1、M1 生活史要 点生活史变异 生物的生活史是指其一生中生长和繁殖的模式。不同种类其生活史类型的变异是巨大的。一些种类能活成百上千年，一些个体身体巨大，而另一些则微小。一些生产许多小后代，而另一些生产后代数量较小，但个体较大。在关这些变异是如何进化而来的问题，是生态学的一个关键。病毒变异An organisms life history is its lifetime pattern of growth and reproduction. The observed in the life history patterns of different species is vast. Some sp
2、ecies live for hundreds or even thousands of years, some grow to vast sizes whilst other are minute. Some produce many, tiny offspring whilst others have few, relatively large offspring. How these differences evolve is a key question in ecology.Key NotesLire history variationM1 LIFE HISTORY能量分配和“ 权衡
3、 ”让某一 生物在出生后短期内达到大型的成体大小，生产许多大个体后代并长寿是不可能的。分配给生活史一方面的能量不能再用在另一方面，所以在不同生活史特性间进行 “权衡 ”是不可避免的。It is not possible for an organism to reach a large adult size shortly after birth, produce many large offspring and live to a great age. Energy allocated to one aspect of life history cannot be spent in anoth
4、er, so trade-offs between different traits are inevitable.Energy allocation and trade-offsr -选择和- 选择r-选择和 K-选择理论描述了两种明显的生活史对策，该理论陈述， r-选择种类适应使其种群增长率最大，而 -选择种类适应使其竞争性强。这样， r-选择种类发育快，成体小，后代数量多但体积小，世代时间短。与此相反， -选择种类发育慢，成体大，后代数量少但体积大，世代时间长。尽管有些种类符合这种理论上的两分法，但也有许多种不符合。由于具有更广预测性的更好的模型出现，该理论已过时了。Two distin
5、ct life history strategies are described by - and -selection theory, which states that - selected species are adapted to maximize the rate of increase of the population size, whilst -selected species are adapted to be competitive. Thus, r-selected species have rapid development, small adults, many a
6、nd small offspring and a short generation time. In contrast, -selected species have slow development, large adult size, few, large offspring and long generation times. Although some species fit this theoretical dichotomy, many do not, and this theory is mow out-dated as better models have wider pred
7、ictive powers. - and -selection 生 殖 价 年龄 x的个体的生殖价（ RVx） 是该个体马上要生产的后代数量加上预期的其在以后的生命过程中要生产的后代数量。个体的生殖价在出生后必然会上升，然后随年龄老化而下降。个体间生殖价的差异提供了一个强有力的生活史对策预报器。The reproductive value (RVx) of an individual of age x is the number of offspring that individual is expected to produce in the immediate future plus th
8、ose expected over its remaining lifespan. The reproductive value of an individual inevitably rises after birth and falls towards old age. The difference in reproductive values between individuals provides a powerful predictor of life history strategy.Reproductive values生境 分类 除 r-和 K-选择概念外，还存在多种方案划分生境，试图辩别一种连接生境与生活史的模式。生境可在生长与繁殖间利益平衡的基础上划分为 “高繁殖付出 ”和 “低繁殖付出 ”生境。另一种可供选择的方法， “两面下注 ”考虑生境对不同生长期死亡率和繁殖力相关变化的影响，利用这种影响来预测最适生活史对策。 Grime的“CSR三角形 ”从植物生活史的观点，利用生境干扰（或稳定）程度及其对植物的严峻性来划分生境。
