TOPIC: NATURAL RESOURCES�CLASS-IX �SUBJECT-BIOLOGY

BY- Mrs Sita Kumari Murmu

PGT-Biology

JNV Cuttack

NAVODAYA VIDYALAYA SAMITI, NOIDA

Introduction�In our daily life, many materials are needed to fulfil our need. What are these material? From where these material are coming.�Example like notebook or pencil, what is its raw materials ?

Grass, Bamboo, Wood, Graphite, etc come from nature are called Natural Resources.

NATURAL RESOURCES: These are the resources that exist in nature without actions of humankind.

OR

• The material/substances, which occur in nature naturally, which can be exploited for economic growth. Eg Air, Water, Soil, Forest, fossil fuel etc.

Basic requirements of life forms on the Earth

i)Resources available on Earth(Natural resources)eg. Air, water, soil, living organism etc

ii)Solar energy from the sun

• PART OF THE EARTH- its outer crust area known as Lithosphere, water cover areas known as Hydrosphere, air cover areas known as Atmosphere.
• These three are life supporting zone known as BIOSPHERE.

Biosphere (factor/component)

• Abiotic factor like air, water, soil, minerals etc
• Biotic factor like microbes, plant & animals.

The breath of life: Air

• Composition of air( O2-20.9%,N2-78%,CO2-0.03%, other gases)
• Support the life
• In Mars & Venus- no life because major component of the atmosphere is CO2 (app. 95 to 97%)

All living organism breath air despite this the percentage of CO2 in our atmosphere is less why?

• CO2 is fixed in two ways

I) All green plant-photosynthesis

II) Many marine animal use dissolved carbonate to make their shell and skeletons.

Role of the atmosphere in climate �control

• Air is bad conductor of heat
• Maintain the average temperature during day and night time.
• Prevent the sudden increase or decrease of temperature during day & night respectively
• In MOON-no atmosphere, therefore temperature ranges from -190*C to 110*C

​

Movement of airs : WIND( uneven heating of atmosphere in different parts the earth)

During day time-sea breeze

• Land heated faster than the sea
• Air above the land get heated faster & start rising
• Create low pressure
• Air move from sea to low pressure
• This movement of air creates Winds.

Night time-land breeze

Both land &water start cool

• Water cool down slower than land
• Air above the water would be warmer than the air above the land
• Develop low pressure above the sea
• Air move from land to low pressure (sea)

Rain formation(water bodies heated)

• The hot air carrying water vapour rises above.
• This hot air first expands & cools causing water vapour to condense into tiny droplets.
• Suspended particles like dust act as Nucleus.
• Nucleus+ tiny droplet form water droplets.
• Water droplets when it becomes big & heavy it fall down in the form of rain or snow when the atmospheric temperature is too low.

Air pollution-undesirable change in the physical, chemical or biological characteristic of air.

• Causes-Burning of fossils fuel release co,co2,oxide of N and S(acid rain)
• Also release unburn hydrocarbon particles form smoke.(respiratory disease)
• In winter season smoke + fog form smog.(reduce visibility)

Water: A Wonder liquid

• Distribution of water 75%-hydrosphere, 2.5%-fresh water(glaciers ice sheet, ground water or surface water)
• Many sources of water are contaminated with industrial waste or sewage. Because of this reason we should conserve water.

Importance of water

• Act as medium for all life process.
• It is a universal solvent.
• Transport many things to different body parts.
• We depend on water for many activities like cooking, agriculture, transportation, production of hydro power etc.
• Maintain the cell shape.

Water pollution-if any physical, chemical or biological changes in the quality of water affecting living organisms and making unfit for use.

• Causes-addition of undesirable substances like sewage, fertiliser (Eutrophication)pesticides(Biomagnification)
• Removal of desirable substance, eg dissolved O2 & minerals consumed by “algae bloom”

​

​

• change in temperature-if hot water is discharge from thermal power plant(affect breeding in animals)

Soil (upper layer of earth crust)

Composition-contains small particles of rocks, humus, microbes,& minerals nutrient.

Types of soil or quality of soil is depend upon its composition.

Quality of soil decide the biodiversity of life in an area.

Top soil-Topmost layer of soil that contains humus & living organism.

• Importance of humus make the soil more nutrient rich.
• Improves the water holding capacity ( sandy soil).
• Provides porous & allow water and air to penetrate.
• Therefore the top soils decide the BIODIVERSITY OF LIFE in an area.

Formation of soil:-factor involved

• THE SUN:-

Day time- rocks heats up and expand.

Night time:-rocks cool down and contract. Due to uneven expansion and contraction form cracks on the rocks and help in formation of soil.

THE WATER:-Help in formation of soil in two ways.

i)When water enters into the cracks in the rocks, which if freeze widen the cracks.

Ii)water carries big/small particles of rocks downstream. These rocks rub against other rocks and which break them up into small particles of rocks and form soil.

​

THE WIND:-

• The strong wind erods rocks down. They also carry sand from one place to another.

THE LIVING ORGANISM:

• LICHEN-it release the chemicals and cause the rocks surface to powder down and form thin layer of soil.
• MOSS-they grow on the rocks surface and cause the rocks to break down.
• BIG TREE-its long roots cracks the rocks as the roots grow bigger the cracks found bigger.

SOIL POLLUTION- If any physical, chemical or biological changes occur in soil is called soil pollution.

• CAUSES

i)Removal of essential components like humus, minerals ions, microbes etc.

ii) Addition of other substances like pesticides, chemo fertilisers kill essential microbes & earthworm etc decrease the soil fertility.

SOIL EROSION- Process of removal of fertile top soils due to climatic and physical process.

• CAUSES OF SOIL EROSION: i) strong wind ii)over grazing iii)improper tilling iv)frequent flooding v) deforestation.
• PREVENTATION: i) intensive cropping ii)proper drainage canal around field iii)practising trace farming in hilly reason iv) plantation etc

BIOGEOCHEMICAL CYCLE- cyclic flow of nutrient between abiotic & biotic factor. Eg C,N,O& water cycle.�its make a dynamic and stable ecosystem.

• THE WATER CYCLE

-water evaporates from water bodies & move upwards

-then vapour condense & form rain droplet & again flow back into water bodies.

-these water used by plants & animals for various life processes.

-living organism also release water through transpiration and respiration goes to atmosphere.

THE NITROGEN CYCLE- It form various biologically important compounds like Neuclic acid, Vitamins, Protein, alkaloid & urea too.

• 78% of atmospheric N2 directly can not utilised plants and animals. ( fixation occur)
• Steps of N2 cycle :

i) Nitrogen fixation (Nitrates and Nitrite)

Biological- Rhizibium bacteria, BGA

Physical – Lightning( nitric & nitrous acid)

Chemical – Industries ( makes nitrogen fertilizer )

ii) Ammonification- release Ammonia from dead organism ( bacteria and fungi)

iii) Nitrification-conversion of Ammonia into Nitrites & then Nitrates ( Nitrobacter, Nitrosomonas)

iv) Denitrification –Nitrate present in soil is reduse to N2

eg Pseudomonas,

Thiobacillus etc.

THE CARBON CYCLE- Cabon in our atmosphere occur in various forms like elemental form-Graphites, Diamonds combined form CO2, CO3 etc

• Biological compound like Nucleic acid, protein, carbohydrates, fats, vitamins.
• Even endoskeleton & exoskeleton also made up of Carbonate salts.

THE GREEN HOUSE EFFECTS :

• Absorption of infrared radiation from sun by green house gases such as CO2 etc thereby increasing the temperature of earth.
• It is called green house effects.
• It leads to Global warming.

THE O2 CYCLE: It is also essential biological compound like carbohydrates, protein, fats etc.

• Also occur in combined form like CO2, oxide of Nitrogen, Sulphur etc.
• Oxygen used in three process-Cumbation, Respiration, formation of oxide of Nitrogen.
• Oxygen retuned to atmosphere by Photosynthesis.

OZONE LAYER: layer of O3 gases present in stratosphere is called the ozone layer.

• It absorb harmful radiation from sun.
• It also prevent the entry of harmful radiation in our atmosphere.
• Main ODS is CFC form ozone hole ( thinning of ozone layer)
• Effect-mutation, skin

cancer, damage the cornea.

THANK YOU