纪录片《进化缺环》 第10期 始祖鸟（在线收听）

But transitional forms are also the rarest of beasts.

不过过渡型物种也是最罕见的动物

By their very nature they were few in number and lived for just a short intermediate time until a wholly new animal evolved.

从它们的性质不难看出，它们不仅数量少，而且只生活在非常短暂的过渡时期，直到进化成全新的物种

In fact for years there was only one accepted transitional form - the archaeopteryx

事实上，多年来只有一种认可的过渡型物种--始祖鸟

which was a dinosaur with feathers that marked the transition to birds.

一只长羽毛的恐龙，标志着向鸟类的过渡

Presumably the transitional forms are very rapidly outcompeted by their more, by their own more advanced descendants

大概是因为过渡型物种很快即被它们自己更先进的后代所取代

so these transitional episodes in the history of life tend to be brief

使得这些生命历史中的“过渡插曲”相当短暂

and involve, it seems, relatively low numbers of species and probably low numbers of individuals.

包括这些动物的物种数量可能比较少，种内数量也可能非常少

The trouble was without anything half fish/half tetrapod between eusthenopteron and ichthyostega

问题是，真掌鳍鱼和鱼石螈之间若是找不到半鱼半四足类的动物

the story of how we got our legs remained incomplete and lurking out there

那么关于我们如何长出腿的故事就会变得很不完整

was a group dedicated to pointing out such gaps in the story of evolution with the aim of its ultimate destruction.

那儿总有一些人，一心想要找出进化理论中的这类破绽，直到它最后整个坍塌。