Our Environment

 OUR ENVIRONMENT
Basic Terms

Environment: Anything which surrounds an organism is said to form its environment. The surrounding can be changed by the animal or plant itself. In simple words, environment is the sum total of all external conditions and influences that affect the life and development of an organism.

Ecology: It is the study of relationship between the organisms and the environment.

Habitat: It is the natural living condition of an organism or animal.

Biodegradable substances: These are those substances which are broken down into simpler, harmless substances in nature within due course of time by the biological process such as action of micro-organisms like certain bacteria.

Example: paper, wood, cloth etc.

Non-biodegradable substances:  These are those substances which cannot be broken down into simpler, harmless substances in nature.

Example: DDT, plastics, polythene bags etc.

Biosphere: All ecosystems taken together make up the biosphere. Biosphere is the zone, including the earth’s surface, the adjacent atmosphere, and the underlying crust where life can exist.

Ecosystem: An ecosystem may be defined as a structural and functional unit of the biosphere in which living and non-living component interact together to form stable and self supporting system. The term Ecosystem was coined by Arthur Tansley in 1935.

Ecosystem (Biotic & Abiotic Component)

Components of ecosystem: There are two components of ecosystem.

Biotic component: Biotic component consists of living part of the environment such as plants, animals, human beings, micro-organisms etc.

Abiotic component: Abiotic component consists of non-living part of the environment such as air, water, soil etc.

Types of Ecosystem: There are two types of ecosystem.
     1.  Natural ecosystem
     2.  Artificial ecosystem

Natural Ecosystems: These ecosystems operate in the nature by themselves without any human interference.
Example: a pond, a lake, a meadow etc.

 

Natural Ecosystem

Artificial ecosystems: These are maintained by man and hence are also termed man-made or made-engineered ecosystems.

Artificially Maintained

Example: Croplands, orchards, gardens, parks etc.

     Producers: 

  These are those organisms which can make their own food. This includes all green plants and certain blue-green algae. These organisms can utilise solar energy with the help of photosynthetic pigments to form glucose. Producers ultimately produce the food for all other members of the community.

      

Cycle of Ecosystem

     Consumers: All animals are consumers. They cannot make their own food. Therefore, they utilize materials and energy stored by the producers.

Example:

         i.        Primary consumers or Herbivores.

  i    ii.        Secondary consumers or Carnivores.

 ii     iii.      Tertiary consumers or omnivores.

         

Types of Consumers in Food Chain

        Decomposers: These are those organisms which feed on dead decaying matter. These include bacteria and fungi.

Functions of decomposers:

    1.  Decomposers cleanse the earth of organic remains and can therefore, are termed as natural scavengers.

    2.  Decomposers create space for newer generations of organisms.

    3.  Decomposers release minerals and other raw materials trapped in organic matter.

          

Role of Decomposers

     

           Food Chain: 

   Food chain is a sequential interlinking of organisms based on their feeding habit. In simple words, a list of living organisms showing “who eats whom” is called a food chain.

i.e., Example:

Food Chain

Food Chain

Food Chain

Properties of food chain:

    1.  Usually, there are four or five tropic levels in a food chain.

2.  A food chain is always straight and proceeds in a progressive straight line.

   3.  In a food chain, there is unidirectional flow of energy.

   4.  Shorter food chains provide more available energy, while longer ones provide little available energy.

   5.  Only 10% of the energy available at each tropic level is transferred to the higher level.

Food Web:

Food web is a network of food chains which are interconnected at various tropic levels so as to form a number of feeding connections.

Difference between Food chain and Fod web

Food web

Properties of food web:

   1.  Unlike food chains, food webs are never straight.

   2.  A food web provides alternative pathways of food availability.

   3.  Greater alternatives available in a food web make the ecosystem more stable.

   4.  Food webs also help in checking the overpopulations.

   5.  Food webs also help in ecosystem development.

Flow of energy in an ecosystem:

    1.  The ultimate source of entire energy, used by living organisms, is the sun.

    2.  Of the total solar radiations falling on the earth, only about 1% are captured by green plants in a terrestrial ecosystem and converted into food energy by photosynthesis. This energy is stored as chemical energy of food and finally used by the consumers.

10% Law:

 It was put forth by Lindeman (1942). It is also termed as second law of thermodynamics or law of entropy. According to this law, on an average, only about 10% of energy is actually available to the next tropic level.

Biological Magnification:

   The phenomenon that involves progressive increase in concentration of harmful non-biodegradable chemicals at different tropic levels in a food chain is called biomagnifications.

In simple words, some harmful non-biodegradable chemicals such as mercury, Cadmium etc. enter the bodies of organisms through the food chains and go on concentrating at each tropic level. This phenomenon is called bio-magnification or biological magnification.

Ozone and its Importance:

Ozone (O₃) is a form of oxygen. It is formed by three atoms of oxygen.

In the stratosphere, ozone is being photo dissociated and generated by the absorption of harmful, ultraviolet (UV) radiations coming from sun.

Ozone layer is very important for the existence of life on earth because it absorbs most of the harmful ultraviolet radiations coming from the sun and prevents them from reaching the sun.

Ozone Depletion

Ozone layer and its Depletion

Ozone depletion and its cause:

 The thinning of ozone layer is commonly called ozone depletion. Ozone is being depleted by air pollutants like CFCs (chlorofluorocarbons), methane (CH₄) and oxides of nitrogen (NO). The excessive use of the fossil fuels and other air pollutants is also one of the  major cause of the ozone depletion. The hole in the ozone layer called as ozone hole was first discovered over Antarctica in 1985.

Harmful Effects of Ozone depletion:

The ozone depletion has following harmful effects.

   1. Ultraviolet radiations cause skin cancer.

  2. These cause damage to eyes and also can cause increased incidence of cataract disease in eyes.

   3. These cause damage to immune system.

  4. Ozone depletion also causes global rainfall and ecological disturbances.

Wastes and moles of waste disposal:

“Waste disposal” literally means “getting rid of waste”.

Some prominent methods of waste disposal are:

  1.   Landfills: In urban areas, majority of the solid wastes are buried in low lying areas to level the uneven surface of land. This method of waste disposal is commonly called landfills.

  2.   Recycling of Wastes: Number of solid wastes (paper, plastics, metals, etc) can be recycled by sending them to respective recycling units.

   3.   Preparation of Compost: Household waste such as peeling of fruits and vegetables can be converted into compost and used as manure.

  4.   Incineration: Incineration is the process of burning of substances at high temperature and ultimately converting them into ashes. It is carried out in an incinerator.

    5.   Production of biogas and manure: Biodegradable wastes can also be used in biogas plants to generate biogas and manure.

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the remaining content  is under process

With Regards

Riya Gupta 

Also See:

1. Control and Coordination (By Simran Kour)

2. Reproduction (By Sazuia Rehman)

3. Carbon and its Compounds (By Ayushi Vaid)

4. Electricity (By Nittika Raj)
5. Our Environment (By Riya Gupta)

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