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普通生态学课件：普通生态学课件
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一、WHAT IS ECOLOGY?A definition of ecologyEcology is the study of the interactions between organisms and their environment,The ‘environment’ is a combination of the physical environment (temperature,water availability,etc.) and any influences on an organism exerted by other organisms-the biotic environment.生态学的定义生态学是研究有机体与其环境相互作用的科学。“环境”是物理环境（温度、可利用水等）和生物环境（对有机体的、来自其他有机体的任何影响）的结合体。生态学的定义,研究生物与其环境相互关系的科学内涵：1）环境对生物的决定和塑造作用2）生物对环境的适应3）适应环境的生物对环境的改善作用为什么要开展生态学研究人类面监的四大危机：（1）环境危机（2）人口危机（3）资源危机（4）能源危机Individuals,populations,communities and ecosystemsThere are four identifiable subdivisions of scale which ec(i) considering the response of individuals t(ii) Examining the response of populations of a single species to the environment,and considering processes such as abunda(iii) The composition and structure of communities (the populations occurring in a defined area);(iv)the processes occurring within ecosystems (the combination of a community and the abiotic components of the environment),such as energy flow,food webs and the cycling of nutrients.个休、种群、群落和生态系统生态学所研究的有4个可辨别尺度的亚部分：(i)探讨个体对其环境的反应；(ii)研究单个物种的种群对于环境的反应，和探讨诸如多度(abundance)及其波动等的过程（iii）群落（出现在确定面积中的种群集合）的组成和结构；(iv)生态系统（群落与环境的非生物成分的结合）内的各种过程，例如能流、食物网和营养物的循环等。生态学的交叉学科在生物学内的交叉：生理生态学，生态遗传学，行为生态学，…与自然科学的交叉：数学生态学，化学生态学，… …与人文、经济和社会科学的交叉：经济生态学，社会生态学，政治生态学，人类生态学，民族生态学，哲学生态学，… …生态学的研究方法1.4.3 生态学研究问题的步骤TEN RULES IN ECOLOGY?What are these rules?The authors’ experience of teaching ecology has given them experience of some common pitfalls which ecology students often make,This list,designed to counter these pitfalls,is neither comprehensive nor mutually exclusive,but we hope will nevertheless serve as a useful guide to protocol,这些规律是什么？生态学的授课实践使得本书作者能够觉察到大学生学习生态学时常常陷入的某些一般性错误。本目录是为克服这些错误而设计的，既不全面，也不互相排斥，但是我们希望它将作为有用的指南。Rule 1 Ecology is a science.Ecology is a purely scientific discipline which aims to understand the relationships between organisms and their wider environment,It is important to segregate political and social impacts of ecological understanding from the scientific viewpoint.规律1：生态学是科学生态学是一门纯科学学科，目标是了解有机体与其广阔环境的相互关系。分清楚科学观点与生态学知识的政治和社会影响这一件事是十分重要的。Rule 2 Ecology is only understandable in the light of evolution.The huge diversity of organisms,and the wealth of variety in their morphologies,physiologies and behavior are all the result of many millions of years of evolution,Those evolutionary history has left an indelible impression on each and every individual,It is only possible to make sense of the patterns we find today in the light of this evolutionary legacy.规律2：生态学只有按照进化论才可理解有机体巨大的多样性，以及其形态学、生理学和行为的变异的丰富性，全都是亿万年进化的结果。这个进化历史对于每一个个体都留下了不能去除的影响。我们今天发现的种种模式，只有按照进化论的观点才可能有意义。Rule 3 Nothing happens’ for the good of the species’.A very common misconception is the idea that patterns of behavior in organisms which appear to be costly to an individual occur’ for the good of the species’,This is absolutely and completely wrong,Natural selection will favor those genes which are passed on to the most offspring,even if these genes may cause a reduction in the species’population size.规律3：“对动物种有利”现象并不存在对于那些看起来对个体是花费的有机体行为模式，认为其出现是由于“对物种有利”的这种想法是一个非常普遍的误解。这是绝对和完全错误的。自然选择将会有利于那些传给大多数后裔的基因，即使这些基因有可能导致物种种群大小的下降。Rule 4 Genes and environment are both important,The environment an organism finds itself in plays an important role in determining the options open to that individual,The genes which define an organism’s makeup are also of fundamental importance,To understand ecology it is important to appreciate the fundamental nature of both of these factors and the fact that they interact.规律4：基因和环境都很重要有机体自己所处的环境，对于它在开放的各种选择中决定取舍上，具有重要的作用。决定有权体构造的基因，同样具有根本的重要性。这两方面因素的基本性质及其相互作用，对于理解生态学都是很重要的。Rule 5 Understanding complexity requires models.Ecology is a complex subject,with huge variation at almost every scale-millions of species,each with considerable genetic variation,varying numbers and ever-changing behaviors in a complex and dynamic environment,To understand it,it is necessary to clearly identify specific questions and then formulate hypotheses which can be tested,It is often very useful to frame the hypothesis in mathematical terms to avoid ambiguity and confusion which are often inevitable in a verbal model,Mathematical models are widely used in ecology.规律5：理解复杂性要求模型生态学是一复杂的对象，几乎每一个尺度都有大量变异――亿万个种，每种有大量基因变异，在复杂和动态的环境中有变化着的数量和随时间而改变的行为。为了理解它，必需清楚的认明特异问题，然后形成可以检验的假设。以数学的思想方法构造假说常常是很有用的，可以躲开在语言模型中不能避免的含糊不清和混淆。数学模型在生态学里被广泛的应用。Rule 6 ‘Story-telling’ is dangerous.In attempting to explain ecological patterns or relationships,it is easy to slip into a make-believe world where every observation is readily explained by some ad hoc assertion C ‘story-telling’,The temptation to advance hypotheses as facts should be avoided at all costs.规律6：“讲故事”是危险的在打算解释生态学种种模式或相互关系的时候，人们很容易滑到虚假世界之中，每一个观察都很容易的被某特设的断言（所谓的“讲故事”）所解释了。无论如何，总想去推进假设实际上是应该避免的。Rule 7 There are hierarchies of explanations.For any observation there is often an immediate cause that can be diagnosed,Often this causal explanation is insufficiently informative and we need to probe deeper to reach a fuller grasp of the situation,Even if a phenomenon is ‘explained’ there may well be further and deeper explanations which allow us to see the fuller picture.规律7：要有分层次的解释对于任何观察，常常可以识别出一个直接的原因，但这种因果解释往往是资料不足的，我们需要进一步探索，以达到更完全的抓住情况。即使是现象已经被“解释”了，更进一步和更深入的解释也是很好的，它允许我们看见更完全的情景。Rule 8 There are multiple constraints on organisms.Whilst the total diversity of form,function and environmental resilience exhibited by organisms is awe-inspiring,each individual (and,to a slightly lesser extent,each species) operates within a relatively narrow range of constraints,Constraints fundamentally take two forms,(i) physical and (ii) evolutionary,Evolution cab never reach ‘perfection’ because of these constraints and organisms are essentially hotchpotches of numerous compromises,规律8：有机体具有很多限制有机体表现出来的形态、功能和环境适应力的总多样性是令人惊叹的，每个个体（和每一个种，但较少程度）则在相对较小的约束范围中运转。约束基本上有两类：（i）物理的，（ii）进化的。由于这些约束，进化从来就没有达到“完善”过，有机体基本上是许多妥协的杂烩。Rule 9 Chance is important.Chance events play a critical role in ecology,The opening of a gap in a forest canopy or the breaching of a sand dunce after a storm will have a major impact on the ecology of the local fauna and flora,but both are unpredictable in either time or location,The importance of chance events in ecology does not mean ecological patterns are wholly unpredictable,but it necessarily places boundaries on the potential level of predictive detail.规律9：机会是重要的随机事件在生态学中起关键性的作用。林冠中出现林窗或沙丘在风暴后裂口，对于当地动植物区系将有重要的影响，但是，林窗和裂口出现的时间和地点都是不可预测的。机会的作用也与有机体过去进化综合在一起。生态学中机会事件的重要性并不意味着生态学中的模式是完全不可预测的，但是它必然是位于预言细节的潜在水平之边缘。Rule 10 There boundaries of ecology are in the mind of the ecologist.Ecology is a broad science,covering both organisms and physical environments and hence excludes little as potentially relevant,Mathematics,chemistry and physics are tools essential to the understanding of ecology.规律10：在生态学家心目中的生态学边界生态学是一门广泛的科学，覆盖着生物和物理环境，从而作为潜在相关的，很少有被排除在外的了。数学、化学和物理学都是理解生态学的基本工具。二、ADAPTATIONFitnessFitness is measure of the ability of an individual to produce viable offspring and contribute to future generations,Individuals vary in their relative fitness,and this variation is due partly to genetic differences among individuals and partly to environmental influences.适合度适合度是个体生产能存活后代、并能对未来世代有贡献的能力的指标。个体的相对适合度是有变化的，这种变化部分决定于个体的遗传区别，部分决定于环境的影响。AdaptationAny heritable trait possessed by an organism which aids survival or reproduction is an adaptation,Such traits may be physiological,morphological or behavioral,Adaptation is the result of natural selection.适应有机体所具有的有助于生存和生殖的任何可遗传特征都是适应。适应性特征可以是生理的、形态的或行为的。适应是自然选择的结果。Natural selectionThe individuals in a species which have the highest fitness will contribute disproportionately to the subsequent generations,If fitness differences have a genetic component,then the genetic make-up of the subsequent generations will be altered,This process is known as natural selection or ‘survival of the fittest’.自然选择种中具有最高适合度的个体将会对未来世代作出特别高的贡献。如果适合度的差别含有遗传的成分，则后代的遗传组成会有改变。这个过程称为自然选择或“最适者生存”。Genotype and phenotypeThe genotype is the genetic composition of an individual,The phenotype is the individual organism,a product of the interaction between its genotype environmental influences on its genotype is known as phenotypic plasticity (e.g,human suntan,wind-shaped plants locust morph (solitary or migratory)).基因型和表型基因型是个体的遗传组成。表型是各个有机体，它是基因型与环境的相互作用的产物。由于环境对基因型的影响，表型发生变化的能力叫做表型可塑性（如人的晒黑、风造形的植物、蝗虫的单生或群居型）。三、COPING WITH ENVIRONMENTAL VARIATIONConditionsVariable environmental factors which organisms respond to are conditions,Examples include temperature,acidity and salinity,Conditions are not depletable C they are not used up or consumed by an organism.条件引起有机体对其反应的,可变的环境因子是条件(conditions)，例如温度、酸度和盐度。条件是不可能被减少的――它不能被有机体用掉或消耗掉。ResourcesAnything which the organism uses up or depletes is a resource for that organism,Thus,nectar is a resource for honey bees,and light is a resource for all green plants.资源有机体消耗的任何东西，对该有机体而言，就是资源。例如，蜜是蜜蜂的资源，光是一切绿色植物的资源。生态因子的相关概念生态因子：环境要素中对生物起作用的因子。生存条件：生态因子中生物生存不能缺少的生态因子的总称。生态环境：一定区域所有生态因子的总和。生境（habitat）：特定生物个体或群体的栖息地的生态环境。生态因子的分类根据性质划分为,气候因子：如温度、水分、光照、风、气压和雷电等土壤因子：如土壤结构、土壤成分的理化性质及土壤生物等地形因子：如陆地、海洋、海拔高度、山脉的走向与坡度等生物因子：包括动物、植物和微生物之间的各种相互作用人为因子：人类活动对自然的破坏及对环境的污染生态因子的分类有无生命特征：生物因子和非生物因子对生物种群数量变动的作用密度制约因子：食物、天敌等生物因子非密度制约因子：温度、降水等气候因子稳定性及其作用特点稳定因子：终年恒定的因子，决定生物的分布，如地心引力、地磁等变动因子,周期性变动因子：一年四季变化和潮汐涨落非周期性变动因子：如风、降雨、捕食等生态因子的作用特征综合作用,生态因子间相互联系、相互影响、相互制约主导因子作用：生态因子的非等价作用的阶段性,生物发育的不同阶段，需要不同不可替代性和补偿性：生态因子间不可替代，但在一定程度上可以补偿直接作用和间接作用,直接因子：直接对生物发生影响的生态因子间接因子：通过影响直接因子而对生物发生影响生态因子限制因子和限制因子定律限制因子 (limiting factor)-限制因子是对生物的生存、生长、繁殖或扩散等起限制作用的因子-当生态因子接近或超过生物的耐受性极限而影响其生存、生长、繁殖或扩散时，这个因子成为该生物限制因子限制因子定律 (Law of limiting factor)-生态因子处于低于生物正常生长所需的最小量和高于生物正常生长所需的最大量时，都对生物具有限制性影响 (Blackman，1905)该定律的应用价值---掌握研究生物与环境复杂关系的钥匙Environmental variationMost organisms have to cope with a continually changing external environment over a range of timescales,Some environmental factors may change over seconds or minutes (e.g,sunlight intensity when,there is patchy cloud) whilst others may change daily or seasonally or over a much change daily or seasonally or over a much longer period (e.g,glaciation cycles).环境变异大多数有机体都必须应付在一定时间尺度范围内不断变化着的外界环境。某些环境因子的变化以秒或分计（如当有云块时的阳光强度），另一些因子的变化以日或季计，甚至更长更长的时期（如冰河周期）。toleranceOrganisms can cope with variation in their external environment (though different species may differ markedly),The upper and lower extremes of species limits of tolerance,Usually,growth will not occur at these extremes but in a narrower range of conditions,and fitness will be greatest only for a yet narrower optimal range.耐受性有机体能够应付其外部环境的变化（虽然不同物质表现很不相同）。种的成员能够生存的环境条件上限和下限是种的耐受限度。在此极端条件下通常不出现生长，但在条件更狭窄的范围内能生长，而适合度最大只能出现在更窄的最适范围内。生物对不同生态因子的耐受范围不同，不同年龄、季节、栖息地等同种生物对生态因子的耐受性不同-对很多生态因子耐受范围都很宽的生物，其分布区一般很广-个体发育的不同阶段，对生态因子的耐受限度不同-不同的生物种，对同一生态因子的耐受性不同-某一生态因子处于非最适状态下时，生物对其他生态因子的耐受限度也下降HomeostasisThe maintenance of a relatively constant internal environment by an organism in a variable external environment is called homeostasis,All organisms adopt a degree of homeostatic control,but,as true,large organisms are more decoupled from their external environment than small ones.稳态有机体在可变动的外部环境中维持一个相对恒定的内部环境，称为稳态（homeostasis）。一切有机体都采取一定程度的稳态控制，但是一般地说，大型有机体比小型的更易从其外部环境中退耦（decouple）。Negative feedbackMost biological homeostatic mechanisms act in a broadly similar way,if the current internal level of a factor(e.g.temperature or osmolarity) is too high,the mech if the level is too low the mechanism will increase it,This process,by which the response is opposite to the signal,is known as negative feedback.负反馈大多数生物的稳态机制以大致一样的方式起作用：如果一个因子的内部水平（如温度或渗透性）太高，该机制将减少它；如果水平太低，就提高它。这个过程叫做负反馈。负反馈反应的方向与信号的相反。B3 THE NICHENicheThe ecological niche of an organism is the position it fills in its environment,comprising the conditions under which it is found,the resources it utilizes and the time it occurs there.生态位有机体的生态位（niche）是它在它的环境中所处的位置，包括它发现的各种条件、所利用的资源和在那里的时间。Multidimensional niche spaceEach condition or resource which defines the niche of an organism contributes one dimension to the space in which the organism’s niche,and is the multidimensional niche space,or’n-dimensional hypervolume’.多维生态位空间定义有机体生态位的每一个条件和资源，对于有机体能出现的空间提供一个维度。一起考虑所有维度，全面确定的有机体的生态位，是多维生态位空间，或“n-维超体积”。Fundamental nicheThe niche space an organism can fill in the absence of competition or predation is known as the fundamental niche.基础生态位在没竞争和捕食条件下，有机体的生态位空间叫做基础生态位（fundamental niche）。Realized nicheThe niche space occupied by an organism when competition and predation occur is the realized niche,which is always a subset of the fundamental niche.实际生态位当有竞争和捕食出现时，有机体所占有的生态位空间是实际生态位（realized niche），实际生态位始终是基础生态位的一个子集。四、SOLAR RADIATIONRadiant energy and photosynthesisRadiant energy is the sole energy source that can be used by green plants,When a leaf intercepts radiant energy it may be absorbed,reflected or transmitted,Part of the fraction absorbed reaches the chloroplast,fuelling photosynthesis,the process where radiant energy is used to convert water and CO2 into sugars,Solar radiation contains a spectrum of different wavelengths,However,only a restricted band of this spectrum is effective for photosynthesis,This is the band of photosynthetically active radiation (PAR) and for green plants lies between 380 and 710 nm.辐射能和光合作用绿色植物能够利用的惟一能源是辐射能。当叶子截获辐射能时，它能被吸收、反射或者透射。吸收的部分能量到达叶绿体，引发了光合作用，在这个过程中，辐射能被用于转化水和二氧化碳成为糖。太阳辐射包含了不同波长的光谱。然而，仅有一个有限的光谱带对光合作用是有效的。这就是光合活性辐射（PAR）带，对绿化植物是位于380nm到710nm之间。Measurement of photosynthesisThe rate of photosynthesis is a gross measurement of the rate at which a plant captures radiant energy and fixes it into carbon compounds,Net assimilation is the difference between photosynthetic assimilation and losses due to respiration,Therefore,not assimilation will be negative in the dark and will increase with increasing PAR,The intensity of PAR at which the gain in photosynthesis equals the losses is known as the compensation point.光合作用的测量光合作用速率是总速率的测量，即植物捕获的辐射能，并把它固定到碳的化合物中。光合作用净同化是同化量的呼吸的丢失量之差。因此，净同化在黑暗中是负值，并随PRA增加而增长。在光合作用的同化量等于呼吸消耗量时的PRA强度，称为补偿点（compensation point）植物的光补偿点示意图(Emberlin,1983)光补偿点 (compensation point)光饱和点(saturate point)光合作用强度和呼吸作用强度相当处的光强度为光补偿点；当光照强度达到一定水平后，光合产物不再增加或增加得很少，该处的光强度即为光饱和点。Changes in the intensity of radiationPlants rarely achieve their full photosynthetic potential,due to water shortage and to variation in the intensity of radiation,The systematic variations in light intensity are spatial and temporal of solar radiation,Less systematic variations in light intensity are caused by the positioning of leaves in relation to each other.辐射强度的变化植物很难获得它们完全的光合作用潜能，是由于水短缺和辐射强度的改变。光强度的系统变化是太阳辐射的空间和时间的差异。光强度中极少部分的系统变化是因叶子彼此的相对位置引起。太阳高度角不同，射程不同，太阳辐射强度不同C3 and C4 plantsA major difference in the photosynthetic capacity of plants is that between C3and C4 plants,C4 plants are able to capture CO2 with greater water use efficiency than C3 plants,but this advantage comes at an energy cost,In C4 plants the rate of photosynthesis increases with light intensity,whilst photosynthesis tails off with increasing light intensity in C3 plants,C3和C4植物植物光合能力中的主要差别是在C3和C4植物之间。C4植物能捕获CO2,伴随着水的利用效率比C3植物更大，而这优点需要消耗能量。在C4植物中，光合作用率随光强度而增加，而C3植物随光强度增加光合作用渐渐减小。Strategic and tactical response of plants to radiationA major strategic difference between plant species in their response to the intensity of radiation is exhibited by ‘sun species’ and ‘shade species’,which possess a range of adaptations to high and low light levels,respectively,Also,plants may grow leaves which develop differently under different light conditions as part of a tactical response to the light environment,This is most clearly seen in the formation of sun leaves and shade leaves within a leaf canopy of single plant.植物对辐射的战略和战术响应植物种间对辐射强度反应的主要战略差异显示为“阳地种”和“阴地种”，它们分别具有适应于高的和低的光辐射范围。同样，植物能够在不同光条件下生长不同的叶子，作为对光环境的部分战术反应。这一点最清楚地在单株植物叶冠内的阳叶和阴叶的结构上看到。1）阳地植物/阳生植物:在强光照下才能正常生长、发育，而在隐蔽条件和弱光条件下生长不良的植物。如松、杉、杨、柳、麻栎、栓皮栎、桦、槐等。2）阴地植物/阴生植物:在弱光照下比在强光照下生长良好的植物。如人参、三七、红豆杉、云杉、冷杉、翠云草、半夏、细辛等。阴地植物与阳地植物对光照强度的适应
动物对光照强度的适应有些动物适应于白天的强光照下活动，称为昼行性动物。因其能忍受的光照范围较广，故又称为广光性动物。有些动物适应于在夜晚或晨昏的弱光下活动，则称为夜行性动物或晨昏性动物。因其只适应于在狭小的光照范围内活动，所以又称为狭光性动物。生物对光周期的适应植物的开花结果、落叶及休眠，动物的繁殖、冬眠、迁徙和换毛换羽等，是对日照长短的规律性变化的反应，称为光周期现象1、植物的光周期,2、动物的光周期1、植物的光周期根据对日照长度的反应类型可把植物分为：长日照植物：只有当日照长度超过它的临界日长时才能开花的植物，否则，只有营养生长，没有生殖生长。如冬小麦、大麦、油菜、菠菜、萝卜等。起源于北方。短日照植物：只有当日照长度短于临界日长时才能开花的植物。这类植物通常在早春或深秋开花。如苍耳、水稻、玉米、大豆、烟草、麻、棉。这类植物通常在早春或深秋开花。起源于南方。中日照植物：是指当昼夜长短近于相等时才能开花的植物。如黄瓜、番茄、番薯、四季豆、蒲公英中间型植物：这类植物对日照长度的要求不严，只要其他条件合适，在不同的日照长度下都能开花。动物的光周期现象（1）繁殖的光周期现象：长日照动物和短日照动物：在温带和高纬度地区许多鸟兽在春夏之际白昼逐渐延长的季节繁殖后代，称长日照动物；与些相反，一些动物只有在白昼逐步缩短的秋冬之际才开始性腺发育和进行繁殖，称短日照动物。前者如雪貂、野兔、刺猬；后者如绵羊、山羊和鹿等。（2）昆虫滞育的光周期现象：很多昆虫在它们生命周期的正常活动中，能插入一个休眠相，即滞育，常由光周期决定的。（3）换毛与换羽的光周期现象：温带和寒带地区，鸟兽的换毛换羽（4）动物迁移的光周期现象：鸟类的长距离迁徙，鱼类的回游五、TEMPERATUREEcological Effects of temperatureThe rate of an enzyme catalyzed reaction increases with temperature,The temperature coefficient (Q10) is an index of the effect of a 10℃ temperature rise on metabolic rate,and is often near 2.0,Within the nonlethal temperature range the most important effect on organism of temperature is likely to be its effect on growth and development,温度的生态作用酶催化反应的速度随温度而增加（温度系数（Q 10) 是温度升高10℃对代谢速度影响的指数，经常大约为2.0）在非致死温度范围内，温度对生物最大的影响很可能是影响了生长和发育。温度与生物生长-“三基点”：对应于酶活性的最低、最适和最高温度-不同生物的“三基点”不一样温度与生物发育-有效积温法则-春化有效积温法则有效积温法则:生物在生长发育过程中必须从环境中摄取一定的热量才能完成某一阶段的发育，而且植物各个发育阶段所需的总热量是一个常数。K=（T-T0）N T0为物理学0℃―活动积温K=（T-C）N C生物学0℃（发育起点温度）――有效积温有效积温法则的实际应用预测生物（特别是病虫害）发生的世代数；预测生物地理分布的北界；预测害虫来年的发生程度；推算生物的年发生历；根据积温制定农业气候区划，合理安排农业生产Vernalization and AcclimationTemperature may also act as a stimulus,determining whether the organisms will begin development,Vernalization is the induction of flowering by low temperatures,Exposure of an organism to higher (or lower) temperatuers in the laboratory can alter the organisms temperature response,The habituation of an organism’s response to changes in laboratory environmental conditions is termed acclimation,Acclimatization is the habituation of an organism’s physiological response to changes in natural environmental conditions.春化和驯化温度能够作为一种刺激物起作用，决定有机体是否将开始发育。春化法是通过低温诱导开花。有机体在实验室里暴露到较高（或较低）的温度能够改变有机体的温度反应。有机体对实验环境条件变化产生的适应性反应称为驯化（acclimation）。有机体对自然环境条件变化产生的生理适应性反应称为气候驯化（acclimatization）。Temperature thresholdsHigh temperatures may lead to enzyme inactivation or the unbalancing of comp for example,in plants,respiration may proceed faster than photosynthesis,leading to death,however,the most frequent effect of high temperature on organism is dehydration,All terrestrial organism must conserve water but at high temperatures rates of water loss can be lethal,There are large differences between the low temperature tolerances of differing species,associated with the processes of freezing,chilling and hardening,Many are killed by temperatures below C1℃ due to the damaging effects of ice-crystal formation within cells.温 度 阈高温可能导致酶失活或代谢组分不平衡，例如植物的呼吸作用快于光合作用而导致死亡。然而高温对生物最普遍的影响是引起脱水。所有陆生生物必须保持水，但在高温下失水率能够成为致死因子。不同物种对低温的耐受性有很大的差异，这与结冰、寒冷和坚硬的过程有关。温度低于-1℃时很多物种被冻死，这是由于细胞内冰晶形成的损伤效应生物对低温的适应植物形态结构：油脂、鳞片、短小、匍匐状，厚皮生理适应：减少细胞内的水分，增加糖类、脂肪和色素动物形态：阿仑规律、贝格曼规律、毛、皮结构、脂肪层生理：基础代谢和非颤抖性产热(褐色脂肪)，行为：迁徙、冬眠、冬睡、滞育、集群、活动位置Allen’s ruleThe effects of temperature on individuals may be moderated by evolved differences,Allen’s rule states that endothermic animals from cold climates tend to have shorter extremities (ears and legs) compared with animals from warmer climates,thus reducing their surface area,volume ratio,This rule has widespread applicability,阿伦法则阿伦法则（Allen’s rule）陈述了来自冷气候中的内温动物与来自温暖气候的内温动物相比，趋向于具有更短的末端（耳朵和四肢）；因此降低了它们的表面积对体积的比率。Bergmann’s rule states that mammals tend to be larger in colder areas than warm climates,again to reduce their surface area,volume ratio.,贝格曼规律贝格曼规律（Bergmann’s rule）讲述了寒冷地区的哺乳动物比温暖地区的哺乳动物个体趋向于更大，也减低了它们的表面积与体积的比率。生物对高温的适应植物形态适应：叶片毛、鳞片、颜色、排列 木栓层生理适应：细胞含水量(糖/盐浓度、代谢强度) 旺盛的蒸腾作用动物生理适应：适当放松恒温性行为适应：栖居地点、活动时间本 章 小 结光照和温度的时空变化规律光质、光强、光周期对生物的影响生物对光质、光强、光周期的适应温度的生态作用，极端温度对生物的影响生物对极端低温、极端高温的影响主要概念春化、光饱和点、光补偿点、阴地植物、阳地植物、长日照植物、短日照植物、长日照动物、短日照动物、温度三基点、有效积温、贝格曼规律、阿仑规律、休眠思考题1,光在时空上的配置对植物和动物产生哪些影响？它们又是如何适应这些变化的？2,低温和高温对生物会产生哪些影响?为什么温度能够限制生物的分布?3,生物是如何适应极端温度条件的？4,在引种驯化中应该注意光照和温度的哪些因素？六、Organism and Water（一）水因子的生态作用1、水是生物生存的重要条件2、水对动植物生长发育的影响3、水对动植物数量和分布的影响生物体的水分获得与损失途径水分的丧失途径植物－蒸发（蒸腾作用、扩散作用）失水，分泌失水。动物－蒸发失水，排泄、分泌失水。水分获得途径植物－－根部吸收，叶面吸收。动物－－食物，体表吸收，代谢水。（二）生物对水因子的适应1、植物对水因子的适应陆生植物,湿生植物、中生植物、旱生植物（少浆液、多浆液植物）水生植物：沉水植物、浮水植物、挺水植物在形态、生理、结构上的不同适应2、动物对水因子的适应水生动物的渗透压调节两栖类动物对环境湿度的适应陆生动物对环境湿度的适应Soil waterFor terrestrial plants the main source of water is the soil,which serves as a reservoir.,water enters the reservoir as rain or melting snow and passes into the soil pores,The upper limit of the water-holding capacity of a soil is called the field capacity,This is the amount of water which can be held by soil pores against the force of gravity.Plants cannot extract all the water held in the soil,as they cannot exert sufficient suction force to extract water from the narrower soil pores,The lower limit of water availability is thus determined by the physiology of the plant species and is known as the permanent wilting point C the soil water content at which plants wilt and are unable to recover.土 壤 水对于陆地植物，水的主要来源是土壤，它起了蓄水池的作用。当下雨或雪融化时，水进入蓄水池，并流进孔隙。土壤的水容量上限称为田间持水量（field cap-acity）。这是土壤孔隙抗地心引力所储蓄的水量。植物不能吸取土壤中储蓄的全部水，因为它们不能产生足够的吸力从更细的土壤孔隙中吸水。因此可利用水的下限是由植物物种的生理特性所决定的，被称为永久萎蔫点（permanent wilting point）――土壤水（soil water）含量在这个点上，植物枯死，不能恢复。The uptake of water by rootsRoots can capture water from the soil in two ways,either water may move through the soil towards a root or the root may grow through the soil towards the water,As a root withdraws water from the soil capillary pores at its surface,it creates water depletion zones around it,If a root draws water from the soil very rapidly,the resource depletion zone (EDZ) will receive water from the surrounding soil at a slow rate,restricting water availability,so plants may wilt even in soil containing abundant water.根对水的吸收根以两种方式从土壤中捕获水：要么水穿过土壤向根移动，要么根生长穿过土壤向水移动。当根以它的表面从土壤毛细管孔隙吸水时，在根的周围产生了水耗竭区。如果根从土壤中吸水很快，资源耗竭区（RDZ）将以一个低速率从周围土壤中接收水，从而限制了水的可利用性，使植物即使在含水丰富的土壤中也可能枯萎。Aquatic plants and waterWater is apparently available in aquatic environments,However,the osmotic regulation of internal fluids can be energetically expensive,especially in saline environments,The salinity of an aquatic environment and of terrestrial habitats bordering the sea has an important influence on plant distribution and abundance,Plants which grow in high salinity,halophytes,accumulate electrolytes in their vacuoles,but the concentration in the cytoplasm and organelles is kept low.水生植物和水在水环境中，水显然是随意可利用的。然而，内部体液的渗透压调节可能消耗能量，特别是在盐水环境中。水环境的盐度与沿海陆地栖息地的盐度，对植物分布移度有重要的影响。生长在高盐度中的植物，即盐生植物，它们的液泡中累积了电解质，但在细胞质和细胞器官中保持着低浓度。Water availability and plant productivityPrecipitation is a key determinant of plant productivity in forests,whilst in arid regions there is an approximately linear increase in primary productivity with increasing precipitation,The amount of water that would be transpired from a site,assuming no soil water limitation and complete vegetation cover is the potential evapotranspiration rate,The difference between this index and the precipitation rate defines whether the environment is moist or arid,水的可利用性与植物生产力降雨量是森林植物生产量的关键决定因子，而在干旱地区，初级生产量随降雨量的增加大致呈一个线形增长。假设一个地区没有土壤的水限制，并完全地被植物覆盖，水从这个地区的蒸发量就是潜在蒸发蒸腾速度（potential evapotranspiration rate）。这个指标和降雨量之间的差异决定了环境是潮湿的，还是干旱的。Water balance in fishMaintaining water balance is problematic in an aquatic environment,which is countered by osmoregulatory mechanisms,Freshwater fish have to continually excrete excess water because the fish is hypertonic relative to its surroundings (the concentration of solutes in body fluids is higher than the solute concentration of the water),and they produce a large volume of very dilute urine.Bony fishes living in seawater have the opposite problem,being hypotonic to their surroundings,The kidneys of marine fish secrete very little urine,and instead function mainly as a means of removal of divalent ions such as Ca2+,Mg2+and SO42-.鱼类的水平衡在水环境中保持水平衡是有疑问的，它是通过渗透调节机制解决的。淡水鱼必须连续地排泄过量的水，因为鱼与它的环境相比，它是高渗透性的（体液的溶质浓度比水的溶质浓度高），它们产生大量的低浓度的尿。生活在海水中的硬骨鱼有相反的问题，它们要的功能是去除两价的离子，如像Ca 2+、Mg 2+ 和SO42-等渗（isosmotic organism）体内和体外的渗透压相等，水和盐以大致相等的速度在体内外之间扩散。仅排泄失水，通过食物、饮水、代谢水获得水，泌盐器官排出多余的盐分。高渗（hyperosmotic organism）体内的渗透压高于体外，水由环境中向体内扩散，体内的盐分向外扩散。通过排泄作用排出多余的水，盐分通过食物和组织摄入。低渗（hypoosmotic organism）体内渗透压低于体外，水分向外扩散，盐分进入体内。通过食物、代谢水和饮水获得水，多种多样的泌盐组织排出多余的盐分。淡水鱼类生活的环境是一种特殊的低盐环境，淡水硬骨鱼类血液和体液的渗透压高于水的渗透压，进入体内多余的水通过鱼的肾脏排除大量低浓度尿，通过食物和鳃主动吸收盐离子，保持水盐代谢的平衡。海洋硬骨鱼类的血液和体液大大低于海水的渗透浓度，如鲱、鲑等。因此保持水分平衡的有效方法是大量饮水；通过细胞膜上具有Na+泵和K+泵，主动排盐。Water balance in amphibiansAmphibian kidneys function much like those of freshwater fishes.However,on land,where dehydration is the most important problem in terms of osmoregulation,frogs conserve body fluid by reabsorbing water across the epithelium of the urinary bladder.两栖类的水平衡两栖类的肾功能很像淡水鱼的肾功能。然而在陆地上，脱水对渗透调节是最重要的问题，蛙保存体液是通过膀胱上皮细胞的重吸收水。Water conservation by terrestrial animalsA major problem faced by terrestrial organisms is the loss of a continuous supply of water necessary to keep tissue surfaces moist.When air is inhaled,it passes along the respiratory tract into the lungs,where it is in contact with the moist respiratory tissues.If the moist air was exhaled,water would be lost,The recovery of respiratory moisture by most terrestrial animals involves countercurrent exchange,Exhaled air from the lungs encounters a countercurrent-like gradient on the way out,This interaction between the departing air and the respiratory surfaces results in an efficient return of moisture to the tissues.陆生动物的水保持陆生动物面对的主要问题是连续地失水，这是供应到组织表面维持潮湿所必需的水。当空气被吸入时，它沿着呼吸道进入肺，和潮湿的呼吸组织相接触。如果潮湿的空气被呼出，水就会丢失。大多数陆生动物呼吸湿度的维持包括了逆流交换（countercurrent exchange）从肺呼出的气体，在呼出的通道上有一个像逆流的梯度。呼出的气体和呼吸表面的相互作用，导致水分有效地返回组织。Water conservation by mammalian kidneysThe water-conserving ability of the mammalian kidney represents a key terrestrial adaptation,Water recovery from the urine before it leaves the kidney takes place in the loop of Henle.Mammals adapted to the desert (such as kangaroo rats) that excrete highly concentrated hypertonic urine,have exceptionally long loops of Henle,In contrast,beavers,which spend much of their time in fresh water,have nephrons with very’short loops,resulting in dilute urine,The kidneys of reptiles are less sophisticated and produce urine that is,at best,isotonic to body fluids,This means that the solute concentration of urine is equal to the solute concentration of the body fluids.哺乳动物肾脏的水保持哺乳动物肾脏的水保存能力表现出关键的陆生适应性。尿离开肾脏之前，水在亨利氏袢中被回收。适应于荒漠的哺乳动物，如更格卢鼠，排泄高浓度的高渗尿，它们有极长的亨利氏袢。相反，河狸大部分时间是在淡水中渡过的，它们的肾单位具有很短的袢，产生低浓度的尿。爬行动物的肾脏结构较简单，产生的尿最多也就是与体液等渗。这意味着，尿的溶质浓度与体液的溶质浓度是相等的。形态结构适应昆虫具有几丁质的体壁，防止水分的过量蒸发；两栖类动物体表分泌粘液以保持湿润；哺乳动物有皮质腺和毛，防止体内水分过多蒸发。行为的适应沙漠动物昼伏夜出：沙漠地区夏季昼夜地表温度相差很大，因此地面和地下的相对湿度和蒸发力相差很大迁徙：在水分和食物不足时，迁移到别处。POPULATIONS AND POPULATION STRUCTUREPopulationA population is a group of organisms of the same species which occupies a given area,The boundaries between populations can be arbitrary,种 群种群是一定区域内同种生物个体的集合。种群间的边界可以是任意的。自然种群的基本特征空间特征：种群具有一定的分布区域数量特征：每单位面积(或空间)上的个体数量(即密度)及变动遗传特征：种群具有一定的基因组成个体可能呈随机、均匀和聚集分布格局 (方差/平均数比)均匀分布：S2/m=0--原因：种群内个体间的竞争。随机分布：S2/m=1--原因：资源分布均匀，种群内个体间没有彼此吸引或排斥。聚集分布：S2/m&1--原因：资源分布不均匀；种子植物以母株为扩散中心；动物的社会行为使其结群。方差/平均数比率：S2/mS2=[Σ(fx)2-(Σfx)2/n]/(n-1)m=Σfx/nx―样方中某种个体数f―含x个体样方中出现频率n―样方总数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 fragment producing many individual ramets.种群可以根据组成种群的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的构件和分支结构。然后这些结构可能分裂，形成许多无性系分株。Population sizeThe 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.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的数量，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）的数目比不同个体的数量更有意义代表多度。Age and stage structureThe age structure of a population is the number of individuals in each age class expressed as a ratio,and is usually displayed as an age pyramid diagram,A population which is neither expanding 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,年龄和时期结构种群的年龄结构是每一年龄阶段个体数目的比率，通常以年龄金字塔图来表示。既不增长也不下降的种群有稳定的年龄分布。增长型的种群有更多的年轻个体，而在下降型种群中年老的个体占优势。
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 as plants),size classes may be more informative.当种群经历离散和发育时期（如昆虫的龄期）时，每一时期个体的数目（“时期结构”）可以对种群进行有效的描述。对于生长率无法预测的物种（如植物），根据大小分类可能更有意义。NATALITY,MORTALITY AND POPULATION GROWTHNatalityNatality 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,出 生 率出生率就是新个体的产生，实际出生率就是一段时间内每个雌体实际的成功繁殖量。特定年龄出生率就是特定年龄组内雌体在单位时间内产生的后代数量。mortalityThe 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.死 亡 率死亡率是在一定时间段内死亡个体的数量除以该时间段内种群的平均大小。这是一个瞬时率，可用来估价整个种群的死亡率或特定年龄群的特定年龄死亡率，死亡的概率是死亡个体数除以在每一时间段开始时的个体数。SurvivorshipSurvivorship is the converse of mortality,Survivorship data are often shown as a survivorship curve for a p a graph showing the proportion of survivors on a logarithmic scale through each phase of life,存 活 率存活率是死亡率的倒数。对于一个特定种群，存活率的数据通常以存活曲线的形式来表示；存活曲线表示的是在每一个生活期存活个体所占的比率的对数值。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).根据各种生活期死亡率的高低，特定年龄存活曲线一般有三种模式：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）。Life Table(1) Definition of life table(2) Types of life table(3) Excellences of life table一、生命表的定义生命表是按种群生长的时间,或按种群的年龄(发育阶段)的程序编制的,系统记述了种群的死亡或生存率和生殖率,是最清楚、最直接地展示种群死亡和存活过程的一览表.最初用于人寿保险,对研究人口现象和人口的生命过程有重要的意义.Dynamic and static life tablesDynamic 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,Static life tables summarize the age structure born at special time.动态和静态生命表动态生命表总结了一组出生时间大体相同的个体从出生到死亡的命运，这样的一组个体称为同生群，这样的调查称为同生群分析。静态生命表根据某一特定时间对种群作一年龄结构调查资料综合生命表：增加出生率生命表的主要优点1,系统性,记录了从世代开始至结束.2,阶段性,记录各阶段的生存或生殖情况.3,综合性,记录了影响种群数量消长的各因素的作用状况.4,关键性,分析其关键因素,找出主要因素和作用的主要阶段.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生命表表示存在于不同生命阶段或年龄个体的数量，以及每一阶段的年龄特定存活率和年龄特定死亡率。每一阶段的死亡率用k值表示，k是通过对数函推导出来的，并且可以相加得出总死亡率。k-Factor analysisThis 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 (ktotal),K-Factor analysis highlights those stages suffering the greatest mortality which are responsible for fluctuations in loss rate and hence population size,K-因子分析这一方法可以辩明关键因子对死亡率的作用。连续几年获得的特定阶段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的阶段，这些阶段是种群丧失率和种群大小波动的关键。The fecundity scheduleFecundity 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 R0,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.生殖力表生殖力是指同一个体生产的卵、种子或处于生活史第一阶段后代的数目。生殖力表可计算基础生殖率R0。R0是在同生群结束时每个亲体产生后代的数量。在一年生种群中，R0表示在这段时间内，种植增长或下降的总的程度。population growthThe 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,(Nt ),and subtracting the number of deaths (D) and emigrants (E) to give a new population size an the time t+1(Nt+1),This is represeN t+1 = N t +B + I C D C E种群增长种群大小随时间的变化可以按如下方法计算：t时间种群原来数量（Nt），加上新出生的个体数（B）和迁入个体数（I），减去死亡个体数（D）和迁出的个体数（E），就可得到t+1时间种群的数量（N t+1），这可用以下方程表示。N t+1= Nt +B + I C D C EFor 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.在一组特定条件下，一个体具有最大的生殖潜力，称为内禀自然增长率r。这是种群在不受资源限制的情况下，于一定环境中可达到的理论最大值。r = lnR0/T （T C 世代时间）种群的增长模型与密度无关的种群增长模型与密度有关的种群增长模型与密度无关的种群增长模型种群在“无限”的环境中，即假定环境中的空间、食物等资源是无限的，则种群就能发挥内禀增长能力，数量迅速增加种群增长率不随种群本身的密度而变化，种群呈指数增长格局Density-independent population growthUnlimited 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 Size at time t = Intrinsic rate of increase × population sizedN/dt = rN非密度制约性种群增长这种无限增长可用连续型种群模型来描述，以在t时间时，种群数量的变化率来表示：t时间种群大小的变化率=内禀增长率×种群大小dN/dt = rNr&0种群上升；r=0种群稳定；r&0种群下降与密度有关的种群增长模型一、两点假设（1）环境容纳量(K)：环境条件所容纳的种群最大值（2）增长率随密度上升而降低的变化，是成比例的。每一个体利用空间为1/K，N个体利用N/K空间，剩余空间为1- N/K。二、种群增长的S形曲线开始期：群大小N很小，密度增长缓慢加速期：随个体数增加，密度增长逐渐加快转折期：当N=1/2K时，种群密度增长最快减速期：当N&1/2K时，密度增长逐渐变慢饱和期,N= K，种群的增长为零，种群达到了一个稳定的大小不变的平衡状态。四、逻辑斯谛方程Density-dependent growth-the logistic equtationThe 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,密度制约性种群增长：逻辑斯谛方程逻辑新谛方程描述的是一个在有限资源空间中的简单种群的增长。在早期，资源丰富，死亡率最小，繁殖尽可能的快，种群内个体可达到内禀增长率。种群呈几何式增长，直到种群数量达到环境可持续支持的最大程度，即环境容纳量（K）。当种群更加拥挤时，种群增长率减少到零，种群大小处于稳定状态。This can be described as the logistic equation,Rate of change of Intrinsic rate Population Density dependentPopulation size at time t = of increase × size × factorDn/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,这可用逻辑斯谛方程来表示：T时间种群大小变化率=内禀增长率×种群大小×密度制约因子dN/dt = rN(1 - (N/K))当种群达到环境容纳量，种间竞争变得更激烈时，密度制约因子（1 - (N/K)）会接近零。该方程预测种群的增长随时间变化呈现出“S”形，如在真实种群中通常所观察的那样。五、重要意义-许多相互作用种群增长模型的基础-确定鱼业、林业、农业等领域的最大持续产量-r、K为生物进化对策理论中的重要概念Equilibrium population densityThe 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.平衡种群密度当单位个体出生率正好平衡单位个体死亡率，种群密度既不增加也不减少时，此时的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。POPULATION DYNAMICS C FLUCTUATIONS AND CYCLESExpanding and contracting populationsMost 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.增长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，而是动态的不断的发生变化。由于周围环境的变化或生物因子的影响，种群可能会增长或收缩。Populations fluctuationsPopulations 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 predato（ii） Overcompensating density dependence,This can lead to dampened oscillations,stable limit cycles (regular cycles that do not damp down) or chaotic fluctuationEnvironmental stochasticity,This is a nondeterministic,unpredictable variation in the environmental conditions,resulting in a changing equilibrium density.种群波动种群波动可能有以下几个原因,（i）时滞或称为延缓的密度制约，存在于密度变化及其对种群大小的影响之间。种群可能超过环境容纳量，然后逐渐减少，在最终达到平衡之前呈现减幅振荡。这种延缓的密度制约可能使捕食者和猎物多度之间产生周期。（ii）过度补偿性密度制约。其可能导致减幅振荡、稳定极限环（非减幅振荡的有规律周期变化）或无规则随机振荡。（iii）环境随机变化。环境条件非确定性的、不可预见性的变化会导致平衡密度的变化。种群调节气候学派-气候学派多以昆虫为研究对象-种群参数受气候条件强烈影响，种群增长主,要受有利气候时间短暂的限制-种群没有时间达到环境容量所容许的数量水平，无食物竞争-强调种群数量的变动，否定稳定性生物学派主张捕食、寄生、竞争等过程对种群调节的决定作用-只有密度制约因子才能调节种群的密度-食物对种群调节的重要作用-气候学派和生物学派的折中：适于不同的环境条件行为调节-种内个体间通过行为相容与否调节其种群动态结构的一种方式-领域性：指由个体、家庭或其他社群单位所占据的，并积极保卫不让同种其他成员侵入的空间。保卫领域方式：鸣叫、气体标志、威胁、直接进攻驱赶入侵者-社群等级：动物种群种各个动物的地位具有一定顺序的等级现象。通过社群行为，可以限制生境中的动物数量内分泌调节-种群数量上升时，种内个体经受的社群压力增加，加强了对中枢神经系统的刺激，影响了脑垂体和肾上腺的功能，使促生殖激素分泌减少(使生长和生殖发生障碍)和促肾上腺皮质激素增加(机体的抵抗力可能下降)，这种生理反馈机制使种群增长受到停止或抑制，社群压力降低-主要适用于兽类遗传调节-种群数量可通过自然选择压力和遗传组成的改变得到调节-种群内的遗传多型是遗传调节的基础-不同遗传结构的个体其生存能力不同-遗传与生物的行为、扩散等因素一起对种群数量进行调节INTERSPECIFIC AND INTRASPECIFIC INTERACTIONSClassifying interactionsInteractions between individuals and species can be classified on the basis of the effects and the mechanism of the interaction,The key interspecific interactions are competition,predation,parasitism and mutualism,whilst the main intraspecific interactions are competition,cannibalism and altruism.相互作用的分类个体或物种间的相互作用可以相互作用的机制和影响为基础来分类。关键的种间相互作用是竞争、捕食、寄生和互利共生，而主要的种内相互作用是竞争、自相残杀和利他主义。Interspecific CompetitionInterspecific competition occurs between two species using the same limited resource,Guilds are groups of species that oc for example,insects feeding on broad-leaved trees form one guild,Very few species can escape from the effects of other species competing for the same resource.种间竞争种间竞争发生在利用同样有限资源的两物种之间。占据相似生态位的物种组合的集团称为同资源种团；如以阔叶树为食物的许多昆虫就形成一个同资源种团。极少种能够逃脱其他种与之竞争共同资源的影响。Competitive exclusionIf two species compete in a stable environment,there are t (i) one species is excluded,or (ii) both species coexist (Gause hypothesis),The competitive exclusion principle states that coexistence can only occur in a stable environment if the species niches are differentiated.竞争排斥如果两个物种在稳定环境中竞争，则有两种可能的结果：（i）一种被排除，或（ii）两种共存（高斯假说）。竞争排斥原理陈述，共存只能发生在两物种生态位分化的稳定环境中。Limiting similarityHow much niche differentiation is needed for species to coexist? This critical threshold of differentiation in resource utilization is termed the limiting similarity,Ii is determined by the balance between intraspecific competition and interspecific competition.极限相似性共存各需要多少生态位分化？在资源利用分化上的临界阈值叫做极限相似性。极限相似性决定于种内竞争强度和种间竞争强度之间的平衡。Exploitation CompetitionThere are two ways in which competition can operate,In exploitation competition,individuals only interact indirectly,by depleting the resource in short supply,Reduced fitness occurs due to a shortfall in resource availability.利用性竞争竞争有两种作用方式。在资源利用性竞争方式下，个体不直接相互作用，而是耗尽资源使供应不足。由于可利用资源不足而造成适合度下降。Interfernce CompetitionIn interference competition,individuals interact directly,most obviously,in the case of some animal species,by fighting,but also by producing toxins (e.g,plant allelopathy),Fitness reduction in the ‘loser’ in such interactions may be due to the interference (e.e,injuries or death) as well as the lack of resource access.干扰性竞争在干扰性竞争方式下，个体直接相互作用，在一些动物种类中，最明显的通过打斗，也通过产生毒物（如植物异株克生）进行竞争。在这种相互作用中“败者”适合度下降，可能由于干扰（如受伤或死亡），也或许由于缺乏可用资源。Asymmetry in the effects of CompetitionCompetition often unevenly affects competitors,such that the cost for one individual is far greater than for another,It is common for competition to kill the losers,either via exploitation or interference.竞争结果的不对称竞争通常不均等的影响竞争者，一个体的竞争代价远高于另一个体。竞争杀死失败者是很普遍的，或通过掠夺资源或通过干扰。Lotka-Volterra模型假设两个物种，单独生长时增长曲线为逻辑斯蒂模型若将两个物种放在一起，他们发生竞争，从而影响其他种群增长,假设α12表示在物种1的环境中，每存在一个物种2的个体，对于物种1的效应。 α21表示在物种2的环境中，每存在一个物种1的个体，对于物种2的效应，则有逻辑斯蒂方程,dN1 /dt = r1N1 (1-N1/K1 C α12N2/K1)dN2 /dt = r2N2 (1-N2/K2 C α21N1/K2）K1&K2/α21,K1/α12& K2，物种2被排斥，物种1取胜K1&K2/ α21,K1/ α12 &K2，物种1被排斥，物种2 取胜K1&K2/ α21,K1/ α12 &K2，不稳定的平衡点，两种可能获胜K1&K2/ α21,K1/ α12 &K2,稳定的平衡点，两种共存Competitive releaseIn the absence of a competitor,a species may expand its niche,Examples of such competitive release include ground doves in New Guinea and gerbils in Israel.竞争释放在缺乏竞争者时，物种会扩张其实际生态位。这种竞争释放的例子包括新几内亚岛上的地鸽子和以色列的沙鼠。Character displacementWhen realized niches contract under the influence of competition,morphological changes may follow as adaptations to the new resource spectrum,Such character displacement is found in the ant Veromessor pergandei and in Darwin’s finches,Geospiza fortis and G,fuliginosa.性状替换当明确的生态位契约受到竞争影响时，为了适应新的资源谱，个体形态会相应变化。这种性状替换发现在收获蚁Veromessor Pergandei 和达尔文雀，Geospiza fortis和G,fuliginosa。Apparent competitionIf a predator attacks two prey species,then each prey species may adversely affect the other,by increasing the local predator population,Therefore,the interaction between the two prey species is exactly as if they were competing,yet they may utilize entirely different resources,This phenomena is known as apparent competition.表观竞争如果捕食者进攻两种猎物，那么每一种猎物，会通过增加当地捕食者种群的数量，相反地影响另一种。因此，两个猎物种群之间的相互作用看上去似乎它们确实是在竞争，然而它们或许利用完全不同的资源。这一现象叫做表观竞争。他感作用他感作用 (allelopathy)植物体通过向体外分泌代谢过程中的化学物质，对其他植物产生直接或间接影响的现象存在于种内和种间克生物质乙烯、香精油、酚及其衍生物，不饱和内脂,生物碱、配糖体等生态意义对农林业生产的影响：歇地形象影响植物群落的种类组成植物群落演替的重要内在因素THE NATUES OF PREDATIONDefining predationPredation can be defined as the consumption of all or part of another individual (the prey),This wide definition thus encompasses,(I)’true predators’,which kill their prey soon
(ii) grazers,which consume only part
(iii)parasites,which live in very close association with a single prey individual (the host),often inside the host’s tissues.捕食的定义捕食可定义为摄取其他个体（猎物）的全部或部分为食。这一广泛的定义包括（i）典型的捕食者，在袭击猎物后迅速杀死而食之；（ii）草食者，只消费对象个体的一部分；（iii）寄生者，与单一对象个体（寄生）有密切关系，通常生活在寄主的组织中。Carnivores and herbivoresPredators can be categorized as (i) herbivores which consume plant tissue,(ii) carnivores which food in animal tissue and (iii) omnivores which feed on both,The difference between animals and plants as prey types required different physiological and behavioral adaptations,and has lead to repeated evolutionary divergence between carnivorous and herbivorous lineages.肉食者和草食者捕食者可以划分为（i）消费植物组织的草食者，（ii）摄食动物组织的肉食者和（iii）既摄食植物组织也摄食动物组织的杂食者。动物、植物食性的差异需要不同的生理和行为适应，从而导致肉食者与草食者世系之间反复的进行分歧。Generalists and specialistsPredators vary in the number of species of prey they will feed on,with some species being specialists,whilst others are more generalist,Generally,parasites tend to be more specialist than true predators and herbivores tend to be more specialist than carnivores.泛化种和特化种捕食者随其摄取猎物的数量多少而变化，某些捕食者是特化种，而另一些是泛化种。一般来说，寄生者比典型捕食者更为特化、而草食者比肉食者更为特化。The impact of predators on prey population sizeDo predators and parasites regulate the population size of their prey? This is not as simple question as it may appear,There are two main issues,(I) the effect of any one predator may only be a small component of the total mortality causes affecting a prey species,so removal of the predator will have(ii) predation may kill animals which were going to die anyway,so there will be no impact on the final prey population size,However,in a number of cases there is clear evidence that predators have a considerable impact on prey numbers.捕食者对猎物种群大小的影响捕食者和寄生者是否能够调节其猎物种群的大小呢？这一问题并不像看上去的那么简单。有两种主要观点：（i）任一捕食者的作用，只占猎物种总死亡率的很小一部分，因此去除捕食者对猎物种仅有微弱效果；（ii）捕食者只是杀死了对象种中即将死亡的个体，所以最终对猎物种群大小没有影响。然而，在一些例子中确有明显证据表明捕食者对猎物数量有重要影响。Lotka-Volterra predator-prey modelThe Lotka_Volterra predator-prey model is a simple mathematical model representing the interaction between predators and their prey,It makes three simplifying assumptions,(i) there is only one predator and one prey species involve (ii) prey numbers increase if the number of predators falls below a threshold and decrease if ther(iii) predator numbers increase if the number of prey rises above a threshold and decrease if there are fewer prey,This simple model makes an interesting prediction,predator and prey populations will tend to cycle,as is observed in natural predator-prey dynamics.Lotka-Volerra捕食者-猎物模型Lotka-Volterra捕食者-猎物模型是描述捕食者与猎物间相互关系的一个简单的数学模型。这一模型做了三个简单化假设：（i）相互关系中仅有一种捕食者与一种猎物；（ii）如果捕食者数量下降到某一阈值以下，猎物数量就上升，而捕食者数量如果增多，猎物种数量就下降和（iii）如果猎物数量上升到某一阈值，捕食者数量就增多，而猎物种数量如果很少，捕食者数量就下降。这一简单的模型做了一个有趣的预测：捕食者和猎物种群动态会发生循环，就像在自然的捕食者-猎物种群动态中所观察到的那样。PREDATOR-PREY RELATIONSHIPSPopulation cycles of snowshoe hares and their lynx predators based on the numbers of pelts received by the udson Bay CompanyPREDATOR BEHAVIOR AND PREY RESPONSEProfitability of preyGiven a choice between two potential prey types,a predator which is optimizing its effort should choose the most profitable prey,Evidence from common shore crabs and pied wagtails demonstrates that prey of a size which return the greatest energy reward per unit time are preferred over smaller and larger individuals.猎物收益率面对两种类型猎物的选择时，捕食者要获得最佳捕获努力，就应该选择收益最大的猎物。真蟹和白脊令的证据表明捕食者优先选择能使其在单位时间内获得最大能量的一定大小的猎物，而不是比该体积更大或更小的猎物。The effect of prey density C functional responsesIt is generally expected that at high densities of prey,a predator’s consumption rate will increase and then flatten out as prey saturation occurs,this relationship is termed the functional response and may adopt different patterns,which can be stereotyped into three classes,functional responses I,II and III.猎物密度影响――功能反应一般认为在高猎物密度下，捕食者的摄食率会增加，然后随猎物饱和达到最大速度。这种关系称为功能反应，可能采用多种模式，传统上分为三种类型：功能反应I、II和III。功能反应Ⅰ：捕食以固定比率增加功能反应Ⅱ：捕食的增加率随食物密度增加而降低功能反应Ⅲ：捕食率随食物密度的增加而增加，随后因饱和而降低Searching and handlingTo obtain food,a predator must first search for its prey and then ‘handle’ (catch,process and eat) it,Diet width can be regarded as being determined by a balance between a generalist strategy of searching for a wide variety of prey (relatively easy) and a specialist strategy of searching for one type of prey and handling that very efficiently.Optimal foraging theory assumes that evolution will have optimized predator behavior to maximize the rate of energy gain and makes predictions about how we should expect predators to balance searching and handling.搜寻和处理为得到食物，捕食者必须首先搜寻猎物，然后处理（抓住、加工和吃掉猎物）。可以认为捕食者食谱的宽度是由泛化种对策与特化种对策之间的权衡决定的。泛化种对策捕食者寻找多种猎物（相对容易），特化种对策捕食者寻找一类猎物，非常有效的处理它。最佳觅食理论假定进化会最优化动物行为以使其获得的能量效率最大，从而做出捕食者如何权衡搜寻与处理的预测。最佳觅食理论计算能量效率的三个因素：猎物的能含量搜寻时间处理时间预言：（1）不会摄取无利可图的猎物（2）搜寻强化 ----- 泛化种（3）处理强化 ----- 特化种（4）多产环境对特化种有利，非多产环境对泛化种有利Heterogeneity and prey refugesPredator-prey experiments in the laboratory indicate that in simple environment,either (i) predators are able to consume all prey individuals,or (ii) the predator population becomes extinct and the prey survives,If,however,the habitat is more complex some prey refuges and coexistence between predators and prey may occur,In corollary with the role of habitat patchiness in maintaining coexistence between competing species (see topic I1),environmental heterogeneity is likely to be of critical importance in allowing predators and prey to coexist.异质性和猎物隐蔽处实验室捕食者―猎物实验表明在一个单纯环境中，或（i）捕食者吃掉所有猎物个体，或（ii）捕食者种群消亡而猎物存活。然而，如果环境更为复杂，则一些猎物个体可能在猎物避难所中摆脱捕食，从而出现捕食者―猎物的共存。由于生境斑块在维持竞争种间共存中所起的作用（见I1）推论，环境异质性很可能在允许捕食与猎物共存中具有关键的重要意义。The ideal free distributionPredators do not solely respond to the distribution and density of prey C they may also respond to the distribution of competing predators,Predators will tend to aggregate in the most profitable patches,but predator crowding will reduce the patch profitability until it is better to move to another less crowded patch,The ideal free distribution theory suggests that predators should move among sites until profitability is equal.理想自由分布捕食者并不单独对猎物的分布与密度做出反应――它们对与之竞争的捕食者的分布也会反应。捕食者趋向于聚集在最有利可图的斑块中，但捕食者之间的拥挤会降低斑块的有利度，直到移到另一块不太拥挤的斑块中去会更好。理想自由分布理论认为捕食者会在各分布区间移动，直到各区有利度相等。Plant defensePlants defend themselves from predation in two main ways,(i) toxicity and unpalatablity,There is a vast variety of chemical ammunition found in the plant kingdom used to defend plants against attacks from predators and parasites,These secondary compounds may either be directly toxic or they may reduce the food value of the plant,for example,by reducing the availability of the leaf tissue protein to the animal gut,(ii) defensive structures,Defensive structures exist on a variety of scales,from small hairs on the leaf surface which may trap insects and other invertebrates,to large spines which deter mammalian herbivores,Both the levels of secondary compounds and the size of defensive structures may be elevated or ‘induced’ in plants that have suffered defoliation.植物防御植物以两种主要方式来保护自己免遭捕食：（i）毒性与差的味道，和在植物王国已发现大量的多种化学武器来保卫植物免遭捕食和寄生者的进攻。这些次生性化合物或直接有毒，或可降低植物的食物价值，如降低动物肠道对植物叶组织蛋白的吸收。（ii）防御结构。防御结构在各种水平上都存在，从叶表面可陷住昆虫及其他无脊椎动物的微小绒毛，到可阻止哺乳类草食动物的大型针刺。经历过落叶的植物，其次生化合物水平及防御结构大小都会提高或“被诱导”。Intraspecific CompetitionAs individuals are quite similar in their resource requirements,such competition may be particularly intense,Intraspecific competition is a major force in ecology and is responsible for phenomena such as dispersal and territoriality,as well as being the primary cause of population regulation via density-dependent processes.当个体对资源的需要非常相似时，竞争会特别强烈。种内竞争是生态学的一种主要影响力，是扩散和领域现象的原因，并且是种群通过密度制约过程进行调节的主要原因。Density dependenceDensity dependence describes the relationship between fitness and population size,A key population regulatory factor is negative density dependence,where declining fitness occurs as population density increases within a species due to intraspecific competition.密度制约密度制约描述适合度与种群大小之间的关系。种群调节的一个关键因子是负的密度制约，当种群密度增加时，由于种内竞争，使适合度下降。Self-thinningSessile organisms,including plants,cannot escape competition by movement,and therefore the losers in the competitive battle die,In a group of plants of the same age,this results in fewer individuals of larger size surviving,This process is described as ‘self-thinning’,Self-thinning results in a relationship between density and individual plant mass,which typically has a slope of C3/2on a log-log plot,This relationship is known as Yoda’s C3/2 law.自 疏固着生长的生物，包括植物，不能通过运动逃避竞争，因此竞争中的失败者死去在同样年龄大小的植物群中，}