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1、 IntroductionIntroduction* Habitat: the place where an organism occurs * Population: a group of organisms of the same species in an area * Community: all population & plants in the same areaIntroductionIntroduction* Ecosystem: a stable, self-supporting system which consists of communities interactin
2、g with each other * Ecology: the study of the interactions between living organisms & their environmentDifferent HabitatsDifferent HabitatsFreshwater PondFreshwater StreamGrasslandDifferent HabitatsDifferent HabitatsMangroveRocky ShoreCoral ReefWhat is Environment ?What is Environment ?Composed of 2
3、 components, Physical Factors & Biotic Factors, which influence the lives of organismsTemperatureLightRainfall & HumidityWind SpeedSoil (esp. for plants)pHPhysical FactorsPhysical FactorsBiotic FactorsBiotic FactorsConsists of all the other organisms living together in the same habitatEnergy Flow wi
4、thin an EcosystemEnergy Flow within an EcosystemSUNProducersPrimary ConsumersSecondary ConsumersTertiary ConsumersDECOMPOSITIONHEATRespirationDead remains, excreta, etcFood Chain / Food WebFood Chain / Food Web shows the feeding relationship between organismsgreen plantsrabbitsnakehawkgrasshopperliz
5、ardtoadDecomposersDecomposers(not shown in food chain(consist of Bacteria & Fungi(break down organic wastes & dead bodies of other organisms to simpler compounds which are then absorbed by green plants(significance: enable the recycling of materials within an ecosystemTrophic LevelGreen plantProduce
6、rFirstRabbitPrimary ConsumerSecondSnakeSecondary ConsumerThirdHawkTertiary ConsumerFourthOrganismTypePyramids of NumbersPyramids of Numbers (Examples)(Examples)ProducersPrimary ConsumersSecondary ConsumersTertiary ConsumersPyramids of BiomassPyramids of Biomass500ProducersPrimary ConsumersSecondary
7、Consumers501 Why is there energy loss ? Uneaten food Respiration Egestion & Excretion solving the food problem by consuming organisms in lower trophic levels down a level, increase at least 10 times of food availableEnergy Lost up a Food ChainEnergy Lost up a Food ChainPyramids of BiomassPyramids of
8、 BiomassBiomass is the total dry mass of organisms at a trophic level500ProducersPrimary ConsumersSecondary Consumers501Effects of DDTEffects of DDTDDT is an effective pesticideDDT has been used for about 20 yearsIt had been banned for over 20 yearsBut, nowadays, the body of every people still has D
9、DTEffects of DDTEffects of DDT Reasons : it has excessively long degeneration period (it requires tens of years) it is not easy be destroyed by metabolism of living organisms, so it is easily accumulated along the food chainIt killed many predatory birds due to its accumulation to high concentration
10、 through the food chainDDT AccumulationDDT AccumulationCarbon CycleCarbon CycleCarbon dioxide in airorganic substancesin plantsorganic substancesin animalsabsorption & photosynthesisrespirationfossilfeedingrespirationburning incomplete decompositionNitrogen CycleNitrogen Cyclenitrate in soilprotein
11、in plantsprotein in animalsammonianitrogen in airabsorption & photosynthesisfeedingputrefyingbacteria (decomposition)faeces, urine, dead bodynitrifying bacteria (nitrification)denitrifying bacteria (denitrification)nitrogen- fixing bacteriaInvestigation of a Balanced AquariumWhy is it necessary to u
12、se tap water which has been standing for a few day ?Ans: Because fresh tap water contains chlorine which is harmful to organisms in the aquarium.lidwaterwater snailfreshwater plantWhy is it unsuitable to introduce large carnivores into the glass jar ?Ans: Because they require more food to survive an
13、d they will eat up all the organisms in the aquarium.lidwaterwater snailfreshwater plantDescribe the appearance of the water snails and the freshwater plants after a few days if the aquarium is balanced ? Ans: The water snails and the aquatic plants will remain healthy even after a few weeks.lidwate
14、rwater snailfreshwater plantWhat will happen to the aquarium if it is placed in darkness all the time ? Why ?Ans: Both the water snails and the freshwater plants will gradually die since there is no light for the aquatic plants to carry out photosynthesis to make foodlidwaterwater snailfreshwater plantWhat will happen to the aquarium if it is placed in darkness all the time ? Why ?Ans: so the plants cannot survive without food supply. As all aquatic plants died, the water snails also die due to starvation.lidwaterwater snailfreshwater plantEcological Independence of Ecological I
