EcologyA definition of ecology.Ecology the study 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。En viro nmentAll that surrounds and affects an organism is its environment.Fitn ess is a measure of the ability of an in dividual to produce viable offspri ng and contribute to future gen erati ons.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 in dividuals in a species which have the highest fitn ess will con tribute disproportionat.e!y_to fhe .subesequenlgeneratlons. _If fitn ess differe nces have a genetic comp onen t,the n the gen etic make-up of the ubequenf_g?neratons_wil _be_.alt?red.This .process - is 一 known . _as 卫aturaLselection 一 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.。Adaptati onAny heritable trait possessed by an orga nism which aids survival or reproductio n is an adaptation.(有机体所具有的有助于生.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.Geno type and phe no typeT.he_genptype_ isthe_genetic_composition .ofannd.i.Yld.ual.-_.The_.Phenotyj&e.the一nd.ixj.dual organism.a .卫 roduct_ of_the , , interaction. _ between .its_.ae.nptype. a.nd_ . . its_ . environment. . The_ . ability ot.the._p.henotYpe.iP. vary jdut.e.nyiron.menJnfluences on jts.genotype is.knowas phenotypic plasticitY(evg_hu.masuntan/wi_nd-shape_p|a_nts,pcus_mprph(so|jtar_ or m.igratoryl).Con diti onsVariable 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。Tolera nceThe upper and lower extremes of environmen tal con diti ons which members of a species can surivive are the species limits of tolerance.种的成员能够生.的环境条件上限和下限是种的耐受限度。NicheThe ecological niche of an orga nism is the positio n it fills in its en vironme nt 0 0 | 0 0 | 0 0 | 0 0 0 0 0 0 compris ing 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 _ jha.s. (i) _ a _ high - .capacity. and_(i)maxmal_density . at 4忆丄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24C 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 gravityThe lower limit of water availability is thus determined by the physioligy of the plant species and is known as thepermanent wilting point the soil water content at which plants wilt and are unable to recoverWater avaolability and pla nt productivityPrecipitati on is a key determ inant of pla nt productivity in forests, whilst in arid region there is an appriximately linear increase _in primar productivity with in creas ing precipitati on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 呈二个线性膨胀。Rates of development and growthphysiological timeis 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 timeSpecies distributi on and temperatureOverall, an organisms limit to distribution is determined not by lethal temperatures,but by conditions that make it a poor competitorRadia nt en ergy and photos yn thesisOnly a restricted band of this spectrum is effective for photosy nthesis This is the _.band._oL_photisyntheically _atiYe_radi.at9n(PAR)and for_green_ plantsie between 380 and 710 nm 二然而，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。Chan ges in the intensity of raditi onPlants rarely achieve their full photos yn thetic 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。Populatio nA population is a group of organisms of the same species which occupies a given area.Age and stage str uct ureThe age_ structure _of a _pp.pulatpn_ is_ the . number of . -individuals. J.n_ each _age _class .expressed as a _ratio.二and .is _ usually displayed _ as_ an _age 卫yrami.d. -diagram.A pppulatipn which is neither expanding npr cpntracting will have a statipnry age distributipn.A grpwing pppulatipn will have mpre ypung,while a declining pppulatipn will be dpminated by plder age chasses.Den sity-depe ndent growt