POPULATION-PRINCIPLES人口学原理

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1、POPULATION-POPULATION-PRINCIPLESPRINCIPLES人口学原理人口学原理OUTLINEFPopulation Characteristics 种群特征种群特征FPopulation Growth Curve 种群生长曲线种群生长曲线FCarrying Capacity 环境容纳量环境容纳量FReproductive Strategies 繁殖策略繁殖策略(R and K)FHuman population growthFChinese PopulationFFood Issues HIT Environmental Science Wang Xiuheng 20

2、08POPULATION CHARATERISTICS种群特征种群特征FPopulation-Group of individuals inhabiting the same area at same time.FNatality and Mortality 出生率，死亡率出生率，死亡率Natality-Number of individuals added through reproductionHigh-seeds,low-large animalsBirth Rate(Humans born/1000/a)Mortality-Number of individuals removed v

3、ia deathDeath Rate(Humans Died/1000/a)HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008nSurvivorshipcurve HIT Environmental Science Wang Xiuheng 2008FSex Ratio-Age DistributionSex Ratio 性比性比-Relative number of males and females in a population.Change with age.hu

4、man:106/100-1:1-fewer maleAge Distribution-Number of individuals of each age in a pop.Tells HOW a pop will growFig.Population Age Structure Diagrams HIT Environmental Science Wang Xiuheng 2008繁殖前期，繁殖期，繁殖后期。繁殖前期，繁殖期，繁殖后期。增长型，稳定型，下降型种群。增长型，稳定型，下降型种群。HIT Environmental Science Wang Xiuheng 2008Pop.Densi

5、ty and Spatial Distribution种群密度与空间分布种群密度与空间分布Population Density-Number of individuals per unit area.Higher/lower density;City/rural area;Spatial Distribution High/competeDispersal-Movement of individuals into new areas.扩散：扩散：生物个体或繁殖体由一个生境转移到生物个体或繁殖体由一个生境转移到另一个生境另一个生境 HIT Environmental Science Wang X

6、iuheng 2008Reason of DispersenPlants:passive disperse by wind,water and animalsnAnimals:active disperse forNatural resourcesInter-competitionEnv.ContaminationClimate change,disasterEmigration-Out movementImmigration-In MovementMigration 迁移迁移 HIT Environmental Science Wang Xiuheng 2008Population Grow

7、th CurveFBiotic Potential-Reproductive capacity 繁殖潜力繁殖潜力Generally,biotic potential is much above replacement level 更替水平更替水平.All living populations follow an exponential growth curve 对数增长曲线对数增长曲线.HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008nLag phase 迟滞期迟滞期:

8、growth and mature take timenExponential phase 对数生长期对数生长期:first batch of young reaches sexual mature,produce together with parentsnStable equilibrium 稳定期稳定期:death rate equal birth rateIndividuals are changingIndication:increase in the death rate followed by a decline in the birth rate.Why?No birth co

9、ntrol.HIT Environmental Science Wang Xiuheng 2008Carrying Capacity 环境容纳量环境容纳量/承载力承载力FCarrying Capacity-Number of individuals of a species than can be indefinitely sustained in a given area.HIT Environmental Science Wang Xiuheng 2008FEnvironmentalResistance-Anyfactor(limitingfactor)intheenvironmentli

10、mitingcarryingcapacity.HIT Environmental Science Wang Xiuheng 2008FFour main factors:Raw material availibilityEnergy availabilityWaste accumulation and disposal-small ecosystem,death phase:decline in population sizeOrganism interaction HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Sc

11、ience Wang Xiuheng 2008Questions BreaknList three characteristics populations might have.Natality,mortality,sex ratio,age distribution,density,spatial distribution.nWhy do some population grow?Birth and immigration exceeds death and emigration.HIT Environmental Science Wang Xiuheng 2008Basic process

12、 that lead to population changenThisleadstoabasicequationofchange:nNt=Nt-1+(B+I)-(D+E)HIT Environmental Science Wang Xiuheng 2008nRateofincrease:r=Nt/Nt-1-1nr-intrinsicrateofincrease.Canbeusedtocharacterizestateofthepopulationandtocomparedifferentpopulations.r=0,B=D,Ndoesnotchanger0,BD,Nincreasesr0,

13、B65 HIT Environmental Science Wang Xiuheng 2008Baby BoomersnBB encouraged growth of industries needed by young families.To emptynToday these babies are having babies of their own.nPeople are now living longer.nGrowing need now for services for the elderly.HIT Environmental Science Wang Xiuheng 2008我

14、我国国人人口口年年龄龄结结构构老老年年化化 HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008 HIT Environmental Science Wang Xiuheng 2008Howbigshouldthe

15、humanpopulationbe?Theenvironmentalproblemwefaceistheresultof growing world population putting demands on shrinking resourcesnSeveralfactorsdeterminetheimpactofasocietyonnaturalresources.nImpactofapop.=Pop.Size/AreaoccupiedxDegreeoftechnologicaldevelopmentPopulationsizePopulationdensityDegreeoftechno

16、logicalDevelopmentalwaysunderestimated,purchasefromotherpart,effectindistantplaces.HIT Environmental Science Wang Xiuheng 2008SUMMARYFPopulation=GroupofindividualsinhabitingsameareaatsametimeFBirthanddeathrates,sexratio,agedistribution,allaffectpop.growthFPopulationGrowthCurves(exponentialgrowth)FCa

17、rryingCapacityFRandKreproductivestrategiesFHumanpopulationgrowthiscomplex,yetultimatelysimple HIT Environmental Science Wang Xiuheng 2008SUMMARY cont.nManyenv.problemscausedbyhumanpopulationgrowth.BiologicalandsociologicalfactorsnMostgrowthoccursinless-developedcountries.nStatusofwomensignificantlyaffectspopulationgrowth.nHighlydevelopednationsshouldexpectincreasingpressureto“SharetheWealth.”HIT Environmental Science Wang Xiuheng 2008结束结束