The newer species arises after some population of the original species adapts to different conditions and diverges genetically so much from the original group that the two can no longer mate.

• 如果原先物种的某个族群，适应了不同生活条件，而在遗传上与原来的物种产生极大的歧异，以致于不能再与原来物种的族群交配，那麽它就是新物种了。