TS Inter 1st Year Environmental Education Study Material Chapter 1 Dimensions of the Environment

Telangana TSBIE TS Inter 1st Year Environmental Education Study Material 1st Lesson Dimensions of the Environment Textbook Questions and Answers.

TS Inter 1st Year Environmental Education Study Material 1st Lesson Dimensions of the Environment

Essay Questions

Question 1.
Explain the term “Environment”.
Answer:
Environment refers to the sum total of conditions which surround a living being’s habitation. It includes both biotic (living) and abiotic (non-living) aspects. The word ‘environment’ has been derived from the French word ‘environir’ which means ‘to surround.’ Environmental Studies is a multidisciplinary subject which systematically studies human interaction with the environment and seeks to find answers to problems such as how the growing population on earth can be sustained with the finite resources of Nature.

Man has had a close relationship with his environment since time immemorial. Primitive man lived in the lap of Nature and derived nourishment and sustenance from the bountiful resources of Nature in the form of the air he breathed, the water he drank, the food he ate and the trees and caves in which he sought shelter. Man’s needs were few and Nature seemed a perennial source and supplier of pristine resources.

However, rapid technological advancements and unchecked urbanization in the last few centuries have altered the relationship between Man and Nature in unimaginable ways. The everincreasing growth in population led to the depletion and degradation of the environment. Over – exploitation of natural resources in the last century has led to an unprecedented crisis and has raised concerns not only about the resource availability for future generations but the very existence of the human race.

Question 2.
Write the relationship between Man and Environment. What are the impacts of Man on Environment?
Answer:
Man – Environment relationship :
The relationship between Man and his Environment can be categorised into four broad stages if we examine the history of the socio-cultural evolution of man. The four stages are :

1. Hunting and Food gathering.
2. Animal domestication and Pastoralism.
3. Agriculture.
4. Industrialization.

i) Hunting and Food gathering :
The life of primitive man was nomadic and unstructured. Man was dependent on his surroundings for food and other needs.

• Primitive man :
a) Man was part of the natural environment.
b) He lived in harmony with the environment and completely depended on the natural resources and food available in his habitation.
c) Later he began to hunt animals for food.

• Discovery of fire, invention of tools :
a) The necessity of tools for hunting and the invention of fire radically changed the life of primitive man and paved the way for the exploitation of natural resources.

ii) Animal domestication and Pastoralism :
The next stage of evolution was the domestication of animals for meat and milk. This led to greater control on the environment and reduced dependence on natural resources alone.

iii) Agriculture :
During this stage man started cultivating crops. There was no further need to lead a nomadic life. He now had a permanent habitation and this, in turn, paved the way for community living and a gradual increase in human population. In subsequent years he started clearing the forests, not only for the purpose of gathering firewood, but for agricultural use as well as for the construction of dwellings.

iv) Industrialization :
The subsequent development of Science and Technology led to the Industrial revolution which began during the late eighteenth century in Great Britain. Goods started being produced on a mass scale in factories. This led, inevitably, in indiscriminate exploitation of natural resources and the fouling of the environment.

Impact of Man on Environment :
Various activities of man have left a profound impact on the environment. Some of the effects are direct while others are indirect.
Activities of Man that affect the Environment :

a) Land use changes :
• Clearing of forests, burning of land, felling of trees, changes in cropping patterns.

b) Agricultural practices ;
• Mechanization of agriculture, use of chemical fertilizers and pesticides.

c) Construction and Excavation :
• Construction of dams, roads and bridges; Mineral extraction by way of excavation; Urbanization.

d) Exploitation of Natural Resources :
• Excessive use of natural resources like wood and water
• Excessive use of conventional sources of energy like coal and fossil fuels.

Question 3.
Describe the Dimensions of the Environment.
Answer:
The Environment has three major dimensions. These dimensions have a mutual influence on each other and have a significant impact on the sustenance of life on this earth. The three dimensions are :
1) Physical 2) Biological 3) Social

The various sub-components in each of the three dimensions of the environment are given in the table below :

I. The Physical Environment :
It comprises the abiotic components or non-living components of the environment such as land, air and water. These components are referred to as the lithosphere (land), atmosphere (air) and hydrosphere (water). Each of these physical components can be sub divided into different components based on their physical properties.

a) Lithosphere :
The word ‘lithosphere’ is derived from the Greek words ‘lithos’ (rock) and ‘spharia’ (globe or ball). The lithosphere includes the crust and the upper most mantle of the earth and constitutes the Biotic Environment. It is the solid part of the earth, made up of rocks and solids. The lithosphere occupies about 29% of the earth’s surface area and provides the habitat for flora (plants) and fauna (animals).

b) Atmosphere :
It is a layer of gases which surrounds the earth on all sides. The word ‘atmosphere’ is derived from the Greek words ‘atoms’ (vapour) and ‘sphaira’ (sphere).

The atmosphere of the earth is composed mainly of nitrogen (about 78%), oxygen (21%) and argon (0.9%). Carbon dioxide and other gases are found in traces.

The atmosphere plays a crucial role for the sustenance of life on the earth. Life, as we know it, would not be possible without the atmosphere. Oxygen is used by most organisms for respiration. Plants and animals need nitrogen to make proteins. Carbon dioxide is used by plants and algae for photosynthesis.

The atmosphere keeps us warm. It holds the surface heat on the earth and prevents it from radiating out into space. It reduces the extreme temperatures between day and night. The atmosphere also gives us weather. Wind, rain and snow depend on the atmosphere. Without winds and rain we would not have water to drink. Plants and animals too would perish. Apart from these functions, the atmosphere also helps to pro­tect living organisms from damage caused by harmful ultra violet radiation from the sun.

The atmosphere of the earth consists of a number of layers which differ in properties such as composition, temperature and pressure.

The lowest layer is the troposphere with extends from the surface of the earth to the bottom of the stratosphere. The stratosphere extends from the top of the troposphere to the bottom of the mesosphere and contains the ozone layer. The ozone layer ranges in altitude between 15-35 km where most of the U.V radiation from the sun is absorbed.

The top of the mesosphere ranges from 50-85 km. The thermosphere extends from 85 km to the base of the exosphere at 690 km and contains the ionosphere, a region where the atmosphere is ionised by incoming solar radiation.

c) Hydrosphere :
The hydrosphere (from Greek ‘hydr’ which means ‘water’) is the combined mass of water found on, under and above the surface of the earth. It includes the oceans, lakes and rivers, water vapour in the atmosphere, water in the soil, aquifers and glaciers. About 71% of the Earth’s surface is covered with water. The oceans hold about 96.5% of all the water on the Earth.

Saltwater accounts for 97.5% of water. Fresh water accounts for only 2.5%. Of this fresh water, about 30% is in the form of fresh gro jnd water and the rest exists as snow and ice on glaciers.

II. The Biological Environment or Biosphere :
The biosphere (from Greek ‘bios’ which means ‘life’) is also known as the ecosphere (from Greek ‘oikos’ which means ‘environment’). It is the worldwide sum of all ecosystems. It contains all forms of life including human, animal and plant life. Flora includes all plants in various forms such as forests, grasslands and other types of vegetation. Fauna refers to all animals and other organisms which live in the air, soil or water. The average thick-ness of the biosphere, consisting of those parts of the air, water, soil and rock where life exists in some form, is about 25 km.

It is difficult to pinpoint the exact time the biosphere came into existence as records of primitive living forms that have been preserved are indistinct and rare to find in the earth’s crust. However, from the evidence available, it is believed that life began about 4 billion years ago when the oceans were formed.

III. Social Environment :
It is also known as cultural or man-made environment. It is concerned with the social behaviour of organisms. All the organisms of the floral and faunal environment organise themselves into social groups and form what is known as the social environment. Social environment involves population interaction and behaviour patterns of animals in response to their environment.

Question 4.
Explain the impact of Man’s Activities on the Environment.
Answer:
Impact of Man’s Activities on the Environment :
Several human activities like industrialization, urbanization and population growth have adversely affected bio-geo-chemical cycles. The impact of man’s activities on the environment is referred to as the anthropogenic impact on the environment. It includes the impact on biophysical environments, biodiversity and other resources.

Man’s activities have caused a rapid depletion of natural resources. Green House Gas (GHG) emissions (carbon dioxide, methane, etc.) have increased, leading to global warming, climate change and natural disasters. Pollution is fouling the air, water and land. Altered bio-geo-chemical cycles combined with climate change have a negative impact on biodiversity, food security, human health and water quality. The National Wildlife Federation, USA, states that every day 100 plant and animal species are becoming extinct as a result of deforestation. It is estimated that global temperature may increase by more than 2 degrees Celsius by the end of the century, making the earth in hospitable to most species.

The impact of man’s activities on the environment may be long lasting and even irreversible. We can stem the damage to some extent by taking appropriate steps like afforestation, change of farming practices, optimal use of resources and changing our patterns of consumption.

If we compare Earth with other planets in the solar system, we find that while sunlight is available on the other seven planets too, with varying intensities, air and water are available only on Earth. Without air and water, Life, as we know it, cannot exist.

The Environment does not require man. It can exist without human interaction or interference and can sustain billions of species that inhabit the earth. Man, on the other hand, requires the environment for sustenance of life. It is our bounden duty to protect it and ensure that future generations too can live in harmony with Nature.

Question 5.
What is the legacy thet we should leave for future generations?
Answer:
It is just multi-storeyed buildings, massive infrastructure and complex electronic gadgets that we should bequeath our children or a clean environment which supports life and provides sustenance? Man is the most intelligent animal on earth. He is well aware of the havoc he is wreaking on the environment and knows too that the damage he is inflicting on Nature may be irreversible. Even now it is not too late for all of us to save the earth. The majestic mountains, the vast oceans, the rich flora and fauna need to be preserved. Small individual actions will collectively make a huge difference.

Let us all take a pledge, ‘I shall go Green’.
Let us all take a decision to

• Conserve Water.
• Conserve Energy.
• Implement the concept ‘Reduce, Reuse and Recycle’ in our day to day life.
• Conserve Natural Resources.
• Minimize activities that cause Pollution Let us not forget.

“We have not inherited the Earth from our ancestors, we have borrowed it from our children.”

Question 6.
Explain water cycle briefly.
Answer:
It refers to the cycle of processes by which water evaporates from the surface of the earth, rises into the atmosphere, cools and condenses into rain or snow in clouds, falls to the surface as precipitation and is collected once again in lakes, rivers and oceans. Solar energy, in the form of heat and light, besides gravity, causes the transfer of water from one state to another over periods ranging from hours to thousands of years. The water cycle is crucial for the sustenance of life and ecosystems on earth.

There are four important stages in the water cycle. In the first stage the sun heats the water on the surface of the earth. The water from lakes, rivers and oceans gets hot and changes into vapour. This process is called evaporation. The water vapour then cools and collects in the sky as clouds. This is called condensation. In the next stage water in the form of rain, snow or hail falls from the clouds. It is called precipitation. The water that falls gets collected in oceans, streams, rivers and lakes. This stage is called collection. The process continues in this manner.

It should be noted that evaporation takes place not only from water but also from snow and plants. Evaporation from snow and ice is called sublimation. Transpiration refers to the expiration of water through the minute pores or stomata of trees. Evapo transpiration is the term used by hydrologists with reference to the three processes together — transpiration, sublimation and evaporation.

Question 7.
Explain Bio-geo-chemical cycle briefly.
Answer:
Bio-geo-chemical cycles are defined as large scale cycles, involving inorganic substances which pass through a biotic phase and then return to an abiotic or inorganic state. The term is used as the process includes a variety of biological, geological and chemical processes. Many chemicals cycle through biotic (biosphere) and abiotic (lithosphere, atmosphere and hydro-sphere) compartments of the earth. Nutrient elements like car-bon, nitrogen, hydrogen, oxygen and sulphur move through the earth’s atmosphere, ocean and sediments. These cycles are important because important elements are transported and stored suclj that they can be used by living organisms. Given below is an example :

• Plants take nutrients (inorganic elements) through their roots from the soil while animals do so through the intake of food and water. These nutrients get recycled back to the earth after the death and decay of the plants and animals.

Bio-geo-chemical cycles are of two types :

1. Those that involve cycling of all elements together e.g. Water cycle
2. Those that involve cycling of individual elements e.g. carbon cycle, nitrogen cycle, oxygen cycle.

Question 8.
Write about Oxygen Cycle.
Answer:

1. Large amounts of oxygen is present in air (21%).
2. Some of this O₂ is dissolved in water. O₂ content in air and water are in equilibrium i.e., whenever O₂ content in water decreases, more amount of O₂ from air gets dissolved in water. So that the ratio of O₂ in air and water always remain constant.
3. O₂ dissolved in water is used for respiration by aquatic plants and animals.
4. Similarly terrestrial plants and animals use oxygen present in air for their respiration.
5. The by – products of respiration – carbondioxide and water are released into air.
6. These two are taken up by plants and are used by photosynthesis.
7. The by – product of photosynthesis is O₂ which is released into air.
8. Carbondioxide is also formed when fuels like wood, coal and petroleum products are burnt.
9. There is a fine balance between these processes, so that the total amount of O₂ present in air remains constants. All these processes together represent O₂ cycle.
   
10. O₂ also has another important role in environment. In the upper layers of atmosphere, O₂ is converted to ozone. This is another form of oxygen in which each molecule has three oxygen atoms instead of two.
11. 
12. Ozone gas is present at a height of 16 – 23 km from the surface of earth. At this height it covers the entire planet like a blanket.
13. Light rays reaching earth from such has three components i.e. Ultraviolet rays (uv), visible rays and Infrared rays. Ozone has the property of absorbing ultraviolet light and does not allow it to fall on Earth.