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Study Materiel

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Document 4

Study Materiel

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srinjoni02
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Note : (+) erafcm orgs Roa WATE ABS aA) wm TAGAeCHR (Nitrification) : FER Dare afee) fi, wRcerrepreba (> FAA Corer eH, 0.00 FRAT ct ARCA GIT ace) iii, FTICMEOPEDA (@ @ wo RRMA om WI) iv, SIBITTaA (¢ aR IAT =) fax. : atae wierbrepreba arene atertes aIcaTesTeA ee SREY FS | 3, Sepa : aot aete Bagata wargtia oc SACANS STAAL aR HATS aR OPAC SPOTS Ee Tied Ge wy Ge eof GeTefoCeHAT | 4.3-2p : F-ar za Ror etige afeemirh TAS sett Aap wee zer Olierangs ufaeI-ae Cog oak ATER Ae SeRaE GAP) STAT ‘Frerea Sorqcen fg aera Tay rat a F-ar apaiis eroneft anpioena fata Fapareatcel Fete FA: © ey aR le MAS BM FATT! © Se AS EP GETPATS siRQU Bea! © warms fas once PSA ae FT Ce Wa! Ferers : Bifren, “erie, Bek, Beigch aa Fiala xt aR re Bomy aS GEAR, Reaprcetes Gey Roirst se | 5, ASI: HEN Sa Oss Boga SPS! ao Fate eae act ES zw aa TPA ANSE sR) wIora Picard acer Borg fafe aa Rqwors Rita elfice ceftes Fat eae! wat: AsagS, QE, ae, a Boros | aerate, watery, crcnita @efra afere Ty aE Cre AEDT cacH AGS VT spebrarrebt Saige ayeTeR BU AS ‘teeta fire Tee = Row: UA «eq FRCS STH MTQOHT WOT TITS OMA oe WIE SHES FAIA FAV TTR doskas Sbvdy civdle chinsuTew- Heoghly-¢— _ (é svirooment) “ V/o6. ENVIRONMENT Everything that surrounds or affects an organism during its lifetime is collectively known as its environment. The jotic and abiotic components. environment comprises both (i) The living components like plans, animals, micro- \o-6-23 (a) The main factors for a positive growth rate are birth and immigration, (b) The main factors for a negative growth rate are death and emigration. ‘organisins are called biotic components, 3. Community: In order to survive, individuals of any (i) The non-living components like fire, soil, water, species depend on individuals of different species ‘Thus the environment is the sum total of living and n In this process they together form a community. living components and influences of nature and events that Thus, a community is a group of orgartisms oF EcoLocy Sr an ere annals or x0 The ctie sny of the ro med facitate autient supply. Thus, both animals and by the environment, how they make use of ‘their environment ‘ommunity are of two types: ‘and environmental resources, including energy flow (a) Major communities: These are large sized, biogeochemical cycles or mineral cycling. German Scientist well-organised and relatively independent of the Earnest Heckel first coined the term ‘Ecology’ in 1866 inputs and outputs from adjacent community Levels of Organisation in Ecology toy sor Communes Unie tis ¥g59 “There are basicaly six main levels of organisation in ecology. ‘organisms or population depend on neighbouring These are: communities. These are also called societies. 4. Ecosystem: An ecosystem can be defined as a 1. Individual: An organism lives as an individual that hs the ability to act and function independently. It may be a unicellular organism like bacterium or @ rmult-celiuar plant or animal 2, Population: Population is defined as a group of organisms of a particular species, occupying @ defined area during a specific time, Population growth rate vary from time to time, It may be positive (ve. increasing) or negative (12. decreasing) community of living organisms along withthe non living components ofthe surrounding environment These biotic and abiotic components are linked together through nurient cycles and energy flows Biotic components of an ecosystem are classified into two categories (a) Producers (Autotrophs): These organisms synthesise carbohydrate from simple Sowkes Skudy cide. chinsutar - HoogMly~. -(fvisonment) — 2/26 inorganic raw material like sunlight, water and carbondioxide through the process of photosynthesis. (©) Consumers (Heterotrophs): These organisms are incapable of producing their own food Heterotrophs are classified into two broad groups, viz., macro-consumers and micro-consumers: () Macro-consumers: These ate organisms that feed on plants or animals or both. On the basis of the consumption, this group is further classified into three categories: (a) Herbivores: Organisms that feed mainly on plants, e.g, COW, Boat, etc. (b) Carnivores: Organisms that feed mainly con animals, eg. lion, tiger, cat, ete. (©) Ommivores: Organisms that consume both plants and animals, eg, humans, rats, chimpanzees, etc. (i) Micro-consumers: These are bacteria and fungi that obtain energy and nutrients by feeding on dead and decaying plants and animals or some time make other living organisms as host for essentials requirements, This group is further subdivided into: (@) Decomposers: These depend mainly on dead and decaying organisms. (b) Saprophytes: These make the body of other living organisms as host for nutrients, eg, lichens. Ecotone: Ecotone is @ zone of junction between two ‘ot more diverse ecosystems. For example, (i) A mangrove represents an ecotone between ‘marine and terrestrial ecosystems, (ii) A siver bank represents an ecotone between terrestrial and aquatic ecosystems. In an ecotone, the species which become abundant are called Edge species ‘Niche: Aspecies'niche include allits interactions with biotic and abiotic components of its environment that are essential for survival, growth and reproduction. A niche is unique for ‘species. Niche basa very important ole in conservation of| species or organises, because if we have to conserve species in itsnative habitat then we should have the knowledge ofits niche, '3. Biome: A biome is a large geographic area defined by characteristic climate feature, vegetation, animal life and general soil type. Climatic conditions like temperature and precipitation determines the boundaries of a biome and abundance of plants and animals. 6. Biosphere: The part ofthe earth where life can exist js known as biosphere. It is commonly known as the global sum ofall eco systems and consists of several layers including the atmosphere, lithosphere and hydrosphere. Places like highest mountains, deep ‘oceans, extremes of the North Pole and South Pole, where the condition is hostile, biosphere is absent. Function of an ecosySteM—--== ‘The function of an ecosystem comprises all biological, geochemical and physical processes and components that take place or occur within ecosystem. These are discussed in detail below: jo-6- 23 (a) Energy flow: To perform any metabolic activity, ‘an organism needs energy and the flow of energy takes place from producer to consumers. This flow is unidirectional and is termed as energy flow in an ecosystem, The energy flow is never in the reverse direction, ic, from the consumers to the producers. (b) Trophic level: The trophic level of an organism is the position it occupies in a food chain. Usually there are five trophic levels and sometimes six or more. ‘The number of trophic level ina food chain depends ‘on how far the organism is placed from the source of food or energy. (©) Food chain: In an ecosystem one living organism ‘becomes the food of the other, thus becoming the source of energy. Ths formsa linear nework between organisms starting from producers and ends with top camivores. This linear network or link is called food chain. In an ecosystem there are generally to types of food chains (9 Grazing food chain: This food chain begins from green plants at the first trophic level and ‘ends at top camivores. Energy for this food chain comes from the sun. (i) Detritus food chain: This food chain begins with dead and decaying organisms eaten by other organisms present in the soil, ie. decomposers. Energy for this food chain comes from the remains of detritus (@) Food web: An ecosystem may consist of several interrelated food chains or may be the same food resource is part of more than one food chain. A food web gives us an idea of all possible ways of transfer of energy or food among organisms. Thus, we can say that a food web is the natural interconnection of food chains dow Kars {¢). Ecological pyramids: An ecological pyramid is @ diagrammatic representation to show the biomass or bio-produetivty at each trophic level. The base of the pyramid is formed by the food producers and the carnivores form the tip of the pyramid. Biomass: It is the amount of living organic matter present in an organism. Often the numbers, biomass and energy of ‘organisms gradually decreases with each step, from the producers to the consumers atthe trophic level. The pyramids are formed according to the numbers, biomass and energy. Gi) il) ‘The ecological pyramids are of following categories: (Pyramid of numbers: This type of pyramid can be observed in grassland ecosystem. Here the numbers of individuals at each trophic level decreases from bottom to top. The grasses occupy the lowest trophic level because of their abundance and then grasshopper atthe next trophic level. Rats are atthe subsequent trophic level. In this way the number of individuals decreases with each trophic level. Sometimes in this type of pyramid, the number of individuals increases from lower level to higher level, like in a forest ecosystem, where the number of primary producers are less as compare to the hyper parasites atthe highest level of the pyramid. ‘As a result the pyramid is inverted in shape. Thus, 1 pyramid of numbers does not take into account the size of the organism being counted at each trophic level. To overcome these shorts comings, the pyramid of biomass is used. Pyramid of biomass: In this pyramid, the organisms teach trophic level is weighted. In this method the total dry weight of all the organisms at each trophic level is taken into account. For example, in the ceosystem of land, the biomass of producers is atthe maximum and gradually decreases with each trophic level due to an upright pyramid of biomass, But if wwe consider an aquatic ecosystem, the producers ‘are tiny phytoplanktons and theit biomass is less a8 compared to the consumer biomass of big aquatic animals and hence we get an inverted pyramid Pyramid of energy: This pyramid is most suitable to show the biomass and bio-productivity at each trophic level. The pyramid follows the laws of ‘thermodynamics, with conversion of solar energy {nto chemical energy and heat energy at each trophic level. This pyramid is always upright and hs a large base atthe bottom. Bioaccumulation: Bioaccumulation refers to an increase in concentration of a pollutant such as pesticides or other chemicals from the environment to the first organism in a food chain. Bio-magnification: Bio-magnification refers to the process in which there is an increase in the concentration of a pollutant from one food chain to another. Pollutants whose concentration increases may be long lived, mobile, soluble in fats or biologically active. dholy circle. aninsudaw - oognly . (iv) Biotic-interacti —n* If the pollutant is long lived or soluble in fats or biologically active then it can be proven dangerous for the successive trophic levels. Every organism must interact with the environment and other organisms and these interactions is fundamental for its survival and 6 functioning of ecosystem as a whole. pom 3/26 2 Interactions among the organisms are categorised in the folowing types [pe feNSpewies 1 | Species’ 1 [Competition 0 oO 2 [Amensalism ( ©) 3_| Parastism o Q 4 Predation Ww () 5 Neutralism_ ) (0) 6 Commensalism @ (0) 7__| Mutuals @ o Nes: (Indl the specs get beet. (nae tate spenes thom (0 eden athe pecs ner gethamed nr bert (w) Biogeochemieal cycle: The circulation of nutrients and energy flow takes place through the ecosystem. The circulation of chemical nutrients Tike carbon, oxygen, nitrogen, phosphorus, water, et, through the biological and physical world is known as biogeochemical eycle. Thus we can define biogeochemical cycle as a pathway through which a chemical substance moves through both biotic and abiotic components of the earth, ‘Some important cyeles are as follows: ‘Water Cycle: The continuous movement of water ‘on above and below the surface of the earth by the physical processes of evaporation, condensation, precipitation and infiltration is known as water cycle. ‘This involves the change in the state of water from liquid to water vapour at the initial stage, followed by the condensation and precipitation, ‘Carbon Cycle: Carbon cycle involves a continuous exchange of carbon between the atmosphere and organisms. Through the process of photosynthesis carbon enters the plant body and then to hetesotrophs. Through the process of respiration and decomposition, it again moves to the atmosphere This is a short-term process. Some carbon also enters a long-term cycle such as in fossil fuels or in deep oceans carbon canbe buried for millions of years Nitrogen Cycle: The conversion of nitrogen into various chemical forms and its circulation in the atmosphere, terrestrial and marine ecosystems is called nitrogen cycle, The conversion of nitrogen can be carried out by both biological and physical Processes, which include fixation, ammonification, nitrification and denitrification. ' Env isonm doskor dhudy elsde, Chinsutar- Hooaws)y. Environ Nitrogen fixation: Itis a process in which atmospherie Regions and Names of Grasslands nitrogen (N2) is converted into ammonia (NH3), Region ‘Name 26. ‘© Ammonification: In dead and decaying plants and | Asia Steppes animals, the initial form of nitrogen is organic, This ‘Africa ‘Savannah ‘can be converted back into ammonium by bacteria and ‘South Afica Velds 1 fungi, this process is called ammonification ‘© Nitrification: Under this process the oxidation of| ‘ammonia or ammonium to nitrate takes place followed USA and Canada Prairies Australia Downs or Rangelands by the oxidation of nitrite to nitrate by the bacteria aceon Lies itrobacter. Brazil cont + Denitrification: Under this process the reduction of| Argentina —— ; nitrate takes place that may ultimately leads to the formation of atmospheric nitrogen, ‘+ Phosphorus eycle: The phosphorus cyele is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere and biosphere. It isan essential nutrient for plants and animals. Unlike nitrogen and carbon, phosphorus does not enter the atmosphere and remains mostly on land in rocks, soils and minerals. + Sulphur eycle: Sulphur enters the atmosphere from several sources like volcanic eruptions, combustion ‘of fossil fuels, from the surface of the ocean, etc. Atmospheric sulphur gets oxidised into sulphur Gioxide which is further converted into weak: sulpburie acid and falls as rain water, In soil this sulphuric acid gets converted into sulphates and is taken up by plants and passed to the next trophic level and finally to the atmosphere by excretion and decomposition, In water bodies planktons absorbs sulphur as sulplates and release it into the atmosphere inthe form of dimethyl sulphide. Classification of Ecosystem. ‘An ecosystem ean be classified in two ways, vie. terrestrial ‘and aquatic. (a) Terrestrial Ecosystem: An ecosystem which is found conly on land forms is called terrestrial ecosystem. Due to variations in the topographic features of valleys, mountains, slopes, some differences occur in the ecosystem foo, which are reflected in both material and biotic diversities. This leads to diversification of climate and the biotic components of the surrounding. The followings are the general categories of terrestrial ecosystem: (i) Tundra: Tundra is 2 type of biome where the tree growth is hindered by low temperatures and short ‘rowing season. There are two types of tundra, viz, arctic and alpine. It is basically found in northern fringe of Canada, Alaska, Siberia, etc. (iv) Desert ecosystem: Regions formed with less. than 25 em of annual rainfall and includes the interactions ‘between both biotic and abiotic components in arid regions, (b) Aquatic Ecosystem: An ecosystem formed by the communities of organisms that are dependent on each other and their environment like in a water body, is called an aquatic ecosystem. An aquatic ecosystem can be classified in the following ways. (i) Fresh water ecosystem: It includes Takes, ponds, rivers, streams, springs and wetlands. The salt content of fresh water bodies is very low and always less than 5 ppt (ii) Marine ecosystem: It includes shallow seas, open oceans, et. The salt content in this ecosystem is very high and is equal to or greater than 35 ppt. (ii) Brackish water ecosystem: It includes water bodies lke estuaries, salt marshes, mangroves, These water bodies have salt content more than 5 ppt. but lss than 35 ppt. + Any water in a sea or lake that is neither close to the bottom nor near the shore can be said to be in the pelagie zone. «Loti refers to flowing water. It is derived from the Latin word lous, which means washed. Lotie waters range from springs, being only a few centimetres ‘wide, to major rivers, having width in kilometres. ‘+ Eutrophication: Eutrophication is the depletion of oxygen in a water body, response to the addition of excess nutrients mainly phosphate and nitrates through fertiliser and sewage which includes explosive growth of plants and algae, the decaying ‘of which consumes oxygen from the water. * Ocean Acidification: It refers to the ongoing decrease in the pH of earth's oceans, caused by the uptake of carbon dioxide from the atmosphere. Generally, sea water is slightly basic that means its pH is greater than 7, and acidification is a shift of pH towards neutral rather then a transition to acidic conditions, ie, pH <7. Basic Causes of acidification are acid rain and Eutrophication. + Bioindieator: A bicindicator is any biological species or group of species whose function, ‘population, or status can reveal the qualitative status (ii) Forests: A forest ecosystem is a natural woodland unit consisting of all plants, animals and micro- organisms in thet area fimetioning together with all ofthe environment. For example: Bioindicators of the abiotic components of the environment. Species (iti) Grasslands: An ecosystem where grasses are the | Stoneflies | High-oxygen water primary form of vegetation is called grassland. In | Masses. ‘Acidic soil different regions of the world grasslands are called [ Greasewood | Saline soil by different names, Lichens Air pollution (Sulplur-dioxide) Fungi Old growth forests Mollusc ‘Water pollution ‘Tubifex worms [Non-potable, stagnant and oxygen-poor water cdowkas dhudy circle. chinsutah- Hooghly - - CEovisontnent) - Marine Organisms 1 Plankton: This group includes both microscopic plants like algae (phytoplankton) and animals like crustaceans and protozoans (zooplankton) found in all aquatic ecosystems, except certain swift moving waters. Based on the length of life eycle, they are grouped as: (@ Holopiankton (or) Permanent plankton: These organisms are planktonic for their entire life cycle. Examples: radiolarians, foraminiferans, amphipods, krills, copepods, salps, and jellyfishes (except: porifera, bryozoa, phoronida, prochordata and mammal). (i) Meroplankton (or) Temporary plankton: ‘These organisms are planktonic for only a part of their life cycle, usually the egg and larval stages. Examples: the larvae of echinoderms, crustaceans, marine worms, and most fishes. Phytoplankton: Derived from the Greek words phyto (plant) and plankton made to wander or dif), phytoplankton are microscopic plant organisms that live in aquatic environments (floats in the surface of the water), both salty and fresh, Some phytoplankton are bacteria, some are protists, and most are single-celled plants. Among the common kinds are cyanobacteria, silica-encased iatoms, dinoflagellates, green algae, and chalk- coated coccolithophores. Based on their size, phytoplankton can be classified as: (i) Macroplankton (more than 1 mm) (ii) Microplankton (less than Imm, retained by nets of mesh size 0.06 mm) ii) Nanoplankton (between 5 and 60 micrometers) (jv) Uttraplankton (les than 5 micrometers) [N.B.: Many phytoplankton species belong mainly to the nanoplankton and microplankton fractions. Zooplankton: They are more abundent within mangrove water-ways than in adjacent coastal waters and a large proportion of the juvenile fish of mangrove habitat are zooplanktivorous, ‘The zooplankton determine the quantum of fish stock. Hence, zooplankton communities, based on their quality and species diversity, are used for assessing the productivity as well as fishery resource, fertility and health status of the ecosystem. ‘Sea- Grass: Sea grasses are specialised angiosperms (marine flowering plants). Major Sea grass meadows in India occur along the south east coast of Tamil 5/26 . [Nadu and in the lagoons of @ few in Lakshadweep Islands. There are few grass beds around Andaman and Nicobar islands ‘ea grass beds physically help in following operation: + Toreduce wave and current energy. + To filter suspended sediments from the water and 10-6-23 + stabilise bottom sediments to control erosion Threats: Eutrophication, siltation, trawling, coastal engineering constructions and over exploitation for commercial purposes are the major threats for sea grass beds. 5. Seaweeds: Seaweeds grow in shallow coastal ‘waters, These are larger and visible marine plants autached to rocks and corals. Based on the colour of their pigmentation, sea weeds are broadly classified into different clases such as: blue-green, green, brown, red etc Products like agar-agar and alginates, iodine which have commercial value, are extracted ftom seaweeds. Seaweeds are also used as the potential bio- indicators of pollution in coastal ecosystem, particularly Reavy metal pollution due to their ability to bind and accumulate metals strongly Funetions of seaweeds: ‘© Food for marine organism ‘habitat for fish breeding grounds # Source of sediment. Harmful Effects: Rotting seaweed isa potent source of hydrogen sulfide (highly toxie gas). It can cause vomiting and diarrhoea, J sropiversiry ‘The word Biodiversity indicates variations among various living organisms be it plants, animals, ete., with their habitation in any sources be it terrestrial, marine or aquatic ecosystems and the ecological complexes. Both the present as well as future generations depend greatly upon diversity and its conservation is thereby fundamental for ecologically sustainable development. ‘The policy of industrialisation and economic development in the past has put enormous pressure and loss inthe ecosystem. India still is in a better position in this regard compared to other nations as the harmonious existence of humans along with preserving our very environment is ingrained in the lifestyles of the people of our country. India being one of the 12 mega diversity countries in the world, itis prudent to preserve both identified as well as unidentified species of flora and fauna.

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