聊聊生物间的共生关系

　　托福听力中的生物学科是托福考试中出现非常高频的话题，其中共生关系在TPO以及真实考试中已经考过很多次。今天就带着大家了解一下共生关系的三个分类，给大家补充一些相关的背景知识。具体可参考TPO 34 L3, TPO48 L3, TPO62 L3

　　1、Parasitism: It is a non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host. Unlike predators, parasites do not kill their host, are generally much smaller than their host, and will often live in or on their host for an extended period. Parasites show a high degree of specialization, and reproduce at a faster rate than their hosts.

　　寄生关系是指一种生物寄付于另一种生物体内或表面，以牺牲另一方而获益的关系。通常来说，寄生物比宿主小，它们不会杀死宿主。寄生物通常高度专业化，繁殖的速度比宿主高很多。

　　2、Mutualism is the way two organisms of different species exist in a relationship in which each individual benefits from the activity of the other. Hummingbird drinking from flowers. Pollination is a classic example of mutualism.

　　互利共赢是指两个不同物种的生物体，能够共同获得益处。例如花利用蜂鸟传粉。蜂鸟则从花蜜中吸取营养。

　　3、Commensalism is a class of relationships between two organisms where one organism benefits without affecting the other. It can be compared with mutualism, in which both organisms benefit, and parasitism, where one benefits while the other is harmed. Remoras (sucker fish) benefit from riding on sharks without helping or harming them.

　　偏利共生（又称共栖）指的是两种生物之间一种获益，另外一种不受影响。例如印鱼通过骑在鲨鱼身上远行，但本身并没有给鲨鱼带来好处或伤害。

　　写在最后

　　好啦，今天关于托福听力生物讲座中的背景知识就补充到这里啦。之后将为大家带来更多的分享！更多关于托福考试的个性化问题敬请咨询新航道官网