第三十八篇 Night of the Living Ants (B级)
When an ant dies, other ants move the dead insect out of the nest. This behavior is interesting to scientists, who wonder how ants know for sure —and so soon —that another ant is dead.
Dong-Hwan Choe, a scientist at the University of California found that Argentine ants have a chemical on the outside of their bodies that signals to other ants, “I’m dead—take me away.”
But there’s a twist to Choe’s discovery. These ants are a little bit like zombies. Choe says that the living ants—not just the dead ones -- have this death chemical In other words, while an ant crawls around, perhaps in a picnic or home, it’s telling other ants that it’s deads.
What keeps ants from hauling away the living dead ? Choe found that Argentine ants have two additional chemicals on their bodies, and these tell nearby ants something like, “Wait— I’m not dead yet. ” So Choe’s research turned up two sets of chemical. signals in ants: one says, “I’m dead,” the other set says, “I’m not dead yet. ”
Other scientists have tried to figure out how ants know when another ant is dead. If an ant is knocked unconscious, other ants leave it alone until it wakes up. That means ants know that unmoving ants can still be alive.
Choe suspects that when an Argentine ant dies, the chemical that says “Wait- I’m not dead yet” quickly goes away. Once that chemical is, gone, only the one that says “I’m dead” is left. “It’s because the dead ant no longer smells like a living ant that it gets carried to the graveyard, not because its body releases new unique chemicals after death ,” said Choe. When other ants detect the “dead” chemical without the “not dead yet” chemical, they haul away the body. This was Choe’s hypothesis.
To test his hypothesis, Choe and his team put different chemicals on Argentine ant pupae. When the scientists used the “I’m dead” chemical, other ants quickly hauled the treated pupae away. When the scientists used the “Wait — I’m not dead yet” chemicals, other ants left the treated pupae alone. Choe believes this behavior, shows that the “not dead yet” chemicals override the “dead” chemical when picked up by adult ants. And that when an ant dies, the “not dead yet” chemicals fade away. Other nearby ants then detect the remaining “dead” chemical and remove the body from the nest.
练习：
1. What is meant by “death chemical” mentioned in paragraph 3 ?
A A chemical that contains poison
B A chemical that causes death.
C A chemical that announces death.
D A chemical that prevents death.
2. Which of the following is closest in meaning to the question “What keeps ants from hauling away the living dead? (paragraph 4)” ?
A How do ants know what is to be hauled away from the dead ants?
B What prevents ants from removing the ants that are not yet dead?
C What do ants do to keep themselves away from the dying ants?
D What prevents ants from being carried away after they die.
3. What is NOT true about Choe’s finding?,
A When an ant dies, it produces a “I am dead” signal.
B Living ants have the death chemical on their bodies.
C Ants have two sets of chemicals on their bodies.
D Ants have the “I am not dead” chemical on their bodies.
4. According to Choe’s hypothesis,
A an ant still smells like a living when it dies.
B the “I am dead” chemical leaves the ant’s body when it dies.
C the “I am not dead yet” chemical is left when an ant dies.
D the “I am not dead yet” chemical leaves the ant’s body when it dies.
5. What is the result of the test on Choe’s hypothesis?
A It proves that his hypothesis is true.
B Not enough evidence has been found to support his hypothesis.
C It shows that his hypothesis is wrong.
D It indicates that his hypothesis needs revising.
参考答案
C B A D A
参考译文
第三十八篇 蚂蚁的死亡
当一只蚂蚁死后，其余的蚂蚁就会把这只死亡的蚂蚁拖出洞。这一行为极大地吸引了科学家，他们奇怪蚂蚁怎么确认——并以如此快的速度——另一只蚂蚁死了呢?
加利福尼亚大学的科学家Dong—Hwan Choe发现：阿根廷蚂蚁在它们的身体外部有一种化学成分信号告诉其他的蚂蚁”我已经死了——把我带走。”
然而，Choe又有了新的出乎意料的发现。这些蚂蚁有点像靠巫术起死回生的僵尸。Choe说，活着的蚂蚁——不仅仅是死的——都有这种死亡化学成分。换句话说，当一只蚂蚁在四处爬行，或许在野餐或是在洞中，也在告诉其他的蚂蚁它已经死了。
是什么阻止蚂蚁运走活着的蚂蚁呢?Choe发现阿根廷蚂蚁在它们身体上有两种额外的化学成分，这些化学成分告诉附近的蚂蚁，”等等——我还没死呢。”因此Choe的研究发现在蚂蚁体内有两种化学信号：一个说：”我已经死了”，另一个说：”我还没死呢。”
其他的科学家也试图弄明白蚂蚁是怎样知道另一只蚂蚁死了的。如果一只蚂蚁被弄成晕迷状态，其他的蚂蚁会不管它，直到它自己醒来。也就是说蚂蚁知道不动的蚂蚁也能是活着的。
Choe怀疑当阿根廷蚂蚁死亡后，那个说”等等——我还没死”的化学成分很快就消失了。一旦那个化学成分消失了，就只留下”我已经死了”的化学成分。”因为死亡的蚂蚁闻起来不再像活蚂蚁，所以被抬到墓地，而不是因为死蚂蚁死后释放出一种新的、独特的化学气味，”Choe说。当其它的蚂蚁发现没有”未死”的”歹E亡”化学成分时，它们就把那个身体拖走了。这是Choe的假设。
为了验证这个假设，choe和他的小组在阿根廷蚂蚁和蛹上放了不同的化学成分。当科学家用这个”我已经死亡”的化学成分时，其它的蚂蚁会快速地把这个蛹拖走。当科学家们用”等等——我还没死”的化学成分时，其它的蚂蚁就会对那个蛹视而不见。Choe相信这一行为表示这”我还没死”的化学成分优先于”我已经死亡”的化学成分。并且当一只蚂蚁死后，这个”我还没死”的化学成分就消失了。其他附近的蚂蚁就会发现留下的”死亡”化学成分并把死蚂蚁拖走。
2010年 职称英语考试教材 现货已到，先到先得，欲购从速！
