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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,本资料仅供参考，不能作为科学依据。谢谢。本资料仅供参考，不能作为科学依据。感谢,H1,种群和种群结构,要 点,种 群,种群是一定区域内同种生物个体集合。种群间边界能够是任意。种群能够依据组成种群生物是单体生物还是构件生物进行分类。在单体生物种群中，每一受精卵发育成一单个个体。在构件生物种群中，受精卵发育成一个结构单位，这一结构单位再形成更多构件和分支结构。然后这些结构可能分裂，形成许多无性系分株。,1/36,肯尼亚斑马种群,2/36,H1,P,OPULATIONS AND,POPULATION STRUCTURE,A population is a group of organisms of the same species which occupies a given area.The boundaries between populations can be arbitrary.Populations may be categorized as consisting of either unitary or modular organisms.In unitary populations,each zygote gives rise to a single individual.In modular organisms,the zygote develops into a unit of construction which gives rise to further modules and a branching structure.The structure may then may then fragment producing many individual ramets.,Key Notes,Population,3/36,种群大小,对于单体生物和种群如哺乳类，其种群大小就是一定区域内个体数量，非常简单。对于构件生物，如植物和珊瑚，情况就较复杂。对于这些种群，“断片”（无性系分株）或枝条（构件）数目比不一样个体数量更有意义代表多度。,4/36,种群密度普通,种群密度很高,5/36,The population size for unitary organisms,such as mammals,is simply the number of individuals in a given area.For modular organisms,such as plants and corals.The situation is more complex.In this case the number of pieces(ramets)or the number of shoots(modules)may give a more meaningful indication of abundance than the number of different individuals.,Population size,6/36,年纪和时期,结构,种群年纪结构是每一年纪阶段个体数目标比率，通常以年纪金字塔图来表示。既不增加也不下降种群有稳定年纪分布。增加型种群有更多年轻个体，而在下降型种群中年老个体占优势。当种群经历离散和发育时期（如昆虫龄期）时，每一时期个体数目（“时期结构”）能够对种群进行有效描述。对于生长率无法预测物种（如植物），依据大小分类可能更有意义。,相关主题,出生率、死亡率和种群增加（,H2,）竞争性质（,I1,）密度和密度制约（,H3,）捕食性质（,J1,）种群动态,波动、周期和混沌（,H4,）,7/36,8/36,The age structure of a population is the number of individuals in each age class expressed as a ratio,and is usually displayed nor contracting nor contracting will have a stationary age distribution.A growing population will have more young.While a declining population will be dominated by older age classes.Where organisms pass through discrete growth stages(e.g.insect larval instars),the number of individuals at each stage(the stage structure)may provide a useful description of the population.In species where growth rates are indeterminant(such ax plants),size classes may be more informative.,Related topics,Natality,mortality and population The nature of competition(I1)growth (H2)The nature of predation (J1)Density and density,dependence (H3),Population dynamics fluctuations,cycles and chaos (H4),Age and stage structure,9/36,H2,出生率、死亡率和种群增加,要 点,出 生 率,出生率就是新个体产生，实际出生率就是一段时间内每个雌体实际成功繁殖量。特定年纪出生率就是特定年纪组内雌体在单位时间内产生后代数量。,死 亡 率,死亡率是在一定时间段内死亡个体数量除以该时间段内种群平均大小。这是一个瞬时率，可用来估价整个种群死亡率或特定年纪群特定年纪死亡率，死亡概率是死亡个体数除以在每一时间段开始时个体数。,10/36,H2,N,ATALITY,MORTALITY AND POPULATION GROWTH,Nntality is the birth of new individuals.The realized natality is the actual successful reproduction per female over a period of time.The age-specific birthrate is the number of offspring produced per unit time by females in specific age classes.,Key Notes,Natality,The death rate,or mortality rate,is the number of individuals dying during a given time interval divided by the average population size over that time interval.This is an instantaneous rate and be estimated for the population as a whole or for specific age classes to give the age specific mortality rate.The probability of dying is the number dying per individual present at the start of the time period.,mortality,11/36,存 活 率,存活率是死亡率倒数。对于一个特定种群，存活率数据通常以存活曲线形式来表示；存活曲线表示是在每一个生活期存活个体所占比率对数值。依据各种生活期死亡率高低，特定年纪存活曲线普通有三种模式：后期死亡率最高（类型,I,），各期死亡率相等（类型,II,），早期死亡率最高（类型,III,）。,生 命 表,生命表总结了一组出生时间大致相同个体从出生到死亡命运，这么一组个体称为同生群，这么调查称为同生群分析。生命表表示存在于不一样生命阶段或年纪个体数量，以及每一阶段年纪特定存活率和年纪特定死亡率。每一阶段死亡率用,k,值表示，,k,是经过对数函推导出来，而且能够相加得出总死亡率。,12/36,人生三无奈,13/36,Survivorship is the converse of mortality.Survivorship data are often shown as a survivorship curve for a particular population;a graph showing the proportion of survivors on a logarithmic scale through each phase of life.There are three generalized patterns of age-specific survivorship depending on whether the probability of dying is highest later in life(Type I),constant through life(Type II)or highest for young stages(Type III).,Survivorship,Life tables summarize the fate of a group of individuals born at approximately the same time from birth to the end of the life cycle.Such a group is known as a cohort and investigation of this kind is termed cohort analysis.Life tables show the number of individuals present at different life stages or ages together with age-specific survival rates and age-specific mortality rates calculated for each stage.Mortality at each stage is expressed by k-values which are derived from logarithms and can be summed to give total mortality,Life tables,14/36,K-,因子分析,这一方法能够辩明关键因子对死亡率作用。连续几年取得特定阶段,k,值与总死亡率（,k,总,）相比。,K,因子分析强调那些死亡率最高阶段，这些阶段是种群丧失率和种群大小波动关键。,生殖力表,生殖力是指同一个体生产卵、种子或处于生活史第一阶段后代数目。生殖力表可计算基础生殖率,R,0,。,R,0,是在同生群结束时每个亲体产生后代数量。在一年生种群中，,R,0,表示在这段时间内，种植增加或下降总程度。,15/36,This technique allows the identification of key factors contributing to mortality.Stage-specific k-values obtained over successive years are compared to the values for total mortality(k,total,).K-Factor analysis highlights those stages suffering the greatest mortality which are responsible for fluctuations in loss rate and hence population size.,k,-Factor analysis,Fecundity is the number of eggs,seeds,or offspring in the first stage of the life cycle produced by an individual.The fecundity schedule allows the calculation of the basic reproductive rate R,0,.This is the number of offspring produced per original individual by the end of the cohort.In an annual population,it indicates the overall extent to which the population has increased or decreased over that time.,The fecundity schedule,16/36,种群增加,种群大小随时间改变能够按以下方法计算：,t,时间种群原来数量（,N,t,），加上新出生个体数（,B,）和迁入个体数（,I,），减去死亡个体数（,D,）和迁出个体数（,E,），就可得到,t+1,时间种群数量（,N,t+1,），这可用以下方程表示。,N,t+1,=N,t,+B+I D E,在一组特定条件下，一个体含有最大生殖潜力，称为内禀自然增加率,r,。这是种群在不受资源限制情况下，于一定环境中可到达理论最大值。,17/36,The changes in population size over time can be calculated by adding birth(,B,)and the number of immigrants(,I,)to the original population at time,t,(,N,t,),and subtracting the number of deaths(,D,)and emigrants(,E,)to give a new population size an the time,t,+1(N,t+1,).This is represented by the equation;,N =N +B+I D E,For a particular set of conditions,an individual has a maximum potential for reproduction which is its intrinsic natural rate of increase,r.This is the theoretical maximum that may be reached in a given environment if the population is not resource-limited.,population growth,18/36,非密度制约性种群增加,这种无限增加可用连续型种群模型来描述，以在,t,时间时，种群数量改变率来表示：,t,时间种群大小改变率,=,内禀增加率,种群大小,dN/dt=rN,19/36,Unlimited growth of this kind is described by a continuous population model and expressed in terms of the rate of change in population numbers at time,t,:,Rate of change of population Intrinsic rate of increase,Size at time t =population size,dN/dt=rN,Density-independent population growth,20/36,密度制约性,种群增加：,逻辑斯谛方程,逻辑新谛方程描述是一个在有限资源空间中简单种群增加。在早期，资源丰富，死亡率最小，繁殖尽可能快，种群内个体可到达内禀增加率。种群呈几何式增加，直到种群数量到达环境可连续支持最大程度，这个最大数量称为环境容纳量（,K,）。当种群愈加拥挤时，种群增加率降低到零，种群大小处于稳定状态。这可用逻辑斯谛方程来表示：,T,时间种群大小改变率,=,内禀增加率,种群大小,密度制约因子,dN/dt=rN(1-(N/K),当种群到达环境容纳量，种间竞争变得更激烈时，密度制约因子（,1-(N/K),）会靠近零。该方程预测种群增加随时间改变展现出“,S”,形，如在真实种群中通常所观察那样。,相关主题,种群和种群结构（,H1,）竞争性质（,I1,）密度和密度制约（,H3,）捕食性质（,J1,）种群动态,波动、周期和混沌（,H4,）,21/36,The logistic equation describes the growth of a simple population in a confined space,where resources are not unlimited.In the early stages resources are abundant,the death rate is minimal and reproduction can take place as fast as possible allowing the individuals to attain their intrinsic rate of increase.The population increases geometrically until the maximum number of individuals the environment can sustainably support is approached.This maximum number is called the carrying capacity(,K,).The population growth rate declines to zero as the population becomes more crowded and the population size stabilizes.This can be described as the logistic equation:,Rate of change of Intrinsic rate Population Density dependent,Population size at time t,=,of increase,size,factor,Dn/dt=rN(1-N/K),Where the density-dependent factor,(1-N/K)approaches zero as the population approaches the carrying capacity and intraspecific competition becomes more intense.This equation predicts growth of a population over time to be sigmoidal,as is commonly observed in real populations.,Related topics,Populations and population structure(H1)The nature of competition(I1),Density and density dependence(H3)Population dynamics-fluctuations,cycles and chaos(H4),Density-dependent growth-the logistic equtation,22/36,H3,密度和密度制约,要 点,密 度,密度为单位面积、单位体积或单位生境中，个体数量，对于一些植物和大型或显眼动物，能够计数它们总数量，对于许多在一定地域只能取得一部分样品动物，其密度就必须进行预计。,23/36,人口密度分布图,24/36,H3,D,ENSITY AND DENSITY DEPENDENCE,Density is defined as the number of individuals per unit area,per volume or per unit of habitat.Total counts may be obtained for some plants and large or conspicuous animals.For many animals only a proportion of the individuals present in a given area will be detected and density must be estimated.,Key Notes,Density,25/36,密度制约,假如种群参数如出生率和死亡率伴随种群密度改变而改变，就能够说是密度制约。假如出生率和死亡率不伴随密度改变而改变，则是非密度制约性。假如没有迁移，除非出生率和死亡率是密度制约性，不然种群会连续增加。,预计密度：,标志重捕法,预计绝对密度能够使用以下方法：捕捉、标识捕捉个体、释放和再次捕捉。假如是随机捕捉，在第二次捕捉到个体中，标识与没有标识个体百分比同整个种群中标识与没有标识个体百分比应该相等。因为已标识总个体数目是已知，所以可依据以下公式来预测种群总数量：捕捉到个体数,/,重捕个体数,原来标识个体数,=,种群总个体数,26/36,Estimates of absolute density can be made with this method which involves trapping,marking trapped individuals,releasing them and trapping a second time.The proportion of marked to unmarked individuals in the traps will be the same as the proportion of marked to unmarked in the whole population,assuming a random proportion of the population is trapped.Since the total number of marked animals is known an estimate of the total population can be obtained from the following equation:,Number trapped,Number recaptured,Number originally marked =Total number in population,Estimation density-mark release recapture,Population parameters such as birth and death rates which vary with density are said to be density dependent.Birth and death rates that do not change with density are density independent.In the absence of immigration,a population will continue to increase in number unless either the per capita birth rate or death rate is density dependent.,Density dependence,27/36,赔偿和密度,制约,密度制约有三种形式：过分赔偿，赔偿不足和准确赔偿。假如密度制约引发数量下降，没有超出或等于开始增加个体数量，则密度制约是赔偿不足。当密度制约效应超出了开始种群数量增加，称为过分赔偿。假如下降个体数与开始增加个体数相等，则称密度制约为准确赔偿。,相关主题,种群和种群结构（,H1,）种群动态,波动、周期和混沌（,H4,）,捕食性质（,J1,）竞争性质（,I1,）,出生率、死亡率和种群增加（,H2,）,平衡种群密度,当单位个体出生率恰好平衡单位个体死亡率，种群密度既不增加也不降低时，此时种群密度为平衡种群密度。平衡种群密度与环境容纳量,K,值相等。,28/36,The equilibrium population density occurs when the per capita death rate exactly balances the per capita birth rate such that the density is neither increasing nor decreasing.The equilibrium population density is equivalent to the carrying capacity K.,Related topics,Populations and population structure Population dynamics-fluctuations,(H1)cycles and chaos(H4),Natality,mortality and population The mature of competition (I1),growth (H2)The mature of predation (J1),Equilibrium population density,Compensation and density dependence,There are three types of density dependence:overcompensating,under compensating and exactly compensating.If a decline in numbers due to density dependence does not outweigh or balance the initial increase in numbers,density dependence is under compensating.Overcompensating density dependence occurs where the effect of increased density more than outweighs the initial augmentation.If the decline in numbers exactly balances the initial increase in density,density dependence is said to be exactly compensating.,29/36,H4,种群动态,波动、周期和混沌,要 点,增加种群和,收缩种群,大多数实际种群并不是在平衡密度停留很长时间，而是动态不停发生改变。因为周围环境改变或生物因子影响，种群可能会增加或收缩。,30/36,种群密度周期性改变,迁徙,耕种,31/36,H4,P,OPULATION DYNAMICS,FLUCTUATIONS,CYCLES,AND CHAOS,Most real populations are not at their constant equilibrium density for very long,but are dynamic and changing.Populations may be expanding or contracting because of changes in environmental conditions or because of changes to their biotic environment.,Key Notes,Expanding and coutracting populations,32/36,种群波动,种群波动可能有以下几个原因：（,i,）时滞或称为延缓密度制约，存在于密度改变及其对种群大小影响之间。种群可能超出环境容纳量，然后逐步降低，在最终到达平衡之前展现减幅振荡。这种延缓密度制约可能使捕食者和猎物多度之间产生周期。（,ii,）过分赔偿性密度制约。其可能造成减幅振荡、稳定极限环（非减幅振荡有规律周期改变）或无规则随机振荡。（,iii,）环境随机改变。环境条件非确定性、不可预见性改变会造成平衡密度改变。,33/36,Populations fluctuations,Populations may fluctuate for a number of reasons:,A time lag between a change in density and its effect on the population size,or delayed density dependence,The population can overshoot the carrying capacity and then show gradually diminishing,dampened oscillations before eventually stabilizing at equilibrium.This delayed density dependence may also produce cycles in predator and prey abundance;,Overcompensating density dependence.This can lead to dampened oscillations,stable limit cycles(regular cycles that do not damp down)or chaotic fluctuations that appear random;,(iii)Environmental stochasticity.This is a nondeterministic,unpredictable variation in the environmental conditions,resulting in a changing equilibrium density.,34/36,相关主题,出生率、死亡率和种群增加（,H2,）捕食行为猎物反应（,J2,）密度和密度制约（,H3,）,混 沌,数学上相关混沌定义与俗语中使用方法是截然不一样。一个混沌系统是受确定性作用控制，而不是随机。混沌结果依赖于初始状态准确值。因为完全准确是不可能到达，所以对混沌系统不能进行有效预测。当前，对于观察到相关种群大小波动在何种程度上是受混沌过程影响还不清楚。一些分析认为，麻疹暴发和一些昆虫种群可能表现出混沌动态改变。,35/36,Related topics,Natality,mortality and population Predator behavior and prey growth (H2)response (J2),Density and density dependence (H3),Chaos,The mathematical definition of chaos is quite distinct from the colloquial use of this term.A chaotic system is driven by a deterministic process,it is not conditions.As perfect accuracy is impossible to attain,chaotic systems are effectively unpredictable.It is currently unclear to what extent observed fluctuations in population sizes are influenced by chaotic processes.Some analyses suggest that measles outbreaks and some insect populations may display chaotic dynamics.,36/36,
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