新航道

  在托福写作练习过程中，相信TPO材料中的作文题目都会是大家的首选练习材料。上海新航道托福小编给考生们带来了托福TPO49综合写作，希望可以帮助广大托福考生轻松备考托福。

  TPO49综合写作

  阅读文本：

  Like many creatures, humpback whales migrate long distances for feeding and mating purposes. How animals manage to migrate long distances is often puzzling. In the case of humpback whales, we may have found the answer: they may be navigating by the stars, much as early human sailors did. What we know about humpback whales makes this a distinct possibility.

  First, humpback whales seem to be intelligent enough to use stars to navigate by. Whales' brains have a high degree of complexity--a common determiner of intelligence. This suggests that the whales' brain power far exceeds that of most other animals. The whales' well-developed cognitive ability seems to provide a sound basis for the ability to use a complex, abstract system of sensory stimuli such as the night sky for orientation.

  Second, humpback whales migrate in straight lines. Animals can maintain movement in a straight direction for long distances only if they orient themselves by some external objects or forces. Many birds and other terrestrial creatures, for example, use physical landmarks to help them stay on track as they migrate. Whales, which swim in the open ocean, cannot rely on land features; they could, however, rely on stars at night to provide them with external signs by which to maintain direction over long distances.

  Third, humpback whales exhibit an unusual behavior: they are sometimes observed floating straight up for minutes at a time, their heads above the water as though they were looking upward. The behavior is known as spy-hopping, and it is very rare among marine animals. One explanation for the function of spy-hopping is that the whales are looking at the stars, which are providing them with information to navigate by.

  听力文本：

  Professor:

  The theory that humpback whales use the stars to navigate the open seas is a fascinating one, but the evidence supporting the theory is not very convincing.

  First, there doesn’t seem to be any real connection between intelligence and an animal's ability to use stars for navigation. You know, there are other animals that use stars to navigate. Some birds have this ability, like ducks for example. Now the general cognitive ability of ducks is only average. They are not highly intelligent. The fact that the ducks evolved the ability to use stars for navigation does not seem to have much of a connection to their overall intelligence. It's just an instinct they were born with, not a sign of intelligence. So the fact that humpback whales happen to be intelligent does not make them particularly likely to use stars for navigation. The two things just don't seem to be connected.

  Second, there may be a different explanation for the humpback whale’s ability to navigate in straight lines. Remember that for animals to be able to do this, they have to sense some external object or force. Well, the external force the whales could be sensing is Earth’s magnetic field. Humpback whales have a substance in their brains called biomagnetite. Generally, the presence of biomagnetite in an animal’s body makes that animal sensitive to Earth’s magnetic field. The fact that there’s biomagnetite in the brains of humpback whales suggests that they orient themselves by the magnetic field rather than the stars when they migrate.

  Third, spyhopping probably has nothing to do with looking at stars. Spyhopping is rare, but there are other animals that exhibit it. Some sharks do it, for example. But sharks don't migrate or look at stars. Sharks spyhop to look for animals they want to hunt. And another thing, humpback whales often spyhop during the day, when no stars can be seen. So to suggest that the function of spyhopping is to look at stars is pure speculation.

    以上就是小编为大家带来关于托福TPO写作 资料供大家阅读参考，新航道托福资料频道 将第一时间为考生发布最全、最新、最专业的托福资讯及托福考试资料及机经.