Our Environment: Types, Components and Functions

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Collegedunia Team

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The word environment originated from the French word “environ” which means surrounding. Thus, the environment can be defined as all the living and nonliving things that surround us and are responsible for nourishing the life that exists on earth. All the organisms, plants, human beings and natural resources such as water, soil, and physical interactions form an important aspect of our environment. Due to rising concerns such as global warming, pollution, deforestation and climate change, there is a need to conserve and protect our environment from further destruction. 

Also Read: Eco-System - What are its components?

Ecosystems

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  • The term ecosystem was first coined by A.G. Tansley 1935. ‘Eco’ means environment and ‘system’ implies a complex of co-ordinated units. 
  • An ecosystem is a community of different species which interact with one another and with their nonliving environment exchanging energy and matter at different levels in the environment.
  • Ecosystem includes all the natural units of earth such as living things (plants, animals and microorganisms) which function together with the nonliving environment (air,water and soil) in a particular area.
  • Examples of ecosystems are: Forest,pond,mountain,sea,river etc.
  • Ecosystems are of two types-natural and man-made.

Types of Ecosystem

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  1. Natural ecosystem:

It is a type of ecosystem which is found naturally on earth.It can be further classified into different types of “biomes”- 

  • Aquatic biomes such as sea,pond, river, lake
  • Terrestrial biomes such as forest, desert, mountains etc.

  1. Man-made ecosystem:

It is an artificial type of ecosystem which is created by human beings. Eg.crop fields, aquariums, gardens,parks,zoos etc.

Ecosystem

Natural and Man-made ecosystem


Components of the ecosystem

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The environment consists of both biotic (living things) and abiotic components (nonliving things)

Biotic components:

Biotic components

Biotic components

  • Producers:

Organisms which are capable of synthesizing their own food are known as the producers (Eg.plants). They are also called autotrophs.

  • Consumers: 

All organisms which get their food by feeding upon other organisms (tiger, man) are called carnivores. They are also known as heterotrophs.

Herbivores – These are the ones who feed directly on producers and are known as primary consumers (e.g. rabbit, human) 

Carnivores – Meat eaters: They feed on other consumers.

» If they feed on herbivores they are known as Secondary consumers (Eg.frog) 

» If they feed on other carnivores directly, they are known as Tertiary consumers (Eg.snake, fish) 

Omnivores – Organisms which feed on both plants and animals. (Eg. humans, rat) 

Detritivores - Organisms which feed on the parts of dead organisms (Eg. ants, earthworms).

  • Decomposers:

Decomposers are known to be the organisms which derive their nutrition through the process of breaking down complex organic compounds into simpler organic constituents (bacteria, fungi).

Abiotic components:

Abiotic components

Abiotic components

  • Physical Factors: The sunlight, average temperature, annual rainfall, wind, soil type, water availability etc. are some of the important physical factors constituting the abiotic component.
  • Chemical Factors: Essential nutrients like carbon, nitrogen, phosphorus, potassium, hydrogen, oxygen and sulphur are some of the chemical factors influencing the ecosystem.

Functions of an ecosystem:

The major functional attributes of an ecosystems are:

  • Cycling of nutrients: In the ecosystem, biotic components and other materials like N, C, H2O are circulated within and outside of the system. This is known as the biogeochemical cycle.
  • Energy can be transferred from one trophic level to the other in the form of a chain called the food chain.
  • Assists in primary and secondary production.
  • Helps in ecosystem development and regulation.

Food Chain

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  • Definition: 

The transfer of food energy from the source in plants through a series of organisms that consume and are consumed is known as the ‘food chain’.

Food Chain

Food chain

  • Examples: 

 Grass(Producer) → Deer(Herbivore) → Tiger(Carnivore),  Grass(Producers) → Insect(Herbivores) → Frog(Carnivores) → Snake(Secondary Carnivore).

  • Significance of food chains:

  1. Helps in understanding of interaction among various organisms at different trophic levels.
  2. Helps in transferring of energy at different trophic levels of the ecosystem.
  3. It gives dynamicity to the biological activities and the ecosystem.

Also Read: Food Chains and Webs


Food Web

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  • Definition: The interlocking pattern of various food chains in an ecosystem is known as the food web. In a food web, many food chains are interconnected and thus there are increased possibilities of eating and getting eaten by different organisms of various species. Example: Insects, rats, deers, etc. may eat grass; these inturn may be eaten by carnivores (snake, tiger). Thus, there is an interlocking of various food chains and this is termed as a food web.

The major environmental threats posed due to human activities are:

  • Problem of waste disposal.
  • Shortage of food and impoverishment of biological diversity.
  • Destruction of ozone layer.
  • Climatic changes and global warming
  • Pollution
  • Depletion of freshwater resources.

The two of the major problems from the above list are ozone layer depletion and waste disposal:

  1. Depletion of ozone layer:

A single molecule of ozone (O3) is formed from the combination of three atoms of oxygen. The major significant function of ozone is to shield the surface of the earth from ultraviolet (UV) radiation from the Sun. This radiation is highly damaging to organisms, and can cause skin cancer in human beings.

Formation of ozone: Ozone is formed when 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 which is depicted below in the equations:

Depletion of ozone layer

Depletion of ozone layer

Depletion of ozone layer: Ozone layer gets depleted – due to the use of chemicals like CFC’s(chlorofluorocarbons), aerosol sprays etc. Depletion of ‘ ozone layer would cause skin cancer in humans and animals and severe damage to the plants and its species.

  1. The problem of waste disposal:

Industrialization, change in lifestyle and attitude of humans, rise in demand of consumer goods have created a major problem in the form of wastes/garbage accumulation and its disposal. These problems are more concentrated in urban areas. The method of disposal of waste should be done properly and in a scientific way. Different methods for waste disposal are: Incineration, Composting, Land fillings, Reusing, Recycling etc.

Also Read: Ozone Layer and How it is getting depleted


Sample Questions

Ques 1. Write any 3 differences between food chain and food web.(2 marks)

Ans. 

Food chain Food web
It is a straight sequence of organisms. Complex networks formed by many food chains interconnected to each other.
May be affected if an organism dies Food web is not affected if there is a death of any organism
Maximum no. of population in the food chain is 5-6. It has many different populations of different species.

Ques 2. What are degradable and biodegradable wastes? Give examples.(2 marks)

Ans. Biodegradable wastes are substances which can be broken down into organic compounds by the action of decomposers such as bacteria etc. They do not cause any kind of harm to the environment. Eg. wood, paper, animal dung etc.

 Non-biodegradable wastes are substances which cannot be broken down into simpler substances and are very harmful to the environment. Eg. plastic, DDT, polythene, radioactive elements etc.

Ques 3. Write the difference between autotrophs and heterotrophs.(2 marks)

Ans. 

Autotrophs (Eg. green plants) Heterotrophs (Eg.lion,man)
They are the producers which can synthesise their own food. They are consumers and are dependent on other organisms for food.
They possess chlorophyll for the process of photosynthesis Chlorophyll is absent in consumers
They form the first trophic level in the food chain They form the second and third trophic levels in the food chain.

Ques 4. Explain any two methods of waste disposal.(2 marks)

Ans. Methods of waste disposal are: 

  • Composting: Organic wastes are filled into a compost pit of specific sizes and then covered with a thin layer of soil. The waste in these pits get converted to manure after a few days.
  • Recycling: The wastes are broken down into simpler constituents and can be later used to make either the same or different products. Eg. Non-bio degradable solid wastes such as metals and plastics can be recycled.

Ques 5. Write a note on energy flow in the ecosystem.(2 marks)

Ans. 

  • Energy is needed for every biological activity. 
  • Solar energy is transferred into chemical energy through the process of photosynthesis. This energy is stored in plant tissue, and then transformed into mechanical and heat form during metabolic activities. 
  • In the biological world, the energy flows from sun to plants and then to all heterotrophic organisms like microorganisms, animals, and man i.e. from producers to consumers. 1% of the total sunlight falling on the green plants is utilized in photosynthesis. 
  • This is enough to sustain all life on this earth. There is no 100% flow of energy from producers to consumers. Some are always lost to the environment. Because of this, energy cannot be recycled in an ecosystem ‘it can only flow one way’.

Previous Year Questions

Ques 1. Why is biogas considered excellent fuel? (2019)

Ans. Biogas is considered to be an excellent fuel due to the following reasons:

  • It doesn't lead to any sort of pollution as it is natural and thus environment friendly.
  • Biogas is formed from various biogas plants which forms a very good method of waste management.
  • Biogas is very economical in nature and produces quite a substantial amount of heat per unit.

Ques 2. Write the essential function performed by ozone at the higher levels of the Earth’s atmosphere ? How is it produced ? Name the synthetic chemicals mainly responsible for the drop of ozone in the atmosphere. How can the use of these chemicals be reduced? (Outside Delhi 2019)

Ans. The essential functions performed by ozone at the higher levels of the Earth’s atmosphere is to absorb the injurious ultraviolet rays reaching from the sun to earth.

Ozone layer is formed by the working of ultraviolet rays on the oxygen gas at a higher level in the atmosphere.

The most harmful synthetic chemical responsible for the depletion of ozone in the atmosphere is chlorofluorocarbons. 

Methods by which the use of such synthetic chemicals be reduced are:

  • Replacing chlorofluorocarbons by hydrochlorofluorocarbons as it disintegrates more quickly.
  • Proper disposal of old gadgets and devices such as tv, freezer, etc.

Ques 3. What is an ecosystem? (2017)

Ans.

 An ecosystem is referred to as the self-sustaining structure where both biotic as well as non-biotic organisms come in contact with each other. 

Examples: Grasslands, ponds, forests, etc.

Ques 4. In the following food chain, 100J of energy is available to the lion. How much energy was available to the producer? (Outside Delhi 2017)

Ans. There are three trophic levels

the producer, the consumer and the secondary consumer according to 10% of energy transfer in trophic level.

If the lion has 100J of energy then 

let's take 10% of x = 100J , then x = 1000J

Hence, the producer had 1000J of energy.

Ques 5. List two natural ecosystems. (2016)

Ans. Two natural ecosystems are:

  • Pond
  • Lake

Ques 6. Give reason to justify the following:
The existence of decomposers is essential in a biosphere.
Flow of energy in a food chain is unidirectional. (2016)

Ans.  Reasons why existence of decomposers is essential in a biosphere are:

  1. Decomposers help in the breaking down of the complex organic particles of waste products and dead residue of organisms into more simpler inorganic substances that can be soaked up by the plants. They are important for the healthy functioning of an ecosystem. 
  • They help in the cycling of the materials present in the biosphere.
  • Decomposers help in cleaning the environment by decomposing dead plants and animals.
  • They help in natural replenishing of the soil.
  1. We can say that the flow of energy in a food chain is unidirectional because energy in the ecosystem flows from one trophic level to another, it flows from the producers such as green plants to the consumers. It doesn’t flow in the backward directions as in from the consumer to the producer and the energy that is being picked up doesn’t go back to the solar input. 

Read More:

Related Topics:
Biodegradable and non-biodegradable substances Natural Resources Management
Food Web Environment (Protection) Act, 1986

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CBSE X Related Questions

1.
Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.

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                  5.
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