Green Science and Environment 6 Final (2076)

3. Answer the following questions.
a. Name any four factors that affect weather.
b. What does rainfall mean? How does it occur?
c. Differentiate between temperature and pressure of a particular place
in any two points.
d. What is humidity? Mention its any one benefit:
e. Name the four major types of weather.
f. Differentiate between hot weather and sunny weather.
g. What is cold weather? Explain briefly.
h. Windy weather during summer season is pleasant, why?
i. 'Storm is destructive.' Justify this statement with examples.

4. Describe water cycle in detail with figure.
5. Draw the figures to indicate the following.

a. Hot weather
b. Windy weather
c. Measuring rainfall

GREEN Science and Environment Book-6 201

UNIT The Sun and the Solar

20 System

Weighting Distribution (Approximate) Teaching periods : 5 Marks (in %): 1

Before You Begin

The sun is the brightest object in the sky. It is a medium sized star
closest to the earth. It is an extremely hot ball of burning gas. The sun
is the most important heavenly body for all the plants and animals.
The sun is the ultimate source of energy. The sun occupies the central
portion of the solar system. The family of the sun which consists of
eight planets, satellites, comets, asteroids, meteors, etc. is called the
solar system.
When an opaque object blocks the light coming from a luminous
object, a dark patch is formed behind the opaque object. This
dark patch is called shadow. There are two types of shadows,
i.e. umbra and penumbra. When the sun, the earth and the moon
lie in a straight line, on some occasions the earth and moon cast
shadow on one another. This phenomenon is known as eclipse.
There are two types of eclipse, viz. lunar eclipse and solar eclipse.

Learning Objectives Syllabus
After completing the study of this unit, students will be able to:
i. introduce the earth as the common habitat of living • Introduction to the sun and
the solar system
beings with its features.
• Brief description of eight
ii. describe the external structure of the earth. planets of the solar system

iii. describe the internal structure of the earth. • Comparion of size of the sun,
earth and the moon

• Introduction to shadow and
eclipse

• Umbra and Penumbra
• Lunar eclipse and solar eclipse

Glossary: A dictionary of scientific/technical terms

umbra : the completely dark central patch of a shadow

penumbra : the lighter patch of the shadow that surrounds the umbra

luminous : having own source of light for shining in the dark

opaque : object which does not allow light to pass through

full moon : the moon when it appears as a full circle

new moon : the moon when it looks like a thin curve

solar : related to the sun or of the sun

planet : the heavenly body that revolves around the sun

satellite : the heavenly body that revolves around the planet

comet : a mass of ice and dust which looks like a bright star with a tail

elliptical : oval shaped

orbit : a curved path followed by a planet

twinkle : to shine with a light that keeps changing from bright to faint to bright again

202 GREEN Science and Environment Book-6

The sun

The sun is the brightest heavenly object. It is a
medium sized star close to the earth. The sun
is extremely hot. It is a huge ball of burning
gas. So it is extremely hot. It releases a large
amount of heat and light energy. All the
plants, animals and human beings use the
solar energy. Life would not exist on the earth 20.1
in the absence of the sun.
Fig. Sun
Fig.
Solar System
Solar System
Solar system is the family
of the sun which consists
of eight planets and their
satellites, comets, asteroids,
meteors, meteorites, etc.
The sun occupies the central
position of the solar system.
All the planets and other
members of the solar system 20.2
revolve around the sun in
fixed paths called orbits.

Project work
Take a chart paper and draw a neat and labelled figure of the solar system.
Put suitable colour on the picture and demonstrate in your classroom

Planets

Planets are the heavenly bodies that revolve around the sun in elliptical paths
called orbits. Planets do not have their own source of light for shining. So they
are called non-luminous bodies. However, planets appear bright in the sky as
they reflect the light coming from the sun. The sun holds all planets together
with its strong force of attraction which is called gravitation.

GREEN Science and Environment Book-6 203

There are eight planets in the solar system. The eight planets of the solar system
in the order of increasing distance from the sun are given below:

(i) Mercury (ii) Venus

(iii) Earth (iv) Mars

(v) Jupiter (vi) Saturn

(vii) Uranus (viii) Neptune

A brief description of all the planets of the solar system is given below:

1. Mercury Fig. Fig.

Mercury is the nearest planet to the sun.
It is the smallest planet of the solar system.
Life cannot exist on the mercury as it has no
atmosphere. The part of the mercury that faces
the sun is extremely hot and the other part is
extremely cold. Mercury has no satellites. 20.3

Mercury

Activity 1 Do You Know

Mercury can be seen just before Mercury is the smallest planet of the solar
the sunrise in September and system.
October. It can also be seen just
after the sun set in March and Venus is the hottest and brightest planet of
April. the solar system.

Observe the mercury in the
sky and write its three features
after your observation

2. Venus Venus

Venus is the nearest planet to the earth. It is
the brightest and hottest planet of the solar
system. Life cannot exist on the venus. The
atmosphere of the venus consists of carbon
dioxide. This planet also has no statellites. 20.4

204 GREEN Science and Environment Book-6

Activity 2
Venus can be seen just before the sunrise and just after the sunset.
Observe the venus and write its three salient features.

3. Earth

The earth is our home planet. It is the third

nearest planet from the sun. The earth has

plenty of water, suitable temperature and life

supporting gases. Therefore, life can exist on

the earth. The earth is the only planet having Fig. Fig. Fig.

all the requirements for the existence of life.

The earth takes 24 hours to complete one The earth
rotation in its own axis. Similarly, the earth 20.5

takes 365.25 days to complete one revolution

around the earth. The revolution of the earth around the sun causes the change

in seasons and the rotation of the earth causes day and night. The earth has

only one satellite, i.e. the moon.

4. Mars Mars

Mars is commonly known as a red planet. It
is the fourth distant planet from the sun. It is
nearly half the size of the earth. The mars can
be seen with our naked eyes and it looks like
a bright orange red star. The atmosphere of
the mars mainly consists of nitrogen gas. The 20.6
mars has two satellites.

5. Jupiter

Jupiter is the largest planet of the solar system.
It looks like a bright star with our naked eyes.

Jupiter is the third brightest object in the night

sky after the moon and the venus. The jupiter

consists of bands of clouds and a big red spot.

This planet has 63 known satellites. 20.7

Jupiter

GREEN Science and Environment Book-6 205

6. Saturn Fig. Fig. Fig. Saturn
Uranus
Saturn is the second largest planet of the solar
system. It is the third farthest planet from the
sun. The saturn is surrounded by rings of dust
and rocks. This planet has 60 known satellites.
Titan is the largtest satellite of the saturn.

20.8

7. Uranus

The uranus is the second farthest planet from
the sun. It is a very cold planet. It has rings
around it like the saturn. This planet has 27
known satellites.

20.9

8. Neptune

Neptune is the coldest planet of the solar
system. It cannot be seen with our naked
eyes. This is the farthest planet of the solar
system. Neptune has 13 known satellites.

20.10
Neptune

Comparison of the size of the sun, earth and the moon

We have seen the earth, moon and the sun; these heavenly bodies are spherical
in shape. When we see the sun from the earth, it seems about the same size of
that of the moon. But the earth seems to be very large in size. In reality, the sun
is the largest and the moon is the smallest heavenly body out of the sun, earth
and moon. The size of the sun is about 110 time, bigger than that of the earth
and the earth is about four times bigger than the size of the moon.

The sun seems small as it is very far from the earth. As we know that when
an object goes far, it appears small. We can compare the size of the sun,
earth and the moon to the size of a basketball, seed of a pea and seed of a
mustard respectively. The distance between the sun and the earth is about 15
crore kilometers and the distance between the earth and the moon is about

206 GREEN Science and Environment Book-6

347,000km. The diameter of the sun is about 1400,000km, that of the earth is
about 12,751km and that of the moon is 3,456km.

Moon

Fig. Earth
Fig.
20.11 Sun

Formation of shadow

Shadow and Eclipse

When the light coming from a source is blocked by an opaque object, a dark
patch is formed behind the object. This dark patch is called shadow.

Luminous objects like Penumbra Earth’s
the sun, torchlight, Umbra orbit
burning candle, etc.
spread light around Moon
them. When an opaque
object is kept in front Sun Total eclipse Earth
of the source of light, Partial eclipse Moon’s
two types of shadows
are formed behind the 20.12 orbit
object. They are umbra
and penumbra. Formation of shadow

Umbra

Umbra is the completely dark patch of the shadow. It is formed at the centre
of the shadow. Umbra appears completely dark as it does not get any light.
Umbra is surrounded by penumbra.

GREEN Science and Environment Book-6 207

Penumbra

Penumbra is the lighter patch of the shadow that surrounds the umbra. It does
not appear completely dark as it receives some light. It can be seen around the
umbra.

Activity 1

Take a torch light and go in a dark room.
Keep an opaque object on a table and turn on the torch light.
Observe the shadow behind the opaque object.
Identify umbra and penumbra in the shadow.

Eclipse

Out of three heavenly bodies, i.e. the sun, the earth and the moon, only the sun
is a luminous object. The earth revolves around the sun and the moon revolves
around the earth. In the course of revolution, on some occasions, the earth and
the moon cast shadow on each other. In this condition, the sun, the earth and
the moon lie in a straight line. This phenomenon is called eclipse. Thus, eclipse
can be defined as the phenomenon in which the shadow of the earth and the
moon fall on one another when the sun, the earth and the moon lie in a straight
line.

During eclipse, the non-luminous Do You Know
body (either the earth or the moon)
blocks the light coming from the The sun is a luminous object and the moon
sun and casts its shadow on another and the earth are opaque and non-luminous
body. Eclipse occurs only in a new objects.
moon day or a full moon night.

Types of eclipse Fig.

There are two types of eclipse, they are:
1. Lunar eclipse
2. Solar eclipse

1. Lunar eclipse 20.13

During the course of revolution, Lunar eclipse

when the earth lies in between the

sun and the moon in a straight line, the shadow of the earth falls on the moon.

208 GREEN Science and Environment Book-6

This phenomenon is called lunar eclipse. During lunar eclipse, we cannot see
all or a part of the moon for a certain period of time. So, lunar eclipse can be
defined as the phenomenon in which the shadow of the earth is cast on the
moon.

Lunar eclipse occurs only on a full moon night when the earth lies in between
the moon and the sun in a straight line.

Lunar eclipse is of two types, viz. (i) partial lunar eclipse and (ii) total lunar eclipse.

(i) Partial lunar eclipse

When the moon lies in a penumbra cone of the earth, it gets some light from
the sun and the moon becomes partially visible. This phenomenon is called a
partial lunar eclipse.

(ii) Total lunar eclipse Do You Know

During lunar eclipse, when the moon The moon when it appears as full circle from
lies in the umbra cone of the earth, the earth, it is called full moon.

the moon does not get any light

and appears completely dark. This

phenomenon is called total lunar eclipse.

Project work
Prepare a model of lunar eclipse and demonstrate in your classroom.

2. Solar eclipse

When the moon lies in between

the earth and the sun in a straight

line, the shadow of the moon falls Fig. Fig.

on the earth and a part of the sun

cannot be seen for a certain period 20.14
of time. This natural event is called
Solar eclipse
solar eclipse. So, solar eclipse can

be defined as the phenomenon in

which the shadow of the moon is

cast on the earth.

Solar eclipse occurs only on a new

moon day when the moon lies in

between the sun and the earth in a

straight line. 20.15

Annular solar eclipse

GREEN Science and Environment Book-6 209

During solar eclipse, the region of the earth that lies in the penumbra cone has
partial solar eclipse. Similarly, the region of the earth that falls on in the umbra
region has total solar eclipse. The sun can be seen as a black circular disc with
a ring of light during total solar eclipse.
Project work

Prepare a model of solar eclipse and demonstrate in your classroom.

Key concepts
1. The sun is the medium-sized star close to the earth. Life would not exist

on the earth in the absence of the sun.
2. Solar system is the family of the sun which consists of eight planets and

their satellites, comets, asteroids, meteors, etc.
3. Planets are the heavenly bodies that revolve around the sun in elliptical

orbits.
4. These are eight planets in the solar system, viz. mercury, venus, earth,

mars, jupiter, saturn, uranus and neptune.
5. Shadow is a dark patch formed behind an opaque objects when the

object blocks the light.
6. Eclipse is the phenomenon in which the shadow of the earth and the

moon fall on one another when they lie in a straight line.
7. Eclipse are of two types, viz. lunar eclipse and solar eclipse.

Exercise

1. Tick (√) the correct statement and cross (×) the incorrect one.
a. Planets revolve around the sun.

b. Venus is the closet planet to the sun.

c. Jupiter is the largest planet of the solar system.

d. Umbra is formed outside the penumbra.

e. Solar eclipse occurs in full moon night.

210 GREEN Science and Environment Book-6

2. Fill in the blanks with appropriate words.
a. ......................... is the brighest planet of the solar system.
b. The natural satellite of the earth is .........................
c. ......................... is also known as the red planet.
d. ......................... is the closest planet to the sun.
d. ......................... is the farthest planet from the sun.
e. Lunar eclipse occurs in .........................

3. Tick (√) the best answer from the given alternatives.
a. Which of the following is the smallest planet?

mercury earth mars nepture

b. Which of the following is the largest planet?

saturn jupiter nepture uranus

c. The diameter of the earth is about 3456 km 5634 km
71251 km 13751 km

d. Which of the following is the nearest planet to the sun?

earth mercury mass neptune

4. Answer the following questions.
a. What is solar system?
b. What are planets? Give any three examples.
c. Name the eight planets of the solar system.
d. Name the nearest and the farthest planet to the sun.
e. Name the smallest and the largest planet of the solar system.
f. What is shadow? How is it formed?
g. What is umbra? How is penumbra formed?

GREEN Science and Environment Book-6 211

h. What is eclipse? Write down the cause of eclipse.
i. Define lunar eclipse. When does it occur?
j. What is solar eclipse? When does it occur?

5. Differentiate between. b. Umbra and Penumbra
a. Jupiter and Mercury
c. Lunar eclipse and Solar eclipse

6. Name the types of the eclipse shown in the given figure.

6. Draw a neat and labelled figure showing.

a. Solar system b. Lunar eclipse c. Solar eclipse

212 GREEN Science and Environment Book-6

Environment Science

UNIT Environment and Its

21 Balance

Weighting Distribution (Approximate) Teaching periods : 12 Marks (in %): 2

Before You Begin
We can see various living beings and non-living things around us. Living
beings like animals, plants, insects, etc. are found around us. Similarly,
various non-living things like air, water, sunlight, land, humidity,
temperature etc. are also available around us. The collective form of all these
living beings and non-living things is environment. Environment is defined
as the totality of all the living beings non-living and other socio-cultural
aspects. In other words, physical, biological and socio-cultural world around
us is called environment. Environment is essential for the existence of all
creatures and plants. Animals and plants obtain food and shelter from the
environment. Natural environment is called balanced environment since
there is the proper relationship and interaction among various living and
non-living, living and living and non-living and non-living components
of environment. For example, relationship between animals and plants
(living and living), relationship between animals and air, water, etc. (living
and non-living), balance between oxygen and carbon dioxide (non-living
and non-living) etc. The natural form of environment where there is proper
interaction between and among all the components of environment for
their survival and existence is called environmental balance.

Learning Objectives Syllabus

After completing the study of this unit, students will be able to: • Introduction to Environment
and Its Importance
i. introduce environment and explain the importance of
environment for living beings. • Environmental Components:
Biotic Components and
ii. classify the environmental components and explain Abiotic Components
them with their relationship.
• Introduction to Environmental
iii. define environmental balance and explain its balance and its Importance
importance.
• Introduction to Natural
iv. introduce natural resources with their broad Resources with their
classification. Importance

v. describe the importance of natural resources for living • Present condition of Natural
beings. Resources: Water, resources,
vegetation and animals
vi. compare the present condition of various natural
resources with that in the past.

Glossary: A dictionary of scientific/technical terms

solar : related to or of the sun
planets : the heavenly bodies that revolve around the sun
satellites : the heavenly bodies that revolve around the planets.
stars: : the bright twinkling objects having their own source of light
constellations : a small group of brilliant stars which seem to form the pattern or shape of

some objects

GREEN Science and Environment Book-6 213

Environment and Its Balance

Environment and Its Importance

The totality of our surrounding that consists of both living beings and non-living
things is called environment. Environment includes various components like
animals, plants, air, water, land, atmosphere, sunlight, socio-cultural aspects,
etc. The combination of all these components forms environment around us.
The interaction between/among various living beings and non-living things
form the natural environment. Living beings like animals and plants and non-
living things like air, water, land, sunlight, climate, temperature, etc. are the
components of natural environment. Similarly, socio-cultural norms and values
like traditions, customs, languages, religions, festivals, food habit, etc. Natural
environment is essential for the survival of all living beings both animals
and plants. But, socio-cultural environment is basically important for human
beings since human beings are directly related to social-cultural environment.
Other animals and plants are also part of socio-cultural environment because
they are also affected by the socio-cultural environment created by human
beings. For example, the people who do not consume meat do not kill animals
for their food. Some people worship various plants and hence they grow and
conserve plants.

Both living beings and non-living things exist in environment. Thus,
environment is essential for all components for their existence. Living beings
get food and shelter in environment. Moreover, one type of component of
environment depends on other types of environmental components. For
example, animals depend on plants for their food and shelter. Plants depend
on non-living components like air, water, soil, sunlight, minerals. etc. for
their food. Thus, there is a continuous interaction between/among different
living beings and non-living things in environment. The major importance of
environment for both animals and plants is given below:

i. Animals and plants obtain food and shelter from environment.

ii. Living beings get oxygen from environment for respiration.

iii. Plants get carbon dioxide, minerals, water, sunlight, etc. to prepare their
food by photosynthesis.

iv. Human beings grow crops in environment (land) to get food.

v. Human beings obtain various materials (water, soil, timber, etc.) from
environment to meet their requirements.

214 GREEN Science and Environment Book-6

vi. Animals and plants get water from various water resources for their
survival.

vii. Human beings carry out various developmental activities in the
environment by mobilizing various natural resources.

Balanced environment is essential for the proper growth and development of
all living beings in environment. Excessive use of natural resources degrade
and pollute environment. Thus, wise and judicious use of natural resources and
their conservation is essential to maintain natural and balanced environment.

Components of Environment

Various components of environment are broadly categorized into biotic
components and abiotic components. All living beings are biotic components
of environment. For example, micro-organisms, animals, plants, etc. The non-
living things found in environment are abiotic components of environment. For
example, air, water, soil, sunlight, humidity, temperature, rainfall, etc. The brief
description of abiotic components and biotic components is presented below.

Abiotic Components of Environment

Air

Air is one of the fundamental abiotic components of environment. It is the
mixture of various gases. It consists of 78% nitrogen, 21% oxygen and 1% other
gases. The other gases include carbon dioxide, helium, neon, etc. The earth is
surrounded by a layer of air. This layer is called atmosphere. Besides, humidity
and dust particles are also found in the air.

Air is basic life component for both animals and plants. Both plants and animals
take oxygen in and throw carbon dioxide out during respiration. Green plants
need carbon dioxide during photosynthesis. Oxygen is the byproduct of
photosynthesis. In this way, there is regular flow of carbon dioxide and oxygen
in environment. It is necessary to maintain the balance of carbon dioxide and
oxygen in the environment for the survival of both animals and plants. There
might be shortage of oxygen in the environment on decreasing green plants.
Absence of oxygen result in difficulty for survival of animals. The imbalance
in the amount of gases in environment results in air pollution. Air pollution is
harmful for both animals and plants.

GREEN Science and Environment Book-6 215

Fig.The increment in carbon dioxide, sulphur dioxide, nitric oxide, etc. causes
air pollution. Similarly, the gas emitted from foul and decayed materials also
pollute air. Thus, it is necessary to reduce consumption of petroleum products
in industries and vehicles to conserve air. Similarly, afforestation should be
done to maintain proper balance among various gases. We can conserve
natural environment by conserving air of atmosphere.

Water
Water is one of the fundamental abiotic component of environment. It is
essential for the survival of all living beings. It is a compound formed by
combination of hydrogen and oxygen. A water molecule contains two atoms
of hydrogen and one atom of oxygen. Water can be found on the earth surface
and under the earth surface. Various types of water bodies like river, streams,
ponds, lakes, wetlands, watersheds, etc. are the sources of water. Two-thirds
parts of the earth is occupied by water bodies.
Sources of water are broadly classified into surface water, under ground water
and rain water. There should be proper balance among these three sources of
water. Surface water evaporates due to the sun light. It takes the form of cloud
in the sky and falls on the earth in the form of rain. This rain is the form of rain
fall. This rain fall is the source of surface water and underground water.
Surface water and underground water is used for various purposes like
drinking, washing, cleaning, irrigating, transportation, industrial activities,
etc. Underground water can be taken on the earth surface by digging well,
through water pump, etc. Rain water is suitable for agricultural activities.
Excessive use of water resources adversely affects environmental balance.
Polluted water due to mixing various types of industrial by products and
other substances is harmful for both animals and plants. Thus, water resources
should be conserved in order to maintain environmental balance.

21.1

216 GREEN Science and Environment Book-6

Land Fig. Fig.

Among various fundamental
abiotic components of environment,
land is one of them. Land is the
combination of soil and rocks. Land
is very essential for both animals
and plants. All living beings get
food and habitat from the land.
Terrestrial plants grow on land, 21.2
animals get their food from land
and all land animals including human beings live in land. Thus, land is very
important for all living beings. It is essential to conserve land to maintain
environmental balance. Various activities of human beings adversely affect
natural condition of land. Excessive use of insecticides and pesticides pollute
soil. Polluted soil is harmful for both animals and plants. Polluted soil is
not suitable for agricultural activities. Similarly, polluted soil pollutes water
bodies. Ultimately, it creates problems in natural environment suitable for
maintaining the ecosystem. Therefore, it is necessary to conserve land in order
to conserve natural environment and maintain environmental balance.

Sunlight

The sun is the major source of heat
and light energy. The sunlight is one
of the important abiotic components
of environment. The existence of
living beings is not possible in
the absence of sunlight. Animals
get warmth from sunlight. Plants
use sunlight to prepare their food
by photosynthesis. Rainfall is not 21.3
possible in the absence of sunlight
because it supports water cycle. In the absence of rainfall, the existence of plants
and animals is not possible in the environment. Thus, sunlight is an essential
component of natural environment for the existence of all living beings.

GREEN Science and Environment Book-6 217

Biotic Components of Environment Fig. Fig.

Various living beings
(microorganisms, animals and
plants) are biotic components of
environment. The living beings of
an environment are called abiotic
components of environment.
The biotic components of an
environment are broadly classified 21.4
into producers, consumers and decomposers. These are the fundamental
biotic elements of environment. The brief description of these components is
presented below.

Producers

Green plants of the environment can prepare their own food by using solar energy,
carbon dioxide and water. These are called producers since they can produce their
food. The process by which green plants prepare their food is called photosynthesis.
Thus, green plants are producers. Producers are also called autotrophs since they
have the ability to prepare their food by capturing solar energy.

Consumers

A large section of living beings in the environment depends upon plants
directly or indirectly for their food. These living beings are consumers. The
living beings which depend on producers for their food are called consumers.
Consumers have no ability to prepare their food on their own. For example,
human beings, animals like goat, cow, sheep, dog, tiger, etc. are all consumers.
On the basis of consuming food, consumers are broadly categorized into
primary consumers, secondary consumers and tertiary consumers.

1. Primary Consumer

The consumers that feed on green
plants only are called primary
consumers. In other words, primary
consumers directly depend on
green plants for their food. For
example, cow, goat, deer, sheep, etc.
Primary consumers are herbivores 21.5
since they feed on the plants only.

218 GREEN Science and Environment Book-6

2. Secondary Consumers

The consumers that feed on primary consumers are called secondary
consumers. Secondary consumers directly depend on animals, but indirectly
depend on plants. For example, dog cat, fox, etc.

3. Tertiary Consumers

The consumers that feed on

primary consumers and secondary

consumers are called teritairy

consumer. For example, tiger feed

on goat, deer, dog, etc. Some more

examples of teritory consumers are

lion, vulture, crocodile, etc. The Fig. Fig.

animals which feed on flesh only

are called carnivores. Likewise, 21.6
the animals that feed on flesh and

plants are called omnivores. Tiger, lion, etc. are carnivores and man, dog, bear,

etc, are omnivores.

Decomposers

The biotic components of

environment that break down

the remains of dead animals and

plants are called decomposers. For

example, bacteria, fungi, etc. They

decompose dead and deacying

bodies into simple substances by

acting upon them. Decomposers

produce nutrients from 21.7

biodegradable materials which is

essential for the growth of green plants in environment.

Activity 1

Prepare a brief description by showing the relationship between/among
various biotic components (producer, consumer and decomposer) in your
locality with the emphasis on their importance to maintain balance in
environment. Also, present it in your classroom.

GREEN Science and Environment Book-6 219

Environmental Balance and Its Importance

There is a continuous interaction between/among various biotic and abiotic
components of environment. This interaction maintains proper relationship
between/among them. The proper and close relationship between/among
various biotic and abiotic components of environment is called environmental
balance. For example, there should be continuous interaction between plants
and animals to create balance between animals and plants. Similarly, the
balance between amount of oxygen and that of carbon dioxide creates balance
in atmosphere for the survival of both animals and plants. The condition of
environment where all the components of environment are closely interrelated
to one another for their existence and survival is called balanced environment.
The disturbance in any components in environment causes imbalance in
environment. For example, in the absence of plants, the existence of animals
is impossible. Similarly, destruction of plants causes increment of amount
of carbon dioxide and reduction of oxygen gas. As a result, animals cannot
survive in the absence of oxygen gas. Therefore, it is necessary to maintain
proper natural relationship between all components of the environment to
maintain environmental balance. The importance of environmental balance is
given in the following points.

i. Living beings can survive only in balanced environment without any
problem.

ii. Balanced environment is useful for both animals and plants for their
existence.

iii. Natural disasters can be minimized by maintaining balanced environment.

iv. Natural resources can be conserved in balanced environment.

v. Environmentdegradationandpollutioncanbeminimizedinenvironmental
balance.

vi. Environmental sanitation can be maintained by maintaining proper
balance in environment.

vii. Rare animals and plants can be saved in balanced environment.

viii. Developmental works are sustainable in balanced environment.

ix. Proper growth and development of all living beings is possible in balanced
environment.

Ways of Maintaining Environmental Balance

Various activities of human beings are responsible for disturbing natural
environment. Therefore, it is the duty and responsibility of human beings to
maintain environmental balance.

220 GREEN Science and Environment Book-6

The following ways can be adopted to maintain the environment in balanced
condition.

i. Wise and judicious use of natural resources with their conservation.

ii. Proper management and disposal of waste materials.

iii. Conserving wildlife and vegetation.

iv. Discouraging deforestation and encouraging afforestation.

v. Conducting environment friendly developmental activities.

vi. Maintaining environmental sanitation.

vii. Scientific way of agriculture.

viii. Proper management of grazing and pastureland for domesticated animals.

ix. General awareness regarding importance of environment.

Natural Resources

Natural resources refer to the resources that are available in natural
environment. These resources are water, air, land, forest, minerals, animals,
plants, sunlight, etc. These resources are naturally created in the environment.
Both living beings and non-living things are natural resources. Living beings
include all types of plants and animals, whereas air, water, soil, minerals,
etc. are non-living things. Natural resources provide suitable environment
to all living beings for their growth and development. All living beings in
the environment get food and habitat from natural resources. Thus, natural
resources are very important for living beings.

Kinds of Natural Resources

Natural resources are classified into perpetual renewable and non-renewable
on the basis of their properties and utility. The brief description of each type of
natural resource is provided below:

a. Perpetual Resources

The natural resources like solar energy, wind energy, tidal energy, etc. have
never-ending supply. These are perpetual natural resources. In this case, the
natural resources which do not get exhausted even after large exploitation
are called perpetual resources of energy since they have never ending supply
of energy and do not get depleted due to their continuous use. Perpetual
resources are unlimited in nature.

GREEN Science and Environment Book-6 221

b. Renewable Resources

The natural resources like, water, air, forests, soil, etc. can be used again and
again by producing them are renewable resources. They never get exhausted
from the environment and can be maintained repeatedly for our use, The
natural resources that can be used repeatedly by creating them again and again
and do not deplete from the environment are called renewable resources.

c. Non-renewable resources

Some natural resources like petroleum products minerals, natural gas, etc. are
limited in nature and get exhausted after their use. They cannot be obtained and
produced again and again. Such types of natural resource are non-renewable
resources. Non-renewable natural resources refer to the resources that cannot
be used again and again and get exhausted after their use. Some examples of
non-renewable resources are petrol, diesel, coal, kerosene, minerals, etc. They
are found in specific places of the earth and their store gets finished after their
use.

Activity 2

Make a list of any 15 natural resources available in your locality and classify
them under the headings perpetual, renewable and non-renewable by
making a table.

Importance of Natural Resources

There is a close relationship between living beings and non-living things
in nature. The lives of living beings is not possible in the absence of non-
living things. Various natural resources available in nature have their own
importance. For example, living beings cannot survive in the absence of food,
water, air, etc. The importance of natural resources can be explained in the
following points.

a. Sources of Food

Various natural resources found in nature are the sources of food for living
beings. Green plants prepare their food from soil, water and carbon dioxide.
Human beings grow various crops in the soil to get their food. Herbivores feed
on plants and carnivores feed on various creatures. Thus, living beings or non-
living beings found in the form of natural resources are the sources of food for
living beings.

222 GREEN Science and Environment Book-6

b. Habitat

Land, water, forest, etc. are the habitats of various kinds of living beings.
For example, human beings build houses on land by using various natural
resources like soil,, water, wood, etc. Aquatic animals live in water and wild
animals live in forest. Various types of plants grow in water and on land. Thus,
natural resources are habitat of both plants and animals.

c. Fresh Air and Water

Air and water are vital components for the lives of living beings. Both animals
and plants need air and water far their survival and these natural resources are
available in nature.

d. Beauty

Natural resources are the sources of beauty of the place where they are
available. For example, forest, wildlife, water bodies, mountains, falls, valleys,
etc. have their own beauty in nature.

e. Tourism

Human beings are attracted towards natural beauty. Natural beauty is the
result of natural resources and natural beauty is the major source of attraction
of tourists. The flow of tourists results in flourishing of tourism. Thus, natural
resources are important for tourism.

f. Economic Development

Various natural resources are used for operating various developmental
activities. For example, soil, stone, etc. are used to construct road, buildings,
etc. Similarly, various natural resources are used as raw materials to produce
various goods in factories or industries. Water resources is used to produce
hydroelectricity. These all activities conducted for physical development are
the sources of economic development also. Thus, natural resources have a
great importance for economic development of a country.

Present Condition of Natural Resources

Natural resources are distributed in different parts of the world. We cannot
find uniform distribution of natural resources throughout the world. Specific
places are best known for availability of different types of natural resources.
For example, Brazil is the first and Nepal is the second richest countries in
water resources. Gulf countries are best known for availability of petroleum

GREEN Science and Environment Book-6 223

Fig.products. Nepal is well known for availability of various types of natural
resources like vegetation, birds, water resources, etc. In this context, the present
condition of some natural resources in Nepal is provided.

a. Land

Land is one of the important natural resources in our country. There are
different forms of land like plain, mountain, hill, valley, slope, cliff, etc. in
Nepal. The land of Nepal is divided into cultivating land, forest covered land,
pasture and grassland, snow covered land, etc. Land is important for all living
beings to obtain food and shelter. Human beings carry out agricultural
activities, grow medicinal plants, etc. In the context of Nepal, diversity in land
structure is responsible for variation in climate condition in the different parts.
Thus, there is biodiversity in Nepal.

As of BS 2008, Nepal has a total of
14718100 hector of land. About 29
percent of the total land is covered
with forest and about 21 percent
of the total land is appropriate
for cultivation. About 7 percent
of the total land is not suitable for
agriculture, about 10 percent of land
is occupied with shrubs and about 21.8
12 percent of the land is pasture and
grass land. Similarly, 2.6 percent of the total land of Nepal is occupied by water
bodies and about 17.8 percent of the total land is barren, rocky and gravel
land. Most of the portion of such land is covered with snow specially in the
mountain region.

b. Water Resources

Nepal is the second richest country in water resources after Brazil. Water
resource is one of the important natural resources of our country. The major
sources of water in Nepal are rainfall, snow and underground water. It is
estimated that about 2.6 percent of the total land of Nepal is occupied by water
bodies. Approximately, 75% rainfall in rainy season is the major sources of
water in Nepal.

Various types of small and big streams, rivers, lakes, ponds, wetlands,
watersheds, etc. are the major water resources in Nepal. About 300095 hector
land in Nepal is covered with rivers and about 1500 hector land is occupied by
water reservoirs. Similarly, about 5000 hector land of Nepal is occupied by lakes

224 GREEN Science and Environment Book-6

Fig.and 6500 hector is covered with rural pools. It has been found that there are
660 lakes in Nepal having an area of more than one hector each. It is estimated
that about 408000 hector of land in Nepal is occupied by water resources.
There is good potentiality and feasibility for generating hydroelectricity from
the rivers of Nepal.

c. Minerals

Various minerals found in the earth crust are important natural resources of
our country. Some minerals found in Nepal are zinc, copper, iron, limestone,
marble, magnesite, lead, etc. Different minerals are used for different purposes.
For example, iron, copper, etc. are used to make construction materials,
weapons, utensils, etc. Similarly, limestone, magnesite, marble, etc. are used to
make construction materials. Mineral oil and coal are used as fuel.

It is estimated that 7 crore ton limestone is in Surkhet, Udayapur and Sindhuli
districts. Similarly, 80 lakhs ton limestone is in Makawanpur district and 53
lakh ton limestone is in Kathmandu (Chobhar). Likewise, the posibility of 1
lakh 40 thousand ton copper is in Makawanpur and 1 lakh 74 thousand ton
iron is in Lalitpur and 30 m3 crore natural gas in Kathmandu. It is found that
78 thousand ton zinc is in Ganesh Himal of Rasuwa district and 28 lakh ton in
Dhading. Thus, there is great possibility of extracting minerals in our country.

d. Flora (Vegetation)

Nepal is rich in diversity in vegetation due to its geographical and climatic
variation. Different types of trees, herbs, shrubs, medicinal plants, etc. are
found in our country.

There are various species of
plants found in Nepal. As of the
Environmental Report of CBS,
2008, it is estimated that about
10633 species of plants are found
in different parts of the country.
Similarly, about 3991 species of
flowering plants, about 400 species
of trees and about 700 species of 21.9
medicinal plants and herbs are found in Nepal. The medicinal plants found
in Nepal are Timur, Aloe vera, Amla, Neem, Dalchini, Titepati, Jatamasi,
Sarpagandha, Bojho, Harro, barro, etc. These plants have great medicinal
value and are also used to prepare various cosmetic items.

GREEN Science and Environment Book-6 225

Different geographical regions of Nepal are famous for different kinds/species
of plants. The common plants found in the Terai region of Nepal are Sal, Sisam,
Khayar, Bijayasal, Simal, Jamun, etc. Similarly, most commonly found plants
in the Mountain region are pine, rhododendron, etc. Likewise, Gobre Salla,
Dhupi, Chilaune, Chiuri, Banjh, Simal, Katus, etc. are found in the Hilly region
of Nepal. Thus, Nepal is rich in different species of vegetation ranging from
herbs, shrubs to big trees.

e. Fuana (Animals)

Various species of fuana are found in Nepal due to its geographical diversity
and climatic variation. As per the Environment Report of CBS, 2008, it is found
that 874 species of birds, 185 species of mammals, 118 species of amphibians, 78
species of reptiles, 187 species of fishes, 651 species of butterfly and 175 species
of spiders are found in Nepal. Among these, different species of animals are
found in different regions of Nepal as per their nature of adaptation.

Fig.

21.10

Tiger Bear Peacock

The animals found in the Terai region of Nepal are elephant, tiger, rhinoceros,
wild buffalo, leopard, bear, swamp deer, etc. The common birds of this region

are peacock, crane, parrot, crow, saras, etc. Similarly, monkey, leopard, barking

deer, wolf, wild boar, porcupine, snake, etc. are the commonly found animals

in the Hilly region of Nepal. The commonly found birds of this region are
parrot, crow, sparrow, partridge, dove, etc. Likewise, the animals found in the
Himalayan region of Nepal are red panda, snow leopard, hispid hare, wild
ass, wild sheep, wild yak, etc. The commonly found birds of the Himalayan

region are munal, lophophorus, vulture, golden eagle, etc. Thus, Nepal is rich

in various species of fauna.

Activity 3

Make a list of any five mammals, reptiles,. birds and amphibians each found
in your region and share it with your friends in your classroom.

226 GREEN Science and Environment Book-6

Key Concepts

1. The totality of our surrounding that consists of both living beings and
non-living things is called environment.

2. Balanced environment is essential for the proper growth and development
of all living beings in environment.

3. Wise and judicious use of natural resources and their conservation is
essential to maintain natural and balanced environment.

4. Water is one of the fundamental abiotic component of environment. It is
essential for the survival of all living beings.

5. It is necessary to conserve land in order to conserve natural environment
and maintain environmental balance.

6. Sunlight is an essential component of natural environment for the
existence of all living beings.

7. The living beings of an environment are called abiotic components of
environment.

8. It is necessary to maintain proper natural relationship between all
components of the environment to maintain environmental balance.

9. The natural resources like solar energy, wind energy, tidal energy, etc.
have never-ending supply.

10. Non-renewable natural resources refer to the resources that cannot be
used again and again and get exhausted after their use.

11. Nepal is the second richest country in water resources after Brazil. Water
resource is one of the important natural resources of our country.

12. Nepal is rich in diversity in vegetation due to its geographical and
climatic variation.

Exercise

1. Tick (√) the correct statement and cross (×) the incorrect one.

a. Natural environment includes biotic components only.

b. Sunlight gives us light and heat.

c. Environmental balance can be maintained by excessive
exploitation of natural resources.

GREEN Science and Environment Book-6 227

d. Nepal is rich in flaura and fauna.

e. Rhinoceros is found in the Mountain region of Nepal.

2. Fill in the blanks using appropriate words.
a. Biotic components of environment include .......................
b. Consumers depend on ....................... for their food.
c. Natural resources can be conserved in ....................... environment.
d. ....................... is found in Surkhet, Udayapur and Sindhuli districts.
e. Various species of flaura are found in Nepal due to its geographical
diversity and ....................... variation.

3. Answer the following questions.
a. Define environment.
b. Name the broad categories of environmental components.
c. What are producers? Give any two examples.
d. What does decomposers mean? Give any two examples.
e. What do you mean by balance in environment? Why is it necessary?
f. Define natural resources with any three examples.
g. Name any four minerals that are found in Nepal.
h. Name any four medicinal plants that can be found in our country.
i. How much land is covered with forest in Nepal?
j. Name any four birds found in the Himalayan region of Nepal.

4. Differentiate between:
a. Biotic components and Abiotic components
b. Primary consumers and Secondary consumers
c. Producers and Decomposers
d. Omnivores and Carnivores
e. Flaura and Fauna

228 GREEN Science and Environment Book-6

5. Write short notes on: b. Sunlight c. Minerals
a. Air e. Land forms
d. Perpetual resources

6. Describe the importance of environment for the existence of living
beings.

7. Enlist any four components of environment and explain any one of
them.

8. What is environmental balance? Explain its importance for the survival
of living beings.

9. Define perpetual, renewable and non-renewable resources with three
examples of each.

10. Explain the present condition of land in Nepal.

11. Describe the importance of water resources in the context of our country.

12. What is the present condition of floura and fauna in Nepal? Explain
briefly with some examples.

13. "Nature-friendly development works are essential to maintain balance
in environment." Justify this statement with suitable examples.

GREEN Science and Environment Book-6 229

UNIT Environmental
Degradation and Its
22
Conservation

Weighting Distribution (Approximate) Teaching periods : 14 Marks (in %): 5

Before You Begin

Environment is the totality of physical and biological world around us. The
major aspects of environment are natural, biological, social and cultural. The
disturbance in any aspect of the environment is the cause of environmental
degradation. Environmental degradation refers to the deterioration in any
aspect of the environment due to the human activities that have adverse
effects on natural environmental degradation. Destruction of natural
resources, pollution of various components of environment, destruction of
natural habitats of animals and plants, excessive use of natural resources,
depletion in cultural heritages, etc. are the major causes of environmental
degradation. Environmental degradation invites various natural disasters
like flood, landslides, earthquake, volcano, etc. It is necessary to maintain
natural environment by conserving various components of environment.

Learning Objectives Syllabus

After completing the study of this unit, students will be able to: • Introduction to environmental
i. introduce environmental degradation with examples. degradation.

ii. tell the causes, impacts and preventive measures of • Causes of Environmental
environmental degradation. Degradation: Natural
causes (flood, landslide,
iii. differentiate between natural causes and Human soil erosion, fire), Human
causes of environmental degradation. causes, (population growth,
excessive use of natural
iv. define flood, landslide, soil erosion and fire and tell resources, urbanization and
their causes, impacts and preventive measure. industrialization)

v. explain the need of environmental conservation. • Major impacts of flood,
landslide, soil erosion and fire
vi. tell the ways of conserving environment. on natural environment.

vii. tell and explain the local efforts that have been made • Preventive measure of flood,
for the conservation of environment in Nepal. landslide, soil erosion and fire.

• Need of Environment
Conservation

• Local efforts for Environmental
Conservation

Glossary: A dictionary of scientific/technical terms

degradation : the damage or disturbance to any aspect of something
conservation : a careful preservation and protection of something, planned management

afforestation of natural resources to prevent exploitation, destruction, etc.
embankment : the act or process of planting a forest
: a raised structure used specially to hold back water or to carry a roadway

230 GREEN Science and Environment Book-6

Environmental Degradation and Its Conservation

Environmental Degradation: Causes, Impacts and Preventive
Measures

Various natural disasters that occur in nature and different human activities
are responsible for environmental degradation. The causes of environmental
degradation are broadly divided into natural causes or human causes. The
description of these causes of environmental degradation are described below
briefly:

Natural Causes of Environmental Degradation

There are some natural causes that are responsible for environmental
degradation. Such natural causes are natural disasters like soil erosion,
landslide, flood, fire, earthquake, volcano, tsunami, snow fall, heavy rainfall,
draught, etc. Among the above mentioned natural disasters, human activities
are much responsible for soil erosion, landslide, flood and forest fire. Other
natural disasters mentioned above are less affected by human activities because
they are out of human control. But, human beings can adopt preventive
measure to minimize their effect on the natural environment. In this context,
causes, impacts and preventive measures of soil erosion, landslide, flood and
fire are mentioned.

Soil Erosion

The gradual destruction of top

soil of land due to natural causes

as well as human activities is

called soil erosion. Heavy rain

fall, wind, unscientific farming,

unmanaged developmental works, Fig.

etc. are responsible for soil erosion.

Generally, soil erosion is most 22.1
common in the Mountain and Hilly

regions. The causes of soil erosion are mentioned below.

Major causes of Soil Erosion
i. Heavy rainfall, flood, landslide, wind, hurricane, etc.
ii. Unmanaged and unscientific agricultural activities.

GREEN Science and Environment Book-6 231

iii. Nature-unfriendly developmental works like construction of roads,
bridges, canals, buildings, etc.

iv. Deforestation, unmanaged grazing and extension of pasture land.

v. Overuse of land resource (eg. soil)

Major Impacts of Soil Erosion
i. Changes in land topography.
ii. Loss of fertile land.
iii. Loss of vegetation and natural resources.
iv. Environmental pollution and degradation.
v. Destruction of habitat of plants and animals.

Major Preventive Measure of Soil Erosion
i. Afforestation and Conservation of Vegetation.
ii. Scientific and terrace farming in sloppy land.
iii. Proper and scientific irrigating system.
iv. Planned and managed grazing and pasture land.
v. Nature-friendly developmental works like construction of roads, buildings,

bridges, etc.
vi. Wise and judicious use of land resource (eg. soil)

Landslide

Weak land structure and heavy

rainfall are especially responsible

for landslide. Landslide is a

natural cause of environmental

degradation. Landslide refers

to the sudden slide of land mass

downwards due to the effect of

gravity. Generally landslide occurs Fig.

during the rainy season in the Hilly

and Mountain region of Nepal. 22.2

It kills animals, damages plants

and destructs structures like road,

bridge, building, etc.

232 GREEN Science and Environment Book-6

Major causes of Landslide
i. Weak structure/form of sloppy land.
ii. Heavy rainfall and flood.
iii. Overgrazing and unmanaged pasture land.
iv. Deforestation and destruction of vegetation.
v. Unplanned and unmanaged developmental works like roads, bridges,

canals, etc.
vi. Unscientific agricultural activities in the Mountains and Hills.
vii. Earthquake and volcanic erruption.

Major Impacts of Landslide
i. Changes land forms/structures in mountains and hills.
ii. Destroys natural resources like vegetation, water resources, etc.
iii. Kills animals and destroys various infrastructures like roads, buildings,

bridges, etc.
iv. Destroys habitats of wild animals and plants.
v. Causes environmental degradation by polluting land, air, water, etc.

Major Preventive Measures of Land
i. Discouraging deforestation and encouraging afforestation.
ii. Managing grazing and pasture land.
iii. Practice of scientific terrace farming in sloppy land.
iv. Constructing walls in slopes.
v. Planned and managed developmental works.
vi. Conserving natural resources like forest, water resources, etc.
vii. Proper management of the flow of water during the rainy season.

Flood

In the rainy season, the level of water in rivers, streams, etc. increases due
to heavy rainfall and overflows from water bodies. It is called flood. Flood
refers to the overflow of water in the left and right sides of streams, rivers, etc.
Generally, flood occurs in the Terai region of Nepal during the rainy season

GREEN Science and Environment Book-6 233

and claims the lives of animals and destroys plants and properties. The other
causes of floods are earthquake, glaciers, etc.

Major causes of Flood

i. Deforestation and destruction
of vegetation.

ii. Heavy rainfall, earthquake,
glaciers, explosion of lakes and
ponds, obstruction in flow of
water in rivers, streams, etc.

iii. Destruction of dams and Fig.
embankment around rivers,
canals, etc. 22.3

iv. Unscientific and unmanaged agricultural activities near streams and
rivers.

v. Global warming (it causes melting of snow)

vi. Soil erosion and landslide

vii. Unmanaged and unplanned urbanization

Major Impacts of Flood
i. Damages lives and properties
ii. Sweeps fertile agricultural land
iii. Causes soil erosion and landslide
iv. Changes structure of land
v. Destroys vegetation and habitats of plants and animals
vi. Destroys infrastructures like roads, canals, buildings, etc.

Major Preventive measures of Flood
i. Construction of embankment, check dams, channel wall, etc. on the banks

of streams, canals, rivers, etc.

iii. Discouraging deforestation and encouraging afforestation

iv. Planned management of grazing and pasture land

v. Controlling landslides and soil erosion

vii. Controlling environmental degradation by conserving natural resources

234 GREEN Science and Environment Book-6

Fire

Fire is a natural disaster which is especially caused by carelessness of human
beings. Fire is the condition of becoming flames out of control. Generally,
it occurs during summer season in the Terai and Hilly regions of Nepal. It
destroys lives and properties.

Major causes of Fire

i. Natural disasters like volcanic
eruption and thunder.

ii. Careless human activities like Fig.
misuse of fire by children,
throwing cigarette buts near
forest, residential areas, etc.

iii. Short circuit in electricity 22.4
supply

iv. Introducing fire in forest, dry grassland, etc.

Major Impacts of Fire
i. Destroys lives and properties.
ii. Damages habitats of wild animals and plants by destroying vegetation.
iii. Kills wildlife and damages vegetation (in case of forest fire)
iv. Causes air pollution
v. Degrades natural environment by destroying natural balance.
vi. Destroys infrastructures like building , electric components, etc.

Major Preventive measures of Fire
i. Proper and safe use of fire during domestic works
ii. Keeping fire producing materials (eg. matchstick, lighter, etc.) out of rich

of children.
iii. Stopping forest fire
iv. Checking electric circuit regularly
v. Proper management of burning firewood, cigarette buts, etc.

GREEN Science and Environment Book-6 235

Fig.Human Causes of Environmental Degradation

Various unwise and careless activities of human beings are especially major
causes of environmental degradation. Overuse and destruction of natural
resources for the immediate benefit of human beings is mostly responsible
in creating imbalance in natural environment. At present, overuse of natural
resources due to rapid growth in population and migration is the major factor of
degradation in environment. Some of the major human causes of environmental
degradation are population growth, excessive use of natural resources, nature-
friendly developmental works, urbanization, industrialization, etc. These
causes of environmental degradation are described below briefly.

Population Growth and Overuse of Natural Resource

Human beings obtain food and
shelter from environment. They
use natural resources for various
purposes like producing food,
constructing shelters, operating
industries and factories, etc.
Growth in population results in
more use of natural resources. As a
result, natural resources are getting
destroyed to fulfill the demands 22.5
of increasing population. It creates
environmental imbalance resulting in environmental degradation. Thus,
it is essential to control rapid population growth to conserve environment.
Similarly, migration of people to urban and city areas in search of facilities
like education, health, transportation, etc. also causes over pressure on natural
resources of urban areas. It becomes a challenge to manage and dispose waste
materials in the areas having dense population. Unmanaged disposal of
wastage, sewage, etc. is also responsible for polluting various components of
natural environment like air, water, land, etc. Therefore, overuse of natural
resources should be stopped and proper management of waste materials is
essential to maintain environmental sanitation.

Industrialization

Industrialization is one of the major causes of environmental degradation.
The rapid growth in industries, factories, etc. is industrialization. With the
advancement in science and technology, many industries and factories are in
operation to meet the various demands of people.

236 GREEN Science and Environment Book-6

Industries and factories

are essential for economic

development of the nation. But,

unplanned and unmanaged rapid

growth in industrialization causes

environmental degradation. More

natural resources as raw materials Fig. Fig.

are needed to operate industries.

It creates over pressure on natural 22.6

resources. Over pressure on

natural resources result in degradation of natural resources. Similarly, the

byproducts, sewage, wastage, gases etc. emitted from industries pollute

environmental components like air, water, soil etc. Sound produced from

industries or factories is the cause of sound pollution. Inorganic components

like plastics produced from industries pollute land. Thus, unmanaged

industrialization degrades natural environment and hence it is necessary

to control rapid growth of unplanned industrialization in order to conserve

environment.

Activity 1

Make a visit to an industry or a factory in your locality and study its adverse
effects on environment of the surrounding area. Prepare a short note on the
basis of your study.

Urbanization

Urbanization is the process of
expanding residential areas or
establishing cities or towns by
construction of large buildings
in search of modern facilities. At
present, people migrate to city
areas in search of various facilities
like employment, education, health,
etc. It causes over population and is
the cause of over pressure and over 22.7
use of natural resources like water,
air, etc. Ultimately, excessive use of natural resources results in environmental
degradation. Similarly, various types of pollutions like air pollution, water
pollution, land pollution, etc. are responsible for environmental degradation

GREEN Science and Environment Book-6 237

in urban areas. Unmanaged and unplanned urbanization is the major cause
of environment degradation in recent days. People have established cities and
markets in farming lands. In the process of urbanization, deforestation has
taken place which is the major cause of air pollution, water pollution, etc. It also
invites natural disasters like soil erosion, landslides, flood, etc. Increasing use
of the vehicles and rapid growth of industrialization in human residential areas
also pollute natural environment essential for animals and plants. Ultimately, it
degrades the whole natural environment and disturbs environmental balance.
Thus, it is necessary to control unmanaged and unplanned urbanization in
order to conserve environment.

Activity 2

Make a study of any one natural disasters (flood, landslide, fire) of your
locality and enlist its causes, impacts and preventive measures. Also, present
it in your classroom.

Need of Environment Conservation

The practice of protecting and promoting various biotic and abiotic
components of environment is called environmental conservation. It includes
proper and wise use of natural resources and their management, protection
and promotion in order to maintain balance in natural environment. The
major ways of environmental conservation are maintaining environmental
balance and environmental sanitation. Environmental balance creates proper
interaction between/among various components of natural environment.
Similarly, environmental sanitation prevents natural components from being
polluted and degraded. Proper and wise use of natural resources is essential to
maintain environmental balance. Likewise, proper disposal of waste materials
is necessary to maintain environmental sanitation. Environment can be
conserved by conducting nature-friendly developmental works, afforestation,
conserving natural resources like air, water, land, etc. using natural resources
judiciously and economically, controlling environmental pollution and
maintaining environmental sanitation. It is the great need of environmental
conservation at present to save natural environment for the existence of all
living beings. The description of the following points illustrates need of
environmental conservation.

a. Protection of Natural Resources

Various natural resources found in the environment are the sources of food
and shelter for all living beings. Moreover, human beings use different natural

238 GREEN Science and Environment Book-6

Fig.resources for developmental
works, industrial and agricultural
activities, etc. Also, there is a
continuous interaction between/
among various components of the
environment. It is necessary to
maintain balance in environment
to protect natural resources for
the survival of all living beings 22.8
and existence of non-living things
in natural environment. Conservation of environment is only the way of
protecting natural resources found in the environment.

b. Protection of Habitats of Animals and Plants

Earth is the common habitat of all living beings. All animals ranging from
micro-organisms to big animals survive on environment. Similarly, plants
ranging from grasses to big trees exist in environment. It is necessary to
protect their habitats for their survival. It is only possible by environmental
conservation. For example, we should conserve forest for the survival of wild
animals and plants. We should conserve water resources to conserve habitats
of aquatic animals, etc.

c. Protection of Living Beings

All living beings exist in environment. Degradation in environment results
in loss of lives of living beings, both animals and plants. All living beings
depend on various components of natural environment for various purposes.
It is essential to conserve and promote natural resources for the survival of
all living beings in the environment. Natural resources can be conserved by
environmental conservation for the protection of living beings in the natural
environment.

d. Protection of Resources of Food

All living beings, both animals and plants get food from the environment.
Human beings produce food crops, vegetables, fruits, etc. on land. Similarly,
herbivores feed on plants that grow on land with the help of water resources.
Green plants prepare their food by using sunlight, carbon dioxide, water and
minerals. Various components of environment are the sources of food for
living beings. Thus, it is necessary to conserve environment to protect food
resources of living beings.

GREEN Science and Environment Book-6 239

e. Social and Cultural Development

Social development is related to carrying out of various developmental
works for economic benefit and meeting the demands of human beings.
Social development is directly related to uplifting the life standards of
people. Various natural resources are essential to conduct different types of
developmental works for social development. Thus, it is necessary to conserve
environment to conserve and promote various natural resources required for
social development. Similarly, conservation of socio-cultural environment is
essential for cultural development of people.

Efforts on Environmental Conservation

Environment can be conserved by conserving and promoting its various
components. Human beings are responsible for conserving environment since
various activities of human beings results in environmental degradation. Also,
human is a wise animal with rationality. Various efforts can be made to save
natural environment with its various biotic and abiotic components. It is our
responsibility to conserve environment for us and our generations. Some of
the ways that can be adopted for environmental conservation are generating
public awareness, afforestation and protecting forest, wise use of natural
resources, environmental sanitation, protection and promotion of cultural
heritages, etc. The brief description of these efforts is presented below.

a. Generating Public Awareness

Public awareness is one of the most effective methods of conserving
environment. All people should have knowledge about the importance
of environment for the existence of all living beings and non-living things.
Conserving environment is possible by the effort of all human beings who use
components of environment for various purposes. It is necessary to generate
various awareness programmes in different level to make people aware
about conserving environment. Generally, it is essential to conduct various
awareness programmes related to conservation of environment in the local
levels. Environmental education is necessary to make people aware about
protecting and conserving environment.

b. Public Participation

It is not possible to conserve environment by individual effort or effort of few
people. More and more people should be involved in conserving environment.
Thus, it is essential to increase public participation so that it becomes
responsibility of all people to conserve environment.

240 GREEN Science and Environment Book-6

c. Integrated Conservation Programmes

The concept of integrated development is one of the effective effort for
conserving environment. Various developmental works like road construction,
water supply, electrification, etc. can be conducted together by conserving
environmental components. It is helpful to reduce pollution in environment.

d. Conservation of vegetation and Afforestation.

Vegetation is one of the important components of environment responsible
for maintaining environmental balance. It is necessary to conserve vegetation
by conserving forest. Similarly, it is necessary to increase the area of forest by
planting trees in barren and unused land. Green forest helps in maintaining
environmental balance by maintaining water cycle and balance between
oxygen and carbon dioxide.

Environmental Sanitation

There is more pressure on natural resources due to the growth in population.
People use various components of environment and create more waste
materials in the environment. Over use of natural resources and creation of
waste materials results in environmental degradation. Thus, it is necessary to
maintain environmental sanitation to conserve environment. The following
efforts can be made in local level for environmental sanitation.

i. Keeping home and surrounding clean and healthy

ii. Proper management and disposal of waste materials.

iii. Conservation of natural resources like water, land, air, vegetation, wildlife,
etc.

iv. Reducing fossil fuels and increasing alternative sources of energy like
solar energy, bio gas, etc.

v. Conducting sanitation and awareness programmes.

Activity 3
Conduct an oratory programme on the "Need of Environmental Conservation"
in your classroom.

GREEN Science and Environment Book-6 241

Key Concepts

1. The gradual destruction of top soil of land due to natural causes as well
as human activities is called soil erosion.

2. Flood refers to the overflow of water in the left and right sides of streams,
rivers, etc.

3. Overuse and destruction of natural resources for the immediate benefit
of human beings is mostly responsible in creating imbalance in natural
environment.

4. Urbanization is the process of expanding residential areas or establishing
cities or towns by construction of large buildings in search of modern
facilities.

5. Environmentcanbeconservedbyconductingnature-friendlydevelopmental
works, afforestation, conserving natural resources like air, water, land,
etc. using natural resources judiciously and economically, controlling
environmental pollution and maintaining environmental sanitation.

6. Natural resources can be conserved by environmental conservation for
the protection of living beings in the natural environment.

7. Human beings are responsible for conserving environment since various
activities of human beings result in environmental degradation.

8. Environmental education is necessary to make people aware about
protecting and conserving environment.

9. It is necessary to maintain environmental sanitation to conserve
environment.

Exercise

1. Tick (√) the correct statement and cross (×) the incorrect one.

a. Human activities are only responsible for natural disasters.

b. Flood is a natural cause of environmental degradation.

c. Landslide is common in the Terai region of Nepal.

d. Public awareness helps in environmental conservation.

e. Degradation in environment protects natural environment.

242 GREEN Science and Environment Book-6

2. Fill in the blanks using appropriate words.
a. Natural disasters are ....................... causes of environmental
degradation.
b. The loss in top soil is called .......................
c. Generally, flood occurs in ....................... region of Nepal.
d. Volcanic eruption and thunder are ....................... cause of .......................
e. Overuse of natural resources is the cause of .......................

3. Answer the following questions.

a. What is environmental degradation? Name any two natural causes of
it.

b. What does human causes of environmental degradation mean? Give
any two examples.

c. Define soil erosion.

d. What is forest fire? Why is it dangerous?

e. What do you mean by urbanization? Why is it called human cause of
environmental degradation?

f. Why is environment conservation necessary for protecting natural
resources?

g. What does local effort for environmental degradation mean? Give any
two examples.

4. Write short notes on:

a. Natural causes of Environmental Degradation

b. Flood c. Landslide

d. Protection of Resources of Food e. Public Participation

5. Mention any five causes of soil erosion.

6. Enlist any five major impacts of landslide.

GREEN Science and Environment Book-6 243

7. How can flood be controlled? Give any five major preventive majors.
8. Mention any three causes and impacts each of fire.
9. "Population growth and overuse of natural resources are the human

causes of environmental degradation." Justify this statement with
examples.
10. Describe the need of environmental conservation in detail.
11. Mention any four efforts that have been taken in the local level for the
conservation of environment. Explain briefly any one of them.
12. Identify the following natural disasters. Also, write causes, impacts and
preventive measures.

244 GREEN Science and Environment Book-6

Environment
UNIT and Sustainable

23 Development

Weighting Distribution (Approximate) Teaching periods : 10 Marks (in %): 2

Before You Begin

Environment and Sustainable development are closely related to each other.
Various natural resources are taken from the environment for developmental
works. Also development that is carried out with sustainable manner helps
in conserving environment.
The totality of biotic and abiotic components around us is environment.
Environment is the natural world around us where plants and animals
live. Environment consists of physical world us well as biological world.
The earth is the common habitat for all plants and animals. Living
beings get air, water, food, habitat, etc. from the earth. Environment is
made of abiotic and biotic components. The abiotic components of the
environment include sunlight, air, water, soil, temperature, pressure,
rainfall, etc. Similarly, the biotic components of an environment include
differnet types of plants and animals.
Sustainable development refers to development that lasts long and
does not degrade the environment. Sustainable development is the
development that meets the need of present generation without
compromising the ability of future generations to meet their own needs.
Sustainable development is nature friendly development because it does
not harm the components of natural environment and conserves natural
resources for the use of future generations.

Learning Objectives Syllabus

After completing the study of this unit, students will be able to: • Introduction to Sustainable
Development
i. introduce sustainable development with its clear
concept. • Importance of Sustainable
Development
ii. explain the importance of sustainable development.
iii. describe the relationship among population, • Interrelationship among
Population, Environment and
environment and development with examples. Development
iv. be familiar with local efforts for sustainable
• Local Efforts for Sustainable
development. Development

Glossary: A dictionary of scientific/technical terms

sustainable : capable of being sustained, able to be used without being completely used
up or destroyed
biodiversity
species : the existence of large number of plants and animals
: the group of closely related organisms which can interbreed freely to
genetic
ecosystem produce fertile offspring
: heritable, relating to or determined by the origin
mutual : the structural, functional and self-sustaining unit made of living beings

and non-living things
: shared between two or more people or groups

GREEN Science and Environment Book-6 245

Environment and Sustainable Development

Introduction to Sustainable Development

Human beings carryout various developmental works for their benefits. Such
works are constructing buildings, roads, bridges, canals, etc. Human beings
use different types of materials from the natural environment to carry out
various development works. Such materials are water, soil, stone, timer, etc.
It is necessary to use these materials by conserving nature to use them again
and again. Also, it is the responsibility of human beings to conserve all the
components of natural environment for the use of future generation.

Sustainable development refers to development that lasts long and does not
degrade the environment. Sustainable development is the development that
meets the need of present generation without compromising the ability of
future generations to meet their own needs. Sustainable development is nature
friendly development because it does not harm the components of natural
environment and conserves natural resources for the use of future generations.

Concept of Sustainable Development

The wise and economic use of natural resources for development is essential
to carry out nature friendly development. Nature friendly development lasts
long without harming environment in a large scale. In this sense, "sustainable
development is development that meets the needs of the present without
compromising the ability of future generations to meet their own needs." In
this sense, sustainable development does not harm environmental components
so that the present condition of environment can be conserved for the future
generations in the same condition.

Sustainable development is a process for meeting human development goals
in a sustainable manner. It is the organizing principle for sustaining finite
resources necessary to provide for the needs of future generation of life on
the earth. Sustainable development does not undermine the integrity, stability
and beauty of various components of natural environment. The principle of
sustainable development suggests us that we can utilize natural resources for
various developmental works, but the natural resources should be conserved
in the same condition as they are now for the utilization of future generations.
It means that sustainable development does not degrade or destruct natural
environment.

246 GREEN Science and Environment Book-6

Sustainable development is based on the following facts

i. consumption of natural resources with their limits.

ii. realization of interconnections among various components of environment.

iii. equitable distribution of natural resources.

Activity 1

Make a study of any one developmental work (road, building, bridge,
hydroelectricity, etc.) to find out the natural resources used in that work.
Also, find out the effects of use of such natural resources in the environment.
Prepare a short description by including the ways of making the development
work sustainable by conserving surrounding environment.

Importance of Sustainable Development

Sustainable development sustains for a long time with the conservation
of environmental components. It does not degrade environment because
it is environment/nature friendly development. Human beings can use
nature resources again and again if they follow the principles of sustainable
development while carrying out developmental activities. The environment
can be conserved for future generation if our developmental activities are
conducted in sustainable manner. Sustainable development is only the
way of conserving various components of natural environment. It helps in
maintaining environmental balance with the wise and judicious use of natural
resources. Thus, sustainable development has great importance to conserve
natural environment for a long time. As a result, human beings can benefit
from natural environment again and again without disturbing the natural
cycle and ecosystem of various components of environment. The importance
of sustainable development can be given in the following points.

i. Protection of natural resources with their promotion.

ii. Conservation of natural environment by maintaining environmental
balance.

iii. Protection of various animals and their food.

iv. Maintaining of limited capacity of natural resources for their use again
and again.

v. Improvement in human living continuously.

vi. Sustainability of natural resources for the future generation.

vii. Conservation of habitats of animals and plants.

GREEN Science and Environment Book-6 247

Fig.viii. Improvement of personal behaviour of human beings for using natural
resources.

ix. maintaining environmental balance and sanitation.

x. Capacity growth of the people in local level.

xi. Cultivation of 'Conservation Spirit' in people.

xii. Development of spirit of mutual cooperation for the conservation of
environment.

xiii. Making developmental works long lasting for the benefit of people for a
long time.

Interrelationship Among People, Environment and Development

People use various resource from
environment to carry out different
types of development work in
environment. Different activities of
people may have adverse effects on
the environment. At the same time,
people can conserve environment by
using environmental components
wisely in a sustainable manner.
Various activities of people have 23.1
direct negative or positive impact in
the environment. Similarly, developmental activities are essential for people to
raise their life standard with economic benefit. Thus, people, environment and
development are interrelated to each other. This interrelation among people,
environment and development can be made more clear by the following points.

i. People need various resources like air, water, soil, etc. for their survival and
to conduct various developmental works. These resources are available in
the environment.

ii. People's various activities are responsible for maintaining environmental
balance or degrading environment. Environment can be conserved
by the effort of people. Environmental conservation helps in making
developmental works sustainable.

iii. People use various raw materials required for industrialization. These
materials are available in the environment. The industrial products are
essential to meet the requirement of people. But, unwise and excessive use
of natural resources for industrial purpose degrade environment and by
products of industries or factories pollute environment.

248 GREEN Science and Environment Book-6

Fig.iv. People follow various social customs, norms and values for their socio-
cultural development. Social customs are the components of socio-cultural
environment. It is duty of people to conserve socio-cultural environment
for their socio-cultural development.

v. People live on land and carry out various activities in land. In the absence
of land, habitat of people is not possible. At the same time, land is one
of the important components of natural environment. Various materials
used for developmental activities are available in land.

Thus, people environment and development are inseparable and there is
close interrelationship between these aspects.

Local Efforts for Sustainable Development

Sustainable development is necessary for the betterment of human beings.
Thus, it is the responsibility of human beings to conserve nature. Conservation
of environment is only possible by following the principles of sustainable
development. At present, there is a huge crisis in natural environment due to
the rapid growth in population, industrial activities and construction works.
Thus, various efforts have been made for conducting developmental activities
in a sustainable manner. These efforts have been made in local, national and
international levels. Some of the efforts that have been made in the local level
for sustainable development are presented below.

i. Afforestation/Plantation

Afforestation is one of the
important efforts that have been
made in local level for sustainable
development. Green plants
maintain environmental balance
by maintaining proper balance
between oxygen and carbon
dioxide. Similarly, afforestation
results in expansion of forest
area to get forest materials for
developmental works. It helps in
making development sustainable. 23.2
It also conserves environment and
provides food and shelter to all living beings.

GREEN Science and Environment Book-6 249

Fig.ii. Conservation of Natural Resources

Natural resources are important for
conducting various developmental
works. Conservation of these
resources helps in making
development sustainable. Human
beings can use natural resources
again and again if they conserve
them. Also, people can conserve
natural resources for the use of
future generations. Thus, various
efforts have been made to conserve 23.3
land resources, water resources, vegetation, animals, etc. in the local level.

iii. Organic Farming

Organic farming is one of the major ways of conserving environment because
it is nature friendly. Nature friendly activities are essential for sustainable
development. People use organic fertilizers in the local level. Organic fertilizers
do not pollute environment and do not harm animals and plants. As a result,
it helps in maintaining environmental activities for a long time in local level.

iv. Generating Public Awareness

Public awareness is necessary to make the people aware about the importance
of environment and necessity of sustainable development. Many people in the
local level may not be familiar with the principles of sustainable development.
Various Organizations are involving in public awareness programmes in the
local level to make the people conscious and aware regarding importance of
sustainable development for the conservation of environment.

Activity 2

Make a list of local efforts that have been made in your locality for sustainable
development. Prepare a brief description by explaining importance of the
local efforts in conserving environment.

Key Concepts

1. Environment is the natural world around us where plants and animals
live. Environment consists of physical world us well as biological world.

2. Sustainable development is the development that meets the need
of present generation without compromising the ability of future
generations to meet their own needs.

250 GREEN Science and Environment Book-6