2010年10月22日托福机经英文版原文(康老师)
2011-11-04来源:和谐英语
2010年10月22日
科学家们研究海龟迁徙靠什么指引方向
开始一种结论是靠星星，可是海龟视力不好，很难看到，而且在乌云密布的晚上还是可以继续迁徙（乌云密布这里有道辞汇题）；然后还有一种是靠气味，可是气味不能维持很久，所以不适用于长途迁徙，而且在过程中有气味干扰，但是海龟依然能找对方向；第三种是磁场，可是如果绑个磁铁在领头的海龟上，它还是可以辨别方向，所以也不是磁场。
但是有一个结论是海龟可能是用combine几种方法，在靠近目的地时味道是有用的（有题）。最后一种解释，是海龟体内的一种DNA，它能记录海龟被孵化出的地点（也就是他们去的地方），并且由母海龟遗传给小海龟。最后说有一个例子可以证明：从前在加勒比海的一个地方有很多绿海龟，但是后来捕杀很严重海龟们就不去了；近几年虽然又保护起来了但是海龟们来得仍然很少。
How sea turtles navigation when they are migrate: First hypothesis is they can see the sun rise and sun sets; second hypothesis is they can feel the magnet (but it won't be disturbed by the change of magnet); third is the most possible one that they find the direction of the wave and the odor. The scientists also find that the female turtles transfer their DNA to their children without mixing with male turtles.
A Sea Turtle Has A Map Sense and a Compass Sense
Studies by Kenneth Lohmann and colleagues at the University of North Carolina at Chapel Hill have been instrumental in bringing to the forefront information about the relationship between sea turtles and geomagnetic navigation.
The results of the study showed that the turtle has a magnetic map that helps it know its position relative to a specific destination, such as feeding grounds, and may be used with the turtle’s compass—or directional—sense, as well as other environmental cues (such as the shoreline) to put itself on a course to reach that specific destination.
The Olfactory Section of the Turtle’s Brain
While researchers have long suspected that a sea turtle’s excellent sense of smell plays a role in navigation, a nasal structure called the Jacobson's organ is thought to be linked with the turtle’s geomagnetic skill. This organ is connected the olfactory bulb in the turtle’s brain. It is possible that small particles of magnetite, an iron ore, are located near the sea turtle’s nose, which help “stimulate the turtle’s brain with a sense of magnetic location,” according to Witherington.
Why Sea Turtles Must Know How to Orient Themselves
All of these advanced skills are important to sea turtles because, after hatching, they may spend up to five years floating in the ocean among various habitats specific to their species. For loggerhead turtles, the journey at sea to maturity is longer, maybe a decade. Each species of sea turtle has its preferred feeding grounds, and every female sea turtle instinctively returns to breed at the beach where she hatched—the same nesting site as her forebears. It is a part of her DNA. This faithfulness to the beach where she was born is called “natal philopatry.”
Perhaps one day researchers will know for sure all of the mysteries behind the sea turtle’s amazing instincts and navigational abilities. It is yet another example of how an animal considered ancient and perhaps simple has more advanced inner workings than man currently understands.
科学家们研究海龟迁徙靠什么指引方向
开始一种结论是靠星星，可是海龟视力不好，很难看到，而且在乌云密布的晚上还是可以继续迁徙（乌云密布这里有道辞汇题）；然后还有一种是靠气味，可是气味不能维持很久，所以不适用于长途迁徙，而且在过程中有气味干扰，但是海龟依然能找对方向；第三种是磁场，可是如果绑个磁铁在领头的海龟上，它还是可以辨别方向，所以也不是磁场。
但是有一个结论是海龟可能是用combine几种方法，在靠近目的地时味道是有用的（有题）。最后一种解释，是海龟体内的一种DNA，它能记录海龟被孵化出的地点（也就是他们去的地方），并且由母海龟遗传给小海龟。最后说有一个例子可以证明：从前在加勒比海的一个地方有很多绿海龟，但是后来捕杀很严重海龟们就不去了；近几年虽然又保护起来了但是海龟们来得仍然很少。
How sea turtles navigation when they are migrate: First hypothesis is they can see the sun rise and sun sets; second hypothesis is they can feel the magnet (but it won't be disturbed by the change of magnet); third is the most possible one that they find the direction of the wave and the odor. The scientists also find that the female turtles transfer their DNA to their children without mixing with male turtles.
A Sea Turtle Has A Map Sense and a Compass Sense
Studies by Kenneth Lohmann and colleagues at the University of North Carolina at Chapel Hill have been instrumental in bringing to the forefront information about the relationship between sea turtles and geomagnetic navigation.
The results of the study showed that the turtle has a magnetic map that helps it know its position relative to a specific destination, such as feeding grounds, and may be used with the turtle’s compass—or directional—sense, as well as other environmental cues (such as the shoreline) to put itself on a course to reach that specific destination.
The Olfactory Section of the Turtle’s Brain
While researchers have long suspected that a sea turtle’s excellent sense of smell plays a role in navigation, a nasal structure called the Jacobson's organ is thought to be linked with the turtle’s geomagnetic skill. This organ is connected the olfactory bulb in the turtle’s brain. It is possible that small particles of magnetite, an iron ore, are located near the sea turtle’s nose, which help “stimulate the turtle’s brain with a sense of magnetic location,” according to Witherington.
Why Sea Turtles Must Know How to Orient Themselves
All of these advanced skills are important to sea turtles because, after hatching, they may spend up to five years floating in the ocean among various habitats specific to their species. For loggerhead turtles, the journey at sea to maturity is longer, maybe a decade. Each species of sea turtle has its preferred feeding grounds, and every female sea turtle instinctively returns to breed at the beach where she hatched—the same nesting site as her forebears. It is a part of her DNA. This faithfulness to the beach where she was born is called “natal philopatry.”
Perhaps one day researchers will know for sure all of the mysteries behind the sea turtle’s amazing instincts and navigational abilities. It is yet another example of how an animal considered ancient and perhaps simple has more advanced inner workings than man currently understands.
以上机经是康老师2011年10月－12月托福预测范围里的。
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