1、Ecology- Concepts1 Natural history 自然史 2 Individuals 个体3 Populations 种群4 Interactions 相互作用5 Communities 群落6 Ecosystems 生态系统What is ecology?Ecology is the study of relationships between organisms and the environment. However, as you can see from the studies we have reviewed, ecologists study those re
2、lationships over a large range of temporal and spatial scales using a wide variety of approaches. Ecology includes bumblebees living around a single bog and vegetation moving across the continent. Ecologists may study processes on plots measured in square centimeters or an entire stream valley. Impo
3、rtant ecological discoveries have come from probing of the rain forest canopy and landscape images on a computer screen. Ecology includes all these approaches and many more. 什么是生态学？生态学是研究生物与环境之间关系的科学。然后，当你回顾我们已有的研究案例时会发现，生态学家应用了广泛的研究方法在一个巨大的时间和空间尺度上研究这些关系。生态学涵盖尺度从生活在一个土丘上的黄蜂到横跨整个大陆的植被。生态学家可以研究小到平方厘米
4、小块土地上的生态过程或整个河流流域。重要的生态学发现已有来自于对热带雨林冠的探索层和电脑屏幕上的景观图像的分析。生态学不仅包括以上所有还有更多其他的研究方法。Life on land: Terrestrial biomesBiomes are distinguished primarily by their predominant plants and are associated with particular climates. They consist of distinctive plant formations such as the tropical rain forest bio
5、me and the desert biome. Because tropical rain forest and desert are characterized by very different types of plants and animals and occur in regions with very different climates, the natural history of these biomes differ a great deal. The student of ecology should be aware of the major features of
6、 those differences.自然史陆地上的生命：陆地生物群系生物群系主要是通过它们的优势植物和相关联的特定气候进行区分的。它们有着与众不同的植被构成比如热带雨林生物群系和沙漠生物群系。由于热带雨林和沙漠是通过非常不同的植被和动物进行刻画并出现在非常不同的气候区域，这些生物群系的自然史有着巨大的差异。生态学的学生应该对这些区别的重要特征给予关注3 Individual Ecology 个体生态学Microclimate: microclimate is climatic variation on a scale of a few kilometers, meters, or even
7、centimeters, usually measured over short periods of time. Macroclimate interacts with the local landscape to produce microclimates.小气候：小气候是指诸如数公里、米以致数分米范围内小尺度并且通常短时间内的气候变化。大气候是与局部景观环境相互作用产生小气候。Fitness: fitness is a measure of the ability of an individual to produce viable offspring and contribute to
8、 future generations. (适合度 )适合度：适合度是一个个体产生具有繁殖能力的后代和对未来世代贡献能力的量度。Adaptation: any heritable trait possessed by an organism which aids survival or reproduction is an adaptation. (适应性)适应性：一个生物拥有的任何有助于生存和繁衍的可遗传特性就是适应性。Homeostasis: biological cells cannot function with a wildly fluctuating environment and
9、 organisms therefore take steps to limit their internal variation. (稳态)内稳态 在变化多端的外部环境中保持体内环境相对稳定被称为内稳态。Negative feedback: most biological homeostatic mechanisms act in a broadly similar way: if the current internal level of a factor is too high, the mechanism will reduce it; if the level is too low
10、the mechanism will increase it. This process, by which the response is opposite to the signal, is known as negative feedback. (负反馈)负反馈 多数生物体的内稳态机制采用大致相同的工作方式；如果当前的内部因素（例如温度或渗透性）水平高，调节机制会降低它；如果水平太低，调节机制会升高它。这种与原始信号相反的过程叫负反馈。Tolerance: organisms can cope with variation in their external environment. T
11、he upper and lower extremes of environmental conditions which members of a species can survive are the species limits of tolerance. (耐受度)耐受性 生物能够应付变化多端的外部环境（尽管不同的物种会有显著的不同） ，一个物种大量个体所能够生存的最高和最低环境条件，称为该物种的忍耐限度。通常，在这种极端情况下，生物无法生长，而是在一个较狭窄的条件范围生长，而且，适合度只有一个相对很窄的适宜范围。Niche: the ecological niche of an or
12、ganism 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)生态位 生态位是一种生物在环境中所占有的位置，包括它所生存的生存条件、它所利用的资源和它所发生的时间。.Temperature thresholds: high temperatures may lead to enzyme inactivation or the unba
13、lancing of components of metabolism; for example, in plants, respiration may proceed faster than photosynthesis, leading to death. However, the most frequent effect of high temperature on ectotherms is dehydration. All terrestrial ectotherms must conserve water but at high temperatures rates of wate
14、rloss 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 species are killed by temperatures below -1 due to the damaging effects of ice-crystal formation within cells; those t
15、hat live through freezing winters often do so at a resistant, dormant stage of their life cycle.临界温度 高温能使酶失活并导致物质代谢成份的不平衡。例如，在植物中，呼吸作用比光合作用快时，会引起植物死亡，然而，高温引起的最经常的后果是脱水。所有的陆生变温生物都必须保持水分，但在高温下高的失水率是致命的。不同生物对低温的耐受程度有很大的不同。要经过一个冻结、冷害和伤害的过程。由于细胞内结冰的危害，许多物种在低于1时即死亡，哪些能构度过寒冷的冬天的物种都经过一个休眠的抗拒阶段。Species distr
16、ibution and temperature: the distribution of the major biomes over the Earth reflects the major temperature zones. However, it is more difficult to attribute a role to temperature when considering species distribution. In certain cases the precludes the species existence. However, a more widespread
17、type of relationship is one which has a correspondence between the distribution limits of a species and an isotherm (等温线). An isotherm is a line on a map that joins location having the same mean temperatures. Overall, an organisms limit to distribution is determined not by lethal temperatures, but b
18、y conditions that make it a poor competitor.物种分布和温度 地球上主要生物的分布反应了主要的温度带。但是，在考虑物种分布时，把其归因于温度是很困难的。在一定的情况下，物种分布的限制原因应归咎于能妨碍物种生存的致命温度。然而，一种应用更广的关系是物种分布与一条等温线之间的关系。等温线是在地图上跟地形一起绘制的一条代表相等温度的线。总之，物种分布不是由致命温度决定的，而是由于环境条件使其竞争力变弱。Soil water: for terrestrial plants the main source of water is the soil, which
19、serves as a reservoir. Water enters the reservoir as rain or melting snow and passes into the soil pores.土壤水 对于陆生植物来说，主要的水源是土壤，它的作用象一个贮水器。雨水和融化的雪水进入这个贮存器后再进入土壤的毛孔。Aquatic plants and water: water is apparently freely available in aquatic environments. However, the osmotic regulation of internal fluid
20、s 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 v
21、acuoles, but the concentration in the cytoplasm and organelles is kept low.水生植物和水 在水生环境中，水的可用性显然是自由充足的。但是，生物体液渗的透调节却是十分昂贵的。特别是在咸水中。水生环境和海边陆生环境的盐度对植物的分布和丰富度有着重大影响。在高盐环境中生长的盐生植物，在液泡中积累许多电解质，而在细胞质和细胞核中的浓度却很低。Radiant energy and photosynthesis: Radiant energy is the sole energy source that can be used by
22、 green plants. When a leaf intercepts radiant energy it may be absorbed, reflected or transmitted. Part of the fraction absorbed reaches the chloroplast, fueling photosynthesis, the process where radiant energy is used to convert water and co2 into sugars. However, only a restricted band of this spe
23、ctrum 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：辐射能是绿色植物能够利用的唯一的能源。植物叶片截获辐射能时，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类。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。这个绿色植物的光合有效辐射带
24、分布在 380 nm 到 700 nm 之间。Nutrient sources: nutrients are gained and lost by communities in a variety of ways. Mechanical weathering (风化/ 侵蚀), chemical weathering, particularly carbonation, are important processes. Simple dissolution of minerals in water also makes nutrients available from rock and soi
25、l. Water may carry nutrients in watercourses (河道) providing an important source in downstream (下游的) areas. Atmospheric gases provide nutrient sources too, particularly carbon dioxide and nitrogen. Other nutrients from the atmosphere become available to communities as wetfall (由降水带来的营养盐) (rain, snow
26、and fog (雾) and dryfall (由空气中的颗粒与气胶带来的营养盐) (settling (沉淀物) of particles during dry periods).营养源：群落以形形色色的方式获得和损失营养物。机械风化、化学腐蚀，特别是碳酸化作用，都是重要的过程。矿物质在水中的简单溶解也使营养物从岩石和土壤中获得成为可能。在河道中的水携带的营养物质给下游地区提供了一个重要的资源。大气也能提供营养物，特别是二氧化碳和氧气。大气中的其它营养物可以湿降落（雨、雪和雾）和干降落（由空气中的颗粒与气胶带来的营养盐）的方式到达群落从而被利用。 Equilibrium populatio
27、n density: 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.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，种群密度即不增加也不
28、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值相等。Compensation and density dependence: there are three types of density dependence: overcompensating, undercompensating and exactly compensating. If a decline in numbers due to density dependence does not outweigh or balance the initial increase in numbers, density d
29、ependence is undercompensating. Overcompensating outweighs the initial augmentation (增加). If the decline in numbers exactly balances the initial increase in density, density dependence is said to be exactly compensating.补偿和密度制约：密度制约有三种形式：过度补偿，补偿不足和准确补偿。如果密度制约引起的数量下降，没有超过或等于开始增加的个体数量，则密度制约是补偿不足。当密度制约
30、的效应超过了开始种群数量的增加，成为补偿过度。如果下降个体数与开始增加的个体数相等，则称为密度制约为准确补偿。Natality: natality 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
31、 age classes. 出生率：出生率就是新个体产生的比率。实际出生率就是一段时间内每个雌性个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性个体在单位时间内产生的后代数量。Mortality: 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
32、can 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：死亡率就是一定时间内死亡个体的数量与该时间段内种群平均大小的比率。这是一个瞬时率，可用于评估整个种群或特定年龄群的特定死亡率，死亡的概率是死亡个体数与每段时间开
33、始时个体数的比率。Survivorship: 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 (对数刻度) through each phase of life. There are three generalized patterns of age-s
34、pecific 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).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。根据各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（类型） ，各期死亡率相等（类型
35、） ，早期死亡率最高（类型） 。Life tables: 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 pr
36、esent 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：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
37、样的一组个体成为同生群，这样的调查称为同生群分析。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值表示，是通过对数函数推导出来的，并且可以相加得出总死亡率。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 。 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， 表示在这段时间内，种群增长或下降的总的程度。Population fluctuations: populations may fluctuate for a number of reasons: (1) a time
38、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 p
39、roduce cycles in predator and prey abundance; (2) overcompensating density dependence. This can lead to dampened oscillations, stable limit cycles (regular cycle that do not damp down) or chaotic fluctuations that appear random; (3) environmental stochasticity. This is a nondeterministic, unpredicta
40、ble 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：（）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性变化。 （）过度补偿性密度制约。其可能导致减幅振荡、稳定有限环（非减幅振荡的有规律周期变化）或无规则随机振荡。 （）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
41、。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 random. The outcome of chaos depends on the precise value f the starting conditions. As perfect accuracy is impossible to attain, chao
42、tic 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.混沌：数学上有关混沌的定义与俗语中的用法是截然不同的。一个混沌系统是受确定
43、性作用控制的，而不是随机的。混沌的结果依赖于初始状态的精确性值。由于完全敬群是不可能达到的，因此对混沌系统不能进行有效的预测。目前，对于观察到的有关种群大小波动在何种程度上是受混沌过程影响的还不清楚。一些分析认为，麻疹的爆发和某些昆虫种群可能表现出混沌的动态变化。Competition: competition is an interaction among individuals utilizing a limited resource, resulting in reduced fitness in the competing individuals. Competition occurs
44、 both between species utilizing a shared resource (interspecific competition) and among members (the conditions under which it is found, the resources it utilizes and the time it occurs there) is critical in determining the degree of competition with other species or individuals. Large niche overlap
45、 (重叠/ 交迭) generally results in intense competition.竞争：竞争是共同利用有限资源的个体间的相互作用，会降低竞争个体间的适合度。竞争即可在利用工作资源的物种间发生（种间竞争） ，也可在同种个体间发生（种内竞争） 。个体或物种的生态位（它所处的环境、利用的资源和发生的时间）是决定该个体或物种与其它个体或物种竞争程度的关键。大范围的生态位重叠一般导致激烈竞争。Asymmetry in the effects of competition: competition often unevenly affects competitors, such tha
46、t 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。Dispersal: organisms can respond to high levels of intraspecific competition by d
47、ispersing away from the area of high population density. Even in species that are sessile (无柄的/ 固着的) for most of the lifecycle, there is a mobile dispersal stage. Dispersal is often undertaken by the younger members of a population, whilst in many mammal species males disperse more than females do.扩
48、散：生物可通过扩散离开种群密度高的地区，来对高水平的种内竞争做出反应。即使生活周期内大部分时间营固着生活的种类，也有一个可运动的扩散期。扩散通常由种群内较年轻的个体进行，而在许多哺乳动物中雄性比雌性扩散更多。Territoriality: in many animal species (including insects, birds and mammals) individuals or groups compete for areas of space. There is active interference between individuals to maintain the ter
49、ritory boundaries. Territoriality gives a benefit to the territory-holder, such that the costs of defending the territory against intruders are outweighed by advantages such as increased food supplies, increased mating success and reduced predation risk.领域性：许多动物种（包括昆虫、鸟类和哺乳动物）的个体或群体为争夺空间而竞争。保持领域边界的个体间有积极的相互干扰行为。领域使其所有者受益，例如为对抗入侵者，保护领域所付出的代价，被增加的食物供应、提高的交配成功率和降低的被捕食的危险所带来的收益超过。Self-thinning: sessile 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 resul
