人類或由有第六感的水中動物進化

We may not have been able to see ghosts, but in our earlier, fish-like form, we did have a sixth sense, according to a study.
　　我們可能真的看不到鬼怪，但是在我們類似魚的那些時候，根據一項科學研究，我們確實是存在第六感的。

Scientists have discovered that we are descended from a predatory fish-like ancestor that roamed the oceans 500million years ago and had 'electrosensors' - the ability to detect electric fields in water.

科學家們發現5億年前在海洋中食肉性的類魚類轉化而來的，這種類魚類的動物有在水中檢測電場的能力。

It used this skill to detect prey, communicate and to find its way around.

它用此項技能探路，與其他魚溝通並且找到周圍正確的路。

Researchers at the University of Cambridge and Cornell University in New York believe that not just humans, but 65,000 living vertebrate species – that’s any creature with a spine or backbone - are descended from the beast.

在劍橋和紐約康奈爾大學的研究者卻相信這不僅僅是人類的祖先，也是6萬5千種活着的脊椎類動物的祖先。

This includes 30,000 species of land animals - including humans - and a similar number of ray-finned fish, the scientists found.

科學家們發現這些動物包括3萬種陸地動物，和一小部分鰭刺類魚。

Their conclusions, which appear in the latest edition of Nature Communications, mark the culmination of 25 years of work into the subject.

在最新版的自然通訊雜誌上，他們發表了他們的結論，標誌着25年的研究工作到達了定點。

‘This study caps questions in developmental and evolutionary biology, popularly called “evo-devo” that I've been interested in for 35 years,’ said Willy Bemis, Cornell professor of ecology and evolutionary biology and a senior author of the paper.

“這項研究覆蓋了我已經研究了35年的發展與演化生物學上的問題”，康奈爾大學生態學和生物進化學的教授維利·彼米斯說。

He explains that hundreds of millions of years ago, there was a major split in the evolutionary tree of vertebrates.

他解釋在幾百萬年前，在脊柱動物的進化史上有一次主要的改變。

One lineage led to the ray-finned fishes, or actinopterygians, and the other to lobe-finned fishes, or sarcopterygians.

一種進化成爲了鰭刺類魚，一種進化成了總鰭類魚。

The latter gave rise to land vertebrates, some of which, such as the Mexican axolotl salamanders, retained electrosense ability.

後者是陸地脊柱動物的祖先，他們當中的一些還保持着探測電磁場的能力。

Some ray-finned fish, including paddlefish and sturgeon, also retained these receptors.

一些鰭刺類魚，包括白鱘和鱘魚，也有這樣的探測神經。

Professor Bernis and his team found that the electrosensors of the ray-finned fish and the salamander developed in precisely the same pattern from the same embryonic tissue in the developing skin, confirming that this is an ancient sensory system.

貝爾尼斯教授和他的研究隊發現具有電磁場探測功能的鰭刺類魚和火蜥蜴正是以同樣的模式發展來自同一胚胎組織在發展中皮膚，因此可以斷定他們有同樣的感官系統。

‘These two sensory systems share a common evolutionary heritage,’ added Bemis.

貝爾尼斯教授還說，“這兩個感官系統共享一個遺傳系統。”

However, over the years reptiles, birds and mammals lost their electrosense as it wasn’t needed for life on terra firma.

但是，由於在陸地上不需要這樣的電子磁場探測系統，爬行類動物，鳥類和哺乳動物都漸漸失去了這一功能。