TOPIC:ENERGY FLOW AND CONSERVATION OF

RESOURCES

Energy flow and its importance:(a brief

introduction)

What is an ecosystem?

• A unit composed of biotic and

abiotic components is called an

ecosystem.

• Biotic components are the

living components and abiotic

components are the non-living

components.

Sun (main source of energy)

• The sun is the main source of energy .

• On earth the energy received by the sun can be divided as

following :

56-60% absorbed by the atmosphere

10% utilized in heating of water and land

8% falls on plants

But,0.02% absorbed by the plants for phoptosynthesis.

The simple food chain

• In an ecosystem producers prepare

their own food.

• Producers in turn are consumed by

the primary consumers which in turn

is consumed by the secondary

consumers

• Secondary consumers in turn are

consumed by the last consumer.

• The existence of living beings

depends on:

i. The energy flow

ii. Nutrient flow

Energy flow

Tertiary consumers(Carnivores)21 cal

6 cal

67 cal

Secondary consumers (carnivores)383 cal

1478 cal

Primary consumers(herbivores)3368 cal

8833 cal

Producers(plants)20810 cal

Gross production

Net production

Sun

Decay

Respiration

Nutrient flow

• Nutritive elements are obtained by the plants and animals from the soil and the atmosphere.

• On decomposition of dead bodies plants and animals by the decomposers they are released in the nutrient food.

• On re-absorption by plants they again enter in the circulation and thus a nutrient cycle.

Carbon cycle

Laws of thermodynamics

• According to the first law of thermodynamics , the energy

can be transformed from one form to another but it can

neither be created nor destroyed.[when certain amount of

energy is created same amount of energy is destroyed]

• When energy is put to work , a part of it is always

converted in unuseful form as heat mainly due to friction

and radiation.[during energy flow in ecosystem ,it is not

100% as a part of it is produced as unuseful heat

during respiration and decay]

Resources and its conservationWhat is a resource?

Matter which is useful and significant for us is called a resource.

• Resources naturally occurring are called natural resources.

• Resources are broadly classified in two categories:

i. Renewable resources

ii. Non-renewable resources

Distinction between renewable and non-renewable resources

Renewable resources

• They can be utilized over a long period of time.

• They are non-conventional.

• They can be regenerated easily.

• These resources will not get exhausted easily.

• Examples:air,waterplants,animals

Non-renewable resorces

• They cannot be utilized over a long period of time.

• They are conventional.

• They cannot be regenerated easily.

• These resources will get exhausted easily.

• Examples: minerals,coal,mineraloil,soil

Principal natural resources and their conservation: SOIL

• Soil covers the surface of the Earth and is a

valuable ecosystem.

• Soil is made up of minerals, nutrients, water,

air, organic matter and microorganisms.

• Because of its makeup, soil has a variety of

uses in a variety of industries.

Conservation of soil can be done by the

following methods:

i. terrace farming

ii. Mixed farming

iii. Crop rotation

iv. Afforestation

v. Stop overgrazing

Water

Use of water:• Domestic use– bathing,washing , drinking ,

sanitation.• Industrial use– washing

of ores,production of chemicals,production of hydroelectricity.

• Agricultural use—irrigation of crops,treesand plants

Methods of conservation of water• Rainwater harvesting

• Terraced farming on hillsides

• Ponds must be created

• Closing the taps when not in use.

Forests

• The terrestrial area densely covered by trees and shrubs is called forests.

• Uses of forests:

i. Maintain ecological balance

ii. Helpful in checking soil erosion

iii. Home to wildlife

iv. Purification of the atmosphere

Minerals• The core of the earth has different types of rocks which

contain different minerals . The quantity of minerals is limited and their distribution is not uniform.

• To conserve minerals :

i. The objects should be reused again

ii. More available minerals should be used in place of less available minerals.

iii. Discarded objects should be recycled to obtain new products

ENERGY

• The conventional sources of energy

are wood,fossil fuels and radioactive

substances.

• These substances are non-

renewable.

• Till now 80%of worlds conventional

sources have been used up where

only 30% of the worlds population

live.

• Apart from these,the production of

energy from these sources have

harmful environmental effects(acid

rain,air pollution &global warming)

Solar Energy

• Solar is a renewable energy because it contains the energy which comes from the sun. Biomass is basically an organic material made from plants and animals. Through the process of photosynthesis, chlorophyll present in plants absorbs the energy from the sun by converting the carbon-dioxide present in air and water from the ground in carbohydrates .

• When you burn biomass fuel, the chemical energy inside releases as heat. It can also be used to produce steam which can further be used to generate electricity .

• Solid biomass : On burning produces heat

• Liquid biomass :can be used as a fuel in engines of automobiles

• Gas biomass includes biogas obtained from animal dung

Hydropower

• It is produced from the kinectic energy of the falling water.

• Nearly 25%of the worlds energy is produced in this manner.

• To produce energy water is stored at great heights in dams and allowed to fall .

Disadvantages of building large dams

• The natural ecosystem in the surrounding gets disturbed.

• The plants and animals get disrupted.

• The people get displaced on a large scale

• The aquatic system gets disrupted.

Wind energy • Wind turbines

convert the kinetic energy in the wind into mechanical power.

• A generator can convert this mechanical power into electricity to power.

• For this the speed of wind must be 25km/hr.

Tidal energy• The kinetic energy

possessed by the tidal waves.

• It is used to turn turbines and to produce electricity

• For example in India tidal energy is obtained in the gulf of Kutch.

Geothermal energy• At some places hot

water comes to the surface as hot springs. The energy possessed by hot water springs is called geothermal energy.

• This has been implemented in Himachal Pradesh.

Social initiatives

• Stop wastage of electricity.

• Public awareness through mass media and children’s participation.

• Role of NGO’s in creating awareness

• Community involvement to reduce the misuse of electricity.