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Thursday, December 7, 2017

CBSE CLASS 10 OUR ENVIRONMENT NOTES AND IMPORTANT QUESTIONS

 OUR ENVIRONMENT  - NOTES AND IMPORTANT QUESTIONS


Environment -  Everything that surrounds us is Environment. It includes both living and non living components like temperature , rainfall, wind, soil and Minerals.

Ecosystem - It is formed by all the interacting organisms in an area with non living constituents like air, water , temperature of environment together.

Natural ecosystem-  These are formed in nature. for example - ponds, deserts, mountains, oceans, Forest

Artificial ecosystem- These are man made ecosystems. for example - Garden , crop field, aquarium .

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Biotic components - All the living components of environment are called biotic components. Example -  plants and animals

Biotic components are of  three types-

1.  Producers - Living organisms which produce their own food are called producers.example - all green plants and certain blue green algae which can produce food by photosynthesis are called producers.

2 . Consumers -  Those organisms which depend directly or indirectly on producers for their food are called consumers.
These are of 4 types-

(i) Primary consumer or herbivore -  Those animals which  depends on plants only for their food. Example -  goat ,  deer etc.

(ii) Secondary consumers or carnivore -  Those animals which eat flesh of the animals. Example-  lion, tiger, crocodile

(iii) Tertiary consumers or Omnivores -  Those animals  which eat plants as well as animals are omnivores.  Example -  cat,  human

(iv) Parasites -  Those organisms which live on the body of host and take food from it . Example -  lice ,  virus

3. Decomposers - Those microorganisms which decompose the dead plants and animals. Example-  bacteria, Fungi,  Hawk,  eagle.
 They help in replenishment of natural resources and clean the environment.

Abiotic components - The non living components of our environment which  interact with biotic components for their growth, reproduction and other activities. Example -  air, water, soil

Food chain - It is a Series of organisms in which one organism eats and other organisms as a food.  Example -  Grass → Deer→ Lion

Trophic level -  Each level of the food chain is called trophic level. There is transfer of energy between each trophic level. Flow of energy in trophic levels in food chain is unidirectional. Energy goes on decreasing from each trophic levels to next trophic level.

Food web - It is formed by interconnecting large number of food chains.

Ten percent law - Green plants capture 1% of Sunlight and convert it into food energy. Only 10% of energy is transferred to the next trophic level. The remaining 90% of energy is consumed in life processes like digestion, growth,  reproduction  by each trophic level.

Biological magnification -  The concentration of toxic substances like pesticides, insecticides increases with each trophic level in food chain. It is called Biological magnification. Humans occupy top position in food chain, so maximum toxic substance are present in human bodies.

Environmental Waste - Waste is any substance which is discarded after primary use, or it is worthless, defective and of no use. Examples - municipal solid waste (household trash/refuse), wastewater (such as sewage, which contains bodily wastes (feces and urine) and surface runoff), etc.

Biodegradable substances -  The substances that can be decomposed by microorganisms and do not persist in environment is can be converted into compost are called biodegradable substances. Example -  plant waste and animal waste.

Non Biodegradable - Substances the substances which cannot be decomposed by microorganisms and persist in the environment are called Non Biodegradable substances. This should be recycled or reused .

Waste management -
  • Biodegradable waste and non biodegradable waste should be put in separate  dust bins.
  • Biogas plant is excellent way of disposal of waste in rural areas.
  • Sewage treatment plants are must in urban areas to detox water before releasing into river.
  • Landfilling can be decomposed in a pit that changes waste into manure and sold to farmers,  home makers for kitchen garden.
  • Recycling of non biodegradable waste is must to clean environment.
  • Newspapers can be recycled very easily and used for making envelopes,  eco friendly carry bags.

Ozone -  It is formed in upper atmosphere by action of UV light on Oxygen.
  • Ozone is Deadly poison. Ozone protect us from harmful UV radiations of the Sun.
  • UV radiation is highly harmful for living organisms, it can cause skin cancer in humans.

Ozone depletion -  Ozone Layer is getting thinner and thinner day by day. It is due to the use of CFC ( chlorofluorocarbons)  in refrigeration,  in fire extinguishers and air conditioners.
  • UNEP (United Nations Environment Programme) has succeeded in reaching in agreement to freeze CFC production to save environment and stop its production. it is called KYOTO  Protocol.

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