Even without speciation, the same outcome could occur through a loss of genetic diversity: If everyone selected the same traits for their offspring, their descendants would be incapable of surviving a sudden, unexpected environmental challenge.
即使没有物种分化，基因多样性的丢失也可能造成同样结果：如果所有人都为后代选择同样的特征，那么他们的后代将无法从突发的意外环境挑战中存活下来。