An ecosystem is a community of livingorganisms (plants, animals and microbes) inconjunction with the nonlivingcomponents of their environment (things likeair, water and mineral soil), interacting as asystem.
Major classes of relatively containedecosystems are called Biomes.There are 3 Major classes of ecosystems Freshwater Ecosystems Terrestrial Ecosystems Ocean Ecosystems
Relatively small in area ~ 1.8% of earthssurface Support many species of life including fish,amphibians, insects and plants. Base of food-web is found in freshwaterPlankton (small microscopic organisms)
Rivers and Streams• Changes greatly from headwater tomouth• Headwaters– Shallow, cool, swiftly flowing, highoxygenated• Mouth– Not as cool, slower flowing, less oxygenin waterLakes and Ponds• Body of freshwater that does not flowThree zones• Littoral Zone - shallow water areaalong the shore• Limnetic Zone - open water beyond thelittoral zone• Profundal Zone - beneath the limneticzone of deep lakes Experience thermal stratification(depending on depth)Thermal Stratification • Temperature changes sharply withdepth • Thermocline – Temperature transition betweenwarmer surface water and colderwater at depth – Only present in warm monthsMarshes and Swamps • Lands that shallow, fresh watercovers for at least part of the year – Characteristic soil- water logged andanaerobic for periods of timeEstuaries • Where freshwater and saltwater mix • Highly variable environment – Temperature, salinity, depth of lightpenetration
Many & diverse types of ecosystems. Thereare seven major types. Location usually dependent on the latitudeof the area, and amount of precipitation
Tropical Rain Forest Precipitation - 250cm/year Little temp.variation/abundant moisture Contains more species thanother biomes.Savannas Precipitation 90-150cm/year Open, widely spaced trees,seasonal rainfall Parts of Africa, South America& Australia
Deserts Precipitation20cm/year Dry, sparcevegetation; scatteredgrasses Parts ofAfrica, Asia, Australia,North America
Deciduous forests 75-250cm/year Warm summers, coolwinters Europe; NE UnitedStates;Eastern CanadaTemperate Grasslands Precipitation: 10-60cm/year Rich soil; tall densegrasses Central North America;Central Asia
Coniferous forest: 20-60cm/year Short growing season, coldwinters. Northern Asia;NorthernNorth AmericaTundra 25cm/year Open; wind swept; dry;ground always frozen Far northern Asia;Northern North America
Very large amount of Earth is covered by ocean(~75%) 40% of all photosynthesis occurs in oceans.3 types of oceanic ecosystems Shallow ocean waters Deep ocean water Deep ocean surface.
Forest Ecosystem These ecosystems have large no. of herbs, trees,climbers, and wide variety of animals and birds.Forest ecosystem is divided into following types:1. Northern coniferous forest2. Tropical rain forest3. Tropical seasonal forest4. Tropical deciduous forest5. Temperate rain forest6. Temperate deciduous forest7. The different components of a forestecosystem follows are:
Abiotic Components The abiotic components inthe forest ecosystem wouldinclude the basicelements, minerals, water,CO,, soil and othercompounds found in theenvironment. These are theinorganic as well as organicsubstances present in thesoil and atmosphere. We also find the deaddebris the litteraccumulation chiefly intemperate climate. Thelight conditions aredifferent due to complexstratification in the plantcommunities.
transfer of foodenergy from oneorganism toanother with itssequence of eatingand being eaten
Biotic Components The living organisms presentin the food chain occur in thefollowing order:Trophic levelI. Producers The producers, in the forestinclude the green plants andtrees which are autotrophscapable of synthesizingcomplex organic foodmaterials using the carbon ofcarbon dioxide taken fromthe atmosphere in thepresence of sunlight.II. Consumers are as follows:(a) Primary consumers: Theconsumers in the forestinclude the herbivorousanimals likeungulates, rodents, deers, bisons etc. which feed upon thegreen grasses, plants andleaves of trees.(b) Secondary consumers:These are carnivores likesnake, birds, and lizards, foxetc. feeding on theherbivores.(c) Tertiary consumers: Theseare the top carnivores likelion, tiger etc. that eatcarnivores of secondaryconsumers level.
III. Decomposers In course of time theautotrophs andheterotrophs die in theforest. The complexcompounds of the deadprotoplasm areeventually decomposedby decomposers whichare mainly bacteria andfungi. Thus the complexsubstances areconverted into simplesubstances, which aresubsequently utilized bythe producers forsynthesizing complexorganic food materials.
an interrelatednumber of foodchainsExample:In one food chain, mancan be the primary consumerwhile in another food chain,he can be the secondary ortertiary consumer.
Carbon is fixed in organic matter in thebodies of plants and animals During respiration, carbon in the form ofcarbon dioxide (CO2) is released by theplants and animals into the atmosphere. In an aquatic environment, carbon dioxide isreleased into the water. Plants utilize CO2 for food production Upon the death of plants and animals, theirbodies are acted upon by the decomposers,thus releasing carbon again.
Some carbon stays in the soil or in thebottom of the bodies of water , which act asthe reservoir for carbon. These organic sediments in the oceans andthe soil later form into coal and oil which aremined and utilized as industrial fuel. This process again ensures the return ofcarbon into the atmosphere.
About 78 % of the atmosphere is made up ofnitrogen gas. In gaseous form, nitrogen is useless to mostorganisms. Bacteria are very useful in the fixation ofnitrogen. Nitrogen- fixing bacteria – convert or fixnitrogen in the atmosphere to nitrates
Nitrate bacteria which are found in thesoil can also convert ammonia releasedby decaying bodies into nitrite which, inturn, is acted upon by nitrate bacteriaand converted into nitrates. As nitrates, nitrogen can be utilized forthe synthesis of proteins. When plants are eaten by animals, theseplant proteins are converted into animalproteins. Lightning also aids in the fixation ofnitrogen in the atmosphere. The amount of nitrates available to plantsis determined by bacteria in the soil andin the water.
Phosphorus – major constituent ofATP, DNA, RNA, cellmembrane, shells, bones, and teeth oforganisms Sources of phosphorus in the atmosphere –phosphate rocks, guano (waste deposits ofbats), and fossil bone deposits Rain dissolves phosphate out of thesereservoir releasing the element in the soil. Plants absorb the phosphorus and use it inthe synthesis of cell parts.
Animals get phosphorus from the plants anduse it in the synthesis of cell parts. Animals get phosphorus from the plants anduse it in the formation of their bones andteeth. Upon decomposition of the plants andanimals, phosphorus is returned to the soil. Excretion of their wastes also ensures thereturn of the element to its reservoir. Major geologic upheavals like volcaniceruptions and earthquakes bring back to usethe phosphorus that had settled as sedimentsin the seas.
is a kind ofrelationship whereinone organism is feedon the otherorganism. Theorganism that isbeing feed is calledas the parasite. Theorganism in whichthe parasite is feedis called as thehost.
is a kindof relationshipwherein both theorganisms benefitfrom each other.
isthe relationshipwherein oneorganism benefitsbut the other willnot, or it is notaffected at all.
is arelationship inwhich oneorganism is huntedby the otherorganism for food.The organism thatis being hunt iscalled as the preywhile the organismthat hunts theprey is called asthe predator.
isanother kind ofrelationshipbetween organismsin theenvironment. Itdoes happen whenthere are morethan one organismthat needs thesame resources
is a significant and lasting change in thestatistical distribution of weather patternsover periods ranging from decades to millionsof years.
Terrestrial ecosystems and biodiversity: With awarming of 3°C, relative to 1990 levels, it islikely that global terrestrial vegetation wouldbecome a net source of carbon. Marine ecosystems and biodiversity: concludedthat a warming of 2°C above 1990 levels wouldresult in mass mortality of coral reefs globally. Freshwater ecosystems: Above about a 4°Cincrease in global mean temperature by 2100(relative to 1990-2000), concluded, with highconfidence, that many freshwater species wouldbecome extinct.Source: (Schneider et al., 2007:792).
The introduction of contaminants into thenatural environment that cause adversechange. Pollutants – components of pollution, can beeither foreign substances/ energies ornaturally occurring contaminants
– therelease of chemicals andparticulates into theatmosphereCommon gaseouspollutants:Carbon monoxide, sulfurmonoxide,chlorofluorocarbons(CFCs) and nitrogenoxides produced byindustry and motorvehicles
Adverse air quality can killmany organisms includinghumans. Water pollution causesapproximately 14, 000deaths per day, mostlydue to contamination ofdrinking water. Oil spills can cause skinirritations and rashes. Carbon dioxide emissionscause ocean acidification The emission ofgreenhouse gases leads toglobal warming whichaffects ecosystems inmany ways. Soil can become infertileand unsuitable for plants. Sulfur dioxide andnitrogen oxides can causeacid rain.
– the mostimportant partof the soilPlanting Trees- Reduce erosion- Trees providebarrier to the windHow we are going topreserve topsoil?
– richsources of rawmaterials forbuilding and formanufacturinggoods There should be an adequatecontrol of logging. Select the correct tree size tocut. The slash and burn systemshould be stopped. Areas where trees have beencut should be replantedpromptly.How can wepreserve our forest?
: Destruction of naturalhabitat. Use of land for farming orhousing Destroyed by pollution of theenvironment by:forest fires flood(deforestation) Solar Wind Wave Tidal Thermal