植物生活史对策的进化

植物生活史对策的进化班勇（中国林业科学院林业研究所,北京１０００９１）ＥｖｏｌｕｔｉｏｎｏｆＬｉｆｅＨｉｓｔｏｒｙＳｔｒａｔｅｇｙｉｎＰｌａｎｔｓ￥ＢａｎＹｏｎｇ（ＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＦｏｒｅｓｔｒｙ,ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏ...     

免疫能力与动物种群调节和生活史权衡的关系

在生物医学和动物科学领域,免疫能力是指有机体对疾病的抵抗能力.近年来,对野生动物免疫能力的研究是一个新兴的热点领域,它与生态学结合,产生了生态免疫学.本文从生态学的角度,介绍了免疫能力的概念、影响因素及其与动物种群调节机理的关系,概述了与小型哺乳动物种群密度波动有关的免疫衰退假说、免疫能力选择假说和冬季免疫增强假说,总结了免疫能力与能量代谢和内分泌特征之间的关系,并对免疫能力在生活史权衡研究中的最新进展,即有机体生长与免疫、繁殖与免疫之间的权衡关系等进行了阐述,最后结合国际上本学科研究的发展动态,提出了一些未来的研究方向.     

植物生活史型的划分及其相互转化

基于环境条件的变化,分析了植物在完成生活史过程中,营养生长、克隆生殖和有性生殖过程的权衡的结果直接导致的植物生活史型形成以及相互转化过程。根据胁迫和扰动程度将植物的生境划分为基本生境型、特殊过渡型和过渡型,其中过渡型(EDF)在自然界中具有普遍意义;与生境过渡型(EDF)相对应,植物形成的生活史型也为过渡生活史型(VCS),其基本型V、C和S以及特殊过渡型VC、VS和CS是其特例。植物的生活史型过渡型(VCS)具有普适性意义,在生境调控下的任一种植物生活史型均可表示为Vx1Cx2Sx3。植物生活史型的相互转化与其生境类型的相互转变是完全对应的,这种相互转化的过程和途径是复杂的,且具有可逆性的特点。     

鸟类生态能量学的几个基本问题

生态能量学是在种群和群落水平上寻求能量与进化适合度之间的关系。本文从能量运行的最适化原理、能量与适合度之间的关系、能量与生活史进化、能量的摄入与需求是如何调节的、能量与有机体结构与功能的联系、能量和觅食理论以及能量分配与性选择等7个方面介绍了鸟类能量学的研究进展,并指出进化的最适化原理是认识能量运行模式的重要理论手段。     

胁迫环境中的进化拯救

生物种群面临致死环境胁迫时能够通过适应性进化摆脱灭绝的命运,这一过程称为进化拯救.进化拯救发生过程中,种群的基因型和表型性状的分布以及生态适合度会发生迅速且显著的改变.进化拯救的发生概率既取决于种群的特征,也受胁迫环境属性的影响;进化拯救发生的机会将随着遗传变异供应的增加和环境选择强度的降低而增加.本文梳理了影响进化拯救概率的主要生物和非生物因素.本文也介绍了有关群落水平进化拯救和自然界中进化拯救的研究进展;讨论了群落水平进化拯救不一定与单物种种群进化拯救具有相同规律的可能原因,强调了实验室研究中所发现的进化拯救也可能与自然界中的进化拯救不同.本文最后展望了进化拯救领域未来的发展方向.     

具有选择差异的随机博弈进化动力系统

为了实现对同一生境两亚种群随机博弈过程的人工控制,本文基于Moran过程和进化博弈论的研究,定义了与生境因素有关的博弈支付矩阵;同时考虑到两类个体受环境影响程度不同,即环境对不同种群的选择强度不同,引入了不同的选择强度,进而得到种群的适合度,建立了具有选择差异的随机博弈进化动力模型;得出种群的固定概率,并讨论了选择差异对种群固定的影响,在此基础上通过控制环境因素对种群进行优化.最后给出算例说明了模型的有效性和可行性.     

动物进化稳定对策(ESS)及其研究进展

介绍进化博弈理论及进化稳定对策的原理及其在进化生物学的应用:简要述评动物进化稳定对策的研究进展及发展趋势。     

鸟类生态能量学的几个基本问题（综述）

生态能量学是在种群和群落水平上寻求能量与进化适合度之间的关系。本文从能量运行的最 适化原理、能量与适合度之间的关系、能量与生活史进化、能量的摄入与需求是如何调节的、能量与有机体结构与功能的联系、能量和觅食理论以及能量分配与性选择等7个方面介绍了鸟类能量学的研究进展,并指出进化的最适化原理是认识能量运行模式的重要理论手段。     

慈姑属植物的生态及进化生物学研究进展

慈姑属(Sagittaria L.)隶属于泽泻科,是世界广布的水生植物,其生境多样、叶形和繁殖表型复杂,进化地位较特殊,是生态和进化生物学研究较典型的材料。笔者在查阅相关慈姑属研究的大量文献的基础上,对前人研究的物种、探讨的问题及研究结果进行了归纳与总结:慈姑属物种存在广布种和濒危种,且个别物种的濒危现状可能与其生境条件相关;慈姑属的个别种类成为稻田入侵杂草,其竞争能力因慈姑种类及水稻栽培品种的不同而各异;环境对慈姑属植物有很强的塑造作用,不同环境还会造成慈姑所在的水生植物群落结构发生变化;慈姑属植物具有较高的遗传多样性;在繁殖方面,慈姑属植物体现出不同繁殖方式和两性功能的权衡,以及在繁育系统上从雌雄同株到雌雄异株的进化途径。本文还提出了相关研究存在的不足、研究中应注意的科学问题,并对慈姑属植物未来的研究方向提供了新思路。     

种子植物的选择性败育及其进化生态意义

种子植物的选择性败育是指植株在花粉源、传粉次序、果实在植株上的位置和发育果实中的种子数目等因素或者这些因素综合作用的基础上对发育中的幼果或种子选择性败育的现象。植株可以选择性地败育位于果序顶部或基部的果实以及位于果实基部、中部或柱头端的种子。此现象在被子植物中比较普遍,特别是在豆科、十字花科和紫草科中最为常见。导致植物选择性败育的主要原因主要有资源限制和遗传因子两个方面。植物通过选择性败育部分自交或基因型较差的果实或种子,不仅可以提高母本和后代的适合度,而且还可以提高果实或种子的扩散效率。因此,对选择性败育的研究在深入了解植物的结实结籽格局、探讨其进化式样与机制等方面具有重要意义。该文系统总结了国际上有关植物选择性败育的研究工作,重点介绍了选择性败育发生的式样、导致选择性败育的因素、选择性败育的进化生态意义,以及目前研究选择性败育现象的主要方法,并对该领域今后研究前景进行了展望。     

How life history and demography promote or inhibit the evolution of helping behaviours

In natural populations, dispersal tends to be limited so that individuals are in local competition with their neighbours. As a consequence, most behaviours tend to have a social component, e.g. they can be selfish, spiteful, cooperative or altruistic as usually considered in social evolutionary theory. How social behaviours translate into fitness costs and benefits depends considerably on life-history features, as well as on local demographic and ecological conditions. Over the last four decades, evolutionists have been able to explore many of the consequences of these factors for the evolution of social behaviours. In this paper, we first recall the main theoretical concepts required to understand social evolution. We then discuss how life history, demography and ecology promote or inhibit the evolution of helping behaviours, but the arguments developed for helping can be extended to essentially any social trait. The analysis suggests that, on a theoretical level, it is possible to contrast three critical benefit-to-cost ratios beyond which costly helping is selected for (three quantitative rules for the evolution of altruism). But comparison between theoretical results and empirical data has always been difficult in the literature, partly because of the perennial question of the scale at which relatedness should be measured under localized dispersal. We then provide three answers to this question.     

Life history theory and evolutionary anthropology

Life-history theory has been developed in biology to explain the variation in timing of fertility, growth, developmental rates, and death of living organisms, as well as events directly tied to these parameters. The theory is useful in explaining variations in age-specific human fertility and mortality patterns, as well as understanding how the human life course evolved to patterns so divergent from those that characterize our close primate relatives. Surprisingly, this same theory can also be used to explain why people often ignore the long-term consequences of behaviors that produce short-term gain.     

Dimensionless numbers and life history evolution: Age of maturity versus the adult lifespan

Summary Within many taxa the age of maturity is not simply positively correlated with the adult lifespan; the two variables are proportional to each other. The dimensionless number which is the constant of proportionality thus becomes something to be predicted by life history theory.     

The fitness costs of senescence: The evolutionary importance of events in early adult life

Summary The increased mortality caused by ageing represents a fitness cost to organisms. This paper develops techniques for determining the proportions of that cost that accrue at each age. A variety of analyses using several different sources of data on human ageing—palaeodemographic life tables and life tables from more recent societies with high mortality rates—all suggest that the fitness cost of ageing was high during most of our evolutionary history, and was largely due to physiological changes occurring early in adult life. These results imply that predictions about the nature of senescence based on evolutionary theory should be tested using data from middle-aged individuals. They also have implications about the relative importances for human evolution of the pleiotropy and mutation-accumulation theories of the evolution of senescence, and for the validity of Gompertz Law' for the shape of the relationship between mortality and age. An analysis of a life table of the African buffalo suggests that the costs of ageing early in adult life are relatively high in at least one non-human species in its natural environment.     

The human post‐fertile lifespan in comparative evolutionary context

There persist two widely held but mutually inconsistent views on the evolution of post‐fertile lifespan of human females. The first, prevalent within anthropology, sees post‐fertile lifespan (PFLS) in the light of adaptive processes, focusing on the social and economic habits of humans that selected for a lengthy PFLS. 1 - 3 This view rests on the assumption that human PFLS is distinct from that of other species, and focuses on quantifying the selective causes and consequences of that difference. The second view, prevalent within gerontology and comparative biology, emphasizes that PFLS is a phylogenetically widespread trait 4 - 6 or that human PFLS is predictable based on life‐history allometries. 7 In this view, human PFLS is part of a broad cross‐species pattern and its genesis cannot, therefore, rely on human‐specific traits. Those who advocate the second view have questioned the “special pleading” for human specific explanations of PFLS, 4 and have argued that human PFLS is quantitatively greater but not qualitatively different than PFLS in many other animals. 5 , 8 Papers asking whether human PFLS is explained by the importance of mothers more than grandmothers, whether paternal or maternal grandparents have more of an effect on child survival, or who is providing the excess calories are associated with the first view that assumes the need to explain the existence of human PFLS on the basis of a uniquely human socioecology. Anthropologists largely see human PFLS as derived, while comparative gerontologists point to evidence that it is one instance of a ubiquitous cross‐species pattern. The two groups generally occupy non‐overlapping research circles, in terms of conferences and journals, and therefore interact little enough to largely avoid the need to reconcile their views, allowing the persistence of misconceptions in each field. Our goal is to identify and address the most important of these misconceptions and thereby make clear that both of these seemingly incongruent views contain valid points. We argue that two distinct but related traits have been lumped together under the same concept of “post‐reproductive lifespan,” one (post‐fertile viability) that is tremendously widespread and another (a post‐fertile life stage) that is derived to hominins, and that the differences and connections between these two traits are necessary for understanding human life‐history evolution.     

Demography,female life history,and reproductive profiles among the chimpanzees of Mahale

Demography provides critical data to increase our understanding of the evolution, ecology, and conservation of primate populations. The chimpanzees of the Mahale Mountains National Park, Tanzania, have been studied for more than 34 yr on the basis of individual identification and standardized attendance records. From this long-term study, we derived the following demographic data: The major cause of death was disease (48%), followed by senescence (24%) and within-species aggression (16%). Fifty percent of Mahale chimpanzees died before weaning. The median ages of female life history variables were: first maximal swelling, 10.0 yr (n = 5); emigration, 11.0 yr (n = 11); and first birth, 13.1 yr (n = 5). The median period of adolescent infertility was 2.8 yr (n = 4) when calculated from the age at immigration to that at first birth. Female fecundity was highest between 20 and 35 yr of age, with an annual birth rate of 0.2. Twenty-six females that were observed from a young age (10-13 yr) to death at various ages (15-40 yr) gave birth to an average of 3.9 and weaned an average of 1.4 offspring. Twenty-five females that were observed from middle age (18-33 yr) to death in older age (31-48) gave birth to an average of 2.7 and weaned an average of 2.0 offspring. The post-reproductive lifespan for female chimpanzees was defined as the number of years that passed from the year when the last offspring was born to the year when the female died, minus 5. Twenty-five percent of old females had a post-reproductive lifespan. The interbirth interval after the birth of a son (x = 72 mo) tended to be longer than that after the birth of a daughter (x = 66 mo). The extent of female transfer, which is a rule in chimpanzees, is influenced by the size and composition of the unit group and size of the overall local community.     

Developmental life history is associated with variation in rates of climatic niche evolution in a salamander adaptive radiation*

Rates of climatic niche evolution vary widely across the tree of life and are strongly associated with rates of diversification among clades. However, why the climatic niche evolves more rapidly in some clades than others remains unclear. Variation in life history traits often plays a key role in determining the environmental conditions under which species can survive, and therefore, could impact the rate at which lineages can expand in available climatic niche space. Here, we explore the relationships among life-history variation, climatic niche breadth, and rates of climatic niche evolution. We reconstruct a phylogeny for the genus Desmognathus, an adaptive radiation of salamanders distributed across eastern North America, based on nuclear and mitochondrial genes. Using this phylogeny, we estimate rates of climatic niche evolution for species with long, short, and no aquatic larval stage. Rates of climatic niche evolution are unrelated to the mean climatic niche breadth of species with different life histories. Instead, we find that the evolution of a short larval period promotes greater exploration of climatic space, leading to increased rates of climatic niche evolution across species having this trait. We propose that morphological and physiological differences associated with variation in larval stage length underlie the heterogeneous ability of lineages to explore climatic niche space. Rapid rates of climatic niche evolution among species with short larval periods were an important dimension of the clade's adaptive radiation and likely contributed to the rapid rate of lineage accumulation following the evolution of an aquatic life history in this clade. Our results show how variation in a key life-history trait can constrain or promote divergence of the climatic niche, leading to variation in rates of climatic niche evolution among species.     

Variation in life history and demography of the American black bear

Variation in life history and demography across a species' range informs researchers about regional adaptations and affects whether managers can borrow information from other populations in decision-making. The American black bear (Ursus americanus) is a long-lived game species whose continued persistence depends on management of harvest and removal of habituated bears that come into conflict with humans. Understanding the demography of black bears guides efforts at management and conservation, yet detailed knowledge of many populations is typically lacking. I performed a hierarchical Bayesian meta-analysis of black bear demographic studies across the geographic range of the species to explore how vital rates vary across the range, what information they give us about population growth, and whether managers can justify borrowing information from other studies to inform management decisions. Cub, yearling, and adult survival and fecundity varied between eastern and western North America, whereas subadult survival did not show geographic structuring. Adult survival and fecundity appeared to trade off, with higher survival in the western portions of bears' range and higher fecundity in the east. Although adult survival had the highest elasticity, differences in reproduction drove differences in population growth rate. Mean population growth rate was higher in the east (0.99; 95% credible interval [CrI]: 0.96, 1.03) than the west (0.97; 95%CrI: 0.93, 1.01). Despite declining trends in the west, 34% of the distribution of population growth rate was >1, compared to 55% in the east. Further work needs to be done to address the cause of the apparent trade-off between adult survival and fecundity and explore how the estimated growth rates are likely to affect population status of black bears. Because population growth rates are close to 1 and small deviations could impact whether a population is considered increasing or decreasing, managers need to employ caution in borrowing vital rates from other populations. © 2011 The Wildlife Society.     

Evolutionary senescence in plants

Senescence is a decline in age-specific survival and reproduction with advancing age. Studies of evolutionary plant senescence are designed to explain this decline in life history components within the context of natural selection. A review of studies of plant demography reveals senescent declines in both annual and perennial plants, but also suggests that there are some plant species which may not be expected to show senescence. Thus, future comparative studies of closely related species, with and without senescence, should be possible. The assumptions of the major evolutionary theories of senescence are evaluated for their validity with respect to plants. Different plant species violate one or more of the assumptions of the theories, yet the consequences of violating these assumptions have never been investigated. Whereas, to date, evolutionary senescence has been studied only indirectly in plants, it is concluded that plants provide good experimental systems for clarifying our understanding of senescence in natural populations.     

A comparison of life history traits of sexual and asexual strains of the parasitoid wasp,Lysiphlebus fabarum (Braconidae: Aphidiinae)

1. This study examined biological characteristics of sexual and asexual strains of the parasitoid wasp, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae). 2. Strains were reared in different instar hosts (the black bean aphid, Aphis fabae Scopoli) under identical environmental conditions (21 °C, 65–75% RH, and LD 16:8 h). 3. Results showed that the second instar of the aphid is the most suitable growth stage for both strains, as the wasps that emerged from the second instar hosts were larger, more fecund, and had larger egg size. Trade‐offs between the fitness components of the parasitoid were clearer when the parasitoids were reared in suboptimal instars. 4. According to the results, sexual females emerged around 1 day earlier and lived around 0.5 day less than asexual females. Also, sexual females emerged with a lower initial egg load, although these wasps tend to have larger eggs than asexual females. Asexual females may enjoy greater longevity and higher developmental plasticity which suggests a higher degree of synchronization with pest population dynamism. 5. The results suggest that sexual wasps, in contrast to asexual wasps, invest more in egg size than in egg load. This study suggests strain‐specific adaptations of L. fabarum to different instars of the black bean aphid by which the allocation of nutritional resources to various functions differs between strains. 6. Furthermore, differences in life history traits between strains can greatly influence the population dynamics of each strain, and hence their effectiveness in suppressing pest populations.