EcologyA definition of ecologyEcology is the study of the interactions between organisms and their environment.生态学是研究有机体与其环境相互作用的科学，环境是物理环境和生物环境的的结合体。
EnvironmentAll that surrounds and affects an organism is its environment.Fitness is a measure of the ability of an individual to produce viable offspring and contribute to future generations.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。
Natural selectionThe individuals in a species which have the highest fitness will contribute disproportionately to the subesequent 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’.物种中具有最高适合度的个体将会对未来世代做出特别高的贡献。
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。
这个过程成为自然选择或‘最适者生存’。
AdaptationAny heritable trait possessed by an organism which aids survival or reproduction is an adaptation.（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。
）Such traits may be physiological,morphological or behavioral. Adaptation is the result of natural selection.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 and its environment. The ability of the phenotype to vary due to environment influences on its genotype is known as phenotypic plasticity(e.g. human suntan,wind-shaped plants,locust morph(solitary or migratory)).ConditionsVariable environment factors which organisms respond to are conditions.ResourcesAnything which the organism uses up or depleres is a resource for that organism.有机体消耗的任何东西，对有机体而言，就是资源。
ToleranceThe upper and lower extremes of environmental conditions which members of a species can surivive are the species limits of tolerance.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。
NicheThe ecological niche of an organism is the position it fills in its environmentcomprising the conditions under which it is found,the resources it utilizes and the time it occurs there.有机体的生态位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。
HabitatThe habitat of an organism is the physical environment it is found in, for example,a temperate broad-leaved woodland. Each habitat provides numerous niches.有机体的栖息地是它所处的物理环境，比如，温带阔叶林。
每一个栖息地提供许多生态位。
Water and temperatureTwo features of water make it particularty suitable as a medium for life-forms to inhabit. Water has (i) a high capacity and (ii)maximal density at 4o C .水的特性使它特别合适于作为许多生物栖息的一种介质。
1》水有高的热容量2》4°C时水的密度最大Soil waterThe 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.The lower limit of water availability is thus determined by the physioligy of the plant species and is known as the permanent wilting point the soil water content at which plants wilt and are unable to recover.Water avaolability and plant productivityPrecipitation is a key determinant of plant productivity in forests, whilst in arid regions there is an appriximately linear increase in primary productivity with increasing precipitation.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岁降雨量的增加大致呈一个线性膨胀。
Rates of development and growth‘physiological time’is a measurement combining temperature and time and applied to ectothermic organisms,which reflects that growth and development of these organisms is dependent on environment temperature as well as time.Species distribution and temperatureOverall, an organism’s limit to distribution is determined not by lethal temperatures,but by conditions that make it a poor competitor.Radiant energy and photosynthesisOnly a restricted band of this spectrum is effective for photosynthesis. This is the band of photisynthetically active radiation(PAR)and for green plants lies between 380 and 710 nm.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，对绿色植物是位于380nm到700nm之间。
Changes in the intensity of raditionPlants rarely achieve their full photosynthetic potential , due to water shortage and to variation in the intensity of radition.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。
PopulationA population is a group of organisms of the same species which occupies a given area. 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 stationry age distribution.A growing population will have more young,while a declining population will be dominated by older age chasses.Density-dependent growth-the logistic equationThe logisitic equation describes the growth of a simple population in a confined space,where resources are not unlimited.In the early stages resoures 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.until the maximum number of individuals the environment can sustainably support is approached. This maximum number is called the carrying capacity(K).逻辑斯蒂方程描述的是一个在有限资源空间中的简单种群的增长。