Creatures that live in the dark may lose their sight over evolutionary time.

凯伦·霍普金报道。 生活在黑暗环境下的生物可能在演化过程中视力逐渐下降。

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Over evolutionary time, they lose unnecessary genes and become streamlined, ultimately leaving them with a tiny fraction of the genes they started out with: only the ones they really need.

在进化的时候，它们失去了不必要的基因，变得精简，最终留下了它们基因原始的一小部分：只有那些它们真正需要的。

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Traditional evolutionary theory suggests that one feature -- a tail for instance -- would slowly evolve over time.

CNN: Pterodactyl fossil fills gaps in evolutionary tale

The scientists stated that they had proved for the first time that changes in the body size and maturation of the fish is "an evolutionary response to over-fishing".

BBC: Fish on a trawler boat