【新托福口语题目】动物成年后繁殖

  2017年9月9日的考试真题解析已经出来了,口语考试题目有哪些呢?出国留学网托福栏目小编整理了相关的资料,希望可以帮助考生度过考试的难关,下面是小编搜集的托福口语真题解析相关资讯,欢迎参考!

  新托福口语Task4题目回忆版本一:

  Reading

  natal homing,动物成年之后回到自己出生的地方进行繁殖

  Listening

  green sea turtle回到出生地繁殖因为温度合适且没有天敌

  新托福口语Task4题目回忆版本二:

  Task 4 阅读 标题:natal homing

  定义:一些特殊物种在繁殖的时候会回到自己的原栖息地寻求更佳适合的条件。

  听力例子:举出一种绿色海龟,在繁殖产卵的时候就会回到原来的栖息地海滩,因为温度更适合,而且能够有效抵御天敌攻击,保护幼崽等。

  新托福口语Task4题目回忆版本三:

  natal homing:一些特殊物种在繁殖的时候会回到自己的原栖息地寻求更佳适合的条件。

  举出一种绿色海龟,在繁殖产卵的时候就会回到原来的栖息地海滩,因为温度更适合,而且能够有效抵御天敌攻击,保护幼崽等。

  新托福口语Task4知识补充;

  Natal homing, or natal philopatry, is the homing process by which some adult animals return to their birthplace to reproduce. This process is primarily used by aquatic animals, such as sea turtles and Pacific salmon. Scientists believe that the main cues used by the animals are geomagnetic imprinting and olfactory cues. The benefits of returning to the precise location of an animal's birth may be largely associated with its safety and suitability as a breeding ground. When seabirds, like the Atlantic puffin, return to their natal breeding colony, which are mostly on islands, they are assured of a suitable climate and a sufficient lack of land-based predators.

  Sea turtles born in any one area differ genetically from turtles born in other areas. The newly hatched young head out to sea and soon find suitable feeding grounds, and it has been shown that it is to these feeding areas that they return rather than to the actual beach on which they started life. Salmon start their lives in freshwater streams and eventually travel down-river and are washed out to sea. Their ability to travel back, several years later, to the river system in which they were spawned is thought to be linked to olfactory cues, the "taste" of the water. Atlantic bluefin tuna spawn on both the east and west shores of the Atlantic Ocean but intermingle as they feed in mid-ocean. Juvenile tuna that have been tagged have clearly shown that they almost invariably return to the side of the Atlantic on which they were spawned.

  Various theories have been put forward as to how the animals find their way home. The geomagnetic imprinting hypothesis holds that they are imprinted with the unique magnetic field that exists in their natal area. This is a plausible theory but has not been proven to occur. Pacific salmon are known to be imprinted on the water chemistry of their home river, a fact that has been confirmed experimentally. They may use geomagnetic information to get close to the coast and then pick up the olfactory cues. Some animals may make navigational errors and end up in the wrong location. If they successfully breed in these new sites, the animal will have widened its breeding base which may ultimately increase the species' chances of survival. Other, unknown means of navigation may be involved, and further research is needed.

  托福考试栏目为您推荐:

  2017年托福考试报名时间

  2017托福听力考试词汇汇总

  托福作文考试零基础备考常识汇总

  2017年9月托福高频词汇表

  2017年托福考试时间安排表

  2017年托福考试成绩查询入口

  托福听力 | 托福词汇 | 托福阅读 | 托福口语 | 托福真题

分享

热门关注

影响托福口语考试的因素 托福口语考试怎么备考

托福口语考试

托福考试口语部分的难点与备考技巧

托福口语考试

托福考试口语的语音问题有哪些

托福考试口语

托福口语与雅思口语的区别有哪些

托福考试口语

托福口语考试的评分标准以及提升的办法

托福口语考试

托福口语题目类型 备考托福口语方法

托福口语题型

托福口语题目 怎样备考托福口语扩展题

托福口语题目

新托福口语题型都有哪些

托福口语考试

托福口语考试题目要点

托福考试

新托福口语考试流程及内容详解

托福口语考试流程

热门问答