英语翻译One answer to the question that heads this chapter is that the climate(oftenrainfall)allows some parts of the land to be green with plant life ,whilemaking other areas arid and brown.However,this green of extensive plant lifeis still a pu
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英语翻译One answer to the question that heads this chapter is that the climate(oftenrainfall)allows some parts of the land to be green with plant life ,whilemaking other areas arid and brown.However,this green of extensive plant lifeis still a pu
英语翻译
One answer to the question that heads this chapter is that the climate(oftenrainfall)allows some parts of the land to be green with plant life ,whilemaking other areas arid and brown.However,this green of extensive plant lifeis still a puzzle---plants are food for a wide range of animals,so why is somuch food left unused?Swarms of locusts,destroying most plants in theirpath(be they biblical plagues or modern day outbreaks),are the exception notthe rule.But why is so Why are so many parts of our world green in the faceof this threat from herbivores?As we will see,if herbivores are the key toour question,then what starts as a question in plant ecology ends up being aquestion about factors that limit the size of herbivore populations .In theeffect ,we need to understand why herbivore populations do not increase indensity to such a level that they destroy all the available plants,giving aland that is brown rather than green.
英语翻译One answer to the question that heads this chapter is that the climate(oftenrainfall)allows some parts of the land to be green with plant life ,whilemaking other areas arid and brown.However,this green of extensive plant lifeis still a pu
统领这一章的问题的一个答案是：气候关系（通常是降雨）使得一些地方长出了绿色植物,同时也会造成其他地区的干燥和贫瘠.然而,这些绿色植物能延续下来仍然是个谜.因为,植物是许多动物的食物,为什么会有这么多植物幸存下来呢?当然,成群的蝗虫（它们是圣经里天灾的象征,也是当代饥荒爆发的原因）是个例外,它们所到之处,植物所剩无几.但是,为什么世界上还有那么多绿色植物,在面对来自食草生物的威胁之下,能够得以生存呢?在我们看来,如果食草生物是我们问题的关键,那么这个有关植物生态的问题的起因最终被一些因素所回答,这些因素限制了食草生物的数量.实际上,我们必须知道食草生物的密度为什么没有达到能够摧毁所有可食用植物这样一个水平,使得一篇土地由生机勃勃变为荒芜.