Ecology And Environment.pdf

Ecology and Environment Credit- 01

3rd Semester

‫ ٭‬Question No - 01 ‫٭‬ Ecosystem Concept and Components? An ecosystem, a term very often used in biology, is a community of plants and animals interacting with each other in a given area, and also with their non-living environments. The non-living environments include weather, earth, sun, soil, climate and atmosphere. The ecosystem relates to the way that all these different organisms live in close proximity to each other and how they interact with each other. For instance, in an ecosystem where there are both rabbits and foxes, these two creatures are in a relationship where the fox eats the rabbit in order to survive. Ecosystems can be huge, with many hundreds of different animals and plants all living in a delicate balance, or they could be relatively small. In particularly harsh places in the world, particularly the North and South Poles, the ecosystems are relatively simple because there are only a few types of creatures that can withstand the freezing temperatures and harsh living conditions. Some creatures can be found in multiple different ecosystems all over the world in different relationships with other or similar creatures. Its a bit unfortunate but ecosystems have been destroyed and vanished by man-made activities like deforestation, urbanization and natural activities like floods, storms, fires or volcanic eruptions. The term ecosystem was coined in 1935 by the ecologist Arthur Tansley to encompass the interactions among biotic and abiotic components of the environment at a given site. The living and non-living components of an ecosystem are known as biotic and abiotic components, respectively. Ecosystem was defined in its presently accepted form by Eugene Odum as, “an unit that includes all the organisms, i.e., the community in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity and material cycles, i.e., exchange of materials between living and non-living, within the system”. Components of Ecosystem

Each ecosystem has two main components: 01

1. Biotic Components: The living organisms including plants, animals and micro-organisms (Bacteria and Fungi) that are present in an ecosystem form the biotic components. On the basis of their role in the ecosystem the biotic components can be classified into three main groups: (A) Producers: The green plants have chlorophyll with the help of which they trap solar energy and change it into chemical energy of carbohydrates using simple inorganic compounds namely water and carbon dioxide. This process is known as photosynthesis. As the green plants manufacture their own food they are known as Autotrophs (i.e. auto = self, trophos = feeder) The chemical energy stored by the producers is utilised partly by the producers for their own growth and survival and the remaining is stored in the plant parts for their future use. (B) Consumers: The animals lack chlorophyll and are unable to synthesise their own food. Therefore, they depend on the producers for their food. They are known as heterotrophs (i.e. heteros = other, trophos = feeder) The consumers are of four types, namely: (a) Primary Consumers or First Order Consumers or Herbivores: These are the animals which feed on plants or the producers. They are called herbivores. Examples are rabbit, deer, goat, cattle etc. (b) Secondary Consumers or Second Order Consumers or Primary Carnivores: The animals which feed on the herbivores are called the primary carnivores. Examples are cats, foxes, snakes etc. (c) Tertiary Consumers or Third Order Consumers: These are the large carnivores which feed on the secondary consumers. Example are Wolves. (d) Quaternary Consumers or Fourth Order Consumers or Omnivores: These are the largest carnivores which feed on the tertiary consumers and are not eaten up by any other animal. Examples are lions and tigers. (C) Decomposers or Reducers: Bacteria and fungi belong to this category. They breakdown the dead organic materials of producers (plants) and consumers (animals) for their food and release to the environment the simple inorganic and organic substances produced as by-products of their metabolisms. These simple substances are reused by the producers resulting in a cyclic exchange of materials between the biotic community and the abiotic environment of the ecosystem. The decomposers are known as Saprotrophs (i.e., sapros = rotten, trophos = feeder) 2. Abiotic Components: The non living factors or the physical environment prevailing in an ecosystem form the abiotic components. They have a strong influence on the structure, distribution, behaviour and inter-relationship of organisms. Abiotic components are mainly of two types: (a) Climatic Factors: Which include rain, temperature, light, wind, humidity etc. 02 (b) Edaphic Factors:

Which include soil, pH, topography minerals etc.? The functions of important factors in abiotic components are given below: Soils are much more complex than simple sediments. They contain a mixture of weathered rock fragments, highly altered soil mineral particles, organic matter, and living organisms. Soils provide nutrients, water, a home, and a structural growing medium for organisms. The vegetation found growing on top of a soil is closely linked to this component of an ecosystem through nutrient cycling. The atmosphere provides organisms found within ecosystems with carbon dioxide for photosynthesis and oxygen for respiration. The processes of evaporation, transpiration and precipitation cycle water between the atmosphere and the Earth’s surface. Solar radiation is used in ecosystems to heat the atmosphere and to evaporate and transpire water into the atmosphere. Sunlight is also necessary for photosynthesis. Photosynthesis provides the energy for plant growth and metabolism, and the organic food for other forms of life. Most living tissue is composed of a very high percentage of water, up to and even exceeding 90%. The protoplasm of a very few cells can survive if their water content drops below 10%, and most are killed if it is less than 30-50%. Water is the medium by which mineral nutrients enter and are trans-located in plants. It is also necessary for the maintenance of leaf turgidity and is required for photosynthetic chemical reactions. Plants and animals receive their water from the Earth’s surface and soil. The original source of this water is precipitation from the atmosphere. Or 1) Inorganic substances:- These are simpler materials which are build up to form complex compounds that makes up the body of living organisms e.g C, N, CO2, H2O etc. 2) Organic substances: - These are compounds of carbon that forms a link between living and non-lving parts of an ecosystem. they are formed from inorganic compounds and passed into the body of living organisms through feeding. 3) Climatic factors:- These includes physical factors such as temprature, light, relative humidity, rainfall etc., they determined abundance of organisms in their habitats and also determined which orgasnism to survive, in which habitat and inn what codition.

‫ ٭‬Question No - 02 ‫٭‬ Ecosystem forms (Types) and Functions? We can classify ecosystems as follows:

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(A) Natural Ecosystems:These ecosystems are capable of operating and maintaining themselves without any major interference by man.A classification based on their habitat can further be made on Terrestrial Ecosystem and Aquatic Ecosystem. (1) Terrestrial ecosystems Terrestrial ecosystems can be found anywhere apart from heavily saturated places. They are broadly classed into a) The Forest Ecosystems They are the ecosystems in which an abundance of flora, or plants, is seen so they have a big number of organisms which live in relatively small space. Therefore, in forest ecosystems the density of living organisms is quite high. A small change in this ecosystem could affect the whole balance, effectively bringing down the whole ecosystem. You could see a fantastic diversity in the fauna of the ecosystems, too. They are further divided into:  Tropical evergreen forest: These are tropical forests that receive a mean rainfall of 80 for every 400 inches annually. The forests are characterized by dense vegetation which comprises tall trees at different heights. Each level is shelter to different types of animals.  Tropical deciduous forest: There, shrubs and dense bushes rule along with a broad selection of trees. The type of forest is found in quite a few parts of the world while a large variety of fauna and flora are found there.  Temperate evergreen forest: Those have quite a few number of trees as mosses and ferns make up for them. Trees have developed spiked leaves in order to minimize transpiration.  Temperate deciduous forest: The forest is located in the moist temperate places that have sufficient rainfall. Summers and winters are clearly defined and the trees shed the leaves during the winter months.  Taiga: Situated just before the arctic regions, the taiga is defined by evergreen conifers. As the temperature is below zero for almost half a year, the remainder of the months, it buzzes with migratory birds and insects. b) The Desert Ecosystem Desert ecosystems are located in regions that receive an annual rainfall less than 25. They occupy about 17 percent of all the land on our planet. Due to the extremely high temperature, low water availability and intense sunlight, fauna and flora are scarce and poorly developed. The vegetation is mainly shrubs, bushes, few grasses and rare trees. The stems and leaves of the plants are modified in order to conserve water as much as possible. The best known desert ones are the succulents such as the spiny leaved cacti. The animal organisms include insects, birds, camels, reptiles all of which are adapted to the desert (xeric) conditions. c) The Grassland Ecosystem Grasslands are located in both the tropical and temperate regions of the world though the ecosystems vary slightly. The area mainly comprises grasses with a little number of trees and shrubs. The main vegetation includes grasses, plants and legumes that belong to the composite family. A lot of grazing animals, insectivores and herbivores inhabit the grasslands. The two main kinds of grasslands ecosystems are:  Savanna: The tropical grasslands are dry seasonally and have few individual trees. They support a large number of predators and grazers. 04

 Prairies: It is temperate grassland, completely devoid of large shrubs and trees. Prairies could be categorized as mixed grass, tall grass and short grass prairies. d) The Mountain Ecosystem Mountain land provides a scattered and diverse array of habitats where a large number of animals and plants can be found. At the higher altitudes, the harsh environmental conditions normally prevail, and only the treeless alp ine vegetation can survive. The animals that live there have thick fur coats for prevention from cold and hibernation in the winter months. Lower slopes are commonly covered with coniferous forests. (2) Aquatic Ecosystems The aquatic ecosystem is the ecosystem found in a body of water. It encompasses aquatic flora, fauna and water properties, as well. There are two main types of aquatic ecosystem - Marine and Freshwater. (a) The Marine Ecosystem Marine ecosystems are the biggest ecosystems, which cover around 71% of Earth's surface and contain 97% of out planet's water. Water in Marine ecosystems features in high amounts minerals and salts dissolved in them. The different divisions of the marine ecosystem are:  Oceanic: A relatively shallow part of oceans which lies on the continental shelf.  Profundal: deep or Bottom water.  Benthic Bottom substrates.  Inter-tidal: The place between low and high tides.  Estuaries  Coral reefs  Salt marshes  Hydrothermal vents where chemosynthetic bacteria make up the food base. Many kinds of organisms live in marine ecosystems: the brown algae, corals, cephalopods, echinoderms, dinoflagellates and sharks. (b) The Freshwater Ecosystem Contrary to the Marine ecosystems, the freshwater ecosystem covers only 0.8% of Earth's surface and contains 0.009% of the total water. Three basic kinds of freshwater ecosystems exist:  Lentic: Slow-moving or till water like pools, lakes or ponds.  Lotic: Fast-moving water such as streams and rivers.  Wetlands: Places in which the soil is inundated or saturated for some lenghty period of time. The ecosystems are habitats to reptiles, amphibians and around 41% of the world’s fish species. The faster moving turbulent waters typically contain a greater concentrations of dissolved oxygen, supporting greater biodiversity than slow moving waters in pools. (B) Artificial Ecosystem:They are also called man-made or man-engineered ecosystems. They are maintained artificially by man where, by addition of energy and planned manipulation, natural balance is disturbed regularly, e.g. croplands such as sugarcane, maize, wheat, rice-fields; orchards, gardens, villages, cities, dams, aquarium and manned spaceship. Functions of an ecosystem involves: The function of an ecosystem is a broad &vast. The function of an ecosystem can be best studied by understanding the history of ecological studies. The function of an ecosystem can be studied under the three heads: 1. Trophic Level Interaction 2. Ecological Succession 3. Biogeochemistry 05

Functions of Ecosystem Functions are simply the activities undertaken by Ecosystems to ensure their persistence. The key functional aspects of ecosystem are: A. Energy flow: - Ecosystem being self sustained and self regulating system needs energy to function. The basic source of energy to ecosystem is sun. Plants capture only a fraction of the total solar energy called PAR {Photo synthetically active radiation}. Plants utilize this energy to prepare their food by the process of photosynthesis. This energy stored at tropic level 1st becomes the source of energy either directly or indirectly to other organisms at different tropic levels. The energy flows through different tropic levels across the food chain by the process of being eating and being eaten away. A substantial amount of energy at each tropic level is lost because of respiration. The dead decaying matter at each tropic level is consumed by detrivors thus providing a path way for detritus food chain to come into existence. Each unit of energy consumed at tropic level 1st is ultimately lost into the space. This whole system of energy flow works in accordance with the laws of thermodynamics. Energy flow is largely unidirectional. There are three major pathways of energy flow in ecosystem:- Transfer of chemical energy from each tropic level to the next higher order tropic level and direct transfer of energy from TL-1 or TL-2 toTL-4. Transfer of chemical energy from dead organic matter to decomposers at each tropic level. Loss of energy in the form of heat at each tropic level. B. Productivity: - Productivity is the rate of biomass production at any tropic level per unit area per unit time. OR Productivity is the amount of organic matter produced at any tropic level per unit area per unit time. Productivity has two aspects: 1. Primary productivity: - The rate at which sunlight is captured by producers for the synthesis of energy rich organic compounds through the process of photosynthesis. It has two aspects: GPP: The rate of total energy capture or rate of total organic matter produced. NPP: The balance energy or biomass remaining after meeting the cost of respiration. 2. Secondary productivity: - The rate at which food energy is assimilated at any tropic level of consumers. Secondary productivity reflects only the utilization of food for the production consumer biomass. Secondary productivity depends upon the loss during energy transfer plus the consumption in respiration. C. Decomposition:- Decomposition is the breakdown of complex organic matter by decomposers to inorganic raw materials like CO2 , H2O and nutrients. Decomposition is brought mainly by Bacteria and Fungi. It is also known as putrefication. Rate of decomposition mainly depends upon two factors: i. Climatic conditions of area. ii. Chemical nature of detritus. Processes involved in Decomposition 1. Fragmentation: - breakdown of detritus into smaller particles due to the action of detritus feeding invertebrates.  Leaching: removal of soluble substances like sugars etc from fragmented detritus by water percolating through the soil. 06

2. Catabolism: - enzymatic conversion of decomposing detritus to simpler compounds and inorganic substances.  All the above three processes operate simultaneously on the detritus. 3. Humification: - Accumulation of dark colored amorphous substances called humus, which is slightly resistant to microbial action and undergoes slow decomposition. 4. Mineralization:- Release of inorganic substances like CO2, H2O and available nutrients like CALCIUM, MAGNECIUM, POTASSIUM Ions etc in the soil. D. Nutrient cycling: - Circulation of nutrients in biospheric ecosystem is accomplished in a series of cyclic path ways, collectively called bio-geochemical cycle. Nutrient cycling involves storage and transfer of nutrients through various components of ecosystem. Unlike energy flow which is unidirectional, nutrients are continuously exchanged between organisms and their physical environment. Nutrient cycling involves: 1) Uptake of nutrients or inorganic elements by plants through their roots in solution from the soils. 2) Transfer and storage of these nutrients through the bodies of living organisms at different tropic levels across the food chain, where these inorganic elements become organic . 3) Release of these organic elements from plants and animals back to the soil by variety of ways. ‫ ٭‬Question No - 03 ‫٭‬

Tropical Levels, Ecological Niche, Ecological pyramid? (Tropical Levels) In a food chain, the energy transfer levels are known as trophic levels. In other words, the trophic level is the position occupied by an organism in a food chain. The levels are broadly grouped into three including producers, consumers, and decomposers. A food chain is a sequence of organisms that feed on each other. Although the design of a food chain can vary by ecosystem, all food chains are made up of the same basic trophic levels. Trophic levels are the levels within the food chain where an organism obtains its energy. Producers (Autotrophs):- Producers are the plants and algae that manufacture their own food from the sun’s energy and nutrients from the soil. Consumers (heterotrophs) cannot produce their own food and have to feed on others to obtain energy. Decomposers and detritivores break down dead plants and animals to release the energy back into the ecological system. The categorization begins from the lowest to the highest energy transfer levels as elaborated below. Consumers: - Consumers are organisms that get their energy from eating other organisms. These are also also known as heterotrophs; Heterotrophs cannot produce their own food.

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1) Primary consumers:- Primary consumers constitute the second trophic level, and they are the organisms (Like cow that eats grass) that consume green plants. Herbivores are the predominantly animals in this category. Examples include sheep, rabbits, cows, giraffe, zebras, gazelle, caterpillars, and some insects. 2) Secondary consumers:- Secondary consumers make up the third trophic level, and they are the animals (Like snake that eat rabbits) that eat up the primary consumers. Majority of the animals in this category are carnivores. Examples include cats, tigers, dogs, wolf, lions, leopards, snakes, and foxes. 3) Tertiary consumers:- Tertiary consumers occupy the fourth trophic level of the food chain. The tertiary consumers are the animals that eat Secondary Consumers and are are eaten by Quaternary Consumers. They mainly include carnivores that feed on other carnivores, especially the secondary consumers. Examples are eagles and snakes. 4) Quaternary Consumers:- Quaternary Consumers are at the fifth trophic level. They majorly prey on animals below them for food including secondary and tertiary consumers. Examples include white sharks, hawks, the golden eagles, and even humans. 5) Apex Predators:- The apex predators are at the highest trophic level. Apex predators top the food chain because they have no predators or natural enemies. They feed on other animals at will. Examples of apex predators include crocodiles, sharks, whales, owls, snakes, wildcats, and eagles. Decomposers and Detrivores: - Decomposers and Detrivores make up the last part of food chains. Dead organisms are often eaten up, and the nutrients are recycled so that they can be used again by primary producers to manufacture food. The organisms responsible for this are termed as decomposers or detrivores. Examples of detritivores include crabs, vultures, and worms while decomposers include fungi and bacteria. These organisms start the cycle once again by returnign the nutrients back in to the soil for use by autotrophs.

(Ecological Niche) The ecological niche describes the role an organism plays in its environment. It consists of the species habitat. The organism’s activity, the period of time it is active. The resources it obtains from the environment Eg, a pukeko lives in marsh areas. It feeds of small insects and grasses. An ecological niche is the part of the environment into which a species fits, and to which it is adapted. A shorthand definition of niche in biology is how an organism makes a living in a place. If you closely look at a typical habitat in the environment, you will see many organisms living and working together, fulfilling their ecological niches. For example, imagine you are walking through the forest where there are leaves scattered on the ground and an old rotting log sitting on the forest floor. If you look closely, you could probably find earthworms just under the soil feeding on decaying organic matter. There could also be 08

centipedes eating small beetles and other organisms as well as a colony of ants that work and feed on dead insects. You may even find a couple of millipedes strolling around feeding on decaying leaves. However, the term has been used in different ways. It is not only a place but a way of life. For example, grazers, insectivores, scavengers and predators can all live their different lifestyles in the same forest. A niche can be occupied by different species in different places even though they 'earn their living' in roughly the same way. Thus the 'bird of prey eating small mammals' niche would in grasslands include the kestrel, but in an Oakwood it would be filled by the Tawny owl. The idea of a niche in natural history is ancient: many writers noticed that animals and plants live in places where they are well adapted to live. The word niche was first used in biology by naturalist Roswell Johnson, but in 1917 Joseph Grinnell was the first to use it in a research program. Later, he described the niches of a variety of species. Grinnell was the first to offer the "exclusion principle" in which only one species could occupy a particular niche at any one time. Scientists who study the interactions between animals and their environment are called ecologists, and their branch of science is called ecology. A niche is a term which describes a position or opportunity into which some organism fits well. Thus, an ecological niche is a place in nature that is filled by an animal or plant because it is well suited to do so. Organisms can be identified as either 1) Generalists Organisms with a broad niche Eat lots of types of food Live in many types of environments Eg. house mice 2) Specialists Organisms with a narrow niche Eat a narrow range of food items Live in few, specific types of habitats Eg. panda bear

(Ecological Pyramid) 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. Ecological pyramid is also known as trophic pyramid or energy pyramid; it is graphically represented to show the biomass or productivity of the biomass at each trophic level in an ecosystem.

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There are 3 types of Ecological Pyramids as described as follows: 1. Pyramid of Energy 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.

2. Pyramid of Numbers 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: I. 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.

II. 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.

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III. 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.

3. Pyramid of Biomass The pyramid of biomass is more fundamental, they represent the quantitative relationships of the standing crops. Biomass is the amount of living or organic matter present in an organism. Biomass pyramids show how much biomass is present in the organisms at each trophic level. 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: I. Upright Pyramid of Biomass This occurs when the larger net biomass of producers support a smaller weight of consumers. Example: Forest ecosystem.

II.

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

‫ ٭‬Question No - 04 ‫٭‬ Energy flow models (U- Shaped & Y- Shaped energy flow model)? Energy is the basic medium and mechanism that generates , maintains , and sustains the bio systems of earth. The existence of living world depends upon the flow of energy and 11

circulation of nutrients. The basic source of energy for earth is sun. This radiant energy by the process of photosynthesis is bio-synthesized into chemical or heat energy. Energy flow is the key function in the ecosystem of the ecosystem. Energy flow is the flow of energy through an ecosystem; flow from external environment through a series of organisms and back to physical environment. Energy flow is based on the laws of thermodynamics: 1. Law of conservation of energy; Energy can neither be created nor destroyed but transformed from one form o another. 2. Law of entropy; No process involving an energy transformation will spontaneously occur unless there is a degradation of energy from concentrated to dispersed form. In an ecosystem order is maintained by continually pumping out disorder (entropy) through respiration. An Energy flow model is a simplified representation of energy flow through an ecosystem , recognizing the various aspects of input and output rates of energy. There are two basic aspects of energy flow models: Energy flow is unidirectional and irreversible. Progressive decrease in energy utilization at each trophic level. Energy flow models are of three types: 1. U-Shaped energy flow model. 2. Y-Shaped energy flow model. 3. Universal energy flow model.  U SHAPED MODEL OF ENERGY FLOW: U shaped or single channel energy flow was proposed by Lindeman in 1942. It conforms to the basic aspects of energy flow i.e unidirectional energy flow , and progressive decrease of available energy at each trophic level. Generally only 10% is the ecological efficiency of any ecosystem.

U-Shaped Model Of Energy Flow (Qualitative Diagram) R₁ R₂ rep heat loss through respiration at various levels. Ʌ₁ Ʌ₂ rep energy available at various trophic levels. λ₁ λ₂ rep energy input to various levels. λ₁′ λ₂′ rep total energy loss at various level

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The figure depicts the standing crop of energy at any level by “Ʌ” using a subscript to identify various trophic levels. R₁,R₂,R₃ depict the respiration at different levels. The energy available at any trophic level is represented by “λ”.

Assuming a total of 3,000 kcal of energy, only 30 kcal form the gross primary production. Releasing 10 kcal in the form of heat the net primary production becomes 20 kcal. 16 kcal of the NPP is released unutilized and only 4 kcal are passed on to the second trophic level. The herbivore and carnivore levels similarly get 10% of their preceding levels. Thus the model balances the inflows and outflows of energy and shows ageneral decrease of energy at successive trophic levels.

U shaped model of energy flow (Quantitative)

 Y-SHAPED MODEL OF ENERGY FLOW. This model was proposed by H.T Odum in 1958. This model resembles the capital letter “Y” having two arms which represent the grazing and detritus food chain. The Y shaped model of energy flow practically separates the two food chains and simultaneously inter links them at predator-prey levels since these organisms are generalists preying upon members of both the live and detritus food chains(i.e phagotrophs and saprotrophs)

Why Is Y Shaped Model Of Energy Flow More Realistic? E.P Odum regards Y shaped model of energy flow as more realistic because: It conforms to the basic stratified structure of ecosystems. The direct consumption of living plants and the consumption of dead matter are usually separated in both time and space. The macro consumers (phagotrophic animals and the micro consumers (saprotrophic bacteria and fungi0 differ greatly in size , metabolic relations and 13 techniques of studying them.

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Flow of energy in an ecosystem lakes place through the food chain and it is this energy which keeps the ecosystem going. The flow of energy through various trophic levels in an ecosystem can be explained with the help of various energy flow models. 1. Single Channel Energy Flow Model: The flow of energy takes place in an unidirectional manner through a single channel of green plants or producers to herbvivores and carnivores. From the energy flow model shown in Figure 1, two things are clear : (i) There is unidirectional flow of energy. The energy captured by autotrophs does not revert back to solar input but passes to herbivores; and that which passes to herbivores does not go back to the autotrophs but passes to consumers. Due to one way flow of energy, the system would collapse if the primary sources of energy (i.e., sun) were cut off. (ii) At each trophic level, there occurs progressive decrease in energy. This is accounted largely by the energy lost as heal in metabolic reactions (respiration) coupled with unutilized

energy. Figure 2 depicts a simplified energy flow model of three trophic levels. One can clearly note that the energy flow is greatly decreased at each successive trophic level starling from producers (autotrophs) to herbivores and then to carnivores. In the Figure, boxes represent the trophic levels and pipes represent the energy flow in and out of each level. Working of both the laws of thermodynamics is clearly seen as energy inflows balance outflows at each trophic level (as per first law of thermodynamics) and energy transfer is accompanied by dissipation of energy into unavailable heat i.e., respiration as per the second law of thermodynamics. Thus, of the total 3,000 kcal of light falling upon green plants, 1,500 kcal (50%) is absorbed level (first trophic level). 1% (15 kcal) is converted at autotroph level (first trophic level). Thus, net production is mearly 15 kcal. Secondary productivity (shown as P2 and P3 in Figure 2) tends to be about 10% at successive consumer levels i.e., at herbivore level and carnivore level. As has earlier been mentioned, there is successive decrease in energy flow at successive trophic levels. Therefore, shorter the food chain, greater would be the available food energy. 2. Y-Shaped or Double Channel Energy Flow Model: Figure, 3 describes Y-shaped energy flow models as pioneered by H.T. Odum in 1956. This model shows a common boundary, light and heat flows as well as the import, export and storage of organic matter. Decomposers is placed in a separate box as a means of partially separating the grazing and detritus food chains. In terms of energy levels, decomposers are, in fact, a mixed group. The significant part in Y-shaped model is that the two food chains are not isolated from each other. 14

Y-shaped energy flow is more realisitc and practical than the single-channel energy flow model because of following points : (i) It conforms to the basic stratified structure of ecosystems. (ii) It separates the two chains i.e., grazing food chain and detritus food chain in both time and space. (iii) Microconsumers (e.g.. bacteria, fungi) and the macroconsumers (animals) differ greatly in size-metabolism relations in two models.

‫ ٭‬Question No - 05 ‫٭‬ Food Chain & Food Web? Energy is never created nor destroyed, but it can be passed from one organism to another. A food chain shows how this energy flow occurs. This lesson will define what a food chain represents, go through specific examples of food chains, and compare and contrast a food chain with a food web. In ecology, a food chain is a series of organisms that eat one another so that energy and nutrients flow from one to the next or a series of organisms each dependent on the next as a source of food. A food chain is a pathway that represents the exchange of energy from one organism to another. In other words, it is the chronological order of who eats whom in a biological community. Food chains go hand-in-hand with food webs, though there are differences between the two. While a food chain is a single pathway of energy transfer, a food web shows all of the different relationships or possible energy transfers between a selected group of species. How Food Chains Work Every biological community can have multiple and diverse food chains, but every food chain starts with a primary source of energy. The most obvious source of energy is the sun. Other food chains may start with a boiling-hot deep sea vent as a source of energy. The next organism to benefit off of this initial source is called the primary producer. These are organisms that can create their own food from the main energy source. Some examples 15

include plants and algae. For example, plants are a primary producer because they can harness and use the energy from the sun through a process called photosynthesis. After the plant goes through the work of photosynthesis, another organism may come along and eat the plant, taking its energy to use as its own. As human beings, we are not primary producers because we cannot create our own energy to survive, and must consume energy from other sources, like plants. By eating plants, we are part of the next sequence in the food chain, called the primary consumer, or organisms that consume primary producers. With each transition of energy, the food chain moves up levels. These levels are called trophic levels. Here is a list of the order of trophic levels.

Examples of which trophic level some species may be on.

Trophic Levels:  Primary Producers: The one that gathers energy from an energy spot such as the sun; an example may be grass.  Primary Consumer: The one that gets its energy directly from the primary producer, such as a grasshopper who eats the grass  Secondary Consumer: The one that gets its energy directly from the primary consumer, such as the rat who eats the grasshopper  Tertiary Consumer: The one that gets its energy directly from the secondary consumer, such as the snake who eats the rat  Quaternary Consumer: I think you are catching on now. This is the one that gets its energy directly from the tertiary consumer, such as the hawk that eats the snake. A food chain from this example would like this

Sun > Grass > Grasshopper > Rat > Snake > Hawk Types of Food Chains in Ecosystem In nature, basically two types of food chains are recognized – grazing food chain and detritus food chain. 1. Grazing food chain: This type of food chain starts from the living green plants goes to grazing herbivores, and on to carnivores. Ecosystems with such type of food chain are directly dependent on an influx of solar radiation. This type of chain thus depends on autotrophic energy capture and the movement of this captured energy to herbivores. Most of the ecosystems in nature follow this type of food chain. The phytoplanktons→zooplanktons →Fish sequence or the grasses →rabbit →Fox sequences are the examples, of grazing food chain. 16

Grazing food chains are of two types: a) Terrestrial grazing food chain: Food chain on land is called terrestrial food chain. It can be represented as follows. For Example Producer (Green plants) - Primary Consumers (herbivores) green plantsSecondary Consumer (small carnivorous) frog - Tertiary Consumer (large carnivorous) snake -Quaternary Consumer (top consumers) hawk

b) Aquatic Food chain: Food chain in aquatic ecosystem is slightly different from terrestrial food chain. It can also be divided in two subtypes. Fresh water food chain and marine water food chain. Fresh water food chain can be represented as follows. For example Producer (green plants) - Primary Consumer (aquatic herbivore insects) Secondary Consumer (crayfish) - Territory Consumer (fish) - Top Consumer (crocodile).

2. Detritus food chain: This type of food chain goes from dead organic matter into microorganisms and then to organisms feeding on detritus (detrivores) and their predators. Such ecosystems are thus less dependent on direct solar energy. These depend chiefly on the influx of organic matter produced in another system. For example, such type of food chain operates in the decomposing accumulated litter in a temperate forest. Significance of food chain: 1. The studies of food chain help understand the feeding relationship and the interaction between organisms in any ecosystem. 2. They also help us to appreciate the energy flow mechanism and matter circulation in ecosystem and understand the movement of toxic substances in the ecosystem. 3. The study of food chain helps us to understand the problems of bio-magnifications. 17

(Food Web) A food web describes the flow of energy and nutrients through an ecosystem, while a food chain is a linear path through a food web. Food web is a network of food chains where different types of organisms are interconnected at different trophic levels so that there are a number of options are eating and being eaten at each trophic level. A network of food chains or feeding relationships by which energy and nutrients are passed on from one species of living organisms to another.In an ecosystem the food chains do not remain isolated but are interconnected with one another form in a king of web called food web. A food web is the interlocking pattern of food chains with all sorts of circuits and connections. In a food web each species is dependent upon other and the number of link species must be sufficient for their continued existence. Food web operators efficiently and an ecological nutritional balance is maintained in an ecosystem. The food web is a illustration of various methods of feeding that links the ecosystem. The food web also defines the energy flow through species of a community as a result of their feeding relationships. All the food chains are interconnected and overlapping within an ecosystem and they make up a food web.

Tropical Forest Food Web

Boreal Forest Food Web

Grassland Food Web

Desert Food Web

Tundra Food Web

Aquatic Food Web

Organisms can be organized into trophic levels: primary producer, primary consumer, secondary consumer, and tertiary or higher-order consumer. Energy decreases in each successive trophic level, preventing more than four or five levels in a food chain. There are different types of food webs including grazing food webs based on photosynthetic plants (such as algae) or detrital food webs based on decomposers (such as fungi). Each organism within a food web can be classified by trophic level according to their position within the web. Depending on an organism's location in a food web, it may be grouped into more than one of these categories. Energy and nutrients move up trophic levels in the following order: (1) Primary producers (2) Primary consumers (3) Secondary consumers (4) Tertiary and other high-level consumers 18

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Question No - 06

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Ecological Adaptations? Organisms are affected by their environment in many ways. An organism needs food, water, air, shelter, suitable temperature and protection from predators in order to survive. The non living environment includes such thing as temperature, light, humidity, air, water and soil which are all important factors for the survival of any organism. The survival of an organism also depends on the characteristics of the organism itself. Each organism has characteristics both behavieral and physical which enable it to survive in its oven particular habitat. These characteristics are called as adaptations. An adaptation can be defined as characteristics of an organism that makes it suitable to its environment or it is particular way of life. It is a structural, physilogical or behavioural characteristics that enables the organisms to survive and reproduce. Anything that helps an organism to survive and successfully reproduce in an ecosystem is regarded as an adaptation. Whether it is a behavieral, physiological or structural adaptation, the adaptation has evolved over a period of time and increases the chances of survival of the organism. Adaptations in Plants: These are the changes that help a plant survive it is environment. How plants survive under water, in the deserts, in cold conditions and where the soil lacks nutrients. Adaptation of Aquatic Plants: Seaweed which is an aquatic plant. It is adopted for underwater life. It has it is own air bubble in each leave that provides the necessary space for the exchange of oxygen from the water to the plant. Also helps keep Seaweed upright. There are many plants adapted for the desert e,g cacti next we have Venus fly trap. This plant is adopted for life in soil with very little nutrients. Dry condition 1. Long roots 2. Small needle like leaves 3. High Volume low surface area 4. They can store water for example cacti Old condition 1. Centifreezing proteins 2. Decideous nature 3. Anti freezing proteins Water logged condition 1. Hydrophytes (very wet places) 2. Xerophytes (very little water) 3. Mesophytes (average conditions) Adaptations in Animals: An adaptation is something about an animal that makes it possible for it to live in a particular place and in a particular way. It may be physical adaptation like the size or shape of the animals body or the way in which it’s Body Works or it may be the way the animal behaves. Each adaptation has been produced by evolution. Adaptation Adopted by animals Prey 1. Warning signals 2. Cryptic coloration 3. Mimery (One sps resembles with others) 4. Migration Prediator 1. Warning signals 2. Hibernation 3. Echolocation 4. Cryptic appearance (Camouflage) 5. Case herelning 6. Thermal imaging Javed Ahmed 9622822905 / 7006824108

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Credit- 02

Javid Ahmad Mattoo (9622822905 / 7006824108) ‫ ٭‬Question No - 01 ‫٭‬

Major Biomes of World – Forests, Deserts, Grassland & Monsoon? Biome is a large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra. A biome is a community of plants and animals that have common characteristics for the environment they exist in. They can be found over a range of continents. Biomes are distinct biological communities that have formed in response to a shared physical climate. "Biome" is a broader term than "habitat"; any biome can comprise a variety of habitats. While a biome can cover large areas, a microbiome is a mix of organisms that coexist in a defined space on a much smaller scale. For example, the human micro biome is the collection of bacteria, viruses, and other microorganisms that are present on a human body. Some of the major biomes of the world are as follows: Desert Biome, Grassland Biome, Forest Biome & Monsoon Biome 1) Forest Biome The forest biome occupies about one third of the Earth's surface and there are three different types of forests found around the world: tropical forests, temperate forests and boreal forests. Tropical Forests Tropical forests are found near the equator, have super hot temperatures all year long and get up to 80 inches (2000 mm) of rain a year. Tropical rainforests are home to jaguars, toucans, gorillas and even tarantulas. Soem people even say that Kidzworld founder Allen Achilles lived in a biome in a previous life. Here you can also find an antelope called the royal antelope that is only as big as a rabbit. Temperate Forests Temperate forests are found in the Eastern United States, Canada, Europe, China and Japan. Temperate forests, which are also known as deciduous forests, have four distinct seasons, which means all the tree leaves fall off in the winter months. Tons of animals live in temperate forests like beavers, black and brown bears, deer, foxes, raccoons, skunks, rabbits and various bird species. Boreal Forests Boreal forests often get less rain than the other forests and are home to evergreen trees, which stay green all year long. This is because they have needles, which don't need as much water as regular tree leaves. Boreal forests are only in the Northern Hemisphere and can be found in every Canadian province. 2) Desert Biome Deserts cover about one fifth of our planet, and are caused by extremely low rainfall over an area. Theses biomes are nonetheless home too many plants and animals which have through the course of their evolution adapted to this dry environment. 20 Arid and Semi-Arid Desert;-

Arid deserts generally occur at low latitudes, and can be found in North-America, SouthAmerica, Africa, and Southern Asia. Seasons in the arid desert are generally dry and hot, with few occurrences of rain during the winter. The heat peaks to extremes during the daytime because there are no clouds to shield the earth from the sun's rays. When it does rain, it is not uncommon for the rain to evaporate before hitting the ground. The soil is usually either sand or coarse, and rocky. Vegetation consists mainly of shrubs and small trees of which the leaves have evolved to retain water. Most desert life forms have followed this train of evolution, with animals species being mostly active at night. Semi-arid deserts are found in North-America, Europe, Russia, and Northern Asia. Seasons are generally more defined than in the Arid desert, with low rainfalls during the winter. Even if the rainfall is kept at a bare minimum, several species of animals and plants thrive in this climate, the animals, while nocturnal, can still be found during the day, mostly in the shade of the various trees and plants. Coastal and Cold Deserts:Coastal deserts are found in areas that are moderately warm to cool, such as the Neotropic and Nearctic realm. The winters are usually cool and short, while the summers are long and warm. The soil is mostly sandy with a high alkaline content, it is also very porous, so rain seeps quite rapidly into the ground. Most of the flora in the coastal desert features thick foliage, with good water retention, and their roots are close to the surface of the ground in order to get enough water before it drains into the soil. Animals of the coastal desert include rough skinned amphibians, birds of prey, scavenger mammal’s reptiles and insects; most have adapted quite well to the climate, and again, they are largely nocturnal during the warmer months. Perhaps the strangest of all desert biomes is the cold desert, as our perception of the desert is usually associated with the heat of the sun. But even if there is a moderately high amount of snow and rainfall during the wintertime, the soil is too heavy and alkaline. Alluvial fans pull some of the salt through the porous soil, so plant life can survive, but then again, as with its arid counterparts, the cold desert offers less than ideal conditions for sustaining delicate plants and animals. Most of the animals in the cold desert are burrowers, even the carnivores and reptiles which even though cold-blooded, have made their homes in the cold desert. Deer and other larger herbivores are only found during the winter, as the supply of grass is more abundant during that period. 3) Grassland Biome: In a grassland biome, the vegetation is dominated by grasses, which may grow to about 2 m in the moist areas and 0.2 m in arid regions of the grassland biome. It is not an exclusively tropical biome but extends into much of the temperate zone as well. The more or less synonymous terms “prairie” (in North America), “pampas” (South America), “steppes” (in Central Asia) “puszta” (Hungary) and many other regional terms underscore the wide distribution of this biome. 21

The common feature of all grasslands is intermittent, erratic rainfall, amounting to about 4 to 16 cm annually. The irregularly of rain, porosity and drainage of the soil, or both factors together prevent a continuous or ample supply of water to plant roots. Grasses of various kinds are particularly adapted to irregularly alternating periods of precipitation and dryness. The environmental conditions vary greatly in different grasslands. There are also non-grass herbaceous species, which are called forbs. Grassland biome probably supports more species of animals than any other terrestrial habitat. In all grasslands, the primary consumers are the large grazing mammals like the bisons, pronghoms (Antilocapra Americana ) and zebra (Equus zebra). African glass-lands support large herds of zebras and several species of grazing antelopes. The grassland ungulates are cursorial. Hares and rodent are also common primary consumers in the grasslands. Many rodents, like the prairie dogs and other ground squirrels or the pocket gophers, are burrowing or fossorial animals. Australian grasslands have herbivores very different in appearance and relationships but ecologically similar. These are large grazing cursorial kangaroos and small, burrowing, rodent-like pouched “mice”. Predators are adapted to the herbivore prey: wild dogs, lions, and the like preying on the ungulates; weasels, snakes, and others on the smaller herbivores. Herbivorous insects such as locusts and grasshoppers are also numerous. Grasslands also support some herbivorous predacious birds. 4) Monsoon Biome Monsoon forest, also called dry forest or tropical deciduous forest, open woodland in tropical areas that have a long dry season followed by a season of heavy rainfall. The trees in a monsoon forest usually shed their leaves during the dry season and come into leaf at the start of the rainy season. Many lianas (woody vines) and herbaceous epiphytes (air plants, such as orchids are present. Monsoon forests are especially well developed in Southeast Asia and are typified by tall teak trees and thickets of bamboo. Monsoon forest of the Tropical latitudes differs from the tropical rainforest in that it is deciduous. Most two trees of these forests shed leaves in the dry season. Shedding Of leaves is response to the stress caused due to water security during the cool or dry season. Height of trees is lower than in the rainforest. Tropical monsoon forests are also called tropical seasonal forests and they are adapted to seasonal precipitation. Nearly 80% of the total precipitation is received in two or three months, and the rest of the year that is only about 20% or less of the total precipitation. The summer is wet and the winters are dry. The satisfaction of the vegetation is relatively simple, and only a single layer of trees of lesser height is found below the main canopy.

‫ ٭‬Question No - 02 ‫٭‬ Carbon Cycle and Nitrogen Cycle? Definition: Nitrogen cycle is the cyclic movement of nitrogen between atmosphere, organisms and soil. or

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Nitrogen cycle is a continuous series of natural processes by which nitrogen passes successively from air to soil to organisms and back to air or soil involving principally nitrogen fixation, nitrification, decay, and denitrification. Nitrogen cycle is a gaseous cycle as atmosphere is the major reservoir of nitrogen with nearly 79%. Why nitrogen is important? Nitrogen is an essential element required for the synthesis of bio-molecules like proteins, DNA, vitamins, chlorophyll, alkaloids etc. It is a critical limiting element for plant growth and reproduction. Atmospheric N2 is extremely stable, unreactive and inert with triple covalent bond between nitrogen atoms. Therefore, plants and animals cannot use atmospheric N2. So it should be converted to some other usable forms such as nitrates (NO 3-). This conversion process is primarily carried out by microorganisms. N2 The Major steps involved in nitrogen cycle

1. Nitrogen fixation 2. Nitrification 3. Nitrate assimilation 4. Ammonification 5. Denitrification and Anammox Step 1: Nitrogen fixation Nitrogen fixation is the conversion of atmospheric N2 to ammonia (NH 3) which can be readily utilized by the plants for synthesis of bio-molecules. 3 Major Methods of Nitrogen fixation a) Biological Nitrogen fixation (BNF): carried out by prokaryotes called as nitrogen fixers or diazotrophs. It accounts nearly 70% of natural nitrogen fixation. Nitrogen fixers include some bacteria likeRhizobium, blue green algae like Anabaena and lichens like Collema. Nitrogen fixers are either symbiotic or free living. Symbiotic N2 fixers include the bacteriaRhizobium and Bradyrhizobium found in the root nodules of leguminous plants (pea, beans etc). Other examples: The water fern Azolla’s symbiosis with a cyanobacterium Anabaena azollae. Anabaena colonizes cavities formed at the base of Azolla fronds. The cyanobacteria fix significant amounts of nitrogen in specialized cells called heterocysts. Examples of free living Nitrogen fixers include species in the genera Azotobacter, Bacillus, Clostridium, and Klebsiella. 23

N2 + 8 H+ + 8 e−+ 16 ATP → 2 NH3 + H2 +16 ADP +16 Pi N2 fixation is a high energy requiring process and N2 fixers uses 16 moles of ATP to fix each molecule of Nitrogen (N2) b) Non-biological N2 fixation by lightning, volcanic eruptions etc. c) Industrial nitrogen fixation (fertilizers) by the Haber-Bosch process N2 + 3H2 2NH3 in the presence of catalyst like Ni at 5000C and 300 atm pressure. Today, nearly 80% of the nitrogen found in human tissues originated from the Haber-Bosch process. 2. Nitrification It is the process that converts ammonia (NH3) to nitrite (NO2-) and then to nitrate (NO3-) by nirtrifying bacteria. Step 1: Oxidation of ammonia (NH3) to nitrite (NO2-) or NH3 NO2Microbes involved: bacteria in the genera Nitrosomonas, Nitrosospira, and Nitrosococcus (Nitrite bacteria) Step 2: Oxidation of nitrite (NO2-) to nitrate (NO3-) or NO2- NO3Microbes involved: bacteria in the genera Nitrobacter (Nitrate oxidizing bacteria) 3. Nitrate assimilation Now soil nitrates (NO3-) formed by nitrification can be taken up by the plants for the synthesis of amino acids, DNA, pigments etc. This is known as nitrate assimilation. From plants (producers) nitrogen as bio-molecules like amino acids enters food chain and moves to animals (consumers) and decomposers. 4. Ammonification It is the conversion of organic nitrogen (amino acids, DNA etc) in plant and animal tissues to ammonia (NH3). After the death of plants and animals, various fungi, actinomycetes and some bacteria (ammonifying bacteria) then decompose the tissue and convert organic nitrogen (e.g. amino acids, DNA) back into the ecosystem as ammonia. This ammonia is available for uptake by plants and other microorganisms for growth. 5. Denitrification It is the conversion of soil nitrate (NO3-) to N2. It is the process that removes fixed nitrogen (i.e., nitrate) from the ecosystem and returns it to the atmosphere in inert form (N2). NO3- NO2- NO N2 Microbes involved: Denitrifying bacteria include species in the genera Bacillus, Paracoccus, and Pseudomonas. Anammox (anaerobic ammonia oxidation) It is the conversion of ammonia (NH3) to N2using nitrite as the electron acceptor under anoxic condition. NH4+ + NO2- N2 + 2H2O Microbes involved: prokaryotes belonging to the Planctomycetes phylum of Bacteria, Brocadia anammoxidans In some areas of the ocean, the anammox process is considered to be responsible for a significant loss of nitrogen Soil nitrogen is replenished by excretion of animals (as ammonia, urea and uric acid), ammonification and nitrification. 24

Carbon Cycle Carbon is an element which has six protons, six neutrons. Carbon is an basis of life of earth and is found in all earth systems. Carbon is the major chemical constituent of most organic matter, from fossil fuels to the complex molecules (DNA and RNA) that control genetic reproduction in organisms. Yet by weight, carbon is not one of the most abundant elements within the Earth's crust. In fact, the lithosphere is only 0.032% carbon by weight. In comparison, oxygen and silicon respectively make up 45.2% and 29.4% of the Earth's surface rocks. Carbon is stored on our planet in the following major sinks (1) As organic molecules in living and dead organisms found in the biosphere. (2) As the gas carbon dioxide in the atmosphere. (3) As organic matter in soils. (4) In the lithosphere as fossil fuels and sedimentary rock deposits such as limestone, dolomite and chalk. (5) (5) In the oceans as dissolved atmospheric carbon dioxide and as calcium carbonate shells in marine organisms. Carbon Cycle: The same carbon atoms are used repeatedly on earth. They cycle between the Atmosphere, Hydrosphere, Geosphere and Biosphere. Processes that transfer Carbon Between Earth Systems  Photosynthesis  Respiration  Consumption  Decomposition  Combustion (Burning)  Weathering (rocks break down and release carbon)  Dissolve/Vaporize (Between ocean and atmosphere)

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Plants Consume and Release Carbon Dioxide: Plants pull carbon from the atmosphere or hydrosphere and use it to make food by the process of photosynthesis. Plants release carbon by respiration. Animals consume and release carbon: When organisms eat (consume) plants or other organisms, they take in the carbon and some of it becomes part of their own bodies. When they breath (respiration) they release carbon.

Plants and Animal Die: When plants and animals die, most of their bodies are decomposed and carbon atoms are returned to the atmosphere. Some are not decomposed fully and end up in geosphere deposits underground (soil, oil, coal, etc.) or at the bottom of ocean. Natural combustion: Forest and grass fires are a natural, required part of the carbon cycle that release carbon into the atmosphere and geosphere. Fire returns carbon to the soil and “cleans out” unhealthy plants, allowing new plants to grow. Carbon Slowly Returns to Atmosphere: Carbon in rocks and underground deposits is released very slowly into the atmosphere. This process takes many years and is usually caused by weathering. Carbon in Oceans: Oceans store large amounts of carbon. Largest exchange of carbon in carbon cycle is the dissolving and vaporization of carbon dioxide between the atmosphere and ocean surface. Many animals pull carbon from water to use in shells, etc. When these animals die, the carbon substances are deposited at the bottom of the ocean. Balanced Carbon Cycle:-

Unbalanced Cycle - Human Impact: Under balanced conditions, fossil fuels release carbon stores very slowly into atmosphere.  When humans burn fossil fuels, it releases a tremendous amount of carbon into the atmosphere over a very short time span.  Increased carbon dioxide in atmosphere increases global warming  Fewer plants mean less CO2 removed from atmosphere What is your carbon footprint? A carbon footprint is the amount of carbon emitted into the atmosphere by your personal, day-to-day activities. Examples: Type of car you drive, how far you drive your car, how much electricity you use (electricity primarily comes from burning coal), where the food you buy is grown and airplane flights. Why do we care? Because of Global Warming Things you can do to reduce your carbon footprint  Promote plant life, especially trees  Buy a fuel efficient vehicle  Purchase locally grown food  Reduce electricity use  Reduce how far/much you drive  Take less airplane trips  Reduce, Reuse, Recycle 26

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Question No - 03

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Biodiversity loss and its Conservation? Biodiversity (biological diversity) it refers “for variety of diversity within the biological world”. Biodiversity is virtually synonymous with "life on earth". This term was coined in 1985 and during the 1990 s has become very widely used in the popular media and in government and scientific circulars. Biodiversity is thus “the totality of genes species and Ecosystem in the region". The term biodiversity is made of tow wards bio and diversity; bio means leaving and Diversity means variety. So the variety or variability of organisms and Ecosystem is referred as biodiversity. The variety of various living organisms present on earth is called as biodiversity. In simplest way we can say variety among living organisms is called as the biodiversity. The bacteria fungi microorganisms insects and human being all are the basic part of the biodiversity. It can occur in a small particular area or in a large area for small aquarium or in a large portion or in desert ecosystem, Terrestrial ecosystem, grassland ecosystem and forest ecosystem. Different varieties are present of the Earth these varieties of organisms are called biodiversity. Biodiversity can be divided into three types or three levels genetic biodiversity, species biodiversity and Ecosystem biodiversity. 1. Genetic Biodiversity: - the particular change will be occurred in the particular same species due to variation of the genus such kind of biodiversity is called genetic biodiversity. For example: Human species we have not same colour, hair and nose etc. Different varieties of rose- rose has a Red Colour, Yellow Colour and White Colour. Variations of genes observable with the species, basic source of diversity. It refers to the variation of genes within the species. This constitutes distant population of some species or genetic variation within population or verieties within a species. 2. Species biodiversity:- varieties of species within region. Meaning of species is kind. All the organisms of same kind which are able to breed in nature and produce live and fertile offspring’s are known as species. So species biodiversity refers to the varieties of species within a region. Such Biodiversity could be measured on the basis of number of species in a region. Taxonomists estimate that there may be somewhere between 3 million to 50 million different species alive today. It can be divided by some sub types (a) Species Richness: - number of particular organisms individual in that area which is rich (which number is highest). The highest number of individual in a particular individual area time. (b) Species evenness: - means there are the similar number of individual in a particular area in a particular time. (c) Global biodiversity (Also called Gamma biodiversity):- in which there are huge variety of different plants and animals and different kind of other living organisms. 3. Ecosystem Biodiversity: - the term Ecosystem coined first by A.G Tansley 1935. A particular biodiversity is present in a particular ecosystem. For example in aquatic 27

ecosystem aquatic plants, animals are in the there they cannot survive in a desert ecosystem. In an ecosystem, there may exist different landforms, each of which support different and specific visitation. Ecosystem diversity is difficult to measure because the boundaries of the communities, which constitute the various sub ecosystems, are elusive. Ecosystem diversity could be best understood if one studies the communities in various ecological niches with the given ecosystem; each community is associated with definite spacious complexes. Why is Biodiversity Important? Biodiversity has a number of functions on the Earth. These are as follows:  Maintaining balance of the ecosystem: Recycling and storage of nutrients, combating pollution, and stabilizing climate, protecting water resources, forming and protecting soil and maintaining ecobalance.  Provision of biological resources: Provision of medicines and pharmaceuticals, food for the human population and animals, ornamental plants, wood products, breeding stock and diversity of species, ecosystems and genes.  Social benefits: Recreation and tourism, cultural value and education and research. The role of biodiversity in the following areas will help make clear the importance of Biodiversity in human life:  Biodiversity and food: 80% of human food supply comes from 20 kinds of plants. But humans use 40,000 species for food, clothing and shelter. Biodiversity provides for variety of foods for the planet.  Biodiversity and human health: The shortage of drinking water is expected to create a major global crisis. Biodiversity also plays an important role in drug discovery and medicinal resources. Medicines from nature account for usage by 80% of the world’s population.  Biodiversity and industry: Biological sources provide many industrial materials. These include fiber, oil, dyes, rubber, water, timber, paper and food.  Biodiversity and culture: Biodiversity enhances recreational activities like bird watching, fishing, trekking etc. It inspires musicians and artists. Reason for Loss of Biodiversity The earth’s biodiversity is in grave danger. In the present era, human beings are the most dangerous cause of destruction of the earth’s biodiversity. In 2006, the terms threatened, endangered or rare were used to describe the status of many species. The “evil quartet” identified by Jared Diamond is overkill, habitat destruction, secondary extinctions and introduced species. Factors identified by Edward Wilson are described by the acronymHIPPO standing for habitat destruction, climate change, invasive species, pollution, human overpopulation and over-harvesting. Habitat destruction is a major cause for biodiversity loss. Habitat loss is caused by deforestation, overpopulation, pollution and global warming. Species which are physically large and those living in forests or oceans are more affected by habitat reduction. Some expert’s estimate that around 30% of all species on earth will be extinct by 2050. According to the International Union for Conservation of Nature (IUCN), globally about one third of all known species are threatened with extinction. Even it is estimated that 25% of all mammals will be extinct within 20 years. Even if a small element of an ecosystem breaks down, the whole system’s balance is threatened. Fresh water ecosystems are nowadays the most threatened ecosystems. Invasive 28

species refer to those that would normally remain constrained from an ecosystem because of the presence of natural barriers. Since these barriers are no longer existing, invasive species invade the ecosystem, destroying native species. Human activities have been the major cause for encouraging invasive species. Species can also be threatened by genetic pollution- uncontrolled hybridization and gene swamping. For instance, abundant species can interbreed with rare species thus causing swamping of the gene pool. Over exploitation is caused by activities such as over fishing, over hunting, excessive logging and illegal trade of wildlife. Over 25% of global fisheries are being overfished at unsustainable levels. Global warming is also becoming a major cause for loss of biodiversity. For example if the present rate of global warming continues, coral reefs which are biodiversity hotspots will disappear in 20-40 years. 10% of all species might become extinct by 2015, if global warming continues. Thus we can see that biodiversity which is crucial for the well being of life on earth, is coming under the threat of many factors related to human activities. There is an urgent need to take action to protect the magnificent biodiversity of our planet. We must create economic policies in order to maintain the Earth’s biodiversity and take appropriate measures to protect habitats and species. ‫ ٭‬Question No - 04 ‫٭‬

Preservation & Conservation of Ecosystem through resource management? Preservation:Merriam-Webster defines preservation as ‘to keep safe from injury, harm or destruction.’ The term preservation was derived from Latin prae– + servare. Prae- is the archaic variant of the prefix pre– which means before, earlier or prior to. Servare is the present infinitive of servō, which means ‘watch over, maintain, protect, keep, guard, save, or store.’ Therefore, the two Latin words taken together and to encompass all the descriptions of preservation means: To watch over, to maintain, to protect, to keep, to guard, to save, and to store. Based on these definitions, in the environmental context, preservation calls for a ‘no touch’ policy, to keep whatever existing natural resources there are, to its present condition. The emphasis is on maintaining the integrity of the natural resource. Strict protection implied for a defined period anticipates the value it can give to present, as well as, future generations. Consequence of overhunting. As a matter of government policy, for example, it may set aside and declare a forest as a protected area. One of the features of a protected area is the core zone. The core zone is that specific area with defined boundaries where no use is allowed at all. This area then gets preserved and able to carry out its ecological functions. Thus, it can serve as a natural water reservoir, habitat for wildlife, erosion prevention, flood control, carbon storage, oxygen production, buffer against storms, maintenance of soil fertility, among others. A game preserve is another example. People are prohibited from hunting game in that region to allow a species with a depleted population to recover. Hence, it is a ‘no take’ zone in view of making it available in the future. 29 To synthesize everything, preservation, therefore, can be defined as a natural resource management approach advocating non-utilization of a natural resource. This approach views

a sustainable flow of benefits that can be enjoyed at present or protecting a resource for future use. Conservation:Using Merriam-Webster’s definition, conservation means ‘to keep (something) from being damaged or destroyed.’ This word sounds similar to preservation. But another definition says, ‘to use (something) carefully to prevent loss or waste.’ The latter appears to be a better definition that distinguishes conservation from preservation. In other words, conservation does not only aim to keep natural resources from being damaged or exploited but to use them optimally. There is the incorporation of the ‘wise use’ policy in this natural resource management approach. Benefits accrues while resources stay the same. Resources are used sparingly or wisely so that they are still available in the future. Conservation emphasizes the use of the natural resource. The resources subject to conservation may be renewable or non-renewable. For example, you can say ‘conserve water’ or ‘conserve oil or fuel’ but you do not say ‘preserve water’ or ‘preserve oil or fuel.’ Water is a renewable resource whereas oil or fuel is non-renewable or exhausted with use. The use of the latter resource relates to pollution. Another good definition of Merriam-Webster is that conservation is ‘planned management of a natural resource to prevent exploitation, destruction, or neglect.’ This definition adequately captures the role of man as a resource manager. This definition suggests that conservation is a broader concept compared to preservation. A planned management can incorporate preservation, protection, wise use, maintenance and reduction of the ill effects or negative externalities associated with its use. Conservation, therefore, can be succinctly defined as a natural resource management approach that seeks to attain sustainable or prolonged use of natural resources with minimal environmental impact. The two approaches described reflects philosophies in natural resource management. While there may be a difference in terms of the approach, the result is to achieve a sustained enjoyment of benefits. UN Environment and its partners support the design and establishment of monitoring systems for ecosystem health and functioning, for example, the Biodiversity Indicators Partnership (BIP), a global initiative to develop and promote indicators for the consistent monitoring and assessment of biodiversity. UN Environment supports species conservation: It hosts the Great Apes Survival Partnership, a United Nations initiative committed to ensuring the long-term survival of chimpanzees, gorillas, bonobos, and orangutans and their habitats in Africa and Asia; as well as species conservation programmes for dugong and sharks. Conserving our biodiversity is extremely important, not only in terms of its intrinsic values but because many of our economic activities are based on healthy and functioning natural systems. An essential part of ecosystem conservation is the establishment of a comprehensive and well managed reserve system There are a range of management programs underway in South Australia to conserve and restore ecosystems both on and off reserves. These programs involve the:  removal of threats, such as environmental weeds or grazing by domestic stock and feral animals  eradication of introduced predators such as foxes and cats  re-introduction of threatened species and the restoration of habitat through revegetation programs. Management programs are crucial if we are to retain healthy and functioning ecosystems in the longer term. 30

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Question No - 05

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Ecological Footprint & Concept of Green Economy? (Ecological Footprint) Ecology : (German biologist , Ernst Haeckel coined the term `oecology` or `oekology` in 1869 . derived from two Greek Words, `oikos` meaning house or dwelling as habitat and `logos` meaning the study of ) to understand the relationships between organisms and environment. Ecology , in a simple term ,is a science which studies ,interrelationships between abiotic and biotic components of the biospheric ecosystem on the one hand and biotic components on the other hand. The ecological footprint is a measure of human demand on the Earth,s ecosystem. It is a standardized measure of demand for natural capital that may be contrasted with the planet`s ecological capacity to regenerate. It represents the amount of biologically productive land and sea area necessary to supply the resources a human population consumes, and to assimilate associated waste . An ecological footprint is the area required to provide the goods and services consumed by individuals, communities or organizations. It can also be derived for products or for particular activities. Using an 'area equivalence' expressed as 'global hectares', the ecological footprint expresses how much of nature's renewable bioproductive capacity (or 'interest') we are currently appropriating. If more of nature's interest is consumed than is available (i.e. nature's 'capital' is being reduced), then it is possible to assume that the rate of consumption is not sustainable (Chambers et al., 2000). Every person, region, organisation or service has an impact on the earth. We all rely on the products and services of nature, to supply us with raw materials and to assimilate our wastes. The impact we have on our environment is related to the 'quantity' of nature that we use to sustain our consumption patterns. Measurement of Ecological Footprint The ecological footprint is measured in terms of carbon land(gray), cropland (yellow), grazing land (green ),forest (dark green), built-up land(orange) and fishing grounds (blue). Water use is not measured, but is quantified and graphed later in the report. The carbon component takes up more than half (55%) of the resources tracked. More than a quarter of the countries have indices in which carbon represents more than half of their total ecological footprint. For the purposes of calculating an ecological footprint, bioproductive land and sea is categorised into four basic types.

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The Ecological Footprint measures the amount of biologically productive land and water area an individual, a city, a country, a region, or all of humanity uses to produce the resources it consumes and to absorb the waste it generates with today’s technology and resource management practices. Ecological footprint is expressed in "global hectares" (gha) or "global acres" (ga), which are standardized units. Footprint helps in 1) Assess the value of country`s ecological assets. 2) Monitor and manage their assets. 3) Identify the risks associated with ecological deficits. 4) Set policy that is informed by ecological reality and makes safeguarding resources a top priority. 5) Measure progress towards their goals.

Conclusion : The Ecological Footprint is a resource accounting tool that helps countries understand their ecological balance sheet and gives them the data necessary to manage their resources and secure their future . Footprint for Nations In today`s world, where humanity is already exceeding planetary limits, ecological assets are becoming more critical. Each country has its own ecological risk profile. Many countries are running ecological deficits, with footprints larger than their own biological capacity. Other countries depend heavily on resources from elsewhere, which are under increasing pressure. In some areas of the world, the implications of ecological deficits can be devastating, leading to resource loss’ ecosystem collapse, debt, poverty, famine and war. It is almost certainly the case that countries and regions with surplus ecological reserve –not the ones relying on continued ecological deficit spending –will emerge as the robust and sustainable economies and societies of the future.

Countries with the biggest ecological footprint per person 1. 2. 3. 4. 5.

Qatar Kuwait United Arab Emirates Denmark United States

6. 7. 8. 9. 10.

Belgium Australia Canada Netherlands Ireland

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Countries with the smallest ecological footprint per person 1. 2. 3. 4. 5.

Occupied Palestinean Territory Timor Leste Afghanistan Haiti Eritrea

6. 7. 8. 9. 10.

Bangladesh Rwanda Pakistan Democratic Republic of Congo Nepal

Inference: The Middle East /Central Asia and European Union had countries whose per capita footprints increased the most. North Americans maintained the highest regional footprint. People in high-income countries have much greater ecological footprints than both middle –and low-income countries. If everyone in the world used the same amount of resources as citizens of the United States, the world wildlife Network points out that “ a total of four earths would be required to regenerate humanity`s demand on nature.”The World Wildlife Fund says that in 2008 the world`s total biocapacity was 12 billion gha. Humanity used 18.2 billion gha in resources, meaning it would take a year and a half for people to regenerate the amount of resources used in a year. Water footprint: The water footprint of a product is the volume of freshwater appropriated to produce the product ‘taking into account the volumes of water consumed and polluted in the different steps of the supply chain. It helps us to promote the transition towards sustainable, fair and efficient use of fresh water resources worldwide. It is an indicator of water use that looks at both direct and indirect water use of a consumer or producer. The global water footprint in the period 1996-2005 was 9087 Gm3/yr (74% green, 11% blue, and 15% grey). Agricultural production contributes 92% to this total footprint. Water scarcity affects over 2.7 billion people for at least one month each year. Carbon Footprint: Historically defined by championne as “the total sets of greenhouse gas (GHG) emissions caused by an organization, event, product or person “ Critique: to calculate the total carbon footprint is impossible due to the large amount of data required and the fact that carbon dioxide can be produced by natural occurrences New definition : Wright ,Kemp ,and Williams defined it as “ A measure of the total amount of CO2 and CH4 emissions of a defined population , system or activity ,considering all relevant sources ,sinks and storage within the spatial and temporal boundary of the population ,system or activity of interest. Calculated as CO2 equivalent using the relevant 100-year global warming potential (GWP100) While not a direct measure of species populations, the ecological footprint provides an indicator of the pressure on ecosystems and biodiversity by measuring the competing level of ecological demand that humans place upon the biosphere. Global Ecological Footprint data show that humanity is using resources and producing CO 2 emissions at a rate 44% greater than what nature can regenerate and reabsorb. This gap known as ecological overshoot, results in the depletion of the natural capital that all species (including our own) depend on for their livelihood. Humanity`s Ecological Footprint has grown 80% over the last four decades .the greater the gap between human demand and nature`s regenerative capacity , the more pressure there will be on the resources other species need to survive ,and the more perilously biodiversity will be under threat. 33

(Green Economy) A green economy is one that results in improved human well-being and social equity, while significantly reducing environmental risks and ecological green economy is an economy or economic development model based on sustainable development and a knowledge of cological economics. Its most disting feature from prior economic regimes is direct valuation of natural capital and ecological services as having economics value (see The Economics of Ecosystems and Biodiversity and Bank of Natural Capital) and a full cost accounting regime in which costs externalized onto society via ecosystems are reliably traced back to, and accounted for as liabilities of, the entity that does the harm or neglects an asset. Green economics" is loosely defined as any theory of economics by which an economy is considered to be component of the ecosystem in which it resides (after Lynn Margulis). A holistic approach to the subject is typical, such that economic ideas are commingled with any number of other subjects, depending on the particular theorist. Proponents of feminism, postmodernism, the ecology movement, peace movement, Green politics, green anarchism and anti-globalization movement have used the term to describe very different ideas, all external to some equally ill-defined "mainstream" economics. The use of the term is further ambiguated by the political distinction of Green parties which are formally organized and claim the capital-G "Green" term as a unique and distinguishing mark. It is thus preferable to refer to a loose school of "'green economists"' who generally advocate shifts towards a green economy, biomimicry and a fuller accounting for biodiversity. Some economists view green economics as a branch or subfield of more established schools. For instance, as classical economics where the traditional land is generalized to natural capital and has some attributes in common with labor and physical capital (since natural capital assets like rivers directly substitute for man-made ones such as canals). Or, as Marxist economics with nature represented as a form of lumpen proletariat, an exploited base of non-human workers providing surplus value to the human economy. Or as a branch of neoclassical economics in which the price of life for developing vs. developed nations is held steady at a ratio reflecting a balance of power and that of non-human life is very low. An increasing consensus around the ideas of natural capital and full cost accounting could blur distinctions between the schools and redefine them all as variations of "green economics". As of 2010 the Bretton Woods institutions (notably the World Bank and International Monetary Fund (via its "Green Fund" initiative) responsible for global monetary policy have stated a clear intention to move towards biodiversity valuation and a more official and universal biodiversity finance. Taking these into account targeting not less but radically zero emission and waste is what is promoted by the Zero Emissions Research and Initiatives. Definition of a green economy:Karl Burkart defines a green economy as based on six main sectors:

Renewable energy (solar, wind, geothermal, marine including wave, biogas, and fuel cell) Green buildings (green retrofits for energy and water efficiency, residential and Commercial assessment; green products and materials, and LEED construction) Clean transportation (alternative fuels, public transit, hybrid and electric vehicles, carsharing and carpooling programs) Water management (Water reclamation, greywater and rainwater systems, low-water landscaping, water purification, stormwater management) Waste management (recycling, municipal solid waste salvage, brownfield land remediation, Superfund cleanup, sustainable packaging) Land management (organic agriculture, habitat conservation and restoration; urban forestry and parks, reforestation and afforestation and soil stabilization) The three pillars of sustainability

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The three pillars of sustainability. The Global Citizens Center, led by Kevin Danaher, defines green economy differently from the use of pricing mechanisms for protecting nature, by using the terms of a "triple bottom line," an economy concerned with being: 1. Environmentally sustainable, based on the belief that our biosphere is a closed system with finite resources and a limited capacity for self-regulation and selfrenewal. We depend on the earth’s natural resources, and therefore we must create an economic system that respects the integrity of ecosystems and ensures the resilience of life supporting systems. 2. Socially just, based on the belief that culture and human dignity are precious resources that, like our natural resources, require responsible stewardship to avoid their depletion. We must create a vibrant economic system that ensures all people have access to a decent standard of living and full opportunities for personal and social development. 3. Locally rooted, based on the belief that an authentic connection to place is the essential pre-condition to sustainability and justice. The Green Economy is a global aggregate of individual communities meeting the needs of its citizens through the responsible, local production and exchange of goods and services. The Global Green Economy Index, published annually by consultancy Dual Citizen Inc., measures and ranks the perception and performance of 27 national green economies. This index looks at 4 primary dimensions defining a national green economy as follows: 1. Leadership and the extent to which national leaders are champions for green issues on the local and international stage 2. Domestic policies and the success/ s of policy frameworks to successfully promote renewable energy and green growth in home market 3. Cleantech Investment and the perceived opportunities and cleantech investment climate in each country 4. Green tourism and the level of commitment to promoting sustainable tourism through government Other issues:Green economy includes green energy generation based on renewable energy to substitute for fossil fuels and energy conservation for efficient energy use. Because the market failure related to environmental and climate protection as a result of external costs, high future commercial rates and associated high initial costs for research, development, and marketing of green energy sources and green products prevents firms from being voluntarily interested in reducing environment-unfriendly activities (Reinhardt, 1999; King and Lenox, 2002; Wagner, 203; Wagner, et al., 2005), the green economy may need government subsidies as market incentives to motivate firms to invest and produce green products and services. The German Renewable Energy Act, legislations of many other EU countries and the American Recovery and Reinvestment Act of 2009, all provide such market incentives. Critique of the 'Green Economy':A number of organisations have critiqued aspects of the 'Green Economy', articularly the mainstream conceptions of it based on using price mechanisms to protect nature, arguing that this will extend corporate control into new areas from forestry to water. The research organisation, Etcgroup, argues that the orporate emphasis on bio-economy "will spur even greater convergence of corporate power and unleash the most massive resource grab in more than 500 years." Venezuelan professor Edgardo Lander says that the UNEP's report, Towards a Green Economy, while well-intentioned "ignores the fact that the capacity of existing political systems to establish regulations and restrictions to the free operation of the markets – even when a large majority of the population call for them – is seriously limited by the political and financial power of the corporations." Ulrich Hoffmann, in a paper for UNCTAD also says that the focus on Green Economy and "green growth" in particular, "based on an evolutionary (and often reductionist) approach will not be sufficient to cope with the complexities of climate change" and "may rather give much false hope and excuses to do nothing really fundamental that can bring about a U-turn of global greenhouse gas emissions.

The three pillars of sustainability

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Javid Ahmad Mattoo (9622822905 / 7006824108)

Credit- 03 ‫ ٭‬Question No - 01 ‫٭‬ Structure and Types of Environment? Nowadays the word environment is often being used by almost all people around us, on television and in newspapers. Everyone is speaking about the protection and pre-serration of environment. Global summits are being held regularly to discuss environmental issues. During the last hundred years, the mutual relationship among environment, social organization and culture has been discussed in sociology, anthropology and geography. All this shows the increasing importance of environment. Besides, it is a fact that life is tied with the environment.

The word environment has been derived from the French word “Environia” which means to encircle to surrounded. The dictionary meaning of the word environment a surrounding. External conditions influencing developed of growth of people animals and plants and their living or working conditions. This involves three basic questions. What is surrounded? By what is surrounded? And where surrounding? Overly the answer of the first question living organism in general and man in particular. If man is taken to be surrounding, physical attributes become answer to the second question which signifies the environment and where is the space or habitat. According to C.C Path 1980 refers to sum total conditioners which surrounded at a man at a given point in space and time. The term environment has been derived from a French word “Environia” means to surround. It refers to both abiotic (physical or non-living) and biotic (living) environment. The word environment means surroundings, in which organisms live. Environment and the organisms are two dynamic and complex component of nature. Environment regulates the life of the organisms including human beings. Human beings interact with the environment more vigorously than other living beings. Ordinarily environment refers to the material sand forces that surround the living organism. Environment is the sum total of conditions that surrounds us at a given point of time and space. It is comprised of the interacting systems of physical, biological and cultural elements which are interlinked both individually and collectively. Environment is the sum total of conditions in which an organism has to survive or maintain its life process. It influences the growth and development of living forms. It consists of atmosphere, hydrosphere, lithosphere and biosphere. Its chief components are soil, water, air, organisms and solar energy. It has provided us all the resources for leading a comfortable life. 1. According to P. Gisbert “Environment is anything immediately surrounding an object and exerting a direct influence on it.” 2. According to E. J. Ross “Environment is an external force which influences us.” Mountain Environment, Plane Environment. Plateau Environment, River Environment, Lake Environment

Littoral Environment, Shallow Environment, Deep-sea Environment Tropical Environment, Temperat Environment, Polar Environment

Environment Plnts

Terrestrial Environment

Animals

Environment Aquatic Environment

Landfunal Aquatic

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Types of Environment There are mainly three types of environment1. The Physical environment (Abiotic)  It is also known as a-biotic environment and natural environment.  The meaning of ‘a-biotic’ or ‘physical’ is non living like land water air conditions atmosphere which constitutes of soil. So we can say that physical or a-biotic environment is the environment which includes non living or physical things which are constitutes of soil and affect the living things.  The physical or a-biotic environment also includes the climatic factors such as sunbeams, rainwater, precipitation, moisture, pressure and wind speed. The Importance of Physical Environment  Just think, the most important thing to make house is residential space, and for residential space, we need land area. The land area is included in physical environment. So it is responsible for the residential for living beings.  The a-biotic environment like soil, water and air are the necessary nutrients element provider for the living beings.  All of living beings are surrounded by atmosphere; it is the combination of different types of gases. The living beings take oxygen and other gases from the atmosphere.  The a-biotic environment also controls the climatic factors like weather.  The physical environment also includes the soil which is responsible for the works and food crops for the living beings. It also provides different types of minerals which are very necessary for growth of life  Water is one of the most necessary things for living beings. Physical environment also deals with the water factor of the earth. 2. Biotic environment  It is also known as biological environment and organic environment.  In the opposite side of the physical environment, the biotic or biological environment is responsible for the living beings.  You have already understood that the meaning of ‘biological’ is living things. So, the biological environment is the environment which involves the living part of the earth. The importance of biotic environment  In this type of environment includes the plants, trees, animals, mammals, underwater living beings including human beings and microorganisms like bacteria and fungi.  There is a concept which is necessary to understand. The living beings are highly dependent to each other. For example humans are highly depend upon plants and trees for food and oxygen, and plants and trees are also depend upon humans and animals because of co2 3. Social or cultural environment (Built Environment)  This type of environment involves the culture and life style of the human beings.  The social or cultural environment means the environment which is created by the man through his different social and cultural activities and thinking.  The historical, cultural, political, moral, economic aspects of human life constitute to the social or cultural environment The Importance of Social or Cultural Environment  Culture involves the religion of the human, relations with each other etc. In a society there involve different types of people, they have different religion, different thinking, which has culture of its own and posses people having their own life style.  The social or culture environment affects the social culture of human beings and hence it has the great importance. 37



The development of a child is highly depends upon culture and society.

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Question No - 02

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Components of Environment? The environment is defined as the whole physical and biological system surrounding man and other organisms along with various factors influencing them. The factors are soil, air, water, light, temperature etc. These are called Abiotic factors. Besides the abiotic factors, the environment is very much influenced by biotic factors which include all forms of life like plants, animals, microorganisms etc. Man is thus an inseparable part of the environment. Man and Environment have very close relationship with each other. The social life of man is affected by environment. This is the reason for various types of social and cultural activities around the world. The hilly people have different life styles than people in the plain area. Similarly people around the world differ in their food, cloth, festivals etc. All these are influenced by the factors around him.

(a) Biotic Components: - The biological constituent of environment is also called biotic component of environment. This component consists of all living things like plants, animals and small micro-organisms like bacteria. This component interacts with the abiotic component of the environment. This interaction of two components forms various ecosystems like pond ecosystem, marine ecosystem, desert ecosystem etc. The self sufficient large ecosystem of the earth is called Biosphere. All ecosystems consist of three different types of living organisms. These three types are named as:

(a) Producers (b) Consumers (c) Decomposers.

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(b) Abiotic Components: - The Physical Constituent of environment includes soil, water, air, climate, temperature, light etc. These are also called abiotic constituents of the environment. This part of the environment mainly determines the type of the habitat or living conditions of the human population. This physical constituent of the environment is again divided into three parts. These are: (i) Atmosphere (gas) (ii) Hydrosphere (liquid) (iii) Lithosphere (solid) 1. Atmosphere: The following points highlight the vital role played by atmosphere in the survival of life in this planet:

a. The atmosphere is the protective blanket of gases which is surrounding the earth. It protects the earth from the hostile environment of outer space. b. It absorbs 1R radiations emitted by the sun and reemitted from the earth and thus controls the temperature of the earth. c. It allows transmission of significant amounts of radiation only in the regions of 300 – 2500 nm (near UV, Visible, and near IR) and 0.01 – 40 meters (radio waves), i.e. it filters tissue damaging UV radiation below 300 nm. d. It acts as a source for C02 for plant photosynthesis and 02 for respiration e. It acts as a source for nitrogen for nitrogen fixing bacteria and ammonia producing plants. f. The atmosphere transports water from ocean to land. 2. Hydrosphere: The hydrosphere is a collective term given to all different forms of water. It includes all types of water resources such as oceans, seas, rivers, lakes, streams, reservoirs, glaciers and ground waters. The distribution of earth’s water supply is shown in figure-1.1.

As can be seen, only 1 % of the total water supply is available as fresh water in the form of rivers, lakes, streams and ground water for human consumption and other uses. The extent of the use of available fresh water for various purposes is shown in the following figure -1.2.

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The major problem with global water supply is its non-uniform distribution, since people in areas with low precipitation often consume more than people in regions with more rainfall. 3. Lithosphere: a. The earth is divided in to layers as shown in figure-1.3

b. The lithosphere consists of upper mantle and the crust. The crust is the earth’s outer skin that is accessible to human. The crust consists of rocks and soil of which the latter is the important part of lithosphere. 4. Biosphere: The biosphere refers to the realm of living organisms and their interactions with the environment (VIZ: atmosphere, hydrosphere and lithosphere) a. The biosphere is very large and complex and is divided into smaller units called ecosystems. b. Plants, animals and microorganisms which live in a definite zone along with physical factors such as soil, water and air constitute an ecosystem. c. Within each ecosystems there are dynamic inter relationships between living forms and their physical environment. The natural cycles operate in a balanced manner providing a continuous circulation of essential constituents necessary for life and this stabilizes and sustains the life processes on earth. d. These inter relationships manifest as natural cycles, (hydrologic cycle, oxygen cycle, nitrogen cycle, phosphorous cycle and sulphur cycle).The shape of the Earth is very close to that of an oblate spheroid, a sphere flattened along the axis from pole to pole. Within the biosphere, there are several major regions containing specific types of ecosystems. These major regions are called biomes. Biomes are then recognized by the types of dominant ecosystem- tropical rainforests, temperate forests, prairies, deserts, and arctic tundra. The ecosystems again are composed of population which is composed of individuals. The global estimate of species of both prokaryotes and eukaryotic life forms are given in Tables 1(A).1 and 1(A).2 These figures imply the fact that how diverse is our biological world on earth is?

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Question No - 03

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Man Induced Environmental & Ecological Changes? Humans have had a profoundly adverse impact on the environment. Generally, people have not conducted activities such as manufacturing, transport, large-scale fishing, agriculture and waste disposal in moderation. This has led to degradation of land, air and water. While the full range of long-term consequences of human intervention on the environment has yet to be seen, some consequences are already taking effect, such as climate change. Land Degradation:Humans' failure to use land sustainably has led to its degradation. People clear forests to use the land either for agriculture or to settle on. Consequently, forest cover dwindles significantly, leading to soil erosion and extinction of plant species. Land animals have also declined in numbers, and some have even gone extinct due to human expansion that encroaches on their natural habitat and limits their ability to spread geographically. Air Pollution:The air has been the hardest hit element of the environment due to a variety of human activities. The transport sector contributes heavily to air pollution because most forms of transport -- including cars, planes and ocean vessels -- use one form of fossil fuel or the other, which when burned releases carbon dioxide and other gases into the environment. The manufacturing industry that grows exponentially with the expansion of the population is another source of air pollution. Manufacturing plants emit carbons and sulfurs that do not occur naturally in the environment, causing an imbalance in the quality and composition of air. Some air pollutants deplete the ozone layer and expose the Earth to dangerous radiation from the sun. Water Contamination:Human intervention in the environment causes water contamination and jeopardizes the supply and flow of clean, natural drinking water. Human activities such as waste disposal from residential, commercial and industrial places, oil spills and agricultural use of artificial fertilizers that contain hazardous chemical substances all contaminate water bodies. Pollutants are either directly deposited into lakes, rivers, seas and streams or hazardous substances are washed into them during the rainy seasons. The water element of the environment has also suffered from exploitation such as when humans overfish or aggressively hunt species such as sharks for their own purposes. The net effect of the contamination has been the death and reduction in diversity of marine life and scarcity of clean water. 41 Climate Change:Human activities in the environment can interfere with the planet's natural balance, making the Earth’s climate less stable and predictable. Occurrences such as unprecedented flooding; increased numbers of storms, hurricanes and typhoons; fiercer brush fires; and most notably tsunamis, which are uncommon in the Earth’s recent history, are being witnessed all across

the world. Phenomena such as rising sea levels, unseasonably high temperatures and drought hint toward an environment that cannot take much more negative human intervention.

Human Induced Changes In Ecosystem Not all changes to an ecosystem are caused by natural forces. Ecosystems are also affected by human disturbances, which are caused by people. Imagine a polluted stream with dead fish floating in the water or a bulldozer clearing forested land and destroying natural habitats to build a new shopping center. Following are some of the human induced changes: Carbon Dioxide Emissions The human activity most widely viewed as changing the planet is the burning of fossil fuels. In order to produce the energy that drives the world’s economy, countries rely on carbonrich fossil fuels like coal, oil and gas. By burning these materials, humans have added nearly 400 billion tons of carbon dioxide into the atmosphere between 1870 and 2013. Right now, atmospheric levels of carbon dioxide are higher than at any point in human history. Carbon dioxide is a heat-trapping gas and as a result of these atmospheric changes, average temperatures on the planet are rising and global weather patterns are changing. Some of the carbon dioxide in the atmosphere is absorbed into oceans, increasing their acidity by 30 percent over the past 100 years. This change has far reaching effects on oceanic ecosystems and the food chains that support underwater plant and animal life. Industrial Agriculture As the world’s population continues to grow, so does the amount of farmland needed to provide sufficient food. According to the UN Food and Agriculture Organization (FAO), over 40 percent of Earth’s surface is now comprised of agricultural lands and a large portion of these lands were once covered by forests. Much of Europe, for example, was once covered with dense temperate forests but over time population growth-driven deforestation has led to more farm land. According to the Union of Concerned Scientists, three billion tons of CO2 enters the atmosphere every year from deforestation. That destruction amounts to 13 million hectares destroyed annually, much of which occurring in the Amazon rain forest. Here, the regional cycle of evaporation and condensation has been disrupted, raising the possibility of the remaining forest becoming a savannah. Furthermore, because the rain forest is shrinking, its carbon-dioxide absorbing capacities are being diminished, which in turn means more of the heat-trapping gas is reaching the upper atmosphere, causing global temperatures to rise. Fertilizers used in farming have had far-reaching effects. Their use has injected vast amounts of nitrogen and phosphorous into regional ecosystems. Wired Science reports that 120 million tons of nitrogen is removed from the atmosphere each year and 20 million tons of phosphorous is mined from the ground in order to produce fertilizer to be used for farming. These practices add a tremendous amount of nitrogen and phosphorus to the biosphere than would occur naturally. Runoff from farmland often carries large amounts of fertilizer into rivers and streams that eventually drain into the sea. All of this fertilizer runoff creates rapidly-expanding marine dead zones. 42 Draining Rivers Life depends heavily on the supply of fresh water that exists in rivers, lakes and aquifers. According to Wired Science, it’s estimated that one fourth of Earth’s river basins run dry before ever reaching the ocean. This is the result of reduced rainfall caused by deforestation and the construction of man-made dams that divert water flow in inefficient ways. Less water flowing through river basins has also altered local weather patterns.

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Question No - 04

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Degradation of Slopes, Simplification of Ecosystem, Eutrophication, Introduction of Alien species? A. Degradation of Slopes Soil degradation is the decline in soil condition caused by its improper use or poor management, usually for agricultural, industrial or urban purposes. It is a serious environmental problem. Soils are a fundamental natural resource, and are the basis for all terrestrial life. Avoiding soil degradation is crucial to our well-being. Soil degradation is the physical, chemical and biological decline in soil quality. It can be the loss of organic matter, decline in soil fertility, and structural condition, erosion, adverse changes in salinity, acidity or alkalinity, and the effects of toxic chemicals, pollutants or excessive flooding. Soil degradation has been defined as a process that leads to decline in the fertility or future productive capacity of soil as a result of human activity (United Nations Environment Programme, 1993). It occurs whenever the natural balances in the landscape are changed by human activity through misuse or overuse of soil. Degraded soils which result in poor or no production are also called problem soils. Waste lands are those which for one or the other reason have poor life sustaining property. Out of 100 per cent potentially active lands only 44 per cent are available for cultivation and 56 per cent of land are non-available for cultivation. The wasteland can be made useful by increasing productivity of land by using some useful methods as afforestation or by using bio-fertilizers. Soil degradation is a complex phenomenon derived by interaction between natural and socio economic factors. The degradation or deterioration of soil may be caused by the following factors: 1. Physical factors, e.g. loss of fertile top soil due to water or wind erosion. 2. Chemical factors e.g. depletion of nutrients or the toxicity due to acidity or alkalinity (salinization) or water logging. 3. Biological factors which affect the micro-flora and reduce the microbial activity of the soil. These factors reduce the yield. Some other factors as deforestation, extensive cultivation on marginal land, improper cultivation practices like mono-cropping, poor manuring, misuse of fertilizers or excess use of fertilizers, excessive irrigation, over-grazing, fragility of soil, adverse weather and mining may accelerate the process of soil degradation. During last decade the nutrients deficiency has been considered as the main cause of poor productivity and crop failure. A study of the current trends in agronomic practices has suggested that the nutrients deficiency is further aggravated by continued use of high yielding crop varieties, intensive cropping pattern and relatively poor fertilizers. Among the major causes of degradation, water erosion is considered to be the most severe one which covers almost 87% of the affected area. The main cause of water erosion is removal of vegetation, over exploitation of vegetation, over grazing and improper agricultural practices. The latest data revealed that erosion has rendered 200 million hectares or 36% of the total area of the country barren (Table 27.1). Soil degradation is a global phenomenon. Of the world’s total land area of 13.5 billion hectares, only 3.03 billion hectares (22 per cent) is actually cultivable and about 2 billion hectares is degraded. The annual loss of land is expected to go up to 10 million hectares by 2000 A.D.(Yadava 1996). In India alone, about 188 million hectares or almost 57% of total 43 land area is degraded (Sehgel and Abrol, 1994).

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Causes of Soil Degradation: The main reasons for unproductiveness or degradation of soils are as follows: 1) Nutrient disorder: Most of the Indian soils are deficient in nutrients and organic matter. Organic matter is rapidly decomposed and leached or eroded by heavy rains. In addition to these causes, intensive cultivation using high-yielding short-duration and fertilizer-responsive cultivars of crops has further accelerated the loss of plant nutrients which is much greater than what is supplemented through fertilizers. According to an estimate of 1992, every year 20.2 million tonnes of NPK is removed by growing crops. The data published by National Bureau of Soil Survey and Land Use

Planning (Sehgal and Abrol, 1994) show that about 3.7 million ha land suffers from nutrient loss or depletion of organic matter. The problem is more severe in the cultivated areas of the subtropical belt. Out of 20.2 million tonnes NPK removed by the plants, only 2.66 million tonnes comes from fertilizers and 3 million tonnes from organic sources. If the loss of nutrients due to soil erosion is included, the loss of nutrients from top soil is 43 million tonnes. 2) Water-logging: Soils become water-logged when the water balance of an area is disturbed because of excess recharge. Important sources of water are heavy rains, overland water flow towards basin, seepage from canals and distribution system and tidal flooding. Natural basins without outlet for water, low permeability of subsurface horizons, internal drainage, low intake rate of surface soils and obstructions to natural flow of rain water etc. are conditions cause water logging. In highly productive areas, canal irrigation is responsible for a rapid rise in water table. Expansion of canal irrigation is also directly concerned with widespread water-logging and salinity problems in arid and semiarid areas. Disturbances in the hydrologic cycle due to inefficient use of surface irrigation water, poor land development, seepage and poor drainage have resulted in higher water tables. Most of the canal areas in arid and semiarid regions are rich in soluble salts. In irrigation these salts are dissolved in soil water and rise to the surface through capillary action. When the water dries up, the salts are left on the upper surface as a crust or layer. According to National Commission on Agriculture (1976), about 6 million ha area is under water-logged condition. Data of World Bank Survey (1995) reveal that India loses 1.2 to 6 million tonnes of food grains production every year due to water-logging of soil. The water-logging and salinity cause a loss of Rs. 12 billion to 27 billion annually. 3) Salinity (Saline and alkali soils): Salinity directly affects the productivity by making the soil unsuitable for crop growth. Indirectly it lowers productivity through its adverse effects on the availability of nutrients. The adverse effect of alkalinity on availability of nutrients is due to deflocculating effect of sodium ions. An area of about 21.7 million hectares of soil is rendered unproductive due to salinity and water-logging. The saline degradation is due to natural causes and poor irrigation practices which disturb the water cycle in areas. Most of the crops in India are affected due to salinity. Productivity loss of some crops is given in Table 27.5.

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4) Erosion: Soil erosion is the major cause of soil degradation. In the soil erosion, uppermost fertile layer of soil which contains essential nutrients is lost. Thus soil becomes deficient in essential minerals and this results in productivity loss. Deforestation or destruction of forests accompanied by reduced frequency of rainfall leads to soil erosion and causes damage to agriculture property. Deforestation causes fast degradation when the soil is steep sloppy or

easily erodible. Destruction of natural vegetation cover is a major factor responsible for erosion of soils by water and wind. According to Global Assessment of Soil Degradation (GLASOD), deforestation is the main cause of soil erosion by wind in about 98% of the area. Overgrazing, cutting of timber trees, collection of fuel wood, shifting cultivation and encroachment of forest areas are some of the important factors responsible for the loss of vegetation cover on the soil which ultimately causes soil erosion. The latest data provided by Sehgal and Abrol (1994) show that the total degraded land in India is 187.8 million ha, of which 162.4 million ha is degraded due to soil erosion alone (Table 27.6). Table 27.6 presents the area under different types of soil degradation in different years:

5) Biological degradation: The factors which affect soil micro flora and fauna also reduce the biological or microbial activity of soil adversely. These factors reduce the yield. It is well known that mono cropping (growing the same crop on the same land year after year) often leads to increasing attack of pests and diseases. The fatal nematodes threaten potato cultivation in the Nilgiris and, if not controlled they may pose threat to potato cultivation in that area. Excess use of pesticide reduces microbial activity and biomass. Applications of some pesticide chemicals (e.g., amitrole, atrazine, bromacil, picloram, etc.) inhibit nitrification. The nodulation and growth of some leguminous crops and nitrogen fixation are inhibited by different pesticides. Disposal of oil shales, heavy metal contamination of soil and spillage of crude oils adversely affect soil micro flora which ultimately affect soil productivity and cause soil degradation. 6) Other Causes of Soil Degradation: a) Extension of cultivation to marginal land: Due to tremendous population increase the use of land is increasing day by day. Marginal lands though sustainable for farming are less fertile and more prone to degradation. Examples of marginal lands are steep sloppy lands, shallow or sandy soils and the lands in dry and semi-dry areas. b) Improper crop rotation: Due to shortage of land, increase of population and economic pressure, the farmers have adopted intensive cropping patterns of commercial crops in place of more balanced cereallegume rotations. During last two decades the area under food crops decreased and that under non-food crops increased. Intensive cultivation leads to removal of large quantities of nutrients from the soil which results to in loss of soil fertility. c) Fertilizer misuse: 46 Soil fertility is reduced due to prolonged intensive cultivation. The farmers maintain productivity of soil by applying chemical fertilizers but make less use of organic manures. Although the yield can be maintained by using fertilizers that provide deficient minerals yet their use often results in deficiencies of other nutrients. d) Overgrazing:

In India pasture land area is decreasing day by day due to expansion of agricultural land. Recent satellite data show that the area under pasture land is severely degraded. This poor condition of pasture lands is due to excessive grazing. The unchecked and indiscriminate grazing on forest land also leads to degradation of forest soils. Overgrazing directly leads to disappearance of vegetation which is one of the important causes of wind and water erosion in dry lands. e) Mining: Mining disturbs the physical, chemical and biological features of the soil. The impact of mining on soil depends on the physical, chemical properties of the waste generated. The soil profile is changed; the top soil is turned deep inside the dumps. The erodible material is almost devoid of organic matter and lacks in mineral plant nutrients. According to an estimate, about 0.8 million ha soil is degraded due to mining activity. Impact of Soil Degradation:

The following are the impacts of soil degradation: 1. Degradation leads to reduction in crop yield in the affected lands and a possible decline in cropping intensity. 2. In extreme cases, soil becomes unfit for cultivation. 3. Silting of drainage, canals, rivers and reservoirs results in increased floods and droughts. 4. In some cases farmers use more fertilizer inputs to compensate reduced soil productivity while in other cases, they use excess fertilizers. 5. The rate of siltation in many water reservoirs are significantly high. According to Central Water Commission (1991), nearly 11 per cent of the total capacity of water reservoirs has been silted. 6. Soil degradation has several adverse impacts on the environment. It affects global climate through alterations in water cycle and energy balances and disruptions of carbon, nitrogen and sulphur cycles. B. Simplification of Ecosystem

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Ecosystem simplification is the ecological hallmark of humanity and the reason for our evolutionary success. Ecological integrity has been defined as “the ability to support and maintain a balanced, integrated adaptive assemblage of organisms having species composition, diversity, and functional organization comparable to that of natural habitat of the region” (Karr and Dudley 1981). By definition, integrity is a comparative term and generally declines with increasing anthropogenic alterations. Landscapes with their integrity intact should express all the potential niche diversity associated with a given complexity. Ecological integrity therefore depends on how well mechanisms controlling complexity–diversity relationships are operating at appropriate spatial and temporal scales. For this article, we address ecological integrity as the degree to which niche diversity expected for a given complexity is actually observed under existing conditions. Integrity is expected to be maximal in relatively pristine settings and reduced in those where particular human influences have disrupted how existing complexity is expressed as niche diversity. The human reduction of complexity and integrity results in ecological simplification. Here, we define ecological simplification as the reduction in niche diversity due to the loss of landscape complexity and ecological integrity, generally resulting from human activities. Simplification can result from either of these processes alone or in combination (figure 1). Simplification is caused by decreased complexity when structural changes to landscapes result in loss of niche diversity (figure 1a). In these cases, reduced niche diversity alters local

interactions controlling biodiversity and ecosystem function. Simplification of this type transforms highly complex landscapes into more homogenous, less complex entities, reflecting exogenous control (i.e., human influences) over endogenous properties such as complex behavior. Although this type of simplification is typically associated with loss of heterogeneity (Tockner et al. 2010), it may occur along any of the three axes of complexity (Cadenasso et al. 2006). For instance, habitat fragmentation results in reduced connectivity and has negative consequences for biodiversity, population genetics, and ecological interactions (e.g., Fahrig 2003). Simplification along the legacy axis is illustrated by homogenization of historical flow regimes caused by impoundments and its influence on biodiversity of fluvial ecosystems (e.g., Poff et al. 2007).

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Figure 1.

Alternatively, human–environment interactions may not reduce the complexity of a landscape but instead alter how it is translated into niche diversity (figure 1b). These types of human influences undermine ecological integrity, causing a decline in niche diversity not directly related to reduced landscape complexity. Chemical pollution is probably the most common example of this type of simplification, because it reduces diversity, not through loss of structural variance in the landscape but by causing stress and mortality to species that would otherwise occupy available niches. For example, the loss of diversity through acidification is well documented in freshwater environments without accompanying structural loss (Vinebrooke et al. 2004). Similarly, metals and pesticides residing in sediments of aquatic systems are notorious for causing diversity loss (Lake et al. 2000). Even elements essential for growth can prove to impair biodiversity depending on form and concentration. For instance, nitrogen (N) pollution generates high levels of ammonia, nitrite, and nitrate that may impair survival, growth, and reproduction in aquatic species, reflecting the direct toxicity of these inorganic compounds (Camargo and Alonso 2006). Pollution that increases phosphorus (P) availability may also indirectly promote toxicity and the loss of biodiversity by enhancing the abundance of toxic cyanobacterial species (Christoffersen 1996). In addition to changes in the abiotic template, invasive species have the potential to alter habitat suitability for an array of species, especially in aquatic ecosystems (Sala et al. 2000). Even though our conceptual model presents complexity and niche diversity as linearly related (figure 1), the relationship might well be nonlinear in specific cases (Wu and David 2002). Nonlinear relationships raise concern over the potential to exceed ecological thresholds (Groffman et al. 2006), such as the establishment of nonnative species. Invasive species can be both a cause and consequence of simplification (Didham et al. 2005). On one hand, they may alter complexity via ecosystem engineering and exclude native species (Crooks 2002) or result in integrity loss via species displacement (Wilson 1992), causing ecological homogenization (Olden et al. 2004). On the other hand, invasive species may access the system as a result of simplification. Reductions in niche diversity due to the loss of landscape

complexity enhance the relative contribution of nonnative species to ecosystem form and function (i.e., effect size; figure 2a). This is particularly true if human-derived structures provide habitat appropriate for invasive species that then aggressively displace native species. Under these conditions, habitat restoration may restore complexity but may not stimulate the expected reduction of invasive effect size. Instead, the effect size may approach an asymptotic decrease because of the competitive superiority of invasive species not eliminated by the structural changes bestowed by restoration (figure 2a). Similarly, simplification via loss of integrity is predicted to promote invasive effect size (figure 2b), reflecting a reduced contribution from native species with specialized niche tolerance compared with that of the more generalist invaders (Snyder et al. 2006). Broad niche tolerance by invasive species is also expected to make effect size relatively immune to the influences of restored integrity; tolerance by resident invasive species should allow them to occupy crucial native niches even after appropriate physical and chemical conditions are restored (figure 2b). Even though invasive species are argued to promote simplification and influence the efficacy of restoration, there is a general lack of knowledge regarding the environmental drivers dictating the establishment of many nonnative communities.

Figure 2.

Although the focus of most restoration plans has been the reconstruction of habitat heterogeneity (Bernhardt et al. 2005), it is likely that this step is necessary but not sufficient to reestablish natural complexity. In the case of running water ecosystems, Palmer and colleagues (2010) demonstrated that very few restoration projects targeting increased habitat heterogeneity, such as channel reconfiguration and in-stream habitat improvement, actually resulted in biodiversity recovery. They emphasized the need for the targeted amelioration of multiple stressors at a time. We contend that the relationships among complexity, integrity, and niche diversity (figure 1) can be used to guide restoration approaches to multiple stressors and that most simplified ecosystems will require multidimensional restoration of this type. C. Eutrophication

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Eutrophication or more precisely hypertrophication, is the enrichment of a water body with nutrients, usually with an excess amount of nutrients. This process induces growth of plants and algae and due to the biomass load, may result in oxygen depletion of the water body. One example is the "bloom" or great increase of phytoplankton in a water body as a response to increased levels of nutrients. Eutrophication is almost always induced by the discharge of phosphate-containing detergents, fertilizers, or sewage, into an aquatic system. All living things need specific nutrients to survive. Usually, nature does a pretty good job of providing just the right amount of nutrients, because too many or too few can cause problems. This is especially true in aquatic ecosystems because they are so dynamic. When too few nutrients are present, the water is Oligotrophic. It makes sense that when there is not

enough nutrition available for the variety of organisms living in an aquatic environment, serious problems will arise. However, problems can also arise when the aquatic system has an overabundance of nutrients. When this happens we get Eutrophication. A Eutrophic stream, river or lake occurs when too many nutrients, like nitrogen and phosphorous, are present, usually as a result of runoff from the surrounding land. Algae, plankton and other microorganisms love these types of nutrients, and when they are plentiful, these aquatic organisms can take over. When a lake, river or other aquatic system becomes Eutrophic, it can have serious negative effects on other organisms like fish, birds and even people. But first, let's look at what causes Eutrophication. Cultural Eutrophication Cultural Eutrophication is the process that speeds up natural Eutrophication because of human activity. Due to clearing of land and building of towns and cities, land runoff is accelerated and more nutrients such as phosphates and nitrate are supplied to lakes and rivers, and then to coastal estuaries and bays. Extra nutrients are also supplied by treatment plants, golf courses, fertilizers, farms, as well as untreated sewage in many countries. Lakes and rivers (Eutrophication in a canal) When algae die, they decompose and the nutrients contained in that organic matter are converted into inorganic form by microorganisms. This decomposition process consumes oxygen, which reduces the concentration of dissolved oxygen. The depleted oxygen levels in turn may lead to fish kills and a range of other effects reducing biodiversity. Nutrients may become concentrated in an anoxic zone and may only be made available again during autumn turn-over or in conditions of turbulent flow. Enhanced growth of aquatic vegetation or phytoplankton and algal blooms disrupts normal functioning of the ecosystem, causing a variety of problems such as a lack of oxygen needed for fish and shellfish to survive. The water becomes cloudy, typically coloured a shade of green, yellow, brown, or red. Eutrophication also decreases the value of rivers, lakes and aesthetic enjoyment. Health problems can occur where Eutrophic conditions interfere with drinking water treatment. Human activities can accelerate the rate at which nutrients enter ecosystems. Runoff from agriculture and development, pollution from septic systems and sewers, sewage 50 sludge spreading, and other human-related activities increase the flow of both inorganic nutrients and organic substances into ecosystems. Elevated levels of atmospheric compounds of nitrogen can increase nitrogen availability. Phosphorus is often regarded as the main culprit in cases of Eutrophication in lakes subjected to "point source" pollution from sewage pipes. The concentration of algae and the trophic state of lakes correspond well to phosphorus levels in water. Studies conducted in the Experimental Lakes Area in Ontario have shown a relationship between the addition of phosphorus and the rate of Eutrophication. Humankind has increased the rate of phosphorus cycling on Earth by four times, mainly due to agricultural fertilizer production and application. Between 1950 and 1995, an estimated 600,000,000 Tonnes of phosphorus was applied to Earth's surface, primarily on croplands. Policy changes to control point sources of phosphorus have resulted in rapid control of Eutrophication. Natural Eutrophication Although Eutrophication is commonly caused by human activities, it can also be a natural process, particularly in lakes. Eutrophy occurs in many lakes in temperate grasslands, for instance. Paleolimnologists now recognise that climate change, geology, and other external influences are critical in regulating the natural productivity of lakes. Some lakes also demonstrate the reverse process (meiotrophication), becoming less nutrient rich with time.

The main difference between natural and anthropogenic Eutrophication is that the natural process is very slow, occurring on geological time scales. Ocean waters Eutrophication is a common phenomenon in coastal waters. In contrast to freshwater systems, nitrogen is more commonly the key limiting nutrient of marine waters; thus, nitrogen levels have greater importance to understanding Eutrophication problems in salt water. Estuaries tend to be naturally Eutrophic because land-derived nutrients are concentrated where run-off enters a confined channel. Upwelling in coastal systems also promotes increased productivity by conveying deep, nutrient-rich waters to the surface, where the nutrients can be assimilated by algae. The World Resources Institute has identified 375 hypoxic coastal zones in the world, concentrated in coastal areas in Western Europe, the Eastern and Southern coasts of the US, and East Asia, particularly Japan. In addition to runoff from land, atmospheric fixed nitrogen can enter the open ocean. A study in 2008 found that this could account for around one third of the ocean's external (nonrecycled) nitrogen supply, and up to 3% of the annual new marine biological production. It has been suggested that accumulating reactive nitrogen in the environment may prove as serious as putting carbon dioxide in the atmosphere. Causes Eutrophication is most often the result of human activity. Farms, golf courses, lawns and other fields tend to be heavily fertilized by people. These fertilizers are the perfect type of nutrients to feed hungry algae and plankton, and when it rains, these fertilizers run off into lakes, streams, rivers and oceans. Concentrated animal feeding operations (CAFOs) are also a major source of polluting nutrients. Eutrophication can also come from natural events. If a stream, river or lake floods, it may wash away any excess nutrients off the land and into the water. However, Eutrophication is less likely to occur in areas that are not surrounded by fertilized lands. Effects Eutrophication can have serious, long-term effects. The most notable effect of Eutrophication is algal blooms. When a bloom occurs, the stream, river, lake or ocean becomes covered with algae, which is usually bright green. In addition to looking pretty ugly, it also blocks light from reaching the water. This prevents the aquatic plants from photosynthesizing, a process which provides oxygen in the water to animals that need it, like fish and crabs. Algae growth from Eutrophication If an algal bloom is so bad that it causes wide-spread death in the water, the organisms that die will all sink to the bottom and start to decompose. The microbes that break down these dead organisms use oxygen to do their work. So, in addition to the lack of oxygen from photosynthesis, there is also now a lack of oxygen from the decomposition of dead organisms. D. Introduction of Alien species The introduction of non-native species to an ecosystem is one of the major causes of decreased biodiversity. Termed alien species, they are also known as exotic, introduced, non-indigenous, or invasive species. As the names imply, these species do not belong to ecosystems in which they are either intentionally or unintentionally placed. They tend to disrupt the ecosystem's balance by multiplying rapidly. These species are often plants, fishes, mollusks, crustaceans, algae, bacteria or viruses. 51

Many alien species are tranferred into marine ecosystems through the ballast water transported during commercial shipping operations. Ship ballast water may transport up to 3,000 species around the world every day. Alien species are often introduced into freshwater ecosystems such as estuaries, rivers, lakes and streams by humans discarding animals or plants formerly held in captivity. In some cases, species used as bait can invade freshwater ecosystems. Well-known invasive species include the Northern Snakehead fish, the Zebra mussel, the Sea Lamprey and the Asiatic Clam, Corbicula fluminea. Effects on Humans: The introduction of an alien species is often responsible for an increase in predation and competition, habitat reduction, a variety of diseases, extinction of native plants or animals and genetic change in populations. Certain strains of cholera have been transported in ballast water, ending up in oyster beds and infecting finfish destined for the dinner table. Alien Species Aboard: Alien species are often transported to non-native habitats in the ballast of ships. The organisms are taken in when ships attempt to balance their load by letting water into their holding tanks. When they reach their destination, the ballast water is released and with it any organisms picked up earlier. Mollusks and other organisms whose habitat includes marine substrate also attach to the surfaces of ocean-going vessels at the point of departure and then fall into the water at the destination. Unintentional Introductions: Aquarium plants and animals, such as the invasive algae Caulerpa, as well as ornamental plants like the purple loosestrife are released innocently into waterways by humans. They quickly overgrow and eventually choke native plants and even interfere with the water flow of lakes, rivers, estuaries, and streams. Unwanted exotic fish, such as the red lionfish, Pteroisvolitans, have invaded the waters of the Southeastern United States. The introduction of this non-native species may cause problems becaues of its poisonous spines that divers or swimmers may be unaware of and it may also pose a risk to native species through predation or competition. Intentional Introductions: Alien species like the cane toad have been introduced intentionally to reduce the number of a native species in the area. Unfortunately, this plan can backfire when the animal multiples quickly and takes over the habitat and beyond. In Hawaii, for example, the mongoose has eliminated many species of birds but it was originally introduced to keep the rat population down. The kudzu plant that blankets much of the southern United States was the result of a program sponsored by the government to control erosion. Development: New seaways or cross-basin connections provide a way for alien species to cross over into novel territories. The Great Lakes became significantly invaded by alien species following the creation of the St. Lawrence Seaway in 1959. Wetlands filled with foreign soil are invaded by seeds and roots of plants from other 52 ecosystems. The Food Industry: Seafood like shrimp, oysters, and Atlantic salmon is farmed in non-native areas like the Pacific Northwest. When juveniles escape into waterways, the potential for spread of disease and harm to the ecosystem is created. Animals like the northern snakehead fish and Asian swamp eel were introduced as a potential source of food, but they soon overwhelmed the ecosystem forcing local communities, scientists, and policy makers to find ways to control them.

Diseases, such as whirling disease, which infects rainbow trout, can infect native species when introduced by alien species, in this case the European brown trout imported from Europe. Seafood is sometime packed in seaweed, which houses alien species that are subsequently introduced to new ecosystems. The Fishing Industry: Recreational fisherman have introduced alien species to their favorite fishing hole so that there are an abundance of fish available to catch. Fish bait, such as crayfish, minnows, and earthworms are often thrown overboard, introducing them to new ecosystems that cannot support them. Earthworms have depleted the topsoil in some northern U.S. forests reducing the organic matter available for native species. Waste: Sewage and wastewater contain seeds and roots of invasive species that are discharged into waterways and transported by water flow to the ocean. Voracious Invaders: Alien species are often able to survive better than native species, which results in increased competition among native species. Alien plants take over the areas with abundant sunlight and use up nutrients essential for other plants. They can also deplete oxygen in the water causing a hypoxic environment that suffocates other marine life. Research and Prevention: Research known as vector ecology is currently taking place to determine exactly how alien species are introduced. Scientific studies in the population ecology of alien species is helping to understand why some species thrive in non-native environments and what impacts they're having on native species. Research in biogeography provides important data about global distribution patterns of alien species and databases with organized information make it possible for scientists to compile and analyze the data to help shape future practices designed to avoid introduction of alien species.

‫ ٭‬Question No - 05 ‫٭‬ Ozone Depletion?

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To understand ozone layer, it would be helpful to know the different layers of the atmosphere. The earth’s atmosphere is composed of many layers, each playing a significant role. The first layer stretching approximately 10 kilometers upwards from the earth’s surface is known as the troposphere. A lot of human activities such as gas balloons, mountain climbing, and small aircraft flights take place within this region. The stratosphere is the next layer above the troposphere stretching approximately 15 to 60 kilometers. The ozone layer sits in the lower region of the stratosphere from about 20-30 kilometers above the surface of the earth. The thickness of the ozone layer is about 3 to 5 mm, but it pretty much fluctuates depending on the season and geography. Ozone layer is a deep layer in earth’s atmosphere that contain ozone which is a naturally occurring molecule containing three oxygen atoms. These ozone molecules form a gaseous layer in the Earth’s upper atmosphere called stratosphere. This lower region of stratosphere containing relatively higher concentration of ozone is called Ozonosphere. The Ozonosphere is found 15-35 km (9 to 22 miles) above the surface of the earth. The concentration of ozone in the ozone layer is usually under 10 parts per million while the average concentration of ozone in the atmosphere is about 0.3 parts per million. The thickness of the ozone layer differs as per season and geography. The highest concentrations

of ozone occur at altitudes from 26 to 28 km (16 to 17 miles) in the tropics and from 12 to 20 km (7 to 12 miles) towards the poles. The ozone layer forms a thick layer in stratosphere, encircling the earth that has large amount of ozone in it. The ozone layer protects life on earth from strong ultraviolet radiation that comes from the sun. Ultraviolet rays are harmful rays that can drive up the risk of deadly disorders like skin cancer, cataracts and damage the immune system. Ultraviolet rays are also capable of destroying single cell organism, terrestrial plant life, and aquatic ecosystems. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. The ozone layer has the capability to absorb almost 97-99% of the harmful ultraviolet radiations that sun emit and which can produce long term devastating effects on humans beings as well as plants and animals. Composition of the Ozone Layer It comes as a surprise that the same UV rays form the bulk of ozone layer. Ozone is an extraordinary kind of oxygen composed of 3 oxygen atoms instead of the normal 2 oxygen atoms. Ozone layer normally develops when a few kinds of electrical discharge or radiation splits the 2 atoms in an oxygen(O2) molecule, which then independently reunite with other types of molecules to form ozone. The ozone layer has been shielding life on planet earth for billions of years, but it’s now being worn out by human activities. People began to value the importance of the ozone layer when scientists released a research finding suggesting that certain human-made chemicals known as chlorofluorocarbons managed to reach the stratosphere and depleted the ozone via a profound series of chemical reactions. The results of this research study prompted the signing of a global treaty known as the Montreal Protocol in 1973. This treaty helped in the reduction of the production of these harmful human-made chemicals. These targeted efforts have seen the ozone layer recovering over the past years. The thickness of the ozone layer varies immensely on any day and location. Due to relentless vertical atmospheric air circulation in both the stratosphere and troposphere, the amount of ozone layer shielding humans from strong UV rays can be lesser or greater. In addition, those residing in higher elevations are at risk of UV radiation than those at lower elevations. The Stratospheric ozone plays a big role in protecting humans from the harshness of the sun. However, there is also a kind of ozone developed just above the ground as a result of sun rays coming into contact with pollution in the atmosphere, which is hazardous to human health. In some individuals, it can lead to complications in breathing and often takes place during summer when pollution is rampant in cities where the air is static. Why Ozone Layer is Necessary? An essential property of ozone molecule is its ability to block solar radiations of wavelengths less than 290 nanometers from reaching Earth’s surface. In this process, it also absorbs ultraviolet radiations that are dangerous for most living beings. UV radiation could injure or kill life on Earth. Though the absorption of UV radiations warms the stratosphere but it is important for life to flourish on planet Earth. Research scientists have anticipated disruption of susceptible terrestrial and aquatic ecosystems due to depletion of ozone layer. Ultraviolet radiation could destroy the organic matter. Plants and plankton cannot thrive, both acts as food for land and sea animals, respectively. For humans, excessive exposure to ultraviolet radiation leads to higher risks of cancer (especially skin cancer) and cataracts. It is calculated that every 1 percent decrease in ozone layer results in a 2-5 percent increase in the occurrence of skin cancer. Other ill-effects of the reduction of protective ozone layer include – increase in the incidence of cataracts, sunburns and suppression of the immune system. 54

Causes of Ozone Layer Depletion Credible scientific studies have substantiated that the cause of ozone layer depletion is human activity, specifically, human-made chemicals that contain chlorine or bromine. These chemicals are widely known as ODS, an acronym for Ozone-Depleting Substances. The scientists have observed reduction in stratospheric ozone since early 1970’s. It is found to be more prominent in Polar Regions. Ozone-Depleting Substances have been proven to be eco-friendly, very stable and non-toxic in the atmosphere below. This is why they have gained popularity over the years. However, their stability comes at a price; they are able to float and remain static high up in the stratosphere. When up there, ODS are comfortably broken down by the strong UV light and the resultant chemical is chlorine and bromine. Chlorine and bromine are known to deplete the ozone layer at supersonic speeds. They do this by simply stripping off an atom from the ozone molecule. One chlorine molecule has the capability to break down thousands of ozone molecules. Ozone-depleting substances have stayed and will continue to stay in the atmosphere for many years. This, essentially, implies that a lot of the ozone-depleting substances human have allowed to go into the atmosphere for the previous 90 years are still on their journey to the atmosphere, which is why they will contribute to ozone depletion. The chief ozone-depleting substances include chlorofluorocarbons (CFCs), carbon tetrachloride, hydrochlorofluorocarbons (HCFCs) and methyl chloroform. Halons, sometimes known as brominated fluorocarbons, also contribute mightily to ozone depletion. However, their application is greatly restricted since they are utilized in specific fire extinguishers. The downside to halons is they are so potent that they are able to deplete the ozone layer 10 times more than ozone-depleting substances. Scientists in this age are working around the clock to develop Hydrofluorocarbons (HFCs) to take the place of hydrochlorofluorocarbons (HCFCs) and chlorofluorocarbons (CFCs) for use in vehicle air conditioning. Hydrochlorofluorocarbons are powerful greenhouse gases, but they are not able to deplete ozone. Chlorofluorocarbons, on the other hand, significantly contribute to climate change, which means Hydrofluorocarbons continue to be the better alternative until safer alternatives are available. There are two regions in which the ozone layer has depleted.  In the mid-latitude, for example, over Australia, ozone layer is thinned. This has led to an increase in the UV radiation reaching the earth. It is estimated that about 5-9% thickness of the ozone layer has decreased, increasing the risk of humans to over-exposure to UV radiation owing to outdoor lifestyle.  In atmospheric regions over Antarctica, ozone layer is significantly thinned, especially in spring season. This has led to the formation of what is called ‘ozone hole’. Ozone holes refer to the regions of severely reduced ozone layers. Usually ozone holes form over the Poles during the onset of spring seasons. One of the largest such hole appears annually over Antarctica between September and November. Natural causes of depletion of ozone layer: Ozone layer has been found to be affected by 55 certain natural phenomena such as Sun-spots and stratospheric winds. But this has been found to cause not more than 1-2% depletion of the ozone layer and the effects are also thought to be only temporary. It is also believed that the major volcanic eruptions (mainly El Chichon in 1983 and and Mt. Pinatubo in 1991) has also contributed towards ozone depletion. Man-made causes of depletion of ozone layer: The main cause for the depletion of ozone is determined as excessive release of chlorine and bromine from man-made compounds such as chlorofluorocarbons (CFCs). CFCs (chlorofluorocarbons), halons, CH3CCl3 (Methyl

chloroform), CCl4 (Carbon tetrachloride), HCFCs (hydro-chlorofluorocarbons), hydrobromofluorocarbons and methyl bromide are found to have direct impact on the depletion of the ozone layer. These are categorized as ozone-depleting substances (ODS). The problem with the Ozone-Depleting Substances (ODS) is that they are not washed back in the form of rain on the earth and in-fact remain in the atmosphere for quite a long time. With so much stability, they are transported into the stratosphere. The emission of ODS account for roughly 90% of total depletion of ozone layer in stratosphere. These gases are carried to the stratosphere layer of atmosphere where ultraviolet radiations from the sun break them to release chlorine (from CFCs) and bromine (from methyl bromide and halons). The chlorine and bromine free radicals react with ozone molecule and destroy their molecular structure, thus depleting the ozone layer. One chlorine atom can break more than 1, 00,000 molecules of ozone. Bromine atom is believed to be 40 times more destructive than chlorine molecules. Main Ozone Depleting Substances (ODS) 1) Chlorofluorocarbons (CFCs) It’s billed as the most extensively utilized ozone-depleting substance because it attributes to more than 80% of overall ozone depletion. It was utilized as a coolant in home appliances like freezers, refrigerators and air conditioners in both buildings and cars that were manufactured prior to 1995. This substance is usually contained in dry cleaning agents, hospital sterilants, and industrial solvents. The substance is also utilized in foam products like mattresses and cushions and home insulation. 2) Hydrofluorocarbons (HCFCs) Hydrofluorocarbons have over the years served in place of Chlorofluorocarbons. They are not as harmful as CFCs to ozone layer. 3) Halons It’s especially used in selected fire extinguishers in scenarios where the equipment or material could be devastated by water or extinguisher chemicals. 4) Carbon Tetrachloride Also used in selected fire extinguishers and solvents. 5) Methyl Chloroform Commonly utilized in industries for cold cleaning, vapor degreasing, chemical processing, adhesives and some aerosols. Serious Effects of Ozone Depletion 1. Damage to human health If the ozone layer is depleted, it means humans will be overly exposed to strong UV light. Overexposure to strong UV light causes skin cancer, cataracts, sunburns, weakening of immune system and quick aging. 2. Devastation to environment Many crops species are vulnerable to strong UV light and overexposure may well lead to minimal growth, photosynthesis and flowering. Some of the crop species vulnerable to UV light include barley, wheat, corn, oats, rice, broccoli, tomatoes, cauliflower just to name a few. Forests equally bear the brunt of ozone depletion. 3. Threat to marine life 56 Certain marine life, especially planktons, is greatly impacted by exposure to strong ultraviolet rays. In the aquatic food chain, planktons appear high up. If planktons decrease in number due to ozone layer destruction, the marine food chain would be disrupted in many ways. Also, overexposure of sun rays could reduce the fortunes of fishers. On top of that, certain species of marine life have been greatly affected by overexposure to ultraviolet radiation at their early stage.

4. Effect on animals In domesticated animals, too much Ultraviolet radiation could also lead to skin and eye cancer. 5. Impacts certain materials Materials like plastics, wood, fabrics, rubber are massively degraded by too much ultraviolet radiation (Solutions to Ozone Depletion) 1. Desist from using pesticides Pesticides are great chemicals to rid your farm of pests and weeds, but they contribute enormously to ozone layer depletion. The surefire solution to get rid of pests and weeds is to apply natural methods. Just weed your farm manually and use alternative ecofriendly chemicals to alleviate pests. 2. Discourage driving of private vehicles The easiest technique to minimize ozone depletion is to limit the number of vehicles on the road. These vehicles emit a lot of greenhouse gases that eventually form smog, a catalyst in the depletion of ozone layer. 3. Utilize environmentally friendly cleaning products Most household cleaning products are loaded with harsh chemicals that find way to the atmosphere, eventually contributing to degradation of the ozone layer. Use natural and environmentally friendly cleaning products to arrest this situation. 4. Prohibit the use of harmful nitrous oxide The Montreal Protocol formed in 1989 helped a lot in the limitation of Chlorofluorocarbons (CFCs). However, the protocol never covered nitrous oxide, which is a known harmful chemical that can destroy the ozone layer. Nitrous oxide is still in use today. Governments must take action now and outlaw nitrous oxide use to reduce the rate of ozone depletion. Why is the hole in the ozone layer over Antarctica? Why does the ozone not diffuse into an even layer around the Earth? Ozone depletion is due to chlorofluorocarbons (CFCs) in the stratosphere above the Antarctica and to some degree the Arctic. Under the right conditions, CFCs can undergo a reaction that releases chlorine ions, which break up ozone molecules. For a couple of reasons, this is most dramatically observed above Antarctica: 1. Meteorologically, the atmosphere above Antarctica is largely isolated from the rest of the world, a phenomenon called the 'polar vortex.' It’s essentially a persistent, giant cyclone over the Antarctic continent. Therefore, the loss of ozone there isn't replaced quickly with influx from the surrounding atmosphere. 2. The reaction that breaks CFCs up to release chlorine ions occurs under very, very cold conditions and when high energy (ultraviolet) photons are present. During the winter in the Antarctica, the stratosphere becomes cold enough for the reaction to occur and in the early spring when the stratosphere starts to receive sunlight again, UV light causes the reaction. Another phenomenon of the Antarctica stratosphere, and sometimes the Arctic stratosphere, is that it becomes cold enough for ice to crystallize out (approximately -80 degrees), creating polar stratospheric clouds (PSCs). Reactions on these ice crystals speed up the chlorine ion production which [email protected]

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Question No - 06

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Air and Water Pollution? AIR POLLUTION

Pollution is now a common place term, that our ears are attuned to. We hear about the various forms of pollution and read about it through the mass media. Air pollution is one such form that refers to the contamination of the air, irrespective of indoors or outside. A physical, biological or chemical alteration to the air in the atmosphere can be termed as pollution. It occurs when any harmful gases, dust, smoke enters into the atmosphere and makes it difficult for plants, animals and humans to survive as the air becomes dirty. Air pollution can further be classified into two sections- Visible air pollution and invisible air pollution. Another way of looking at Air pollution could be any substance that holds the potential to hinder the atmosphere or the well being of the living beings surviving in it. The sustainment of all things living is due to a combination of gases that collectively form the atmosphere; the imbalance caused by the increase or decrease of the percentage of these gases can be harmful for survival. The Ozone layer considered crucial for the existence of the ecosystems on the planet is depleting due to increased pollution. Global warming, a direct result of the increased imbalance of gases in the atmosphere has come to be known as the biggest threat and challenge that the contemporary world has to overcome in a bid for survival. Types of Pollutants In order to understand the causes of Air pollution, several divisions can be made. Primarily air pollutants can be caused by primary sources or secondary sources. The pollutants that are a direct result of the process can be called primary pollutants. A classic example of a primary pollutant would be the sulfur-dioxide emitted from factories Secondary pollutants are the ones that are caused by the inter mingling and reactions of primary pollutants. Smog created by the interactions of several primary pollutants is known to be as secondary pollutant. Causes of Air Pollution 1. Burning of Fossil Fuels: Sulfur dioxide emitted from the combustion of fossil fuels like coal, petroleum and other factory combustibles is one the major cause of air pollution. Pollution emitting from vehicles including trucks, jeeps, cars, trains, airplanes cause immense amount of pollution. We rely on them to fulfill our daily basic needs of 58 transportation. But, there overuse is killing our environment as dangerous gases are polluting the environment. Carbon Monooxide caused by improper or incomplete combustion and generally emitted from vehicles is another major pollutant along with Nitrogen Oxides, that is produced from both natural and man made processes. 2. Agricultural activities: Ammonia is a very common by product from agriculture related activities and is one of the most hazardous gases in the atmosphere. Use of insecticides, pesticides and fertilizers in agricultural activities has grown quite a lot. They emit harmful chemicals into the air and can also cause water pollution. 3. Exhaust from factories and industries: Manufacturing industries release large amount of carbon monoxide, hydrocarbons, organic compounds, and chemicals into the air thereby depleting the quality of air. Manufacturing industries can be found at every corner of the earth and there is no area that has not been affected by it. Petroleum refineries also release hydrocarbons and various other chemicals that pollute the air and also cause land pollution.

4. Mining operations: Mining is a process wherein minerals below the earth are extracted using large equipments. During the process dust and chemicals are released in the air causing massive air pollution. This is one of the reason which is responsible for the deteriorating health conditions of workers and nearby residents. 5. Indoor air pollution: Household cleaning products, painting supplies emit toxic chemicals in the air and cause air pollution. Have you ever noticed that once you paint walls of your house, it creates some sort of smell which makes it literally impossible for you to breathe. Suspended particulate matter popular by its acronym SPM, is another cause of pollution. Referring to the particles afloat in the air, SPM is usually caused by dust, combustion etc. Effects of Air Pollution 1. Respiratory and heart problems: The effects of Air pollution are alarming. They are known to create several respiratory and heart conditions along with Cancer, among other threats to the body. Several millions are known to have died due to direct or indirect effects of Air pollution. Children in areas exposed to air pollutants are said to commonly suffer from pneumonia and asthma. 2. Global warming: Another direct effect is the immediate alterations that the world is witnessing due to Global warming. With increased temperatures world wide, increase in sea levels and melting of ice from colder regions and icebergs, displacement and loss of habitat have already signaled an impending disaster if actions for preservation and normalization aren’t undertaken soon. 3. Acid Rain: Harmful gases like nitrogen oxides and sulfur oxides are released into the atmosphere during the burning of fossil fuels. When it rains, the water droplets combines with these air pollutants, becomes acidic and then falls on the ground in the form of acid rain. Acid rain can cause great damage to human, animals and crops. 4. Eutrophication: Eutrophication is a condition where high amount of nitrogen present in some pollutants gets developed on sea’s surface and turns itself into algae and and adversely affect fish, plants and animal species. The green colored algae that is present on lakes and ponds is due to presence of this chemical only. 5. Effect on Wildlife: Just like humans, animals also face some devastating affects of air pollution. Toxic chemicals present in the air can force wildlife species to move to new place and change their habitat. The toxic pollutants deposit over the surface of the water and can also affect sea animals. 59 6. Depletion of Ozone layer: Ozone exists in earth’s stratosphere and is responsible for protecting humans from harmful ultraviolet (UV) rays. Earth’s ozone layer is depleting due to the presence of chlorofluorocarbons, hydro chlorofluorocarbons in the atmosphere. As ozone layer will go thin, it will emit harmful rays back on earth and can cause skin and eye related problems. UV rays also have the capability to affect crops. When you try to study the sources of Air pollution, you enlist a series of activities and interactions that create these pollutants. There are two types of sources that we will take a look at: Natural sources and Man-made sources. Natural sources of pollution include dust carried by the wind from locations with very little or no green cover, gases released from the body processes of living beings (Carbon dioxide from humans during respiration, Methane from cattle during digestion, Oxygen from plants during Photosynthesis). Smoke from the combustion of various inflammable objects, volcanic eruptions etc along with the emission of polluted gases also make it to the list of Natural sources of Pollution. While looking at the man-made contributions towards air pollution, smoke again features as a prominent component. The smoke emitted from various forms of combustion like in bio

mass, factories, vehicles, furnaces etc. Waste used to create landfills generate methane, that is harmful in several ways. The reactions of certain gases and chemicals also form harmful fumes that can be dangerous to the well being of living creatures. Solutions for Air Pollution 1. Use public mode of transportation: Encourage people to use more and more public modes of transportation to reduce pollution. Also, try to make use of car pooling. If you and your colleagues come from the same locality and have same timings you can explore this option to save energy and money. 2. Conserve energy: Switch off fans and lights when you are going out. Large amount of fossil fuels are burnt to produce electricity. You can save the environment from degradation by reducing the amount of fossil fuels to be burned. 3. Understand the concept of Reduce, Reuse and Recycle: Do not throw away items that are of no use to you. In-fact reuse them for some other purpose. For e.g. you can use old jars to store cereals or pulses. 4. Emphasis on clean energy resources: Clean energy technologies like solar, wind and geothermal are on high these days. Governments of various countries have been providing grants to consumers who are interested in installing solar panels for their home. This will go a long way to curb air pollution. 5. Use energy efficient devices: CFL lights consume less electricity as against their counterparts. They live longer, consume less electricity, lower electricity bills and also help you to reduce pollution by consuming less energy. Several attempts are being made world wide on a personal, industrial and governmental levels to curb the intensity at which Air Pollution is rising and regain a balance as far as the proportions of the foundation gases are concerned. This is a direct attempt at slacking Global warming. We are seeing a series of innovations and experiments aimed at alternate and unconventional options to reduce pollutants. Air Pollution is one of the larger mirrors of man’s follies, and a challenge we need to overcome to see a tomorrow. WATER POLLUTION

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Water they say is life, and indeed they were right. With about 70% of the earth’s cover being water, it undeniably becomes one of our greatest resources. As young students, we learned about the various ways to conserve water; coming to think of it, water is used in almost every important human chores and processes. It is an important element in both domestic as well as industrial purposes. However a closer inspection of our water resources today, give us a rude shock. Infested with waste ranging from floating plastic bags to chemical waste, our water bodies have turned into a pool of poison. The contamination of water bodies in simplest words means water pollution. Thereby the abuse of lakes, ponds, oceans, rivers, reservoirs etc is water pollution. Pollution of water occurs when substances that will modify the water in negative fashion are discharged in it. This discharge of pollutants can be direct as well as indirect. Water pollution is an appalling problem, powerful enough to lead the world on a path of destruction. Water is an easy solvent, enabling most pollutants to dissolve in it easily and contaminate it. The most basic effect of water pollution is directly suffered by the organisms and vegetation that survive in water, including amphibians. On a human level, several people die each day due to consumption of polluted and infected water. As per the Economist report (dated 2008) each day over 1000 children die of diarrheal sickness in India and the numbers have only increased alarming in the last five years. Water is polluted by both natural as well as man-made activities. Volcanic eruptions, earthquakes,

Tsunamis etc are known to alter water and contaminate it, also affecting ecosystems that survive under water. Sources of Water Pollution There are various classifications of water pollution. The two chief sources of water pollution can be seen as Point and Non Point. Point refer to the pollutants that belong to a single source. An example of this would be emissions from factories into the water. Non Point on the other hand means pollutants emitted from multiple sources. Contaminated water after rains that has traveled through several regions may also be considered as a Non point source of pollution. Causes of Water Pollution Let us now study the causes of water pollution. 1. Industrial waste: Industries produce huge amount of waste which contains toxic chemicals and pollutants which can cause air pollution and damage to us and our environment. They contain pollutants such as lead, mercury, sulphur, asbestos, nitrates and many other harmful chemicals. Many industries do not have proper waste management system and drain the waste in the fresh water which goes into rivers, canals and later in to sea. The toxic chemicals have the capability to change the color of water, increase the amount of minerals, also known as Eutrophication, change the temperature of water and pose serious hazard to water organisms. 2. Sewage and waste water: The sewage and waste water that is produced by each household is chemically treated and released in to sea with fresh water. The sewage water carries harmful bacteria and chemicals that can cause serious health problems. Pathogens are known as a common water pollutant; The sewers of cities house several pathogens and thereby diseases. Microorganisms in water are known to be causes of some very deadly diseases and become the breeding grounds for other creatures that act like carriers. These carriers inflict these diseases via various forms of contact onto an individual. A very common example of this process would be Malaria. 3. Mining activities: Mining is the process of crushing the rock and extracting coal and other minerals from underground. These elements when extracted in the raw form contains harmful chemicals and can increase the amount of toxic elements when mixed up with water which may result in health problems. Mining activities emit several metal waste and sulphides from the rocks and is harmful for the water. 4. Marine dumping: The garbage produce by each household in the form of paper, aluminum, rubber, glass, plastic, food if collected and deposited into the sea in some countries. These items take from 2 weeks to 200 years to decompose. When such items enter the sea, they not only cause water pollution but also harm animals in the sea. 5. Accidental Oil leakage: Oil spill pose a huge concern as large amount of oil enters into the sea and does not dissolve with water; there by opens problem for local marine wildlife such as fish, birds and sea otters. For e.g.: a ship carrying large quantity of oil may spill oil if met with an accident and can cause varying damage to species in the ocean 61 depending on the quantity of oil spill, size of ocean, toxicity of pollutant. 6. Burning of fossil fuels: Fossil fuels like coal and oil when burnt produce substantial amount of ash in the atmosphere. The particles which contain toxic chemicals when mixed with water vapor result in acid rain. Also, carbon dioxide is released from burning of fssil fuels which result in global warming. 7. Chemical fertilizers and pesticides: Chemical fertilizers and pesticides are used by farmers to protect crops from insects and bacterias. They are useful for the plants growth. However, when these chemicals are mixed up with water produce harmful for plants and

animals. Also, when it rains, the chemicals mixes up with rainwater and flow down into rivers and canals which pose serious damages for aquatic animals. 8. Leakage from sewer lines: A small leakage from the sewer lines can contaminate the underground water and make it unfit for the people to drink. Also, when not repaired on time, the leaking water can come on to the surface and become a breeding ground for insects and mosquitoes. 9. Global warming: An increase in earth’s temperature due to greenhouse effect results in global warming. It increases the water temperature and result in death of aquatic animals and marine species which later results in water pollution. 10. Radioactive waste: Nuclear energy is produced using nuclear fission or fusion. The element that is used in production of nuclear energy is Uranium which is highly toxic chemical. The nuclear waste that is produced by radioactive material needs to be disposed off to prevent any nuclear accident. Nuclear waste can have serious environmental hazards if not disposed off properly. Few major accidents have already taken place in Russia and Japan. 11. Urban development: As population has grown, so has the demand for housing, food and cloth. As more cities and towns are developed, they have resulted in increase use of fertilizers to produce more food, soil erosion due to deforestation, increase in construction activities, inadequate sewer collection and treatment, landfills as more garbage is produced, increase in chemicals from industries to produce more materials. 12. Leakage from the landfills: Landfills are nothing but huge pile of garbage that produces awful smell and can be seen across the city. When it rains, the landfills may leak and the leaking landfills can pollute the underground water with large variety of contaminants. 13. Animal waste: The waste produce produce by animals is washed away into the rivers when it rains. It gets mixed up with other harmful chemicals and causes various water borne diseases like cholera, diarrhea, jaundice, dysentery and typhoid. 14. Underground storage leakage: Transportation of coal and other petroleum products through underground pipes is well known. Accidentals leakage may happen anytime and may cause damage to environment and result in soil erosion. Water pollutants also include both organic and inorganic factors. Organic factors include volatile organic compounds, fuels, waste from trees, plants etc. Inorganic factors include ammonia, chemical waste from factories, discarded cosmetics etc. The water that travels via fields is usually contaminated with all forms of waste inclusive of fertilizers that it swept along the way. This infected water makes its way to our water bodies and sometimes to the seas endangering the flora, fauna and humans that use it along its path. The current scenario has led to a consciousness about water preservation and efforts are being made on several levels to redeem our water resources. Industries and factory set-up’s are restricted from contaminating the water bodies and are advised to treat their contaminated waste through filtration methods. People are investing in rain water harvesting projects to collect rainwater and preserve it in wells below ground level. Water Pollution is common, and is an area of high alert. Water needs to be preserved and respected today, for us to live a tomorrow. ‫جاوید احمد متو (الرم گنجی پورہ ) اننت ناگ‬

Javed Ahmed Mattoo (9622822905/ 7006824108) [email protected]

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Short Answer Type Questions 1. Biosphere? The biosphere, (from Greek bios = life, Sphaira, sphere) is the layer of the planet Earth where life exists. The parts of the land, sea, and atmosphere in which organisms are able to live. The biosphere is an irregularly shaped, relatively thin zone in which life is concentrated on or near the Earth's surface and throughout its waters. All the Earth's ecosystems considered as a single, self-sustaining unit. 2. Biome? Biome is a large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra. A large community of plants and animals that occupies a distinct region. Terrestrial biomes, typically defined by their climate and dominant vegetation, include grassland, tundra, desert, tropical rainforest, and deciduous and coniferous forests. 3. Enhanced Greenhouse effect? The enhanced greenhouse effect, sometimes referred to as climate change or global warming, is the impact on the climate from the additional heat retained due to the increased amounts of carbon dioxide and other greenhouse gases that humans have released into the earths atmosphere since the industrial revolution. The disruption to Earth’s climate equilibrium caused by the increased concentrations of greenhouse gases has led to an increase in the global average surface temperatures. This process is called the enhanced greenhouse effect. 4. Food Web? Food web is a network of food chains or feeding relationships by which energy and nutrients are passed on from one species of living organisms to another. 5. Pyramid of biomass The Pyramid of Biomass is a graphical representation that depicts the extent of biomass per unit area within different trophic levels in an ecological system. The bottom level of the representation is usually occupied by the producers whereas the carnivals are shown in the top levels. 63

6. Montreal Protocol? The Montreal Protocol, finalized in 1987, is a global agreement to protect the stratospheric ozone layer by phasing out the production and consumption of ozonedepleting substances (ODS). 7. Ozone Toxicity? Ozone is a colorless toxic gas formed from oxygen by an electrical discharge. ... It also has a very strong smell, which is how it got its name; a German chemist took the name from the Greek Ozon, meaning "to smell." 8. Fundamental Niche? A niche includes more than what an organism eats or where it lives. Environmental factors, such as climate, soil chemistry, and elevation, also play a role in defining a niche. ... A fundamental niche is the term for what an organism's niche would be in the absence of competition from other species. A fundamental niche is the full range of environmental conditions that a viable population of species can occupy and use, without any other limiting factors present which could constrain the population.

9. Biological Oxygen Demand (BOD)? Biological oxygen demand (BOD) refers to the amount of dissolved oxygen (DO) that aerobic organisms need in order to break down organic material in water over time. Likewise, BOD can also be used to describe the chemical procedure used for determining the amount of dissolved oxygen that said aerobic biological organisms need in their water supply. 10. Acidic Rain? Acid rain is a rain or any other form of precipitation that is unusually acidic,meaning that it has elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Precipitation, as rain, snow, or sleet, containing relatively high concentrations of acidforming chemicals, as the pollutants from coal smoke, chemical manufacturing, and smelting, that have been released into the atmosphere and combined with water vapour harmful to the environment. 11. Green Economy? The green economy is defined as an economy that aims at reducing environmental risks and ecological scarcities, and that aims for sustainable development without degrading the environment. The green economy is defined as an economy that aims at reducing environmental risks and ecological scarcities, and that aims for sustainable development without degrading the environment. It is closely related with ecological economics, but has a more politically applied focus. 12. Bio geochemical cycle? In Earth science, a biogeochemical cycle or substance turnover is a pathway by which a chemical substance moves through both the biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) components of Earth. 13. Ecological efficiency? Ecological efficiency describes the efficiency with which energy is transferred from one trophic level to the next. It is determined by a combination of efficiencies relating to organismic resource acquisition and assimilation in an ecosystem. Primary production occurs in autotrophic organisms of an ecosystem. Ecological efficiency describes the efficiency with which energy is transferred from one trophic level to the next. It is determined by a combination of efficiencies relating to organismic resource acquisition and assimilation in an ecosystem. 64 14. Define Ecological Adaptation? Adaptations help Plants & Animals survive (live and grow) in different areas. An adaptation is a characteristic of an organism that improves its chances of surviving and/or reproducing. Organisms are generally well adapted to the Abiotic and Biotic conditions of the environment in which they live. An organism’s adaptations are a result of the genes the organism inherits from its parents. The proportion of well-adapted organisms in a population can increase over the generations by the process of evolution by natural selection. Animals can live in many different places in the world because they have special adaptations to the area they live in. An adaptation is a way an animal's body helps it survive, or live, in its environment. Camels have learned to adapt (or change) so that they can survive

‫جاوید احمد متو (الرم گنجی پورہ ) اننت ناگ‬