ECOSYSTEM NOTES (2).pdf
- 1. F1g. D. 5.12 ECO-SYSTEM A biotic community lives in an environment, which provides material, energy Tquirement and other living conditions to it. "An ecological system in which the Community and the non-living environment function together is called Ecosystem." Ihe term Ecosystem was introduced by Sir Arthur Tansely (1935). "An ystem is a group of biotic communities ofspecies interacting with one another w t h their non iiving environment exchangingenergy and matter. Now ecology ET defined as "the study ofecosystems" in other words". An ecosystem 2De defind i.e. as a structural and functional unit ofbiosphereor segment of Consisting ofcommunityof living beings and the physical environment both cting and exchanging materials between them." cach other. This relationship is called " h o l o c e n o s i s " . cCosystem the biotic communities and abiotic environment influence CCOSystem is a natural grouping ofnutrients, minerals, plants animals and astes linked together by flow of food, nutrients and energy from on part astes linked OS y stem to another part. Thus, the ecosystem is the smallest units of Te that has all the characteristic to sustain life. Pond stream, seas, deserts, d s etc. are all examples of ecosysteim. of the sy wsphere 239
- 2. An ecosystem may be natural (e.q. forest, grassland lake et (eg. on aquaria, crop field etc.) temparary (rainted pond) or permar forestetc.)or terrestrial (e.g. grassland, torest etc.). The aquatic. be either fresh water (e.g. ponds, lakes, streams) or salt water em estuaries type) Fig.5.13 (1) Natural Ecosystem: These systems perate by themselves un natural eonditions without any major interrererance Dy man. These aro e divided into: 5.13 TYPES OF ECOSYSTEM or man made nent (eg. lake aquatic ecosyystem can mar ne, water (e.g. ma under rther (i) Terrestrial ecosystem : which include forest, grassland and des. (i) Aquatie ecosystem: may be further distinguished (a) Fresh water: as which may be lotic (running water as spring or rivers) or lentic (standing water as lake, pona, pools, ditch, pudd swamp etc.). (b) Marine water : such as ocean (deep bodies) or sea (shallow onesi (2) Artificial (Man-made) Ecosystem : These are maintained artificial h man where, by addition of energy and planned manipulations, natural balance is destributed regularly. For e.g. croplands like maize, wheat, rice fields etc. Where man tries to control the biotic community as well as the physio-chemical environment, are man engineered ecosystem. desertet Ecosystem Artificial ecosystem (crop, urban industrial. laboratory, space Lentic(standingwater) (lake, pond swamp) Natural ecosystem Terrestrial (Forest, grassland deserl) PFresh water- >Aquatic Lontic (running water) (River, springstream Marine (ocean, sea) Fig. 5.13 : Types of Ecosystem ECOSYSTEM-STRUCTURE AND FUNCTION 5.14 The structure of an ecosystem is characterised by the physical org a n i s a t e of biotic and abiotic components. The major structural features or are speciescompoSition, stratification, trophic organisation and nutric 1. Species composition. Each ecosytem has its own tyYpe A Species composition. 1Difierent ecosystems have different species compositto 240 BAsIc ENvIRONMENTAL ENGINEERIN
- 3. T 241 EcooGY
- 4. variety of species is found in forest ecosystem, whereas a few a desert ecosystem. 2. Stratification. The organisms in each ecosystem form On. or strata, each comprising the population kind of species. In son species ocCurs more layer ecosystems und vegeta form different strata and are occupied by different species. Onthe eta Sumers s the desert ecosystem shows a low discontinuous herb layer consicti. ha ne such as tropical rain forest, the crown of trees, bushes and orocOsy other hand of fewe ous herb layer consistir and extensive bare patches of soil. 3. Trophic organisation. Food relationship of producers and another way to depict ecosystem structure. Trophic (food) structure of is based on the existence ofseveral trophic levels in the ecosystem. The , and (autotrophs) form the firsttrophic level or T1, herbivores the second Or T There may be 2-3 levels ofcarnivores. The top carnivore belong to T.o trophic levels. Decomposers form ultimate or detritus trophic level (Fio 141 carnivores constitute the third or Ta. Parasites feed upon the organisms ofall trophic levels. Therefore, they have a fixed trophic level. Similarly there is no fixed trophic level for omnivorou donot organism like man. Secondary Top Primary carnivores carnivores Producers Herbivores carnivores T T2 T3 T4 Ts Decomposers Fig. 5.14: Trophic levels in an ecosystem In an ecosystem there can be only 4-5 successive trophic levels, becau (i) All the food available at one trophic level is not eaten by tneanimals the next trophic level. Some of the food energy is lost in this mannn i) All the food eaten by an animals is not useful, thus a gooddca containing food is passed out as waste. good deal ofeneie () A large amount of energy is lost in respiration to deriv metabolism, and thus, there is not much energy left to support e levels. Trophic structure may also be described in terms of the amo material present in different trophic levels. The amount of the i of live n a t e 242 DASIC ENVIRONMENTAL ENGINEERIM
- 5. ditierent tnophie levels at a given time is called standing crop. It is as the number or biomass of organisms per unit area. n monly enpressed as of a species may be expressed in terms of either fresh or dry wcight. i erally dry weight is prelerred so that the variations in weight mass ot But. g e n e r a l l y due to moisture differ terenees in biomass can be avoided. S Nutrients. In each ccosystem, the nutrients necessary for the growth of 4. N i n t Organism are accumulated in the biomass and the abiotic components like ingorganism il. The anmoun the ail at any given time IS termed as standing state. Different ecosystems Qunt of nutrients such as nitrogen phosphors and calcium present in have different standing state of nutrients. The standing state of nutrients may vary at ditterent time even in the same ccosystem. 15 FOOD CHAIN AND FOOD WEB In the ecosystem various trophic levels connected through food chain. The transfer of food energV from the source in plants through a series of organisms with repeated eating and being eaten is referred to as a food chain. Or the ransfer of energy from one trophic level (e.g. producers) to the next trophic evel (e.g. consumers) is called food chain. AII types of ecosystems posses wo types of food chain : grazing food chain and detritues food chain. 1. Grazing food chain. It extends from producers through herbivores to carnivore. Producers are autotrophic organism which synthesis organic food from simple inorganic raw materials through photosynthesis utilizing solar energy. A part ofthefood systhesised by the producers is used in their body building, while the rest is utilized in providing energy for various life activities. The animals that feed on other organisms are called consumers. The consumers which directly take their food plants are called herbivores or first consumers e.g z0onplanktons, smalI fish, grass-hooper, field mouse, rabbit, deer, goat, elephant A part of the plant food eaten by herbivores become constituentof their body, ile major part is utilized by them in production of energy for various life Ves. The herbivores are eaten by second order consumers or primary carnivore Irog, some birds, fishes, wild cat, fox etc. A part of flesh or food obtained nerbivores is used in body building by the primary consumers, while the rest sumed in providing energy for various life activities. The larger carnivores CoPo the primary carnivores are called tlhird order consumers or secondary Conres. e.g. Snake (prey upon frog), wolf (prey upon fox). The lest order Consumers are not are not preyed upon by other animals. They are called topcarnivores ed top carnivores &shark, crocodile, tiger, lion etc. Ome common food chains are given below. )Vegetation (i) Vegetation Shrew Hawk. > Grasshopper Fox >Wolf- > Tiger. Rabbit EcoLOGY 243
- 6. Peacock. Snake Frog (ii) Vegetation Frog Snake Hawk (iv)Plant B u t t e r f l y Trophic level Quaternary consumers Tertiary consumerrs Secondary consumerrs Primary consumerrs Producers A terrestrial food chain An aquatic food chain Fig. 5.15: Food chains and trophic levels in terrestrial anu aquatie ecosystems Aquatic Food Chains () Phytoplankton Zooplankton SmallCrustacean 244 BASIC ENvIRONMENTAL ENGINEERING
- 7. ArLr ish Crosdile Predator insects Small fish Mrk/K.ing fisher Zooplankton Smallfish aryer fish Shark ( i ) P h y t o p l a n ankton> Zooplankton> Fish Crane>Hawk. ankton P h y t o p l a n k t e Detritus food chain. It starts with dead organic matter and passes itus feeding organism in soil to organisms feeding on detritus feeders throughdetritus fee Mangrove leaves Fungi hacteria Phytoplakton protozoa and benthic algac Hoingestionand Croprophagy. Harpacticoid copepod Crabs Bivalve mollusc Nematode Grass shrimp ) Sheephead minnow Detritus consumcrs Small carnivores (Minnow small game fish etc.) Large top carnivores (Game fish, fish cating birds) Fig. 5.16 : 245
- 8. and their predators e.g. decomposition of a c c u m u l a t e d 1litter i. ecosystems exhibiting detritus food chain are thus less depen in forest. The endent or irect solar energy. These depend chiefly on the influx or organic matter producedCtso food chain A good system. In fact. detritus food chain is simply a s u b - c o m p o n e n t ofanoth A much larger fraction of energy flows through the detritus food c matter producediin another another ecosystem example of a detritus food chain based on mangrove levels is descri," 800M Small fishes Large fishes is describe below > Carbs and shrimns Mangrove l e v e s > D e t r i t u s Micro organisms are at interconnected with one another. 'A network of food chains wh:.e interconected at various trophic levels, so as lo Jorm a number of fan FOOD WWEB ich are In nature, the food chains are not isolated sequences but a. ber of feeding . Fig. 5.17 : A food web shows the main food links and infora nau of many food chains. An organisms may form a food souree i n t e r c o n n e c other organism, thus forming a web. BASIC ENvVIRONMENTAL ENGINEER 246
- 9. amongst different organisms of a hiotic community is called Fi ecti 3.6). A food web opens several alternate pathways for the flow [t also allows an organism to obtain its food from more than one ONnections mdweh | energy. It also allows pe forganismof by wild cat,a snake of tood the lower trophic level. Thus, a field mouse may be eaten at a snake or an owl. Similarly. wild cat eats a number of herbivores ice. squirrels etc. A wolf or jackal can eat both rabbit and deer ike birds, Gene rally, a food web operates according to taste and food preferences of orgar isms at each trophical level, yet availability of food source and other eions are equally important. For example, tiger normally do not eat fish or the npulsions are equa oft in Sunderbans, they are forced to feed on them in absence or their crabs. but in natural prey Decomposers or Reducers These are saprophytic (rapro to decompose) micro-organism such as bacteria nd fungi. which obtain their food form dead bodies of producers (plants) oOnsumers (animals) and their organic wastes Decomposers are offer called micro consumers because of their small size. They are also called reducers because they decompose and remove the dead hodies of the organisms. Decomposers secrete digestive enzymes in the surrounding medium to digest theorganic materia (extracelluardigestion).They absorb a part of the decomposition products for their own nourishment. The remaining substances add materials and minerals to the substration. This process is called mineralization : The relased mineralsare reutilized as nutrients by the bioduces Secondary cosumers or primary carnivores The animals which feed or prey upon other animals. The carnivores which Iecd upon herbivores are calted primary carnivores or second order consumers cq frog, brids, fox, cat e.c. C) Tertiary consumers: Third orderconsumers ECOndary consumers are prefed upon by some larger carnivores. They are Caled tertiary consumers and so on. (d)Quaternary They are the largest not caten up consumers or Fourth order consumers or omaivores. 5.16ECOLOGICAL PYRAMIDS est carnivores which fuel on the tertiay consumers and are other aninmals eg. lion and tiger. by any stem, starting with producers at the base and successive trophie Graphic repre ientation of trophic structure aud function of an levels forming Pramids B the apex is knows as an ecological pyramid. Ecological WTamids are of three ypes Pyre o f nunmbers: It represents the number of indivIdual organisms at EcoLoGY 247
- 10. each trophic level. We may have upright or inverted pyramid of numbers 5.18. A grassland ecosystem (Fig. 5.18 a) and a pond ecosystem show an upright in a pondare S lepending upon the type of ecosystem and food chain as shown in fig. 5.18 Pendine pyramid of phytoplanktons (algaeetc.), which are small in size and very large in nu are number So nd are insects while and le the producers from a broad base. The herbivores in a grassland are ince S tertiary carnivores are hawks or other birds which are gradually less an numbers. The producers in the grasslands are grasses and that in a upright pyramid. Similar is the case with the herbivores, carnivores carnivores in pond which decrease in number at higher trophic levels number and hence the pyramid apex becomes gradually narrower foS es and top Top carnivores Top ca Hawks, Lion, Tiger other birds Carnivores Frogs.birds Insects Herbivores Carnivores Snakes, foxes lizards Herbivores Insects. birds Producers Grasses T Trees (b) (a) Fleas. microbes Lice, bugs Herbivores Birds |Producers Trees Hyper parasites Parasites (c) Fig. 5.18: Pyramid of numbers (a) grassland (b) forest (c) Parasitic food chain In a forest ecosystem, big trees are the producers, which are less in nuu and hence from a narrow base. A larger number of herbivores including ou insects and several species ofanimals feed upon the trees (on leaves, flowers, bark etc.) and form a much broder middle level. The secondary consu hke fox, Snakes, lizards etc. are less in number than herbivores while topcanu d like lion, tiger etc. are still smaler in number. So the pyramid is narro mivor sides and broader in the middle (Fig. 5.18 b). Parasitie food chain shows an inverted pyramid of number. 1he pi like a few bigtrees harbour fruit eating birds acting like herbivores ites larger in number. A much higher number of lice, bugs etc. grow leas these birds while a still greater number of hyperparasites like dugo "asites and microbes fecd upon them, thus making an inverted pyramid (18 at 5.18 o Pyramic of biomass: It is based upon the total biomass (dry T right trophic level in a food chain. The pyramid of biomass can also Dc (drymatter) BAsIc NMENTAL ENGINEERIN 248
- 11. Fig. 19 (a, b) shows pyramids of biomass in a forest and an aquatic The pyramid of t e pyramid ofbiomass in a forest is upright in contrast to its pyramid seThis is because the producers (trees) accumulate a huge biomass imered mbers. This mer's total biomass feeding on them declines at higher trophic c o n s u m e r ' whle the resulting in broad base and narrowing top. Tertiary Carnivores Snakes. frog. birds Big fish Carnivores Small fish Squirrel, rabbit, Herbivores Insects Herbivores insects Grasses, Producers Phytoplanktons herbs (a) b) Fig. 5.19 : Pyramid of biomass (a) Grassland (b) Pond The pond ecosystem shows an inverted pyramid of biomass(Fig. 5.19 b). The tal biomass of producers (phytoplanktons) is much less as compared to herbivores 20oplanktons, insects), Carnivores (small fish) and tertiary carnivores (big fish). Thus the pyramid takes an inverted shape with narrow base and borad apex. Pyramid of Energy: The amount of energy present at each trophic level is considered for this type of pyramid. Pyramid ofenergy gives the best representation 07 the trophic relationships and it is always upright. very successive trophic level, there is a huge loss ofenergy (about 90%) orm ofheat, respiration etc. Thus, at each next higher level only 10% of e passes on. Hence, there is a sharp decline in energy level ofeach the rophic level as we move from producers to top carnivores. Therefore, e pyramid of energy is always upright as shown in Fig. 5.20. College o Top carnivores Carnivores LIBRARY Herbivores S17 MAJOR ECOSYSTEMS Producers nt interacting systems in the biosphere. The major ecosystems with their 30202 Fig. 5.20 Pyramid ofenerg Different ecosystems like a pond, a lake, a river, a stream, a spring, an y, the sea, a Cst, grassland, a desert, and a cropland are operating as self- 249 Kukae.a ueyoy
- 12. malaria, is obtained from Chinchonaledgeriana, and (i) Taxol, an drug is obtained from the bark ofthe yew tree (Taxus baccata andT nticance f plants Most of the traditional drugs over the world are prepared from plants. Aho bout 2 of the pharmaceutical drugs are derived from a mere 120 species Several plant species are used for the manufacture of innumerahlePan products. Such plant based synthetic products are called botanochemi synt icak, aesthetio 3. Aesthetic and cultural benefits. Biodiversity also has great a bird watching value. It provides a good deal offun and recreation. Ecotourism, bird rewardsof wild lie, pet keeping gardening, etc. are some examples of aesthetic rewa biodiversity ts and Biodiversity is also related to out cultural and religious beliefs. Plants ritage animals are considered to be the symbols of national pride and cultural herita Many plants like Ocimum samctunm (Tulsi), Ficus religiosa (Pipal), Pros cineraria (Khejri), etc. are considered sacred and worshiped by the people majority of Indian villages and towns. Several birds, animals and even snakesa considered sacred and worshipped. 4. Ecosystem services. Biodiversity is essential to keep natural cycle going and make the ecosystem self sustaining unit. It is esseential for the maintenance and sustainable utilization of good and services from ecological systems as well as from individual species. Some of these forests are:Ro maintenance of gaseous composition of the atmosphere, (ii) climate control by orests and oceanic systems, (ii) natural pest control, (iv) formation and protection of soil, (v) conservation and purification of water, and (vi) nutrient eyeling, etc. It is estimated that the value of ecosystem services is in the range of 16 to S4 trillion (10) US dollars per years. 5. Unknown benefits. It is unpredictable that which species may become useful in future. If Penicillium and cinchona tree of Peru had become extinet before the Penicillin. 5.6 ENERGY FLOW To maintain life activites, energy in required living organisnms are operated oy means of energy, which is derived from the environment. As we known the su Energy is the main source of energy in an ecosystem. The plant make use of the ra materials from the environmental in the form of water salts and CO to prepa food, namely strach. This synthesis is aided by the energy the derivetro a r e the sunlight trapped by the chlorophyll. Thus, energy from the sun enters the Iivmg to words through photosynthetic organism and passes on from one organis BASIc ENVIRONMENTAL ENGINEERING 224
- 13. another in the form of food. l.at energy flows through AN ecosystem is unidirectonal and non another W e s a w ayflow of energy 1s governed by laws ofthermodynamics hich e l h c . his one way state t h a t Energy is neithe is neither created nor destroyed but may be transferred from one rm to a n o t h e r , and (b) During energytransfe there is degradations of energy froma cncentrates f o r m ( m e c h a n , CH,O carbohydrate Oxygen hanical, chemical or electrical etc.) to a disperssed form (heat) + O2 CO HO Carbondioxide Water Respiration equation Thils, there is a continious loss of energy within each tropic level from groducer to consumer Within ecosystem. This is accounted for largely by the energy dissipated asheatduring metabolism of the organism present in the food chain. It also indicates that shorten the food chain, greats would be the available food energy and with an increase in the length of the food chain, there is a corresponding theorem in loss of energy. Routes of usage In an ecosystem energy's usage takes places in following ways Ihe sunshine provides the necessary heat to maintain the required range in Which proper physical end chemical processes can take place. me bacteria obatin useful energy by oxidation ofcertain elements such as sulphur and iron. s is very limited because most oftheiron and sulphur on earth surface is already oxidized. in photosysnthesis Potosysnthesis, plants use chlorophyll to transform sunlight in to chemical which is stored in chemical compounds (foods). These compounds ergy enters c c o s y s t e m from the solarradiations and is convertedint Cner ansterred from organism to organism and utilized as a source of energy nergy flow in Ecosystem The f Oning ecosystem depends on the flow of energy through matter. EcoLOGY 225
- 14. chemical form by the producers. The plants make use of the ra the environment in the form of water, salts and carbondioxide t namely starch. naterials to prepare f raw The flow of energy in the ecosystem is governed by t thermodynamics i.e. It law ofTheromodynamics : state that energy can neither bedestroved but it can be transformed from one form to another from one component to another. Imd law of thermodynamics: slats that during energy transf degradation ofenergy form a concentrated from (mechanical, chemical e etc.) to a dispessed form (heat) As energy tlows through the food chain, there occures dissipations at every tropic level The loss ofenergy takes place through respiration,los of energy in locomes running. hunting and other activities. At every level then is about 90% loss of energy and the energy transe wo basic la be created transfeme sfer here chemical or eleat f enen omotin from one tropic level to the other is only 10%. These are two aspects with respect to energy flow in ecosystem. G)There is unidirectional or one way flow of energy in the ecosystemie.fin producers through herbivore to carnivores. The energy can not betransfem in the reverse direction i.e. the energy that is captures by theautotrophs is capature by the autotrophs does not revert back to solar input: or energy which passes to the herbivores does not pass back to the autotrtgs (in) The amount ofenergy flow decreases with successive trophic levels.Proga captures only small fraction of solar energy (1-15% oftotal radiation)ands bulk of utilization energy is dissipated mostely as heat. Part energy capu in gross production of producers gross primary production (GPP) 13 maintenance oftheir standing crop (respiration) and for provi1dng herbivores. sedir The Natural Cycles of the Environment or Biogeochem (Material cycles) or Nutrient eycles The biosphere in its widest sence consists of the earth's crust, tne and various species oflife which exist in the zone 600 meters abov meters below sea level. The biosphere is very large and comp divided into smaller units called ecosystems. andlu hen 226 BASIC ENvIRONMENTAL ENGINEER
- 15. he earth is like an energy or entropy pump that revejves enerey frm sun he it power and drive the eyoles of water, nutrients and otherelements, INO as biogechemienl-eyeles L a n s sof thermodynamies dictate that all the natural processes eu accompained by an inereases in entropy or randomens y N m t a n e v n u s uarh does not cireulate in nature. It is used only once by an organiem and rted into heat which in lost to the ecosystem 1hu, these ia ething i s t h e n c o n v e r t e The materials i.e,chemiealelementsincludingall the esentia ike energy Cele. tend to cinculate in the biosphere in characteristic paths from the environmert e k m e n t s of protpplasm ike water, carbon, nitrogen, phosphorus ett, hepwever These paths are generany knoWn as biogeochemieal-eyeles. Riogeochemical cycles in the cnvironment are the cyclid pathways in which a regular andcontinuustransistionof elements occur Irom theenvironmentsnto the organism and from organism into the environment "The word bio represents living organisms, geo denotes soil environment while chemical means elements such as carbon, phosphorus, Nítrogen and wulphur which undergo transition regularly. Biogeochemical cycles There are two basic types of biogeochemical cycles Types of biogeochemical eyeles Sedimentary type PS. iodine Gaseous Type e.g Carbon and nitrogen cycle (a)Gaseous Type: In thisgroup of biogeochemicalcycles, the atmosphere constitutes the major v O i r of the element that exist there in gascous phase. Such cycles show ittle O permanent change in the distribution and abundance if the element. The oxEC carbon and nitrogen cycles are good examnples of biogeochemnIcal cycle with a prominent gaseous phase. (6)Sedimentary Types Sedimentary type ofcycle, the major reservoir is the lithosphere, from Ch the elements are released by weatherng cycles The sedimen 1ypes arebest examplilied by phosphorus, sulphurandiodine p e s ofcycles involve biotic and abiotic agents. Both are driven by flow of energ cycles. Both type Cnergy and both are tied to the waler or hydrological cycle. EcoLOGY 227
- 16. BASICS OF ENVIRONMENT 1 Water Cycle or HydrologicalCycle: IPITATION RECIPITATION PREC ON CLOUDS EVAPORATION RAIN RAIN FALL PLANTS WATER BODIES SOIL MOISTURE WMTERCCAE 1 Water Cycle: The circulation of water b/w living organisms & their environment is called water cycle. This cycleincludes: The evaporation of water takes place from lakes. seas, etc. The transpiration from plants also increases water vapors in atmosphere. The water vapor rises up in the skywhere it condensed to form clouds. Water from clouds comes down in the form of rain, which fills the rivers & sea. The rain water penetrates deep inside the earth crust & form ground water source. 2. Oxygen Cycle: Oxygen important component of life as it essential for aerobic respiration in plants & animals which is released in atmosphere by plants in photosynthetic process. The atmosphere contains 20.99% of O2 The 02 Cycle involves circulation of O2 b/w living organisms å environment 16 NOLLVLaSNVa
- 17. BASICS OF ENVIRONMENT pote ATMOSPHERIC OXYGEN ORGANIC COMPOUNDS PHOTSYNTHESIS IN RESPIRATION IN PLANTS PLANTS&ANIMALS CARBON-DIOXIDE WATER OXGEN GCLG The cycle includes:- The main source of Oz is photosynthetic process in plants in which it absorbed CO2& H2O in the presence of light & Chlorophyll produce CsH1206&O2. hv 6CO2+6H20 C6Hi206+6 O2 The other source of O2 is the photolysis reaction of H2O & N20 occurring in the atmosphere in the presence of UV-rays 2 H20 +4H+O2 2NO 4N +OO2 Oxygen is mainly consumes in respiration in plants & animals & natural decay in which consumption of O2 takes place & produce CO2. respiration CoHi206 + 6 Oz 6CO2+ 6H20 Carbon Cycle: 17
- 18. BASICS OF ENVIRONMENT pHOTOSYNTHESTS ATMOSPHERIC CO COAL GAS PRODUCERS VOLCANIC (GREEN PLANTS) ERUPTIONS DEAD ORGANIC MATTER ANIMALS cARBONCYELE Carbon is an important constituent of all organic compounds. About 49% of dry wt. of organism is made up of Carbon. Atmosphere contain 0.03% CO2 gas. The Carbon cycle involves:- CO2 from atmosphere is absorbed by plants for the production of food in photosynthetic process in presence of sunlight & chlorophyll hv 6CO2+6H20 CoHi20s+6 Oz The carbon moves along food chain through consumers at different tropic level. Carbon returns to atmosphere through respiration, decay of dead animals & plants, combustion of fossil fuels & volcanic eruption. Nitrogen Cycle: 18 RESPIRATIoN
- 19. BASICS OF ENVIRONMENT Nitrogen is an important constituent of all organisms because it forms the structural part of proteins, nucleic acid &chlorophyll molecules. Earth atmosphere contains 79% of N2 but it can not be used by living organisms as such, it has to be combined with other elements like C, H, O to make itusable. The nitrogen cycle involves:- Fixation of Nitrogen in atmosphere: The nitrogen in atmosphere is fixed by three ways I. Atmospheric Fixation:_N2 in atmosphere combines with Oz in the presence of thunder lightening forms nitrogen oxides like NO,NO2 , NO3 etc. These oxides dissolve in rain to form nitrates. II. Industrial fixation:_N2 & H2 combines in presence of catalyst to form NH; in industries which is used in manufacturing of urea &fertilizers III. Biological fixation: it involves conversion of free Na in to organic nitrogen by symbiotic bacteria ( present in roots leguminous plants) & free bacteria Rhizobium N2 NO2 NOg Bacteria Nitrobacter Azotobacter +NH3 Nitrosomonas NO2 NO3 Bacteria Bacteria Bacteria Release of Nitrogen in atmosphere: Nitrogen in the atmosphere comes by denitrification process carried out by bacteria like pseudomonas & colestridium which convert nitrate back into nitrogen gas. 19
- 20. BASICS OF ENVIRONMENT NIN ATMOSPHER E| E N I T R I F Y T N s ACTERT PROTETN SYNTHESTS NITROGEN PLANT BODY PROTEIN NITRATE FIXATION BY PROTOPLASM BACTERIA, ALGAE ETC. ANIMALS E ORGANIC DEAD ORGANIC NITROGEN MATTER NITRITE DECOMPOSER TTRITE &ACTERIA AMMONIA Niroged Cyee Sulphur Cycle: Sulphur is one of the important component of protein, vitamins, & hormones. It plays a crucial role in health of plants & animals. The sulphur cycle involves:- Sulphur enters in atmosphere in the form of H2S, SO2 through human & natural activities like industrial, automobile emission, volcanic eruption, decay of dead organic materials. In atmosphere S02 react with O2 to form SO3 which get dissolved in water & produce H2504 which comes down on the earth with fog & rain where it is absorbed by plants in the form of sulphates for the synthesis of proteins From plants it transferred to animals through food chain. After the death of animals bacteria decomposed the animal & produce H:S gas which is absorbed by the plants. 20
- 21. BASICS OF ENVIRONMENT HS, SO Oxidation So3 H20 Nere HSOA FOG PRECIPITATION INDUSTRIAL OCEAN EARTH PROCESS i n e r a l SULPHATE VOLCANIC ERRUPTION PLANTS Protein & Amino Acids ANIMALS Death Decay ANAEROBIC AEROBIC DECAY DECAY SULPHATES HS SOIL SOLRHOR CCLE Phosphorous Cycle: It is sedimentary cycle because it does not enter into atmosphere. It can be found on earth in water, soil & sediments. So, it is the cycle which describes the movement of phosphorous through lithosphere, hydrosphere & biosphere.it involves:- 21
- 22. BASICS OF ENVIRONMENT PLANTS Protiens,Nucleic acids ANIMALS DEAD PLANTS, ANIMALS EXCreia of Arimals BONES, TEETH Decomposition by Phosphate Bacteria PHOSPHATES DISSOLVED Lnler i PHOSPHATE VelC p h e WATER BODIES (ehli3e s PHYOPLANKTONS ZOOPLANKTONS FOSSIL FOSSILS ROCKS Phosphorous Cyele I t is an important nutrient for plants & animals in the forn of P04°".It is the building block of parts of human & animals body like bones, teeth etc After decomposition of plants & animals P come back to soil & ocean in the form of POA P in the form of PO4 salt come into soil through weathering process of rocks. 22
- 23. BASICS OF ENVIRONMENT Pfrom the soil is absorbed bythe plants where it is converted into organic phosphate wnich is transferred to animals through food chain. Energy flowinanEcosystemn: The capacity to do the work is known as energy. In an ecosystem the ener9y flows fhrough one organism to another in the form of food & it is unidirectional & flows laws of ollos thermodynamics- "Energy can neither be created nor be destroyed". (1s" law of thermodyrnamics) & "When energy is changed from one form to another it accompanied with loss energy in the form of heat". (2"d law of thermodynamics). The mair source of energy is sun. The solar energy is trapped & stored by producers in the form of chemical energy which passed to primary consumer, secondary & tertiary consumer through food chain. Green plants absorbed < 5% of solar energy & rest of the energy is lost in the form of pavau Cev heat. Some of this energy is used by plants in respiration & rest is used in production of food which is ecten by herbivores. Only 10 % of this energy is absorbed by herbivores & rest is lost in the form of heat. 10% of energy is absorbed by carnivores from herbivores. The net energy keeps on decreasing with increase of tropic level. ww Sun 5%Energy 10% of Ener Herbivores Producers w Phorasyihesis N 10% of Energy 10% of Energy Decomposers Carnivores Energy flow in an Ecasystem w.t