新托福模拟考试满分作文(1).doc

新托福模拟考试满分作文(1)
　　New findings in scientific areas can examine and challenge previous assumptions. A recent finding concerning the meerkat, a burrow-dwelling animal in the African grasslands, has cast doubt upon the conventional ideas of altruism, the type of behavior in which an animal sacrifices its own interests for the benefit of another.
　　Meerkats were previously thought to be a typical altruistic animal. When the other meerkats feed, there is usually one meerkat watching out for predators. The sentinel meerkat gains nothing, it seems, for it can neither eat nor escape quickly and successfully after raising an alarm.
　　However, in the new findings, it`s shown that the sentinel meerkat has already eaten food before standing guard, thus contradicting the thought that it has an empty belly while on the lookout. In addition to this, the sentinel is the first to see a predator, so it is the first to escape. It is also placed nearest a burrow, making it relatively easier to flee. Moreover, its alarm calls may cause the group either to gather or to spread rap