暨大本科生态学课件General Ecology 8-2

1、任课教师：段舜山 暨南大学生命科学技术学院生态学系 E-mail: tssduan,普通生态学 GENERAL ECOLOGY,段舜山 2020/6/21,2,第8章,种群生态学 Population Ecology,段舜山 2020/6/21,3,8.3 Life history patterns 生活史模式 8.4 Human population growth 人口增长,主要内容,段舜山 2020/6/21,4,第3节 生活史模式,JINAN UNIVERSITY,Concepts: Life history 生活史 Stages of development 发育阶段 Survivor

2、ship curves 生存曲线 Two extreme patterns 极端模式 Life history of guppies 虹鱼生活史 Reproductive strategies 生殖对策,段舜山 2020/6/21,5,Life history 生活史,The adaptations of an organism that influence aspects of its biology such as the number of offspring it produces, its survival, and its size and age at reproductive

3、maturity. 一个生物从产生到死亡所经历的全过程。其关键内容是指生物后代的繁殖数量、生存率、个体大小、生殖年龄和寿命等。,段舜山 2020/6/21,6,Stages of development 发育阶段,Populations are not made up of identical individuals (种群中的个体并非完全相同). In most species, individuals pass through several different stages of development (多数物种均会经历不同的发育阶段). And each stage proceeds

4、 in the context of interactions with other organisms and with the environment (处在不同阶段的生物与生物以及生物与环境之间存在着相互作用).,段舜山 2020/6/21,7,Survivorship curves 生存曲线,Each species has a characteristic life span (寿命), but few individuals reach the maximum age possible. Individuals tend to reproduce at certain ages.

5、Researchers keep track of a cohort, a group of individuals from the time of birth until the last one dies. Plots of age specific survival of a cohort are called survivorship curves. 研究者追踪一个生物群体（种群）, 观察从第一个个体出生到最后一个个体死亡的全过程，由此得到生存曲线。,段舜山 2020/6/21,8,Three types of survivorship curves,段舜山 2020/6/21,9,

6、三类存活曲线的差异特征,型：表示生物接近生理寿命前只有少数个体死亡。 如人类、大型哺乳动物、阴性阔叶树种、农作物等。 型：表示各个年龄期的死亡率基本相等，呈稳定一致的状态。如蜥蜴、小型哺乳动物、鸟类、水螅等。 型：表示幼体的死亡率高，成熟个体的死亡率低且稳定。如青蛙、鱼类、草本植物等。,段舜山 2020/6/21,10,图2-1 型生存曲线：如大象及大型哺乳动物(包括人类)具有后代个体数少、成活率高，在接近最大生存年龄时死亡率才迅速上升.,段舜山 2020/6/21,11,图2-2 型生存曲线： 小型哺乳类、蜥蜴、鸟类具有该类型存活曲线，不同年龄阶段的死亡率基本稳定，多死于捕杀、疾病等。,段舜

7、山 2020/6/21,12,图2-3 型生存曲线：海星等海洋生物属该类型，它们产生数量多的后代（卵或幼体），但对后代缺乏照顾，幼体阶段的死亡率高。,段舜山 2020/6/21,13,Two extreme patterns 2种极端模式,Ecologists thought that selection favored either the early, rapid production of many small offspring or the late production of only a few large ones 生态学家认为，自然选择要么有利于早生、多生小个体后代（广种薄收

8、策略），或者适宜于晚生、少生大个体后代（少生优育策略） These two patterns are now known to be extremes at opposite ends of a range of possible life histories 关于生物生活史对策的2种极端类型.,段舜山 2020/6/21,14,Life history of guppies 虹鱼生活史,Several years ago, John Endler and David Reznik discovered that predation has profoundly influenced the

9、life history patterns of guppies in Trinidad. 生态学家发现：捕食作用显著影响guppies的生活史模式发生变化。,段舜山 2020/6/21,15,捕食作用可以改变猎物鱼的生活史模式,图3 热带淡水鱼Pike-cichlids(梭鱼)喜欢捕食成熟个体大的guppies；而killfish(将鱼)则更喜欢捕食尚未成熟或个体较小的guppies。,段舜山 2020/6/21,16,现场监测：捕食改变了guppies的生活史模式,In streams where pike cichlids reign, the individuals of guppy

10、populations mature faster than their counterparts in killfish inhabited streams. Besides this, these guppies are smaller in size at maturity and reproduce at a younger age. They also produce far more offspring and do so more often. It seems as if the life history pattern has been shaped by predation

11、. 梭鱼占优势的河流，guppy成鱼个体变小，繁殖年龄提前，后代数量增加，繁殖更频繁。将鱼占优势的河流，情况则相反。,段舜山 2020/6/21,17,小型化,图4-1 室内实验：guppies在梭鱼和将鱼不同捕食压力下的自然选择,段舜山 2020/6/21,18,大型化,图4-2 室内实验：guppies在梭鱼和将鱼不同捕食压力下的自然选择,段舜山 2020/6/21,19,生物的生活史对策或生态对策,各种生物在进化过程中形成各自特有的生活史对策，人们可以把它理解为，生物在漫长的生存斗争中进程中，通过自然选择获得的生存对策。例如： 生殖对策 取食对策 逃避对策 扩散对策 等等。,段舜山 20

12、20/6/21,20,Reproductive strategies 生殖对策,MacArthur和Wilson(1967)将生物按栖息环境和进化对策分为r-对策者和k-对策者，前者属于r-选择，后者属于k-选择。 E. Pianka(1970)提出r/k选择理论：r-选择种类是在不稳定环境中进化的，因而使种群增长率r最大化。 k-选择种类是在接近环境容纳量K值的稳定环境中进化的，因而个体的适应性和竞争力更强。,段舜山 2020/6/21,21,r-选择: 使种群增长率最大化, 快速发育，小型成体，数量多而个体小的后代，高繁殖能量分配，短的世代周期。 k-选择: 使种群竞争能力最大化, 慢速发

13、育，大型成体，数量少但体型大的后代，低繁殖能量分配，长的世代周期。,段舜山 2020/6/21,22,不同生殖对策在进化过程中的特点,K对策者: 种群竞争性强，数量较稳定；但一旦受危害造成数量下降，种群恢复比较困难。 r对策者: 死亡率高，但高r值能使种群快速恢复；且具有高扩散能力；更有利于形成新物种。,赤潮生物属于哪一种类型？,段舜山 2020/6/21,23,第4节 人类种群增长,In 1995, the human population reached 5.7 billion. Our staggering population growth continues even though

14、at least 1 billion individuals are malnourished or starving, without even drinking water or adequate shelter.,即使地球上目前至少还有10亿人口营养不良，没有干净的饮用水和适当的房屋，但是世界人口增长仍在持续着。,段舜山 2020/6/21,24,2005年 （推迟了4年）,段舜山 2020/6/21,25,人口持续增长的地区原本已经过于拥挤,And it continues mainly in regions that are already overcrowded. About 4.

15、5 billion people are now clumped together on 10 percent of the land 超过45亿的世界人口聚居在10%的陆地区域. How did we get into this predicament?,段舜山 2020/6/21,26,为什么最近2个世纪以来人口增长迅猛？,We steadily developed the capacity to expand into new habitats and new climate zones. 人类持续不断地扩张到新的栖息地和气候带. Humans increased the carryin

16、g capacities in existing habitats. Human populations sidestepped several limiting factors. 回避若干环境限制因子而不断增大现存环境的承载量.,段舜山 2020/6/21,27,图1 17000年以来世界人口增长曲线,最近几个世纪以来世界人口迅速增长,11000年前： 开始驯养植物和动物,农业化基础的城市社会,工业革命开始,段舜山 2020/6/21,28,早期人类的人口增长缓慢,Early humans lived mostly in the open grasslands called savannas

17、. They were vegetarians who added scavenged bits of meat to their diet. 早期的人类生活在热带大草原，人们以植物性食物为主，偶尔辅以少量的肉食。,段舜山 2020/6/21,29,人类用很短的时间扩散到新的环境中,By 200,000 years ago, small bands of hunters(狩猎者) and gatherers(采集者) had emerged. By 40,000 years ago, they had spread through much of the world. The human po

18、pulation expanded into diverse new environments in an extremely short time span compared with the long- term geographic dispersal of other kinds of organisms.,段舜山 2020/6/21,30,饥饿、疾病和卫生不良等因素限制了人口的增长,About 11,000 years ago, humans began to shift from hunting and gathering to agriculture. Agriculture i

19、ncreased the carrying capacity for the human population. Until about 300 years ago , malnutrition(营养不良), diseases, and poor hygiene(疾病和卫生不良) kept death rates high enough to more or less balance birth rates.,段舜山 2020/6/21,31,污水处理和疫苗对人口增长的贡献,They plumbing and sewage treatment methods were developed. V

20、accines(疫苗), antitoxins, and antibiotics against many pathogens(病原体) appeared. The death rate dropped sharply, and rapid population growth was under way.,段舜山 2020/6/21,32,图2 1995年世界平均人口增长率.如果维持目前每年1.55%的平均增长率，30年后世界人口将达到85亿。,段舜山 2020/6/21,33,许多国家政府试图通过降低出生率来控制人口增长,Most governments are attempting to

21、lower birth rates, for example, through family planning programs. The programs vary in their details from country to country, but all provide information on methods of birth control. 许多政府正在试图通过计划生育政策降低出生率。,段舜山 2020/6/21,34,实施计划生育世界人口仍将持续增长60年,Suppose family planning programs(计划生育政策) were wildly succ

22、essful and each couple decided to have only two children. The human population would keep on growing for at least another sixty years! Why? An immense number of existing children will eventually be reproducing.,段舜山 2020/6/21,35,肯尼亚 尼日利亚 沙特阿拉伯,图3 人口年龄结构图,人口增长率不同的国家具有不同的年龄结构,段舜山 2020/6/21,36,家庭人口增加与经济

23、状况相联系,When individuals are economically secure, they appear to be less pressured to produce large numbers of children to help them survive. Changes in population growth can be correlated with changes that unfold in four stages of economic development. This is the premise of the demographic transition model. 世界人口统计模型：世界人口增长速度与人类社会的4个经济发展阶段密切相联系。,段舜山 2020/6/21,37,图4-1 人口模型：人口增长特征及人口数量与经济发展阶段相关,段舜山 2020/6/21,38,图4-2 工业化前阶段: 生存条件艰苦，出生率高，死亡率也高，人口增长缓慢,段舜山 2020/6/21,39,图4-3 过渡阶段: 开始工业化进程，食物产量增加，