逻辑斯谛方程

相关主题
出生率、死亡率和种群增长（H2） 密度和密度制约（H3）
竞争的性质（I1） 捕食的性质（J1）
种群动态——波动、周期和混沌（H4）
Age and stage structure
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. Natality, mortality and population competition (I1) The nature of predation (J1) The nature of growth (H2) Density and density dependence (H3) Population dynamics – fluctuations, cycles and chaos (H4)
Natality
mortality
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）。
人生三无奈
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 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).
H1 种群和种群结构
要
种
点
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。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。
Related topics
H2 出生率、死亡率和种群增长
要
出 生
点
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。 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wenku.baidu.com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。
k-Factor analysis
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 (ktotal). K-Factor analysis highlights those stages suffering the greatest mortality which are responsible for fluctuations in loss rate and hence population size.
肯尼亚的斑马种群
H1 POPULATIONS AND
POPULATION STRUCTURE
Key Notes
Population 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.
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。
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。
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。
种群密度很高
种群密度一般
Population size
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.
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。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。
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 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
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。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。
死 亡
率
H2 NATALITY, MORTALITY AND
POPULATION GROWTH
Key Notes
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. 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.