這種微小的海藻化石已經(jīng)有10億年的歷史，是所有陸地植物祖先的親戚

這種微小的海藻化石已經(jīng)有10億年的歷史，是所有陸地植物祖先的親戚

Around 450 million years ago one of the most important developments in the history of Earth occurred: plants colonized the land for the first time. Now a fossil has been found that could resemble the first species that developed this capacity, from which all modern land plants descend. Most remarkably, the fossil comes not from around the time of this epic event, but from more than twice as long ago.

大約4億5千萬(wàn)年前，地球歷史上最重要的發(fā)展之一發(fā)生了:植物第一次在陸地上殖民?，F(xiàn)在，人們發(fā)現(xiàn)了一塊化石，它可能類似于第一個(gè)發(fā)展出這種能力的物種，所有現(xiàn)代陸生植物都起源于這種能力。最引人注目的是，這塊化石并不是來(lái)自這一重大事件前后，而是來(lái)自兩倍多以前。

Professor Shuhai Xiao of Virginia Tech announced the discovery of fossilized green seaweed in billion-year-old ocean sedimentary rocks from Liaoning Province, north-eastern China, in Nature Ecology and Evolution under the name Proterocladus antiquus. P. antiquus exceeds the previous record for green seaweed by some 200 million years.

弗吉尼亞理工大學(xué)的肖樹海教授在《自然、生態(tài)與進(jìn)化》雜志上發(fā)表文章稱，他在中國(guó)東北遼寧省10億年前的海洋沉積巖中發(fā)現(xiàn)了綠色海藻化石。安帝古藻的數(shù)量比之前的記錄多了2億年。

Stephen Luntz

Like many paleobotanists, Xiao thinks all land plants evolved from green seaweeds, which continue to compete in the oceans with brown and red seaweeds, both of which failed to make the same transition to land. However, he acknowledged in a statement, "Not everyone agrees with us; some scientists think that green plants started in rivers and lakes, and then conquered the ocean and land later.”

和許多古植物學(xué)家一樣，肖認(rèn)為所有的陸生植物都是由綠色的海藻進(jìn)化而來(lái)，而綠色的海藻在海洋中與棕色和紅色的海藻競(jìng)爭(zhēng)，而這兩種海藻都沒有向陸地過(guò)渡。然而，他在一份聲明中承認(rèn)，“并非所有人都同意我們的觀點(diǎn);一些科學(xué)家認(rèn)為綠色植物起源于河流和湖泊，后來(lái)征服了海洋和陸地。”

Dr Qing Tang, who brought the fossils to Xioa's attention noted, “These seaweeds display multiple branches, upright growths, and specialized cells known as akinetes that are very common in this type of fossil.”

引起了肖教授注意的Qing Tang博士指出:“這些海藻顯示出多種分枝，直立生長(zhǎng)，以及一種特殊的細(xì)胞，即秋刀藻，在這類化石中很常見。”

The fossil dates back 1 billion years, and was captured using a microscope because it is only 2mm long, the size of a flea. Virginia Tech

As a forerunner of the tallest redwood or the extraordinary expanse of quaking aspen, Xiao's fossils are underwhelming, being just 2 millimeters (0.08 inches) long. Proverbs about mighty oaks and tiny acorns are underselling the truth.

作為世界上最高的紅杉樹的先驅(qū)者，或者是顫楊的非凡廣布，肖的化石令人印象深刻，只有2毫米(0.08英寸)長(zhǎng)。關(guān)于強(qiáng)大的橡樹和微小的橡子的諺語(yǔ)低估了真理。

Some of P. antiquus' descendants, however, appear to go by the principle that when you are on to a good thing, stick to it.

然而，安帝古斯的一些后代似乎遵循這樣的原則:當(dāng)你想要做一件好事時(shí)，就要堅(jiān)持下去。

“There are some modern green seaweeds that look very similar to the fossils that we found,” Xiao said. “A group of modern green seaweeds, known as siphonocladaleans, are particularly similar in shape and size to the fossils we found.” Intriguingly, P. antiquus bears considerable similarity to the next oldest fossil of this type, P. major, which has been found in 800 million-year-old rocks at Svalbard. The P. major fossils were less well preserved, however, making confirmation they are the same species difficult, and boosting hopes we will learn a lot more from the new find.

“有一些現(xiàn)代的綠色海藻，看起來(lái)和我們發(fā)現(xiàn)的化石非常相似，”肖說(shuō)。“一群現(xiàn)代的綠色海藻，被稱為吸蟲藻，在形狀和大小上與我們發(fā)現(xiàn)的化石特別相似。有趣的是，安帝古猿與這種類型的第二古老化石P. major極為相似，后者是在斯瓦爾巴特群島8億年前的巖石中發(fā)現(xiàn)的。然而，P.主要化石保存的不那么完好，這使得確認(rèn)它們是同一物種變得困難，也增加了我們從新發(fā)現(xiàn)中獲得更多信息的希望。

Red seaweeds fossils date back 1.05 billion years ago, but previously no green seaweeds had been found of similar ages. Molecular clocks suggest the first green photosynthesizing plants appeared somewhere between 1,600 and 720 million years ago, but scientists find such a wide range unsatisfying and hope fossil discoveries will narrow it down.

紅色海藻的化石可以追溯到10.5億年前，但是在此之前，還沒有發(fā)現(xiàn)過(guò)與之年齡相近的綠色海藻。分子鐘顯示，最早的綠色光合植物出現(xiàn)在16億到7億2千萬(wàn)年前，但科學(xué)家們發(fā)現(xiàn)如此廣泛的范圍并不令人滿意，希望化石的發(fā)現(xiàn)能縮小范圍。

The discovery raises the question of why green seaweeds took so long to move onto dry land, given the speed with which they adapted to most environments once they did.

這一發(fā)現(xiàn)提出了一個(gè)問題:考慮到綠色海藻一旦適應(yīng)大多數(shù)環(huán)境的速度，它們?yōu)槭裁匆ㄟ@么長(zhǎng)時(shí)間才能遷移到干燥的陸地上呢?