Environment, Ecology and Ecosystem

Environmental StudiesUNIT-1

Environment

• Environmental science is an interdisciplinary field that includes both scientific and social aspects of human impact on the world.

• The word environment is usually understood to mean the surrounding conditions that affect organisms.

• In a broader definition, environment is everything that affects an organism during its lifetime.

• In turn, all organisms including people affect many components in their environment

Environmental Science

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Classification of Environment

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Components of Environment

• The two major Components of environment are :

Abiotic components : Air, Water, and Land etc

Biotic components: All living organisms around us viz. plants, animals, and microorganisms

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Components of Environment

• Earth’s environment can be further subdivided into the following four segments:

(1) Atmosphere

(2) Lithosphere

(3) Hydrosphere

(4) Biosphere

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Atmosphere It is the gaseous envelope surrounding the earth and

extends upto 500 kms above the earth’s surface.

Constituent Volume %– Nitrogen 78.1– Oxygen 20.9– Water vapour 0.1–5– Argon 0.9– Carbon dioxide 0.03– Trace constituents* Balance– *The trace constituents include Helium, Neon, Krypton,

xenon, SO2, NO2, Ammonia, Ozone, and– Carbon monoxide etc.

The atmosphere, which is a gaseous cover, protects the earth from cosmic radiations and provides life sustaining Oxygen, the macronutrient Nitrogen and Carbon dioxide needed for photosynthesis.

The atmosphere screens the dangerous UV radiations from the sun and allows only radiations in the range of 300 nm – 2500 nm (near UV to near IR) and radio waves.

The atmosphere plays a major role in maintaining the heat balance of the earth by absorbing there-emitted radiation from the earth.

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Five Layers of the Atmosphere

Troposphere : lowest layer – extends up to 10km; contains 99% of the water vapor and 75% of the atmospheric gases• The troposphere is the first layer above the surface and contains most clouds and half of the Earth's atmosphere. • Weather occurs in this layer

Stratosphere – directly above troposphere, extending from 10 km to about 50 km above Earth’s surface• Portion of the upper layer contains high levels of a gas called ozone• Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbsharmful rays from the Sun

Mesosphere – extends from the top of the stratosphere to about 85 km above Earth• Coldest layer with little ozone• Meteors or rock fragments burn up in the mesosphere.• Ionosphere here – layer of charged particles

Thermosphere – thickest atmospheric layer found between 85 km and 500 km above Earth’s surface• The thermosphere is a layer with auroras, known for its high temperatures.

Warms as it filters out X-rays and gamma rays from the SunIonosphere here, too – help carry radio waves

Exosphere - The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere. • Outer layer where space shuttle orbits.

Lithosphere• The earth’s crust consisting of the soil

and rocks is the lithosphere. The soil is made up of inorganic and organic matter and water.

• The main mineral constituents are compounds or mixtures derived from the elements of Si, Ca, K, Al, Fe, Mn, Ti, O etc. (Oxides, Silicates, and Carbonates).

• The organic constituents are mainly polysaccharides, organo compounds of N, P and S.

• The organic constituents even though form only around 4% – 6% of the lithosphere, they are responsible for the fertility of the soil and hence its productivity

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Hydrosphere

This comprises all water resources both surface and ground water.

The world’s water is found in oceans and seas, lakes and reservoirs, rivers and streams, the Polar Regions in addition to ground water below the land areas. The distribution of water

among these resources is as under– Oceans and Seas 96–97 %– Glaciers and polar icecaps 2–3 %– Fresh water < 1%

The water locked up in the Oceans and Seas are too salty and cannot be used directly for human consumption, domestic, agriculture or Industrial purposes.

Only less than 1% of water resources are available for human exploitation. Water is considered to be a common compound with uncommon properties. These uncommon properties (e.g. anomalous expansion of water) are mainly responsible for supporting terrestrial and aquatic life on earth.

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Biosphere

• The biosphere is a capsule encircling the earth’s surface wherein all the living things exist.

• This portion extends from 10000 m below sea level to 6000 m above sea level.

• Life forms do not exist outside this zone. • The biosphere covers parts of other segments of the

environment viz. Lithosphere, Hydrosphere and Atmosphere.

• Life sustaining resources like food, water and

oxygen present in the biosphere are being withdrawn and waste products in increasing quantities are being dumped.

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Types of Environment

• Natural Environment– The environment that comes in

its existence by its own or naturally.

– Without interference of humans– It operates through self

regulating mechanism(Homeostasis)

• Man-made Environment(Anthropogenic)– Env. Is modified by human activity– Scientific technology which is result

of human brain is decorating the natural environment.

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Objective of Environmental education

• Awareness:• Knowledge• Attitudes• Skills• Participation

Importance of Environmental science

• Solving the issues related to environment – Pollution – Over exploitation of non-renewable sources– Food problem– Sustainable development– Maintain the ecological balance– Eco friendly product – Conservation of natural sources– Understand the food chain– Inculcating attitude and value– Encouraging Environment protection

Scope of Environmental Science

• Natural Resources• Ecology• Biodiversity and its conservation• Environment pollution and control• Natural disaster• Development• Social issues in relation to development and

environment• Human population and environment 13

Learning to Live More Sustainably

Man and Environment

• Natural Conservations– Sacred Groves of India– Water storage : Water reservoir

• Traditional methods of Agricultures• Traditional Methods of fishing• Ecosystem Balance

Traditional Man and environment relationship

Sacred Groves of India

• Traditional uses: – Ayurvedic medicines. – Replenish able resources like fruits and honey. – The vegetation cover helps reduce soil erosion and prevents

desertification,– Water requirements of local communities.

• Modern uses: – biodiversity hotspots, – Sacred groves often contain plant and animal species that have

become extinct in neighboring areas.– sacred groves in urban landscapes act as "lungs" to the city as

well, providing much needed vegetation cover.

• Threats – Urbanization, over-exploitation of resources – Environmental destruction due to religious practices. – Other threats to the sacred groves include invasion.

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Traditional Method of Farming• Traditional Use

– Planting were coordinated with the movement of plant and stars

– Harmony with the local Environment and Seasons

– Cultivate large no of Crops varieties.– Rotation of crop and Soil fertility– Mixing sand, Slit and clay in right

proportion.• Modern Use

– Heavy use of chemical and pesticides– Local biodiversity affected – Use of Vehicles.

• Treats – Food security– GMO Food– Pesticides

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Traditional method of fishing• Traditional

– Fishers have extensive knowledge of oceans and fisheries

– Mesh size of the nets was designed to catch only a particular species, and among them only the adult fish

• Modern – Mechanized boats and later big

trawlers.– Outsiders entered in the business

with the aim of cating as much fish as possible

• Threats– No regards for conservation of

resource.

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Impact of Science and technology on the environment

• Invention of Engines and Automobiles• Efficient machines were made for sawing and

felling trees.• Cutting down the trees • Invention of concrete building of dams, and

diversion of rivers water for agriculture and power production

• Chemical fertilizer and pesticides• Huge amount of ground water is extracted with

pumps

Environmental Degradation What is environmental degradation? Let us understand it.

It is the process by which our environment i.e., air, water and land, is

progressively contaminated, over- exploited and destroyed.

When the environment becomes less valuable or damaged,

environmental degradation is said to occur.

In specific term, environmental degradation is the deterioration of the

environment through depletion of resources such as air, water, soil and

forest; the destruction of eco-systems and the extinction of wildlife.

Causes of Environmental Degradation

Social factors Growing Population Poverty Urbanization Changing life style

Economic factors Agricultural Development Industrialization Economic Development

Growing Population

Population is the greatest resource of any country and a major contributory factor for development, and yet it is a major cause of environmental degradation. As we find, the rapid pace of population growth has led to the excessive utilization of natural resources. Huge population also leads to huge production of wastes. The resultant outcomes are loss of biodiversity, pollution of air, water and soil and increased pressure on arable land. All these have been putting great stress on the environment.

Poverty

Poverty is said to be both the cause and effect of environmental degradation. You may have seen that the poor people use natural resources more than the rich. They use these for building their huts, for cooking, for their food and for meeting many other needs. In this way they deplete these resources faster as they have no opportunity of gaining access to other types of resources that are primarily exploited by the rich. As we know, the more the resources are utilized, the more degraded the environment becomes. The more the environment deteriorates, the more impoverished the poor will be.

Urbanization

You may have observed a large number of poor people from villages moving to towns, cities and mega cities to earn their livelihood. This has led to unplanned and rapid expansion of cities, creating enormous pressure on the infrastructural facilities. If you live in a city, you may be experiencing these pressures on housing, water and electric supply and sewage. You would be aware of the growing slums. Urban slums are major sources of pollution and suffer from the worst kind of unhygienic conditions. The fast pace of urbanization has also been responsible for the depletion of forests and irrational use of other resources.

Changing Life Style

There has been a remarkable change in the style of living of people. This change is visible not only among the people living in cities and towns but also among those who live in villages. The changing life style of people has enormously increased their level of consumption. It has also resulted in the increase of human activities that are causing serious damage to environment in many ways. It has contributed to air, water, sound, vehicular and industrial pollution. The fallout of the fast increasing use of modern gadgets like refrigerators and air conditioners is the release of harmful gases in the atmosphere. This has been causing global warming which is very dangerous. In fact, due to overuse of modern gadgets, harmful gases like carbon monoxide and carbon dioxideare released which lead to global warming

Agricultural Development

Agricultural development is so important for a countrylike ours. But this has been affecting the environment adversely.

Biological interactions are the interactions between organisms in a community.

In the natural world no organism exists in absolute isolation, and thus every organism must interact with the environment and other organisms.

Inter relationship amongst living organisms

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There are six possible combinations, ranging from mutually beneficial through neutral to mutually harmful interactions.

The level of benefit or harm is continuous and not separate, such that an interaction may be trivially harmful through to deadly,

for example. It is important to note that these interactions are not always static. In many cases, two species will interact differently under different conditions.

• There are six types of symbiotic relationships.Parasitism +/-Mutualism +/+Commensalism +/0Neutralism 0/0Competition -/-Predator/Prey +/-

• Each relationship can be shown using + - or 0.

Effect on X Effect on Y Type of interaction

0 0 Neutralism

- 0 Amensalism

+ 0 Commensalism

- - Competition

+ + Mutualism

+ - Predation or Parasitism

Mutualism• Mutualism—mutually beneficial

interaction between individuals of two species (+/+).

• The contact between the two organisms may be intimate or it may be occasional or periodic.

• The best example for mutualism relationships between animals, can be of Egyptian plover and the crocodile. In the tropical African jungles, the crocodile lies keeping its mouth open.

• The plover flies in to the mouth of the crocodile and eats the decaying meat stuck in its teeth. The crocodile does not eat the plover, but appreciates the free dental care. This way, both of them are benefited from each other.

Plover and Crocodile

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• Commensalism: Individuals of one species benefit, while individuals of the other species do not benefit and are not harmed (+/0).

• example is of a birds nest in a tree. The bird is benefitting because the tree is giving the bird shelter and the tree is not getting anything in return.

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Parasitism: Parasitism is the situation where one organism benefits while the other is harmed. A + / - relationship.

For example, mosquito is a parasite, feeding on a human while transferring the disease called Malaria.

Similarly, lice are an example of parasitism because they feed on blood from the humans head.

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• Neutralism: is the situation where both species remain unaffected A 0 / 0 relationship.

• A Bactrian Camel and a Longtailed Tadpole Shrimp, both living in the Gobi desert

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• Amensalism: is a relationship in which a product of one organism has a negative effect on another organism.

• The bread mold penicillium is a common example of this; penicillium secrete penicillin, a chemical that kills bacteria.

• This antibiotic compound inhibits the growth of many species of bacteria (in this picture, it's Staphylococcus aureus) by interfering with the normal formation of peptidoglycan in the cell wall.

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• A second example Allelopathy, in which some plants produce chemical compounds that inhibit the growth of nearby would-be competitors, is one type of amensalistic interaction is the black walnut tree (Juglansnigra), which secrete juglone, a chemical that harms or kills some species of neighboring plants, from its roots.

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• Competition: can be defined as an interaction between organisms or species, in which the fitness of one is lowered by the presence of another.

• Limited supply of at least one resource (such as food, water, and territory) used by both is required.

• Competition is one of many interacting biotic and abiotic factors that affect community structure. Male-male

interference competition in red deer.

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Book/Web Resources

• Environmental Studies by R. Rajagopalan