环境生态学第十章捕食的性质

泛化种和 特化种
捕食者随其摄取猎物的数量多少而变化，某些捕 食者是特化种，而另一些是泛化种。一般来说， 寄生者比典型捕食者更为特化、而草食者比肉食 者更为特化。
健壮的肉食者
新西兰美利诺羊
The impact of predators on prey
population size
Do predators and parasites regulate the population size of their prey? This is not as simple q question as it may appear. There are two main issues: (I) the effect of any one predator may only be a small component of the total mortality causes affecting a prey species, so removal of the predator will have only a minor effect; (ii) predation may kill animals which were going to die anyway, so there will be no impact on the final prey population size. However, in a number of cases there is clear evidence that predators have a considerable impact on prey numbers.
J1 捕食的性质
要
捕食的定义
点
捕食可定义为摄取其他个体（猎物）的全部或部 分为食。这一广泛的定义包括（i）典型的捕食者， 在袭击猎物后迅速杀死而食之；（ii）草食者， 只消费对象个体的一部分；（iii）寄生者，与单 一对象个体（寄生）有密切关系，通常生活在寄 主的组织中。
捕食
一个物种的成员以另一物种成员 为食,被捕食者常常被杀死.
捕食者对猎物 种群大小的 影响
捕食者和寄生者是否能够调节其猎物种群的大小 呢？这一问题并不像看上去的那么简单。有两种 主要观点：（i）任一捕食者的作用，只占猎物种 总死亡率的很小一部分，因此去除捕食者对猎物 种仅有微弱效果；（ii）捕食者只是杀死了对象 种中即将死亡的个体，所以最终对猎物种群大小 没有影响。然而，在一些例子中确有明显证据表 明捕食者对猎物数量有重要影响。
肉食者和 草食者
捕食者可以划分为（i）消费植物组织的草食者，（ii） 摄食动物组织的肉食者和（iii）既摄食植物组织也摄 食动物组织的杂食者。动物、植物食性的差异需要不 同的生理和行为适应，从而导致肉食者与草食者世系 之间反复的进行分歧。
Generalists and specialists
Predators vary in the number of species of prey they will feed on, with some species being specialists, whilst others are more generalist. Generally, parasites tend to be more specialist than true predators and herbivores tend to be more specialist than carnivores.
猎物呢？
Lotka-Volterra predator-prey model
The Lotka_Volterra predator-prey model is a simple mathematical model representing the interaction between predators and their prey. It makes three simplifying assumptions: (i) there is only one predator and one prey species involved in the interaction; (ii) prey numbers increase if the number of predators falls below a threshold and decrease if there are more predators; and (iii) predator numbers increase if the number of prey rises above a threshold and decrease if there are fewer prey. This simple model makes an interesting prediction: predator and prey populations will tend to cycle, as is observed in natural predatorprey dynamics.
狭义捕食: 动物吃动物
广义捕食则包括动物以植物为食的现象 （植食）Baidu Nhomakorabea及茅膏菜、捕蝇草、瓶子草、猪 笼草和狸藻等少数植物捕捉昆虫将其消化以 吸取含氮物质的情况。
Carnivores and herbivores
Predators can be categorized as (i) herbivores which consume plant tissue, (ii) carnivores which food in animal tissue and (iii) omnivores which feed on both. The difference between animals and plants as prey types required different physiological and behavioral adaptations, and has lead to repeated evolutionary divergence between carnivorous and herbivorous lineages.