Environmental Studies - Biodiversity, Environmental Pollution and Legislation along with miscellaneous topics

ENDANGERED AND ENDEMIC SPECIES OF INDIA
A plant, animal or microorganism that is in immediate risk of biological extinction is called endangered or threatened species.
The following are the threats to biodiversity:-
-Habitat destruction (Draining and filling-up of inland wetlands)
-Extension of agriculture
-Filling-up of wetlands
-Conversion of rich biodiversity site for human settlement and industrial development
-Destruction of coastal areas
-Uncontrolled commercial exploitation
-Fragmentation
-Pollution (Frog eggs, Tadpoles and adults are extremely sensitive to pollutants especially pesticides)
-Over-hunting
-Populations can be adversely affected by introduction of non-native predators and competitors
-Disease producing organisms play an important adversary in reducing populations of endemic species.
Asia's rarest animals found in India are:
-Asiatic Cheetah
-Asiatic Lion
-Asiatic Wild Ass
-Bengal Fox
-Gaur
-Indian Elephant
-Indian Rhinocerous
-Marbled Cat
-Markhor
Endemic species are species concentrated in a particular region. 60% of the endemic species are found in the himalayas and western ghats in India.
-NE India
-NW Himalayas
-Western Ghats and
Andaman & Nicobar islands
Endemic flora found in India are:
-Sapria Himalayana
-Ovaria Lurida
-Nepenthis Khasiana
Endemic species of conservation significance in the western ghats are:
-Lion Tailed Macaque
-Nilgiri Langur
-Brown palm civet and
-Nilgiri Tahr
187 endemic reptiles and 110 endemic amphibian species are found in India.
IUCN (International Union for Conservation of Nature and natural resources) defines conservation as management of human use of biosphere so that it might yield the greatest sustainable benefit while maintaining its potential to meet the needs and aspirations of future generations.
BIODIVERSITY
Biodiversity is one of the important tools for sustainable development. The commercial, medical, genetic, aesthetic and ecological importance of biodiversity emphasizes the need for its conservation.
Biodiversity:
-provides recreation and tourism
-preserves genetic diversity of plants and animals
-ensures sustainable utilization of life supporting systems on earth
-is essential for conservation of ecological diversity and life supporting systems
-helps maintain a stable and healthy environment
-is an important source for drugs, herbs, food and other important raw material as these are derived from plants and animals
CONSERVATION OF BIODIVERSITY
Types of biodiversity conservation
1. In-situ conservation and
2. Ex-situ conservation
In-situ conservation involves protection of flora and fauna within its natural habitat. These areas are called protected areas. It is the ultimate conservation strategy.
Ex: National parks, Gene Sanctuaries, wildlife Sanctuaries and Biosphere reserves
Biosphere reserves:-cover large areas (>5000 sq. km)
-are used to protect species for a long time
Role of biosphere reserves are:
-long time survival of evolving ecosystem
-protection of endangered species
-protect maximum number of species and communities
-serve as site of recreation and tourism
-used for educational and research purposes
Biosphere reserves serve as an open system and changes in land use are not allowed. Explosive activities are not allowed in biosphere reserves.
A national park is an area dedicated for the conservation of wildlife along with its environment. It covers an area ranging from 100 to 500 sq km. One or more national parks may exist within a biosphere reserve.
A national park is used for enjoyment through tourism without affecting the environment. It is used to protect, propogate and develop wildlife.
Grazing domestic animals inside national parks is prohibited. All private rights and forestry activities are prohibited inside a national park.
Wildlife sanctuary is an area that is reserved for conservation of animals only. It allows operations such as harvesting of timber, collection of forest products, private ownership rights and forest operations provided it does not affect animals adversely.
Gene sanctuary is an area where plants are conserved.
Few notable projects for the conservation of animals are listed below:
-Project Tiger
-Gir Lion Project
-Crocodile breeding project
-Project Elephant, etc
The advantages of this type of conservation are listed below:
-It is cheap and convenient
-Species get adjusted to natural disasters like flood, drought, forest fires, etc
The disadvantages of this type of conservation are listed below:
-large surface area of earth is required to preserve biodiversity
-Inadequate maintenance due to shortage of staff and pollution
Ex-situ conservation refers to conservation of flora and fauna outside their natural habitat.This type of conservation is mainly done for conservation of crop varieties and wild relatives of crops. It provides back-up solution to in-situ conservation projects.
Ex-situ conservation involves maintenance and breeding of endangered plant and animal species under controlled conditions
It identifies those species that are at high risk of extinction
It prefers species that are important for man in near future among the endangered species.
Ex: Seed banks, botanical gardens, microbial culture collections, cell cultures, pollen storage, tissue culture, genetic engineering centres and zoological gardens.
Methods of Ex-situ conservation
-National Bureau of Plant Genetic Resources (NPBGR)
 It is located in New Delhi
 It uses CRYOPRESERVATION technique to preserve agricultural and horticultural crops
 This technique involves using liquid nitrogen at -19 C
 Varieties of rice, turnip, radish, tomato, onion, carrot, chilli, tobacco, etc have been successfully preserved for years using this technique.
-National Bureau of Animal Genetic Resources (NBAGR)
 It is located in Karnal, Haryana
 It preserves the semen of bovine domesticated animals
-National Facility for Plant Tissue Culture Repository (NFPTCR)
 It conserves varieties of crop plants or trees using tissue culture
 This facility has been created within the NBPGR.

Benefits of biodiversity conservation:
1. Increase in food supplies by developing new crop plants, animal sources, etc
2. Increased use of biological control agents to control pests
3. Source of genes through hybridization and genetic engineering

Threats to biodiversity:
Human population growth, industrialization and change in land-use pattern (Ex: Urban sprawl)
Poaching
Man-wildlife conflicts
Habitat loss
The reasons for loss of biodiversity are listed below:
-Destruction of forests
-Over-exploitation of bio-resources
-Overgrazing
-Shifting cultivation
-Urbanization
-Illegal trade
-Smuggling and biopiracy
-Soil degradation and erosion
-Diminishing green cover
-Mining for ores
-Infrastructure development (Roads, river valley projects)
-Exploitation of timber and non-timber forest produce
-Loss of land fertility
-Devegetation
-Tourism business
-Globalization
-Greed vs Need

Issues involved in enforcement of environmental legislation
Environmental legislation has minimal impact on the social fabric and people in a community without effective enforcement. Environmental legislation evolved to protect the human population, the environment and the earth's resources. Successful implementation of environmental legislation involves data collection and analysis. This information is then passed on to an enforcement agency that takes necessary legal action on all defaulters. The issues essential for enforcement of environmental legislation are:
-Precautionary principle: This principle evolved to deal with risks and uncertainities faced by environmental management. It does not prevent problems but mau reduce their occurrence and ensures preparation of contingency plans.
-Polluter pays principle: This principle states that a polluter pays for damaging the environment in addition to monitoring and policing. There is a debate if this principle should be retrospective.
Freedom of Information: Environmental planning and management is hindered if anyone is not given access to information. Under this principle, every citizen of the country, or any organization, Ex: NGO is provided access to information on the environment due to infrastructure development projects.

Natural resources: Water resources

Water resources
Almost 71% of earth's surface is covered by water of which 97% is ocean waterwhich is unusable due to high salt concentration. Almost 2.6% of fresh water is  is trapped in ice caps and glaciers along with some part stored underground. Only 0.4% of the total quantity of water is available in swamps, rivers, lakes and streams.

Surface water sources
Sea water
River and streams
Natural lakes and ponds
Artificial impounding reservoirs

Ground water sources
After glaciers, ice caps and snow fields, ground water is the next largest fresh water reservoir. Precipitation that does not run-off over the surface, percolates through the soil and either accumulates in an underground basin or flows underground in sub surface streams.

Effects of over-utilizing ground water
-Excessive pumping of ground water causes porous formations to collapse resulting in subsidence
-Heavy pumping can lower water table and cause shallow wells to dry-up or even deplete the entire aquifer.
-Over-use of freshwater reservoirs along coast lines often allows salt water to intrude into aquifers rendering the water unfit for domestic, industrial or agricultural purposes.

Ecological pyramids

Ecological Pyramid
Ecological pyramids are of three types:
i. Pyramid of numbers
ii. Pyramid of energy
iii. Pyramid of biomass
The concept of ecological pyramid was developed by Charles Elton; these pyramids are also known as Eltonian pyramids. The pyramids are a graphical representation which depicts the number of organisms, biomass and productivity at each trophic level. All ecological pyramids begin at the bottom with the produces and proceed through different trophic levels. 

Ecological pyramids begin with the producers at the bottom like plants and they proceed to various trophic levels like herbivores consume plants, carnivores prey on herbivores and so on. The highest level is at the top of the food chain.                                                                      

Consider a grassland ecosystem for example:
In a grassland ecosystem, the producer is grass which is small in size but large in number. Hence, it
occupies the lowest trophic level (I trophic level).
The primary consumers are rats (herbivores) and they are more in number than grass. Therefore they
occupy the second trophic level (II trophic level)
The secondary consumers are snakes (carnivores) and they are fewer in number than the rats. They
occupy the third trophic level(III trophic level)
Eagles are the tertiary consumers that feed on snakes and they are at the top of the pyramid with the
least in number. They form the apex in the pyramid of numbers. The diagram is shown above which is self-explanatory.

The pyramid of energy or the energy pyramid describes the overall nature of the ecosystem. During the flow of energy from organism to other, there is considerable loss of energy in the form of heat. The primary producers like the autotrophs there is more amount of energy available. The least energy is available in the tertiary consumers. Thus, shorter food chain has more amount of energy available even at the highest trophic level. 

• The energy pyramid always upright and vertical. 
• This pyramid shows the flow of energy at different trophic levels. 
• It depicts the energy is minimum as the highest trophic level and is maximum at the lowest trophic level. 
• At each trophic level, there is successive loss of energy in the form of heat and respiration, etc. 

The pyramid of numbers depicts the relationship in terms of the number of producers, herbivores and the carnivores at their successive trophic levels. There is a decrease in the number of individuals from the lower to the higher trophic levels. The number pyramid varies from ecosystem to ecosystem. There are three of pyramid of numbers:

• Upright pyramid of number 
• Partly upright pyramid of number and
• Inverted pyramid of number.

Upright Pyramid of Number 

This type of pyramid number is found in the aquatic and grassland ecosystem, in these ecosystems there are numerous small autotrophs which support lesser herbivores which in turn support smaller number of carnivores and hence this pyramid is upright.

Partly Upright pyramid of Number 

It is seen in the forest ecosystem where the number of producers are lesser in number and support a greater number of herbivores and which in turn support a fewer number of carnivores.

Inverted Pyramid of Number 

This type of ecological pyramid is seen in parasitic food chain where one primary producer supports numerous parasites which support more hyperparasites.

The pyramid of biomass is more fundamental, they represent the quantitative relationships of the standing crops. In this pyramid there is a gradual decrease in the biomass from the producers to the higher trophic levels. The biomass here the net organisms collected from each feeding level and are then dried and weighed. This dry weight is the biomass and it represents the amount of energy available in the form of organic matter of the organisms. In this pyramid the net dry weight is plotted to that of the producers, herbivores, carnivores, etc. 

There are two types of pyramid of biomass, they are:

• Upright pyramid of biomass and 
• Inverted pyramid of biomass. 

Upright Pyramid of Biomass
This occurs when the larger net biomass of producers support a smaller weight of consumers.
Example: Forest ecosystem.

Inverted Pyramid of Biomass

This happens when the smaller weight of producers support consumers of larger weight.
Example: Aquatic ecosystem.

Energy flow in an ecosystem

Energy flow in an ecosystem

The manner in which energy flows in an ecosystem is known as energy flow. It is unidirectional. The

following points are important with regard to understanding energy flow in an ecosystem:

i. Efficiency of producers in absorption and conversion of solar energy.

ii. Using the converted energy (chemical energy – starch) by consumers

iii. Total input of energy as food and its efficiency of assimilation

iv. Energy lost through respiration, heat, excretion, etc at each trophic level

v. Gross production and net production

Two important points to be noted about energy flow in ecosystems are:

i. Energy flow is unidirectional and

ii. There is a progressive decrease of energy as we progress along the food chain. The

energy is lost as heat in metabolic activities such as respiration, hunting, etc.

Structure and Function of an Ecosystem

Structure and function of an ecosystem

The two important aspects of an ecosystem are:

• Structure and
• Function

Structure of an ecosystem consists of

• Composition of biological community (eg: plants, animals and microbes), biomass, life cycles and distribution in space.
• Quantity, distribution and cycling of non-living materials (macro and micro nutrients, trace elements and water)
• Variation of conditions like temperature, rainfall, sunlight, relative humidity, wind and topography.

Function of an ecosystem consists of

• Rate of biological energy flow (production and respiration rates)
• Rate of nutrient cycles
• Ecological regulation (Environment regulation in the form of photoperiodism and Organism regulation in the form of nitrogen fixation by organisms)

From the trophic stand-point, an ecosystem has two components

• Autotrophic component and
• Heterotrophic component

Autotrophic component involves

• Fixation of light energy
• Use of simple inorganic substances like carbon and water
• Synthesis of hexose sugars (glucose) to complex substances such as polysaccharide carbohydrate (starch), fat and protein synthesis.

Heterotrophic component involves

• Utilization
• Rearrangement and Decomposition of complex substances
• Herbivores, Carnivores and Omnivores (Phagotrophs) and microconsumers (decomposers, osmotrophs and saprotrophs) comprise the heterotrophic component.

Food chains Vs Food webs

FOOD CHAINS FOLLOW A SINGLE PATH AS ANIMALS EAT EACH OTHER.
Example:
GRASS manufactures its food using SUNLIGHT, WATER, NUTRIENTS from soil and CHLOROPHYLL
The GRASS is eaten by a GRASSHOPPER
The GRASSHOPPER is eaten by a FROG
The FROG is eaten by a SNAKE
The SNAKE is eaten by a HAWK.

FOOD WEBS SHOW HOW PLANTS & ANIMALS ARE INTERCONNECTED BY DIFFERENT PATHS.
Example:
TREES produce ACORNS which act as food for many MICE and INSECTS.
Because there are many MICE, WEASELS and SNAKES have food.
The insects and the acorns also attract BIRDS, SKUNKS, and OPOSSUMS.
With the SKUNKS, OPPOSUMS, WEASELS and MICE around, HAWKS, FOXES, and OWLS can find food.
They are all connected! Like a spiders web, hence it is called a FOOD WEB.

In a food chain, any disturbance in the food supply affects the entire food chain. However in the food web, any disturbance in the food supply is compensated by other organisms available as food at the same trophic level.

Food webs are far more complex than the simple food chain

Several interconnected food chains form a food web.

The real world we find food webs everywhere. Food chain is only a simplistic view of the complex real world phenomena.

Agriculture - Effects of modern methods and options

The widespread use of chemicals in agriculture as fertilizers, pesticides, insecticides and rodenticides without proper technological information have multiplied the hazards to which human beings are exposed. These chemicals spread through the environment and pose a threat to all animals.
Fertilizers are materials that are added to soil to restore and enhance soil fertility to improve the quality and quantity of plant growth.
Fertilizers may be natural or artificial (synthetic). Natural fertilizers are further divided into Organic and inorganic fertilizers. Examples of inorganic fertilizers are Gypsum, Crushed limestone and sulphur rock phosphate while those for organic fertilizers are manure, animal excreta, plant wastes and humus.
Excess fertilizers that are not taken-up by plants, leech into sub-soil water sources and contaminate them. They are non-biodegradable and thus accumulate to reach objectionable levels as they pass through different levels of the food chain.
The main problem with fertilizer use is the contamination of water with nitrates, phosphates and potassium.
Nutrients are lost from agricultural fields through:
-Runoff
-Drainage and
-Attachment to eroded soil particles
Amount of nutrient lost depends on:
-Soil type and organic matter content
-Climate
-Slope
-Depth to groundwater and
-Amount and type of fertilizer and irrigation used
The major nutrients in fertilizers are:
-Nitrogen (N)
-Phosphorus (P) and
-Potassium (K)
Nitrogen is readily lost due to high solubility in nitrate form. Leaching of nitrate from agricultural fields can increase groundwater concentrations to unacceptable levels for drinking water supply
High nitrate levels in drinking water are dangerous to human health
Phosphorus cannot be washed out of soil but can be washed into surface waters together with the soil that is being eroded.
Phosphorus is not dangerous. However, it stimulates the excess growth of algae and this process is called "eutrophication". The algae eventually die and decompose resulting in depletion of dissolved oxygen thereby killing fish.
Potassium does not cause water quality problems. Its solubility is similar to phosphorus i.e., it is similarly bound by soil particles and can be by erosion.
Pesticides:
Qualities of an ideal pesticide:
-It should only kill target pest
-Have no short term or long term effects on non-target organisms
-Should be able to be broken down into harmless compounds in a short time
-Should prevent the development of genetic resistance in target organism
-Save money compared to making no effort to control pest
Since 1945, different types of synthetic organic chemicals have been used as pesticides.
Worldwide, 2.3 million Tonnes of pesticides are used (85% in developing countries.
Synthetic nsecticides are of the following types:
Chlorinated hydrocarbons
Organophosphates
Carbamates
Pyrethroids

DDT and other slowly degradable chlorinated hydrocarbon insecticides were banned in mid 1970s
Organophosphates are more rapidly biodegradable but are water soluble and could possibly contaminate surface and groundwater sources.
Chlorinated hydrocarbons are fat soluble
Farmers apply non-persistent pesticides at regular intervals to ensure effective insect control. The regular use of using non-persistent pesticides is almost as good as using persistent pesticides.
Pyrethrin (from wild chrysanthemum type plants) and Rotenoids (from roots of rain forest legumes) are produced from wild plants and can be effectively used as biological control agents as they are:
-Biodegradable
-Effective in low doses and
-Cause little harm to mammals
ADVANTAGES OF USING PESTICIDES
The following are the benefits of using pesticides:
-pesticides save lives
-they increase food supplies and lower food costs
-they increase profits of farmers
-they work faster and better than alternatives
-safer and more effective products are continuously being developed.
PROBLEMS OF PESTICIDES
Development of genetic resistance
ALTERNATE METHODS OF INSECT CONTROL
Modifying cultivation process
-crop rotation
-planting rows of hedges or trees in and around crop fields
-adjusting planting times
-destroy diseased or infected plants
-growing crops in areas where their major pests do not exist
-using plant diversity to control pests by adopting:
                         intercropping
                         agro-forestry and
                         polyculture
-artificial selection, cross breeding and genetic engineering varieties of plants and animals that are genetically resistant to certain pest insets, fungi and diseases.
-biological pest control against various natural parasites and pathogens can be introduced to control the populations of specific pests.
ORGANIC AGRICULTURE:
Organic agriculture is defined as an ecological production management system that promotes and enhances biodiversity, biological cycles and soil biological activity. It is based on minimal use of off-farm inputs and on management practices that restore, maintain and enhance ecological harmony.

EFFECTS OF MODERN AGRICULTURE
Agriculture has been a practice in use for hundreds of years. It provides countless people with sustenance and livelihood all over the world. However, modern practices in agriculture have led to several damaging effects on the environment listed below:
1.Agriculture increases carbon dioxide levels making it one of the main sources of carbon dioxide emissions for decades. This in-turn aggravates the problem of global warming and consequent sea level rise.
2.Animal waste from farms contains harmful pathogens known to cause disease and infection. By getting into soil and water systems they create irreversible damage to land and pose health risks towards humans. These problems lead both directly and indirectly to these health risks, and may causes disorders such as hepatitis and meningitis.
3.Fertilizers also put forth several complications. They contain harmful elements such as nitrogen and phosphates, both of which negatively affect air and water quality. Its use causes the release of ammonia, nitrogen runoff and eutrophication, all of which have negative effects on the environment.
4.Impacts also include increased water or wind erosion, depleted groundwater supplies in irrigated areas,
5.Modern agriculture converts an ever-increasing portion of the earth's land surface to monoculture. As a result, the genetic and ecological diversity of the planet erodes. The conversion of diverse natural ecosystems to new agricultural lands and the narrowing of the genetic diversity of crops contribute to this erosion.
6.In addition to adding pollutants to water, soil and air, modern agriculture practices can cause soil disturbance by using heavy machines and tilling equipment. This, in turn, creates soil erosion and degrades the quality of surrounding farmland.
7.A number of "ecological diseases" have been associated with the intensification of food production. They may be grouped into two categories: diseases of the ecotope, which include erosion, loss of soil fertility, depletion of nutrient reserves, salinization and alkalinization, pollution of water systems, loss of fertile croplands to urban development, and diseases of the biocoenosis, which include loss of crop, wild plant, and animal genetic resources, elimination of natural enemies, pest resurgence and genetic resistance to pesticides, chemical contamination, and destruction of natural control mechanisms.

Natural resources - Land resources

LAND AS A RESOURCE

Human and natural activities need space for their location and development. This space is provided by land which is put to various uses like food and energy production, waste-disposal, industrial, commercial and residential purposes.

Land houses the living species, water resources and raw material resources (minerals and ores).

Pattern of land use on earth is:

Arable land

Land for pastures and meadows

Forest land

Urban land and

Non-agricultural land

Land-use involves economic activities leading to environmental problems like:

Pollutant discharge

Waste disposal

Consumption of natural resources for economic activity

Disturbing ecological cycles and wildlife habitats

Changes within a particular land-use category result in major changes in landscape thereby reducing its capacity support a diversified and balanced wildlife. This reduces tourist and recreational value. Ultimately this results in reduced potential for multiple use of these areas. Land being used for one purpose may be used for another purpose. The following examples are listed:

Agricultural land might be used as an urban area

Agricultural land may be used for forestry

Forest land may be cleared for agricultural purposes

Significant negative effects are seen on the environmental quality as a result of the above listed land use changes:

Impact on water cycle

Impact on ground and surface water

Emission of water pollutants

Emission of air pollutants

Destruction of wildlife due to habitat destruction

Degradation of soil

List of environmental conflicts between adjacent land owners

Residential areas located near industrial areas are affected due to air pollution due to effluents due to effluents of energy and industrial effluents.

Residential areas located near airports and along highways and motorways suffer from nuisance due to air pollution

Intensive live-stock breeding units are a source of offensive odours to nearby dwellers

Development of linear infrastructure (roads and railway tracks) in rural areas affects existing land-use as well as natural ecosystems (forests, etc)

LAND DEGRADATION:

The surface layer of land is called soil. 

Fertility or productive capacity of the soil depends on the minerals it contains. 

Minerals are mainly available to the top layer of the soil. Hence, the top layer is the best for vegetation.

Land degradation refers to deforestation or deterioration or loss of fertility or productive capacity of soil. The factors contributing to land degradation are listed below and discussed subsequently.

Soil erosion

Soil pollution

Salination and water logging

Shifting cultivation

Desertification

Urbanisation

Soil erosion is the loss or removal of the superficial layer of soil by the action of water, wind or human activities. Factors influencing the extent of soil erosion are:

Distribution, intensity and amount of rainfall:

Unequal distribution of rainfall results in heavy rainfall being restricted to a few months. The soil unable to absorb this heavy rainfall causes run-off water that removes layers of soil as it moves, resulting in soil erosion.

Slope of the ground: Steep slopes cause decreased infiltration and increased run-off resulting in more soil erosion.

Nature of the soil: Light, open soils lose more silt than heavier soils (loam) that swell-up by wetting.

Vegetation cover: Vegetation holds the soil in place by forming a network of roots of plants. Rainfall on thick vegetation causes negligible soil erosion. Rain falling on bare land causes soil erosion as top soil is loose.

Soil mismanagement: The following techniques listed below contribute to soil mismanagement:
Faulty methods of soil drainage
Overgrazing
Wrong methods of cultivation
Forest fires and
Removal of forest litter are common practices that aggravate soil erosion.
Erosion, floods and sedimentation result in deposition of silt and consequent clogging of irrigation canals.

Soil pollution: Soil pollution is defined as the reduction in productivity of soil due to presence of soil pollutants.

• Pesticides, fertilizers, organic manure, chemicals, radioactive wastes, discarded food and clothes, leather goods, plastic, paper, bottles, tin cans and carcasses contribute towards soil pollution.
• Industrial wastes contain chemicals like iron, lead, mercury, copper, zinc, cadmium, aluminum, cyanide's, acids, alkalies, etc that reach soil either directly through water or indirectly through air (acid rain).
• Improper and continuous use of herbicides, fungicides and pesticides to protect crops from pests and fungi alter the basic composition of soils and make it toxic for plant growth.
• Organic insecticides like DDT, Aldrin, Benzene-hexachloride, etc used against soil borne pests accumulate in the soil due to slow degradation by soil and water bacteria. They result in stunted growth of plants and reduced size of fruit. Their bye-products of degradation reach animals including man through food chain.
• Radioactive wastes from mining and nuclear processes may reach soil via water or as 'fall-out'. From soil they reach plants and live stock from where they enter human beings through milk and meat. This causes retarded and abnormal growth in human beings.
• Human and animal excreta used as organic manure to increase crop yield, pollute soil by contaminating soil and vegetable crops with pathogens that may be present in excreta.
• Intensification of agricultural production by excessive irrigation, excessive fertilizers,  pesticides, insecticides, etc causes soil pollution.

SALINATION & WATER LOGGING

• Salination in the increase in the concentration of soluble salts in soil
• It occurs mainly in arid areas due to:
• Low rainfall
• Poor drainage and
• High temperature causing water to evaporate quickly leaving behind salts in high concentration
• Salination occurs due to:
• Poor drainage of irrigation and flood waters
• In summers, salts from deeper strata are drawn up by capillary action and get deposited on the surface. Excess salts form a white crust on the soil surface and adversely affect the water absorbing capacity of the plant.
• Salinity can be checked by improving drainage and saline lands can be reclaimed by the process of leeching with plenty of freshwater. By this technique, salts at the surface are leachead down to greater depths.
• Excessive use of canal irrigation disturbs the water balance and creates a problem of water logging due to rise in water table. Water logging causes less oxygen available for respiration of plants.

SHIFTING CULTIVATION

DESERTIFICATION

URBANIZATION

CONTROL OF LAND DEGRADATION

BETTER AGRICULTURAL PRACTICES

PLANTING WIND BREAKS AND SHELTER BELTS

Multidisciplinary nature of Environmental Science

Multidisciplinary nature of Environmental Science
Environmental Science is a multidisciplinary science because it comprises of various branches of studies such as chemistry, physics, medical science, life science, agriculture, public health, sanitary engineering, etc. It is the science of physical phenomena in the environment. It educates individuals from various walks of life about the delicate balance of nature and the recklessness with which we are damaging this environment thereby endangering our very existence. This has been illustrated in real life in the past and continues through the present age. Environment science is a study of the sources, reactions, transport, effect and fate of human activities on biological species in air, water and soil. An understanding of the working of the environment require knowledge from wide ranging fields. The multidisciplinary nature of environmental science with respect to air pollution is shown in the table below:

Environmental issue / topic                                                 Major Subject

Nature and reaction of air pollutants                                          Chemistry and chemical engineering
Effects of air pollution on humans, animals and plants                  Zoology, Botany, and various branches of                                                                                                    life science, physics and chemistry
Effects of air pollutants on materials                                           Chemistry and chemical engineering
Effects of air pollution on climate                                                Mathematical modelling
Air pollution control devices                                                       Physics, Chemistry and various branches of                                                                                                  engineering
Economic effects of Air pollution                                                Economics, Demography
Conservation of resources and pollution control                          Various branches of physical and political                                                                                                     science
Alternative fuels                                                                          Various branches of physical science.

Environmental Science - The need for public awareness

It is essential to make the public aware of the formidable consequences of the Environmental Degradation. If these are not addresses and reformative measures undertaken, the extinction of life is inevitable. We are facing various environmental challenges as discussed below:

• Growing Population A population of over thousands of millions is growing. Over 17 million people are added each year. It puts considerable pressure on its natural resources and reduces the gains of development. Hence, the greatest challenge before us is to limit the population growth. Although population control does automatically lead to development, yet the development leads to a decrease in population growth rates. 

• Poverty India has often been described a rich land with poor people. Poverty and environmental degradation have a nexus between them. The vast majority of our people are directly dependent on the natural resources of the country for their basic needs of food, fuel, shelter and fodder. 
• Environment degradation has adversely affected the poor who depend upon the resources of their immediate surroundings. Thus, the challenge of poverty and the challenge of environment degradation are two facets of the same challenge. 
• Population growth is essentially a function of poverty. Because, to the very poor, every child is an earner and helper and global concerns have little relevance for him.
• Agricultural Growth People must be acquainted with the methods to sustain and increase agricultural growth without damaging the environment. High yielding varieties have cause soil salinity and damage to physical structure of soil.
• Need for Ground water It is essential to rationalize the use of groundwater. Factors like community wastes, industrial effluents and chemical fertilizers and pesticides have polluted our surface water and affected quality of the groundwater. It is essential to restore the water quality of our rivers and other water bodies as lakes. Deciding on suitable technologies for restoring the quality of groundwater aquifers is essential.
• Development And Forests Forests serve catchments for the rivers. The increasing demand of water, led to using rivers for irrigation projects. These caused forests to submerge and displacement of local people apart from damaging the local flora and fauna. 
• Forests in India have been shrinking for several centuries owing to pressures of agriculture and other uses. Vast areas that were once green, stand today as wastelands. These areas are to be brought back under vegetative cover. The tribal communities inhabiting forests respects the trees and birds and animal that gives them sustenance. We must recognize the role of these people in restoring and conserving forests. 
• The modern knowledge and skills of the forest department should be integrated with the traditional knowledge and experience of the local communities. The strategies for the joint management of forests should be evolved in a well planned way.
• Degradation of land A small portion of land possesses potential for production. Agricultural land suffers from varying degrees of soil degradation. Land degradation mainly occurs due to overgrazing and soil erosion due to wind and water.
• Reduction of Genetic Diversity Proper measures to conserve genetic diversity need to be taken. At present most wild genetic stocks have been disappearing from nature. Wild animals including the Asiatic Lion are facing problem of loss of genetic diversity. The protected areas network like sanctuaries, national parks, biosphere reserves are isolating populations. So, they are decreasing chances of one group breeding with another. Remedial steps are to be taken to check decreasing genetic diversity.
• Evil Consequences of Urbanisation Nearly 27 per cent Indians live in urban areas. Urbanisation and industrialisation has given birth to a great number of environmental problem that need urgent attention. Over 30 percent of urban Indians live in slums. Out of India’s 3,245 towns and cities, only 21 have partial or full sewerage and treatment facilities. Hence, coping with rapid urbanization is a major challenge.
• Air and water Pollution: Majority of our industrial plants are using outdated and population technologies and makeshift facilities devoid of any provision of treating their wastes. A great number of cities and industrial areas that have been identified as the worst in terms of air and water pollution. Acts are enforced in the country, but their implementation is not easy. The reason is their implementation needs great resources, technical expertise, political and social will. Again the people are to be made aware of these rules. Their support is indispensable to implement these rules.

SCOPE OF THE ENVIRONMENT

SCOPE OF THE ENVIRONMENT

The environment consists of four segments.
Atmosphere:
This is the protective blanket of gasses surrounding the earth.
It sustains life on earth
It saves the earth from the hostile environment of outer space
It absorbs most of the cosmic rays from outer space and a major portion of the electromagnetic radiation from the sun
It transmits only the near UV, visible and near IR (300 - 2500 nm)and radio waves (0.4 - 40 m) waves
It filters-out damaging UV waves wave length less than 300 nm.

The oxygen is composed of Nitrogen and Oxygen besides Argon, CO2 and trace gases.

Hydrosphere: The hydrosphere comprises of all types of water resources (oceans, seas, rivers, streams, reservoirs, polar icecaps, glaciers and ground water). Almost 97% of earths water supply is in the oceans. More than 2% of water resources is locked in polar ice caps. The remaining water (less than 1%)is available as fresh water in the form of rivers, streams, lakes and ground water. It is this meagre amount that is fit for human consumption.

Lithosphere: Lithosphere is the outer mantle of solid earth. It consists of minerals occurring in the earth's crust and the soil.

Biosphere: Biosphere indicates the realm of living organisms and their interaction with the environment (Atmosphere, Hydrosphere and Biosphere)

Four basic principles of ecology

The four basic principles of ecology are:
(i) Holism
(ii) Ecosystem
(iii) Succession
(iv) Conversation.
Holism has been considered as the real base of ecology. 

Importance of Environmental Science

Environment science enlightens us, about the importance of protection and conservation of our indiscriminate release of pollution into the environment. Environmental issues have grown in size and complexity
day by day, threatening the survival of mankind on earth. We study about these issues besides suggesting effective solutions to these problems.

Environment Issues Being of International Importance
It has been recognized that environment issues like global warming, ozone depletion, acid rain, marine pollution and biodiversity are not merely national issues but are global issues and hence must be tackled with international efforts and cooperation.

Problems Cropped in The Wake of Development
Development, in its wake gave birth to Urbanization, Industrial Growth, Transportation Systems, Agriculture and Housing etc. When the West developed, it ignored of the environmental impact of its activities. Such a path is neither practicable nor desirable.

Increase in Pollution
World census reflects that one in every seven persons in this planet lives in India. With 16 per cent of the world's population and only 2.4 per cent of its land area, there is a heavy pressure on the natural resources including land. Agricultural experts have recognized soils health problems like deficiency of micronutrients and organic matter, soil salinity and damage of soil structure.

 Need for An Alternative Solution
It is essential, for developing countries to find alternative paths. A goal needs to be developed as described below:

• A goal, which ultimately is the true goal of development an environmentally sound and sustainable development.
• A goal common to all citizens of our earth.
• A goal to prevent the developing world from the over-consuming wasteful activities of the “developed” world.

Need To Save Humanity From Extinction

It is necessary for us to save the humanity from extinction. Consequent to our activities constricting the environment and depleting the biosphere, in the name of development.

Need For Wise Planning of Development

Our survival and sustenance depend. Resources withdraw, processing and use of the product have all to by synchronize with the ecological cycles in any plan of development. Our actions should be planned ecologically for the sustenance of the environment and development.

Environmental Science - Introduction

The word environment is derived from the French word “environner” which means to encircle or surround. Thus our environment can be defined as the physical, chemical and biological world that surround us and the complex social and cultural conditions affecting an individual or community.

This broad definition includes the natural world and the technological environment as well as the cultural and social contexts that shape human lives. It includes all factors living and nonliving that affect an 

individual organism or population at any point in the life cycle.

The three reasons for studying the state of the environment are listed below.

• There is a need for information that clarifies modern environmental concepts like equitable use of natural resources and a sustainable life style.
• There is a need to change the way in which we view our environment, using practical approach based on observation and self learning.
• There is a need to create a concern for our environment that will trigger pro-environmental action including simple activities we can do in our daily life to protect it.

Environmental science is essentially the application of scientific methods and principles to the study of environmental issues. It is a multidisciplinary subject and its components include Biology, Geology, Chemistry, Physics, Engineering, Sociology, Health Sciences, Anthropology, Economics, Statistics and Philosophy. An Understanding of the working of the environment requires the knowledge from wide ranging fields. Environment is not a single subject, it is an integration of several subjects that include both science and social studies.

Thus, the scope of environmental science is extremely wide and covers some aspects of nearly every major discipline. 

ENERGY FLOW IN AN ECOSYSTEM

ENERGY FLOW IN AN ECOSYSTEM

Energy is the capacity to do work. Energy that runs ecosystems ultimately comes from the sun. Green plants trap solar energy through photosynthesis; convert it into chemical energy and store it in the form of chemical energy. The conservation and expenditure of energy is described by the two laws of thermodynamics. The first law states that energy can neither be created nor destroyed but only be converted from one form to another and the other law states that when energy is converted, there is a loss of energy in the form of heat.

In an ecosystem when the energy is transferred from one trophic level to the other, only a part of it is utilized and the rest is wasted or dissipated (in accordance with the second law of thermodynamics).

The energy production in the ecosystem is categorized into primary production and secondary production.

Primary production: Green plants are capable of fixing only 1.5% of the solar energy reaching the earth. This level is called primary trophic level. The plant tissues convert this solar (radiant) energy to chemical energy.

6CO2     +             6H2O                     hυ                           C6H12O6              +             6O2

Only a part of this chemical energy is utilized by plants for their metabolic activities and the rest is taken up by heterotrophs or consumers belonging to the next trophic level. As a result the energy is transferred from one trophic level to the second trophic level.

The glucose produced in the plant cell is either stored in the form of starch or combined with other sugar molecules forming specialized carbohydrates like cellulose. It may also combine with Nitrogen, Phosphorus and Sulfur which help in synthesis of complex molecules like proteins, nucleic acids, pigments and hormones. All these are necessary for the normal growth of the plant, maintenance of body tissues and carrying out various physiological activities. Carbohydrates are oxidized to give Carbondioxide, water and chemical energy.

C6H12O6              +             6O2                                       6CO2     +             6H2O     +             Energy

The total amount of energy converted into sugar by a plant (by photosynthesis) is called ‘Gross primary production’ or ‘Gross productivity’. Some of this energy is lost through respiration and when it is deducted from gross primary production the remaining energy is known as ‘Net primary production’

Secondary production: In an ecosystem, the potential energy derived from the primary production meets the energy demands of the other trophic levels. Some of the primary production is consumed by herbivores and omnivores in the form of food. These consumers are in-turn eaten by carnivores of higher trophic levels. No animal can digest or assimilate all the food it has eaten. For example, a herbivore can assimilate only 10% of the food it ingests and in the case of carnivores it may go up to 20%. The energy thus assimilated is retained in the body of consumers in different forms. The food that cannot be digested leaves the animal bodies as feces which is an important source of energy for detritus feeders and saprotrophs.

A part of the energy assimilated by the herbivores is utilized in various metabolic activities like respiration, excretion, secretion, locomotion and reproduction. The remaining is stored in their tissues. This energy is called ‘Net secondary production’. The ‘Gross secondary production’ is equivalent to the total plant material ingested by herbivores minus the matter lost as feces.

The energy flow through different stages of an ecosystem occurs as shown below:

Solar energy                       Producers                           Primary consumers                         Secondary consumers  

                                                (Green Plants)                  (Herbivores)                                      (Primary carnivores)

 

Tertiary consumers

(Secondary carnivores)

Environmental Studies Syllabus (Osmania University)

UNIT I
Environmental studies: Definition, scope and importance, need for public awareness. Natural
resources: Water resources; use and over utilization of surface and ground water, floods,
drought, conflicts over water, dams - benefits and problems. Effects of modem agriculture,
fertilizer-pesticide problems, water logging salinity. Energy resources, growing energy needs,
renewable and nonrenewable energy sources. Land Resources, land as a resource, land
degradation, soil erosion and desertification.

UNIT II
Ecosystems: Concepts of an ecosystem, structure and functions of an ecosystem, producers,
consumers and decomposers, energy flow in ecosystem, food chains, ecological pyramids,
aquatic ecosystem (ponds, streams, lakes, rivers, oceans, estuaries).

UNITIII
Biodiversity: Genetic species and ecosystem diversity, bio-geographical classification of India.
Value of biodiversity, threats to biodiversity, endangered and endemic species of India,
conservation of biodiversity.

UNIT IV
Environmental Pollution: Causes, effects and control measures of air pollution, water
pollution, soil pollution, noise pollution, thermal pollution and solid waste management.
Environment Protection Act: Air, water, forest and wild life acts, issues involved in
enforcement of environmental legislation.

UNIT V
Social Aspects and the Environment: Water conservation, watershed management, and
environmental ethics. Climate change, global warming, acid, rain, ozone layer depletion.
Environmental protection act, population explosion.
Disaster management: Types of disasters, impact of disasters on environment, infrastructure,
and development. Basic principles of disaster mitigation, disaster management, and
methodology, disaster management cycle, and disaster management in India.


Suggested Reading
1. A. K. De, Environmental Chemistry, New Age Publications, 2002.
2. E.P. Odom, Fundamentals of Ecology, W.B. Sunders Co., USA.
3. GL. Karia and R.A. Christian, West Water Treatment, Concepts and Design Approach, Prentice Hall of India, 2005.
4. Benny Joseph, Environmental Studies, Tata McGrawHill, 2005
5. V.K. Sharma, Disaster Management, National Centre for Disaster Management, IIPE, Delhi, 1999.

Important questions and answers

Write about function of producers, consumers and decomposers in an ecosystem
The ecosystem can be divided, from the energetic view point into three types of organisms:
producers, consumers, and reducers. These can be explained as under:
(1) Producer
Photosynthetic algae, plants and bacteria are the producers of the ecosystem; all other
organisms depend upon them directly or indirectly for food.
(2) Consumers
Consumers are herbivorous, carnivorous, and omnivorous animals; they eat the organic
matter produced by other organisms.
(3) Decomposers
Decomposers are heterotrophic organisms like animals; they are fungi and bacterial that
decompose dead organic matter.

Describe the concept of an ecosystem
Every living organism has to depend and interact with different nonliving or abiotic and living or biotic components of the environment.
The abiotic environmental components include basic inorganic elements and compounds such as water and carbon dioxide, calcium and oxygen, carbonates and phosphates besides physical factors such as soil, rainfall, temperature, moisture, winds, currents and solar radiation.
The biotic environmental factors comprise plants, animals, and microbes.
The scientific study of the interactions of organisms with their physical environment and with each other, is called ecology.
The eco-system can be defined as any spatial or organizational unit including living organisms and non-living substances interacting to produce an exchange of materials between the living and non-living parts. The eco-system can be studied from either structural or functional aspects.
1. Structural Aspect
The structural aspects of ecosystem include a description of the arrangement, types and
numbers of species and their life histories, along with a description of the physical features
of the environment.
2. Functional
The functional aspects of the ecosystem include the flow of energy and the cycling of
nutrients.

Write brief notes about endangered and endemic species of India
Endangered species in comprise of a variety of rare species of wild animals, aquatic animals and insects. Some of the endangered species in India are Himalayan wolf, crocodile nico barica, red panda, etc. Endangered species are of four types:
Critically endangered (CR)
Endangered (EN)
Vulnerable (VU) and
Threatened
Endemic species are those species that are specific to a specific locality. It may also relate to a disease or pathogen that is confined to one particular area. One particular species endemic to India is the black buck.

Write briefly about conservation of biodiversity
Biodiversity is the degree of variation of life forms within a given species, ecosystem, etc. Biodiversity generally tends to cluster in hotspots. Biodiversity is commonly used to replace the more clearly defined and long established terms. Biologists define biodiversity as the totality of genes, species or ecosystem of a region.
Biodiversity is not evenly distributed. It varies greatly across the globe as well as within regions. Biodiversity is directly and indirectly related to human health as it provides support for drug discovery and is a valuable medicinal resource.
It plays a part in regulating the chemistry of our atmosphere and water supply. It is directly involved in water supply, recycling nutrients and providing fertile soil.
Habitat destruction in the form of deforestation of tropical forests has led to extinction of wildlife.
Biodiversity can be conserved by the following techniques:
In-situ conservation and
Ex-situ conservation

Write briefly about the biogeographical zones in India

There are 10 biogeographical zones in India. They are briefly described below:

1. Trans-Himmalayas: The Trans-Himmalayas is an extension of the Tibetean plateau.

2. Himalayas: The Himalayas form the northern boundary of India. The Himalayas comprises a diverse               range of biotic provinces and biomes.

3. Desert: Three kinds of deserts are found in India. They are, Desert of western Rajasthan, Desert of               Gujarat and the high altitude cold desert of Jammu & Kashmir and Himachal Pradesh

4. Semi-arid: This zone lies in between the desert and the Deccan plateau.

5. Western Ghats: This is a mountain range that runs along the western coast of India. This ghat section             covers a diverse range of biotic provinces and biomes.

6. Deccan Plateau: It is a large triangular plateau south of Narmada valley. The Satpura mountains cover           the north side, western ghats and eastern ghats cover the west and east sides respectively. The plateau           slopes towards east. The plateau is covered with deciduous vegetation.

7. Gangetic plain: The Gangetic plains cover from south of the Himalayas to north of tropic of cancer.               These plains were formed by the Ganges river system and are relatively homogenous. The famous                 'sunderban' forests are located in these plains.

8. North-east India: The plains and non-himalayan hill ranges of northeastern India fall in this zone. This             zone is filled with a wide variety of vegetation.

9. Islands: The Andaman and Nicobar islands in the bay-of-bengal is a group of 300 small and large                 islands. Mostly tribes live in Nicobar islands. These islands have a highly diverse set of biomes.

10. Coasts: The Indian subcontinent is blessed with a long coastline on the east and west with distinct                   differences between the two.

Write notes on threats to biodiversity

Biodiversity has evolved simultaneously with human culture. Man has met the changing needs and pressures of increasing population by applying knowledge and skills. People have hunted, fished and gathered species for food, fuel, fiber and shelter thereby eliminating competing or threatening species.

Activities mentioned above destroys and depletes the basis of an ecosystem (genes and species). As a result, mankind loses food, medicine and industrial products in the present and future.

According to the World Conservation Union's Red List, the threat to biodiversity is due to human activity particularly, habitat destruction.

Few of the Major biodiversity threats are listed below:

i. Habitat destruction

ii. Extension of agriculture

iii. Filling-up of wetlands

iv. Conversion of rich biodiversity site for human settlement and industrial development

v. Destruction of coastal areas

vi. Uncontrolled commercial exploitation

One of the primary causes of loss of biodiversity is habitat destruction. The main causes for the same are listed below:

i. Agricultural activities

ii. Extraction including mining, fishing, logging and harvesting

iii. Developmental activities including human settlement, industry and associated infrastructure

Millions of hectares of forest area is lost due to illegal encroachment of forest land. Forest land is also lost due to construction of river valley projects, introduction of transmission lines and roads, etc. Change in forest composition and quality can lead to decline in primary food species for wildlife.

Fragmentation is the process of division of a population into several small groups. Habitat loss and fragmentation leads to formation of isolated, small and scattered populations which are susceptible to inbreeding, depression, high infant mortality and eventually possible extinction.

Introduced species are responsible for many recorded species extinctions, especially on islands. In these isolated ecosystems, a new predator, competitor or pathogen can rapidly endanger species that did not evolve simultaneously with the newcomer.

Several forest, fisheries and wildlife resources have been over-exploited to the point of extinction. A few cases are mentioned below as a point in case. Poaching of wild animals (The Tiger, Elephant, Rhinoceros) has resulted in their extinction. Population pressures adversely affect the forest resources on which the local communities depend while having a negative impact on biodiversity.

Pollutants strain ecosystems. Contamination affects the food chain. A point in case is marine pollution from non-point sources that ruins estuaries and coastal seas throughout the world. Pesticides used to control agricultural pests have shown to negatively impact birds due to severe air pollution in Spain.

Write about energy flow in an ecosystem

Energy is an essential requirement for all living organisms. Solar energy is the only source of energy for the Earth. Solar energy is transformed to chemical energy by photosynthesis in plants (primary producers). Though lot of sunlight falls on plants, only 1% of this is utilized for photosynthesis.

Some amount of energy is used by the plant for growth and the remaining is transferred to consumers by the process of eating. Thus energy enters the ecosystem through photosynthesis and passes through different feeding levels (tropic levels)

The flow of energy through an ecosystem follows two laws of thermodynamics:

1. First law of thermodynamics states that “energy can neither be created nor destroyed, but can be converted from one form to another.” Ex: Energy for an ecosystem comes from the sun. It is absorbed by plants where it is converted and stored as chemical energy or solar energy is converted into chemical energy.

2. Second law of thermodynamics states that “whenever energy is transformed, there is a loss of energy through the release of heat.” Ex: Whenever energy is transferred between tropic levels, loss of energy takes place through respiration, running, hunting, etc.

Describe aquatic ecosystem

Aquatic ecosystem deals with water bodies. Types of organisms found in aquatic environment depend on salinity of water (salt content).

Types of aquatic life zones:

1. Fresh water life zones (Ponds, Streams, Rivers, Lakes)

2. Salt water life zones. (Oceans and Estuaries)

Pond ecosystems

i. Pond is temporary, only seasonal

ii. It is a stagnant freshwater body

iii. It is easily polluted due to limited amount of water.

Structure and function

Examples of abiotic components are temperature, light, water, organic and inorganic compounds.

Biotic components are comprised of 

i. Producers: These include green photosynthetic organisms. They are of two types:

a) Phytoplankton and

b) Microphytes

Phytoplankton are microscopic aquatic plants, which float freely on the surface of water. Examples of phytoplankton are Algae, Volvox, Pandorina, Anabena and Cosmarium.

Microphytes are large floating plants and submerged plants. Examples of microphytes are hydrilla, jussiaea, wolfia and demna.

 

ii. Consumers:

Primary consumers (Zooplanktons): These are microscopic animals that freely float on the surface of water. Zooplanktons are found along with phytoplanktons which they eat. Examples of zooplanktons are planktons, very small fish, ciliates, flagellates and protozoans.

Secondary consumers (Carnivores): They feed on zooplanktons. Examples of carnivores are insects like water beetles and small fish.

Tertiary consumers: They feed on smaller fish. Examples of tertiary consumers are large fish like game fish.

iii. Decomposers: They decompose dead plant and animal matter and their nutrients are released and reused by green plants. Examples of decomposers are fungi, bacteria and flagellates.

Lake ecosystems:

i. Lakes are natural shallow water bodies

ii. Lakes are supplied with water from rainfall, melting snow and streams.

iii. Lake is a permanent water body with large water resources.

iv. Lakes help in irrigation and supplying drinking water.

Structure and function of Lake Ecosystem: The abiotic components of lake ecosystems consist of temperature, light, proteins, lipids, turbidity, oxygen and carbon-dioxide.

The biotic components are classified into:

i. Producers: Green plants (Floating, Submerged and amphibious). Examples of producers are phytoplanktons, algae and flagellates.

ii. Consumers: Primary consumers are zooplanktons like ciliates, protozoans, etc that feed on phytoplanktons.

Secondary consumers  are carnivores like insects and smaller fishes that feed on zooplanktons

Tertiary consumers feed on smaller fish. Examples are large fish and game fish

iii.     Decomposers: Decomposers decompose dead plants and animals. Examples of decomposers are bacteria, fungi and actinomycetes.

River Ecosystem: 

i. It is fresh water and freely flowing water system

ii. Flowing water allows mixing of water resulting in higher dissolved oxygen

iii. River deposits large amount of nutrients.

Structure and function of River Ecosystem: The abiotic components of river ecosystems are temperature, light, pH, nutrients, organic and inorganic compounds.

Biotic components are classified into:

i. Producers: Phytoplankton, Algae, water grasses, aquatic grasses and other amphibious plants.

ii. Consumers: Primary consumers feed on phytoplanktons. Examples are water insects, snails and fishes.

Secondary consumers are feed on primary consumers.

iii.     Decomposers: Decomposers decompose dead plants and animals. Examples of decomposers are bacteria, fungi and actinomycetes.

 

Ocean ecosystems:

i. Oceans occupy a large surface area and made up of saline water.

ii. Commercial activities are carried out in oceans.

iii. Oceans are rich in biodiversity

iv. Oceans moderate the temperature of the earth.

Structure and function of Ocean Ecosystems:

The abiotic components of ocean ecosystems are temperature, light, NaCl, K, Calcium and Magnesium salts and alkalinity.

The biotic components comprise of 

i. Producers: Phytoplanktons (diatoms, unicellular algae, etc) and marine plants (sea weeds, chlorophyceal, phaeophyceae)

ii. Consumers: They are heterotrophic macroconsumers which depend upon producers for their nutrition.

a. Primary consumers or herbivores feed on producers (Ex: Crustaceans, Mollusks, Fish

b. Secondary consumers or carnivores feed on herbivores (Ex: Herring, Mackerel, etc)

c. Tertiary consumers are the top consumers and feed on small fishes. (Ex: Cod, Haddock, etc)

iii. Decomposers decompose dead organic matter. (Ex: Bacteria and fungi)

Estuarine ecosystem:

i. Estuaries are transition zones that are strongly affected by tides of the sea.

ii. Water in estuaries change periodically

iii. The organisms in estuaries have a wide tolerance

iv. Salinity remains highest in summer and lowest in winter.

Structure and function of Estuarine Ecosystems:

Abiotic components of estuarine ecosystems are temperature, pH, sodium and potassium salts and nutrients.

Biotic components consist of

i. Producers: Examples are marsh grasses, seaweeds, seagrasses and phytoplankton.

ii. Consumers: Examples are Oysters, Crabs, Seabirds, and small fishes

iii. Decomposers: Examples are Bacteria, fungi and actinomycetes.

Write in detail about structure and function of an ecosystem.

Ecology is the study of ecosystems and ecosystem is the basic functional unit of ecology. A group of organisms interacting amongst themselves and with the environment is called ecosystem. An ecosystem is a community of different species interacting with each other and their non-living environment thereby exchanging energy and matter.

Structure of an ecosystem shows the relationship between abiotic and biotic components. 

All the living members of an ecosystem form the biotic community. Ex: Plants (producers), animals (consumers) and microorganisms (decomposers).

The non-living components (physical and chemical) of an ecosystem collectively form the abiotic community. Ex: Climate, Soil, Energy, Nutrients, Water and Air.

Physical components are necessary for the growth and maintenance of living components of the ecosystem.

Chemical components are the source for essential nutrients. They consist of organic substances (protein, lipids, carbohydrate) and inorganic substances (Al, Co, Zn, Cu-micro elements C, H, O, P, N, P, K-macro elements)

Function of an ecosystem is of three types:

Primary function: The primary function of all ecosystems is to manufacture starch (photosynthesis)

Secondary function: The secondary function of all ecosystems is to distribute energy to all the           consumers in the form of food.

Tertiary function: All living organisms die and these dead systems are decomposed to initiate the third system of ecosystems called “cycling”.

Define and differentiate between food chain and food web with a diagram

A food chain is a model that shows the flow of energy from autotrophs to a series of organisms in an environment. The energy that flows can be different for each food chain. The food chain describes the flow of food from one organism to the next thereby giving energy to the organism digesting the food. The number of steps involved in a food chain is restricted to four or five. The energy available decreases with each step. The energy loss takes place in the form of heat. The three types of food chains are: 

Grazing food chain,

Detritus food chain and 

Parasitic food chain. 

All food chains start with the sun.

The interlocking pattern of various food chains in an ecosystem is known as food web. In a food web many food chains are interconnected. In a food web different types of organisms are connected at different tropic levels resulting in several opportunities of eating and being eaten at each tropic level.

An important difference between food chain and food web is that food chain is linear and this implies that if one species becomes extinct, the species in the subsequent tropic levels are also affected. However, in a food web, if one species is affected, there is no serious effect on other tropic levels as there are several options available at each tropic level.

Enumerate the value of biodiversity

The value of biodiversity is classified into:

Direct values and

Indirect Values

Direct value of biodiversity: Biodiversity has direct value in the form of consumption in agriculture, medicine and industry. Among all plant species identified as fit for human consumption, only 150 have been cultivated on a large scale. Two types of direct values are:

  Consumptive use value and 

Productive use value

Consumptive use value is the value placed on nature's products that are consumed directly without passing through a market. Consumptive use value is not included in national income accounts. Consumptive use value benefits the communities closest to the resource if harvested sustainably with proper management. Product examples of consumptive use value are firewood, food and game meat.

Productive use value refers to products that are commercially harvested and sold in a market. Its value is estimated at production end after addition of cost and value. The productive use value has a major impact on national economy. Product examples of productive use value are timber, fish, honey, mushrooms, game meat sold in markets and medicinal plants.

Biodiversity has indirect value since it provides economic benefits without being harvested. Direct value of biodiversity is derived from its indirect value. Indirect value of biodiversity is listed below:

Non consumptive use value

Optional value

Existence value and

Information value

Non consumptive use value refers to nature's functions and services. Examples of this are photosynthesis by plants that provides support system for other species, maintenance of water cycle, regulating climate, production and protection of soil, absorption and breakdown of pollutants, recreational, aesthetic, socio-cultural, scientific, educational, spiritual and historic values of natural environments.

Option value refers to the indirect value of a species potential to produce economic benefits to the society in the future.

Existence value is the value gained from continuous knowledge of existence. An example in this context is the expense incurred by the administration of various countries to develop techniques in order to prevent a species from becoming extinct (Giant Panda, Blue whale, White tiger, etc).

Information value refers to the educational, scientific, aesthetic and tourism values of biodiversity in an ecosystem.

What are the types of  biodiversity conservation

With the rapid increase of human population and resulting expansion of man's needs coupled with scientific knowledge led to over-exploitation of natural resources. Eventually, conservation of biological diversity became a global concern. This involves influencing behaviour of people at local level through education, at the national level through policy work and awareness programs. International corporations should ensure that their business do not contribute to further loss of biodiversity.

The two main types of biodiversity conservation are:

In-situ conservation and

Ex-situ conservation

In-situ conservation is defined as the conservation of genetic resources through their maintenance within natural or man-made ecosystems in which they occur.

In-situ conservation effort is setting-up of protection areas. This technique is the best conservation strategy. However, its implementation is sometimes unfeasible. National Parks, Sanctuaries and Biosphere reserves are some types of in-situ conservation.

Ex-situ conservation is defined as conservation made outside the habitat of an ecosystem. In case the habitat of rare or endangered species is destroyed, ex-situ conservation is the only means of conserving  a species. It also provides a back-up solution to in-situ conservation projects. A few examples of ex-situ conservation are seed banks, botanical gardens, pollen storage, tissue culture and genetic engineering