海天考研网

　　男人很危险

　　1、Being a man has always been dangerous. There are about 105 males born for every 100 females, but this ratio drops to near balance at the age of maturity, and among 70-year-olds there are twice as many women as men. But the great universal of male mortality is being changed. Now, boy babies survive almost as well as girls do. This means that, for the first time, there will be an excess of boys in those crucial years when they are searching for a mate. More important, another chance for natural selection has been removed. Fifty years ago, the chance of a baby (particularly a boy baby) surviving depended on its weight. A kilogram too light or too heavy meant almost certain death. Today it makes almost no difference. Since much of the variation is due to genes, one more agent of evolution has gone.

　　做男人总是充满危险，出生时男女比例大约是105:100，但到了成熟期，这一比例几乎持平，而在70岁的老人中女性是男性的两倍，但是男性死亡率普遍偏高这种情况正在改变，现在男婴存活率几乎同女婴一样高。这就意味着男孩到了寻找伴侣的关键年龄将首次出现男孩过剩现象。更重要的是，又一次自然选择的机会不复存在了。50年前，婴儿（尤其是男婴）存活的机会取决于体重，过轻或过重几乎意味着必死无疑。今日体重几乎不起什么作用，因为大部分差异是由基因引起的，又一个进化的因素消失了。

　　2、There is another way to commit evolutionary suicide: stay alive, but have fewer children. Few people are as fertile as in the past. Except in some religious communities, very few women has 15 children. Nowadays the number of births, like the age of death, has become average. Most of us have roughly the same number of offspring. Again, differences between people and the opportunity for natural selection to take advantage of it have diminished. India shows what is happening. The country offers wealth for a few in the great cities and poverty for the remaining tribal peoples. The grand mediocrity of today — everyone being the same in survival and number of offspring — means that natural selection has lost 80% of its power in upper-middle-class India compared to the tribes.

　　进化自杀还有另一种方法：存活，但少生孩子。现在没有几个人像过去那样具有旺盛的生育力。除了在一些宗教社区之外，没有几名妇女有15个孩子。当今婴儿出生的数量同死亡年龄一样已趋于平均化，我们多数人的子女数量大致相同。人与人之间的差异和利用差异进行自然选择的机会再一次减少。印度可以说明正在发生的一切。这个国家给大城市里的少数人提供财富，而给其余的各部落民族以贫困。今天这种极其显着的平均化——每个人的生存机会和子女数量都相同——意味着与部落相比较，自然选择在印度中、上层已经失去了80％的效力。