1、H1 种群和种群结构要 点种 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。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。肯尼亚的斑马种群H1 POPULATIONS AND POPULATION STRUCTURE A population is a group of organisms of the same species which occupies a given area. The
2、 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 furt
3、her modules and a branching structure. The structure may then may then fragment producing many individual ramets.Key NotesPopulation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。种群密度一般种群密度很高The population size for unitary organisms, suc
4、h 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 diffe
5、rent individuals.Population size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。相关主题 出生率、死亡率和种群增长（ H2） 竞争的性质（ I1） 密度和密度制约（ H3） 捕食的性质（J1） 种群动态 波动、周期和混沌（ H4）The age struct
6、ure 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. W
7、here 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.Re
8、lated topics Natality, mortality and population The nature of competition (I1) growth (H2) The nature of predation (J1) Density and density dependence (H3)Population dynamics fluctuations, cycles and chaos (H4)Age and stage structureH2 出生率、死亡率和种群增长要 点出 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。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。
