Natural Resources

Natural Resources

Intended Learning Outcomes

At the end of this session, students will be able to

• Explain natural resources

Contents

• Natural resources

Natural Resources

• Our environment provides us with a variety of goods and services necessary for our day to day lives

• These natural resources include, air, water, soil, minerals along with the climate and solar energy, which form the non-living or ‘abiotic’ part of nature

• The ‘biotic’ or living parts of nature consists of plants and animals, including microbes

• Thus, forests, grasslands, deserts, mountains, rivers, lakes and marine environment all form habitats for specialised communities of plants and animals to live in

• Interactions between the abiotic aspects of nature and specific living organisms together form ecosystems of various types

• Many of these living organisms are used as our food resources

• Others are linked to our food less directly, such as pollinators and dispersers of plants, soil animals like worms, which recycle nutrients for plant growth and fungi and termites that break up dead plant material so that micro-organisms can act on the detritus to reform soil nutrients

• History of our global environment

• About ten thousand years ago, when mankind changed from a hunter-gatherer, living in wilderness areas such as forests and grasslands into an agriculturalist, we began to change the environment to suit our own requirements

• Natural ecosystems were developed into agricultural land

• Most traditional agriculturists depended extensively on rain, streams and rivers for water

• Later they began to use wells to tap underground water sources and to impound water and created irrigated land by building dams

• Recently we began to use fertilizers and pesticides to further boost the production of food from the same amount of land, all this has led to several undesirable changes in our environment

• Mankind has been overusing and depleting natural resources

• Over-intensive use of land has been found to exhaust the capability of the ecosystem to support the growing demands of more and more people, all requiring more intensive use of resources

• Industrial growth, urbanisation, population growth and increase in the use of consumer goods, have all put further stresses on the environment

• Pollution of air, water and soil have begun to seriously affect human health

• Changes in land and resource use

• During the last 100 years, a better health care delivery system and improved nutritional status has led to rapid population growth, This phenomena aids to a great demands on the earth’s natural resources

• Large stretches of land such as forests, grasslands and wetlands have been converted into intensive agriculture

• Land has taken for industry and urban sectors

• These changes have brought about dramatic alterations in land use patterns and rapid disappearance of valuable natural ecosystems

• Need for more water, food, energy, consumer goods is not only the result of a greater population, but also result of over utilization of resources by people from the more affluent societies and the affluent sections of our own

• Industrial development is aimed at meeting growing demands for all consumer items

• Growth of industrial complexes has led to a shift of people from their traditional, sustainable, rural way of life to urban centres

• Last few decades, several small urban centres have become large cities, some have even become giant mega-cities

• Urban centres cannot exist without resources such as water from rivers and lakes, food from agricultural areas, domestic animals from pasture lands and timber, fuel wood, construction material and other resources from forests

• Rural agricultural systems are dependent on forests, wetlands, grasslands, rivers and lakes

• The result is a serious inequality in the distribution of resources among human beings, which is both unfair and unsustainable

• Earth’s Resources and Man

• Resources on which mankind is dependent are provided by various sources or ‘spheres’

Atmosphere

• Oxygen for human respiration

• Oxygen for wild fauna in natural ecosystems and domestic animals used by man as food

• Oxygen as a part of carbon dioxide, used for the growth of plants (in turn are used by man)

• Atmosphere forms a protective shell over the earth

• Lowest layer, troposphere is the only part warm enough for us to survive, is only 12 kilometers thick

• Stratosphere is 50 kilometers thick and contains a layer of sulphates which is important for the formation of rain

• Also contains a layer of ozone, which absorbs ultra-violet light known to cause cancer and without which, no life could exist on earth

• If its nature is disrupted it affects all mankind

• Most air pollutants have both global and regional effects

• Living creatures cannot survive without air even for a span of a few minutes, hence air must be kept clean

• Major pollutants of air are created by industrial units such as carbon dioxide, carbon monoxide and toxic fumes into the air

• Air is also polluted by burning fossil fuels

• Buildup of carbon dioxide which is known as ‘greenhouse effect’ in the atmosphere is leading to current global warming

• Growing number of scooters, motorcycles, cars, buses and trucks which run on fossil fuel (petrol and diesel) is a major cause of air pollution

• Air pollution leads to acute and chronic respiratory diseases

Hydrosphere

• Clean water for drinking (a metabolic requirement for living processes)

• Water for washing and cooking

• Water used in agriculture and industry

• Food resources from the sea, including fish, crustacea, sea weed, etc.

• Food from fresh water sources and aquatic plants

• Water flowing down from mountain ranges harnessed to generate electricity in hydroelectric projects

• Hydrosphere covers three quarters of the earth’s surface

• A major part of the hydrosphere is the marine ecosystem in the ocean, while only a small part occurs in fresh water

• Fresh water in rivers, lakes and glaciers is perpetually being renewed by a process of evaporation and rainfall

• Some of this fresh water lies in underground aquifers

• Human activities such as deforestation create serious changes in the hydrosphere

• Water pollution threatens the health of communities as all our lives depend on the availability of clean water

Lithosphere

• Soil, the basis for agriculture to provide us with food

• Stone, sand and gravel used for construction

• Micronutrients in soil, essential for plant growth

• Microscopic flora, small soil fauna and fungi in soil, important living organisms of the lithosphere, which break down plant litter as well as animal wastes to provide nutrients for plants

• A large number of minerals on which our industries are based

• Oil, coal and gas extracted from underground sources (provides power for vehicles, agricultural machinery, and industry and for our homes)

• Lithosphere began as a hot ball of matter which formed the earth about 4.6 billion years ago

• Of the 92 elements in lithosphere only eight are common constituents of crustal rocks

• Of these constituents, 47% is oxygen, 28% is silicon, 8% is aluminium, 5% iron, while sodium, magnesium, potassium and calcium constitute 4% each

• Together, these elements form about 200 common mineral compounds

• Rocks, when broken down form soil on which man is dependent for his agriculture

Biosphere

• Food from crops and domestic animals, providing human metabolic requirements

• Food for all forms of life which live as interdependent species in a community and form food chains in nature on which man is dependent

• Energy needs: Biomass fuel wood collected from forests and plantations, along with other forms of organic matter, used as a source of energy

• Timber and other construction materials

• This is the relatively thin layer on the earth in which life can exist

• Within it the air, water, rocks and soil and the living creatures, form structural and functional ecological units, which together can be considered as one giant global living system, that of our Earth itself

• Within these, smaller biogeographical units can be identified on the basis of structural differences and functional aspects into distinctive recognizable ecosystems, which give a distinctive character to a landscape or waterscape

• Simplest of these ecosystems to understand is a pond

Natural cycles between the spheres

• All four spheres are closely inter linked systems and are dependent on the integrity of each other

• Disturbing one of these spheres in our environment affects all the others

• Linkages between them are mainly in the form of cycles

• For instance, atmosphere, hydrosphere and lithosphere are all connected through the hydrological cycle

• Water evaporated from the hydrosphere, forms clouds in the atmosphere

• This becomes rain, which provides moisture for the lithosphere, on which life depends

• Rain also acts on rocks as an agent of erosion and over millions of years has created soil, on which plant life grows

• Atmospheric movements in the form of wind, break down rocks into soil

• All living organisms which exist on earth live only in the relatively thin layer of the lithosphere and hydrosphere that is present on the surface of land and in water

• Biosphere which they form has countless associations with different parts of the three other ‘spheres’

• It is therefore essential to understand the interrelationships of the separate entities soil, water, air and living organisms etc