Question

explain the lesson our environment in class 10
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Answer 1

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CH:15 OUR ENVIRONMENT  :  ( CLASS 10TH )

ENVIRONMENT : Our surrounding is called environment.

• Ecosystem and its components.
• Biotic and abiotic components.
• Food chain and Food web.
• Energy transfer through trophic levels.
• Ozone layer and its concerns.

ECOSYSTEM : This is a system of interdependencies among various living beings and non-living things in a given habitat.

COMPONENTS OF ECOSYSTEM : An ecosystem has two types of components, biotic component and abiotic component.

ABIOTIC COMPONENT : All non living things make the abiotic component of an ecosystem. Air, water, and soil are the abiotic components.

BIOTIC COMPONENT : All living beings make the biotic component of an ecosystem.

• Green plants play the role of producers ; because they prepare the food by photosynthesis.
• Animals and other living beings play the role of consumers; because they take food from plants.
• Bacteria and fungi play the role of decomposers; as they decompose dead remains of plants and animals.

FOOD CHAIN : It is a simple representation of transfer of energy from the sun to different biotic components of an ecosystem. Sun is the ultimate source of energy. Green plants convert solar energy into chemical energy during photosynthesis.

PRODUCER -------> PRIMARY CONSUMER ---------> SECONDARY CONSUMER

FOOD WEB : A network of interconnected food chains.

TROPHIC LEVELS :

It is each step or level of the food chain.

I - TROPHIC LEVEL : Producers Eg green plants, blue green algae , Phytoplanktons. etc

II - TROPHIC LEVEL : Primary consumers or herbivores

III- TROPHIC LEVEL : Secondary consumers or small carnivore

IV - TROPHIC LEVEL : Tertiary consumers

FLOW OF ENERGY :

• 1 percent energy available from the sun to the terrestrial plants is converted into food.
• 10 percent energy in food is transferred to next level of consumer. 90 percent is lost.
• No of steps of food chain is only 3 or 4 as very little energy is available to higher levels.
• No of organisms decrease as we move up in a food chain.
• Flow of energy in a food chain is unidirectional.
• Biomagnification of pollutants : Progressive accumulation of harmful substances like pesticides take place.

TYPE OF WASTE :

I) Biodegradable : Can be broken down by the enzymes of bacteria or fungi Eg : Plant and animal waste , paper, wood etc.

II) Non Biodegradable : Can't be broken down by the enzymes of bacteria or fungi ( decomposers ) Eg : plastic etc.

BIOLOGICAL MAGNIFICATION :

• The process of increase in concentration of a toxic chemical with increasing trophic level in a food chain.

OZONE LAYER DEPLETION :

• Ozone layer is also known as stratosphere. When ultraviolet radiations act on oxygen, the oxygen gets converted into ozone.  

       UV radiation

O₂ -------------------------->  O + O

O + O₂ ----> O₃

• Ozone layer works like a protective shield for living beings.

EFFECT OF DEPLETION OF OZONE LAYER :

• Due to depletion of ozone layer more UV rays reach to the earth and cause skin cancer , immune deficiency , reduces crop yield , reduce population of phytoplanktons and zooplanktons.

EFFECT OF CFCs : Use of CFCs ( chlorofluorocarbon ) has damaged the ozone layer. It is used in refrigerators and aerosol spray.

PROBLEM OF WASTE DISPOSAL :

• Plastic waste is a serious concern because plastic is non biodegradable.

• Proper segregation of wastes before disposal helps us to save our environment.

WASTE MANAGEMENT :

• Landfills
• Recycling
• Sewage treatment
• Incineration
• Use of Disposable

• Paper cups.

• I THINK THIS MUCH ONLY IS HERE IN THIS CHAPTER...