Normally, an animal will evolve from its original species when it finds itself isolated by some kind of great ecological barrier.

通常当一种生物因为某些生态障碍而被隔离开时就开始从原种进化变异。

Hence very few of the original species will have transmitted offspring to the fourteen-thousandth generation.

因此，很少有原始物种将后代传给第 14000 代。

The new species in our diagram, descended from the original eleven species, will now be fifteen in number.

我们图表中的新物种从原来的 11 个物种衍生而来， 现在的数量将增加到 15 个。

They would start off as hybrids -- but what would we call them as they begin to look and act more like the original species?

它们一开始是杂交种——但是当它们的外观和行为开始更像原始物种时，我们会怎么称呼它们呢？

If the new species is too strong or uses too much of the resources in the hatitat, some of the original species may become endangered.

如果新物种过于强大或使用了过多的生态区资源，一些原有物种可能会濒临灭绝。

The intermediate species, also (and this is a very important consideration), which connected the original species (A) and (I), have all become, except (F), extinct, and have left no descendants.

连接原始物种（A）和（I）的中间物种（这是一个非常重要的考虑因素），除了（F）外， 都已经灭绝， 并且没有留下后代。

Owing to the divergent tendency of natural selection, the extreme amount of difference in character between species a14 and z14 will be much greater than that between the most distinct of the original eleven species.

由于自然选择的趋异趋势，物种 a14 和 z14 之间的极端性状差异将远远大于最初 11 个物种中最不同的物种之间的差异。

We may suppose that only one (F) of the two species (E and F) which were least closely related to the other nine original species, has transmitted descendants to this late stage of descent.

我们可以假设， 与其他九个原始物种关系最不密切的两个物种（E 和 F）中， 只有一个（F）将后代传到了这个后代的后期阶段。

It seems, therefore, extremely probable that they will have taken the places of, and thus exterminated, not only their parents (A) and (I), but likewise some of the original species which were most nearly related to their parents.

因此，它们似乎极有可能取代并因此灭绝， 不仅是它们的父母（A）和（I），而且还有一些与它们的父母关系最密切的原始物种。