cybernetic) or feedback control mechanisms

Food Chains and Food Webs

this is a series of organisms that are directly linked with each other as they eat or being eaten by some other. This series of organisms taking part at various biotic levels form a food chain.

As several chains or series overlap each other as one animal can be eaten by more than one, this overlapping in the food chain gets complicated, termed as food wave.  So instead of a straight-line food chain, the relationship of organisms can be shown as a series of branching lines called a food web.

The various steps at which the energy, in form of food in the food chain is transferred at a various level called tropic level

  • Autotrophs or the producers are at the first trophic level– autotrophs capture the sun’s energy and convert it into chemical energy. this energy is vital for all living to perform their activities.
  • The herbivores or the primary consumers come at the second tropic level.
  • small carnivores or secondary consumers get energy from herbivores at the third tropic level.
  • larger carnivores or the tertiary consumers form the fourth trophic level
tropic level of environment
fig- showing the tropic level

Example of tropic level-  Grass-  grasshopper—frog- eagle.

From autotrophs, the energy goes to the heterotrophs and decomposers. when one form of energy is changed to another form of energy, some energy is lost to the environment in forms that cannot be used again.

The flow of energy is irreversible, as it does not go in the backward direction, it is unidirectional. Some important facts of energy flow-

  • green plants in a terrestrial ecosystem use about1% of the energy of sunlight for conversion into food energy.

By the process of photosynthesis, the total rate at which the radiant energy is stored in the green plants is called Gross Primary Production (GPP)

The remaining amount is stored by the plant as Net Primary Production (NPP) which is available to consumers

  • when primary consumers eat green plants, a great amount of energy is lost as heat to the environment. An average of 10% of the food eaten turned into its own body made available for next-level consumers. So 10% of total energy consumed can be transferred to the next level.
  • Therefore, as the trophic level increases, the % of the level of energy highly decreases.
  • In an ecosystem, individuals at the lower trophic levels are greater in number. Producers are the greatest in number.
Flow of energy in ecosystem

Biological magnification

progressively accumulation of several pesticides and other harmful chemicals absorbed by the plants along with water and minerals, and from the water bodies, these are taken up by aquatic plants not degradable and goes to other trophic levels. As humans are on the top level in food chain, we get the maximum concentration of these chemicals gets accumulated in our bodies. This phenomenon is known as biological magnification.

Depletion of the ozone layer and waste disposal is a very big problem as it is affecting our lives directly large scale.

Ozone Layer

As we all know Ozone (O3) is a molecule formed by three atoms of oxygen. as oxygen is essential for all aerobic organisms. Ozone is a deadly poison but at higher atmospheric level ozone performs a very important role, as it works as a barrier of UV rays coming from the sun. These rays are so harmful to all living; they can cause many diseases. For example, it Causes skin cancer in human beings.

Depletion of ozone-  ozone is a product of oxygen molecule reaction with UV rays acting on O2.  The higher energy UV radiations split apart some molecular oxygen (O2) into free oxygen (O)

formation of ozone
formation of ozone by oxygen molecule

Atoms. These free atoms then combine with the molecular oxygen to form ozone (O3).

In the 1980s The amount of ozone in the atmosphere began to drop. The main causes of the decrease in ozone were found as synthetic chemicals like chlorofluorocarbons (CFCs). The CFCs are used as refrigerants and in fire extinguishers.

In 1987, United Nations Environment Programme (UNEP) made an agreement to freeze CFC production at 1986 levels. Now it is mandatory for all manufacturing companies to make CFC-free refrigerators throughout the world.

Managing the Garbage

Garbage management includes activities and actions required to manage waste throughout the process of final disposal. The generation of garbage or waste materials is increased by Improvements in our lifestyle. The waste we generate may be biodegradable or non-biodegradable. These waste disposals generated by us causing serious environmental problems.


As some garbage is organic and can be decomposed by bacteria and decomposer, called biodegradable. These substances easily decompose and that’s why they keep the environment clean.


There are many human-made materials like plastics that will not be broken down by the action of bacteria or other saprophytes said to be non-biodegradable. They cause bio-magnification in the food chain and end up in humans with various diseases. They cause air, water, and soil pollution in various aspects. In our daily life so many harmful non-biodegradable gazets we using as such- mobile -having elements like silicon, lead, and many other things having harmful materials which are not easily degradable.

 To manage this waste there are various processes including- a collection of waste, their transport, treatment of waste, and final disposal. The waste can be managed by reducing, recycling, and reusing materials.

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  • sushma kumari · September 12, 2020 at 8:58 pm

    Based on 10th standard NCERT and additional knowledge for other exams

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