托福TPO核心词汇—A Warm-Blooded Turtle
新托福之TPO阅读重点单词语境记忆40
A Warm-Blooded Turtle
When it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. It swims farther into the cold of the northern and southern oceans than any other sea turtle, and it deals with the chilly waters in a way unique among reptiles.
A warm-blooded turtle may seem to be a contradiction in terms. Nonetheless, an adult leatherback can maintain a body temperature of between 25 and 26°C (77-79°F) in seawater that is only 8°C (46.4°F). Accomplishing this feat requires adaptations both to generate heat in the turtle’s body and to keep it from escaping into the surrounding waters. Leatherbacks apparently do not generate internal heat the way we do, or the way birds do, as a by-product of cellular metabolism. A leatherback may be able to pick up some body heat by basking at the surface; its dark, almost black body color may help it to absorb solar radiation. However, most of its internal heat comes from the action of its muscles.
Leatherbacks keep their body heat in three different ways. The first, and simplest, is size. The bigger the animal is, the lower its surface-to-volume ratio; for every ounce of body mass, there is proportionately less surface through which heat can escape. An adult leatherback is twice the size of the biggest cheloniid sea turtles and will therefore take longer to cool off. Maintaining a high body temperature through sheer bulk is called gigantothermy. It works for elephants, for whales, and, perhaps, it worked for many of the larger dinosaurs. It apparently works, in a smaller way, for some other sea turtles. Large loggerhead and green turtles can maintain their body temperature at a degree or two above that of the surrounding water, and gigantothermy is probably the way they do it. Muscular activity helps, too, and an actively swimming green turtle may be 7°C (12.6°F) warmer than the waters it swims through.
Gigantothermy, though, would not be enough to keep a leatherback warm in cold northern waters. It is not enough for whales, which supplement it with a thick layer of insulating blubber (fat). Leatherbacks do not have blubber, but they do have a reptilian equivalent: thick, oil-saturated skin, with a layer of fibrous, fatty tissue just beneath it. Insulation protects the leatherback everywhere but on its head and flippers. Because the flippers are comparatively thin and blade-like, they are the one part of the leatherback that is likely to become chilled. There is not much that the turtle can do about this without compromising the aerodynamic shape of the flipper. The problem is that as blood flows through the turtle’s flippers, it risks losing enough heat to lower the animal’s central body temperature when it returns. The solution is to allow the flippers to cool down without drawing heat away from the rest of the turtle’s body. The leatherback accomplishes this by arranging the blood vessels in the base of its flipper into a countercurrent exchange system.
In a countercurrent exchange system, the blood vessels carrying cooled blood from the flippers run close enough to the blood vessels carrying warm blood from the body to pick up some heat from the warmer blood vessels; thus, the heat is transferred from the outgoing to the ingoing vessels before it reaches the flipper itself. This is the same arrangement found in an old-fashioned steam radiator, in which the coiled pipes pass heat back and forth as water courses through them. The leatherback is certainly not the only animal with such an arrangement; gulls have a countercurrent exchange in their legs. That is why a gull can stand on an ice floe without freezing.
All this applies, of course, only to an adult leatherback. Hatchlings are simply too small to conserve body heat, even with insulation and countercurrent exchange systems. We do not know how old, or how large, a leatherback has to be before it can switch from a cold-blooded to a warm-blooded mode of life. Leatherbacks reach their immense size in a much shorter time than it takes other sea turtles to grow. Perhaps their rush to adulthood is driven by a simple need to keep warm.
托福核心单词
Physiology生理学;生理机能
原文：When it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. 从生理学上讲，棱皮龟在某些方面上更像爬行的鲸鱼。
强化记忆： Physiology and anatomy are basic to medical science. 生理学和解剖学是医学的基础。
He bought a book about physiology. 他买了一本生理学方面的书。
Leatherback棱皮龟
原文：When it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. 从生理学上讲，棱皮龟在某些方面上更像爬行的鲸鱼。
强化记忆：Leatherback turtles usually mate every other year. 棱皮龟通常是隔年才交配一次。
Scientists have appealed for international cooperation to protect leatherback sea turtles.科学家呼吁国际性合作来保护棱皮海龟。
Reptilian爬虫类动物
原文：When it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. 从生理学上讲，棱皮龟在某些方面上更像爬行的鲸鱼。
强化记忆：The chick is ugly and almost reptilian in its appearance. 这只小鸡长得很丑，看起来几乎像个爬行动物。
The reptilian brain is much like a baby's brain. 爬行动物脑有点像婴儿的大脑。
Chilly寒冷的，可怕的
原文：It deals with the chilly waters in a way unique among reptiles. 它们在应对寒冷水域时有其独特的方式。
强化记忆： I was feeling chilly. 我感到冷得难受。
Contradiction矛盾，反驳
原文：A warm-blooded turtle may seem to be a contradiction in terms. 温血海龟似乎是一个自相矛盾的术语。
强化记忆：There is a contradiction between the two sets of figures. 这两组数据相互矛盾。
Your attitude is in contradiction to your character. 你的态度和你的性格相抵触。
Radiation辐射，放射物
原文：Its dark, almost black body color may help it to absorb solar radiation. 其深色近乎黑色的体色有助于吸收太阳辐射。
强化记忆： the biological effects of radiation 辐射对生物体的影响
unusually high levels of radiation 超高的辐射强度
Bask晒太阳，取暖，舒适
原文：A leatherback may be able to pick up some body heat by basking at the surface. 棱皮龟可能会通过晒太阳来收集身体所需的热量。
强化记忆：Turtles like to bask in the sun. 海龟喜欢曝于阳光中。
Each had a private little sun for her soul to bask in. 在她们每一个人心里，都独有一个小太阳，晒着她们的灵魂。
Proportionate相称，成比例
原文：For every ounce of body mass, there is proportionately less surface through which heat can escape. 体重每增加一盎司，相应的容易流失热量的表面就越少。
强化记忆：The number of accidents is proportionate to the increased volume of traffic. 交通事故的数字与交通量的增长成正比。
Wages will rise at a rate proportionate to the amount of work you do. 工资将与你所做的工作量成比例增加。
Loggerhead 红海龟，笨蛋
原文：Large loggerhead and green turtles can maintain their body temperature at a degree or two above that of the surrounding water, and gigantothermy is probably the way they do it. 红海龟和绿甲海龟可以维持与周围水温略高1摄氏度或2摄氏度或的体温，可能就是利用的巨温性。
强化记忆：Mrs Smith enjoys setting people at loggerheads. 史密斯太太喜欢挑拨离间。
Blubber 鲸油，鲸脂
原文：Leatherbacks do not have blubber. 棱皮龟没有鲸鱼那样的脂肪。
强化记忆：The whale is rich in blubber. 这种鲸油多。
The whale blubber is rendered down to make oil. 鲸的脂肪被煎熬成油。
Equivalent等价的，相等的
原文：they do have a reptilian equivalent. 它们和爬行类的动物有着相似的结构。
强化记忆： Eight kilometers is roughly equivalent to five miles. 八公里约等于五英里。
You will receive the full equivalent of your money. 你将收到与你的款项价值完全同等的物品。
Flipper鳍
原文：Insulation protects the leatherback everywhere but on its head and flippers. 除了头部和鳍，这个“绝缘”结构可以保护它们的所有部位。
强化记忆：The seal's flipper is homologous with the human arm. 海豹的鳍肢与人类的手臂同源。
It's almost like a flipper action as she kicks down. 她向下踢腿时有鱼鳍的效果。
Blade 刀片，刀锋
原文：Because the flippers are comparatively thin and blade-like, they are the one part of the leatherback that is likely to become chilled. 因为棱皮龟的鳍相对较薄且呈叶片状，这一部位很有可能会被冻僵。
强化记忆：Blade and handle are the component parts of a knife. 刀身和刀柄是一把刀的组成部分。
The knife's blade gleamed dully in the dark. 刀刃在黑暗中幽幽地闪着光。
Aerodynamic 空气动力学的
原文：There is not much that the turtle can do about this without compromising the aerodynamic shape of the flipper. 在不损害鳍部气动外形的情况下很少有海龟可以做到这些。
强化记忆：The newspaperman summarized the crux of the aerodynamic phenomenon. 记者总结了空气动力现象之谜。
These effects appear to be negligible with respect to aerodynamic coefficients. 就空气动力系数这方面来说，这些影响似乎可以略去。
Countercurrent 逆流，相反
原文：The leatherback accomplishes this by arranging the blood vessels in the base of its flipper into a countercurrent exchange system. 棱皮龟通过鳍下排列的血管流入逆流交换系统来实现这一点。
强化记忆：Countercurrent washing is applied to reduce acid pollution effectively. 逆流洗涤方式能有效减轻酸污染。
Compromising妥协的，让步的
原文：There is not much that the turtle can do about this without compromising the aerodynamic shape of the flipper. 在不损害鳍部气动外形的情况下很少有海龟可以做到这些。
强化记忆：He made the fatal mistake of compromising early. 他犯了过早妥协的致命错误。
She turned red and then white in the most compromising fashion. 她的脸始而变红，继而转白，一副妥协的样子。
Floe 浮冰
原文：That is why a gull can stand on an ice floe without freezing. 这就是为什么海鸥可以站在冰川上而不被冻结。
强化记忆：Two penguins are standing on ice floe. 两只企鹅站在一块浮冰上。
Two Atlantic walruses snuggle on an ice floe near Igloolik, Nunavut, Canada. 加拿大努勒维特伊格卢利克附近，两头大西洋海象在浮冰上相互偎依。
Fibrous纤维的
原文：They do have a reptilian equivalent: thick, oil-saturated skin, with a layer of fibrous, fatty tissue just beneath it. 它们和爬行类的动物有着相似的结构：厚且含油的皮肤，皮肤下有一层纤维，而脂肪组织就在这个纤维层下面。
强化记忆：Wetting of fibrous materials can critically affect many manufacturing processes. 纤维材料的润湿，会严重影响它的许多加工工艺。
Cellophane is made of long, fibrous molecules. 玻璃纸系由长形纤维分子组成。
Gull海鸥
原文：That is why a gull can stand on an ice floe without freezing. 这就是为什么海鸥可以站在冰川上而不被冻结。
强化记忆：The gull held the fish in its beak. 海鸥嘴里叼着鱼。
A lone sea gull flew across the sky. 一只孤独的海鸥在空中飞过。
