達爾文對我的影響

查爾斯·達爾文生于1809年2月12日。200年后，他在我的祖國英國成了民族英雄。全世界各地都在以各種形式紀念他的200年誕辰，比如，電視、廣播、圖書、博物館展覽、研討會，以及各種各樣的活動。今年也正值達爾文的著作《物種起源》——這本備受爭議的書——出版150年。

在達爾文誕辰100周年時，對他的紀念活動并不多。1959年，我給自己的一群中學學生作了一個關于達爾文的報告，他們相聚只是來討論文化與文學。第二年，我去劍橋大學讀書，在劍橋大學基督學院的餐廳里掛著達爾文的畫像，因為學生時代的他也在劍橋學習和生活過。我的第一份工作是在倫敦大學學院做一名講師，上午茶歇的時候，我經常和一位來自生物系的達爾文專家Richard Freeman聊天，所以我的一生都對達爾文和他的著作非常熟悉。

達爾文間接地為我開啟了我作為地質學家的事業。《物種起源》一書的整個第10章都用來介紹他對自己理論的科學反證，其中最有力的是“寒武紀生命大爆炸”。在形成于5億3500萬年前的寒武紀的巖石中，突然發現了大量古生物的化石，這段時期對于地球整個45億6000萬年的歷史而言僅僅是短暫的一頁。1859年，當達爾文寫《物種起源》的第一版時，人類還不能準確地判斷巖石的年代，而且寒武紀這個名稱也沒有被使用。他曾經的導師Adam Sedgwick推薦以此命名志留紀早期的古巖石，達爾文隨后采用了這個名字。

達爾文寫道：“如果進化論的理論是正確的，在寒武紀地層沉淀之前，應該存在一個很久的時代，這是無可爭論的，這段時期可能與從寒武紀到現在的時間一樣長，甚至還要久。而且，在這段時期地球上物種繁多。對于為什么我們沒有發現大量的屬于這個比寒武紀還要早的時期的化石，我無法給出滿意的答案。以R. Murchison爵士為首的一些杰出的地質學家，直到最近才證實，志留紀最底層的有機物遺留是生命的第一道曙光。”達爾文認為，也許未來在早于寒武紀或前寒武紀的地層中發現化石，才能回答這個問題。當時，地質學家只調查研究了地球上的很少的一部分巖石，比如當時中國的地質幾乎絲毫不為人們所了解。他注釋道，加拿大在前寒武紀地層中發現了一塊可能是化石的沉積物。

自《物種起源》發表一個世紀過去了，地質學家研究了地球上越來越多的地層，化石生物的每一次新發現都出現在寒武紀的初期。似乎達爾文錯了。

1957年的一天，下午放學后，我和兩個同學從英國中部小城萊斯特騎車去附近的charnwood森林山區。我們帶著繩子去一個廢棄的采石場玩攀巖。我爬到一個小懸崖的頂上，把繩子放下去，我的朋友在下面等著。其中一個人注意到一塊石頭上有葉子形狀的印記，就讓我下來看看，因為我對地質學感興趣。我的老師告訴我這些巖石是前寒武紀的，因此不應該還含有化石，因此我告訴了我的父親，他邀請他的一位朋友來幫忙看看。他就是Trevor Ford，萊斯特大學的地質學老師。我們穿過樹林看到了巖石，他說，“我的上帝，這是一塊化石！”

幾周后，他把發現告訴了地質系的主任，并為當地一本英國地理學雜志寫了一篇科學文章，且于1958年發表，他為這種化石命名為Charnia masoni。Ford博士帶領英國地質調查隊考察了這塊化石，發現前寒武紀化石的新聞迅速傳遍全球。這在地球另一端的南澳大利亞阿德萊德市也引起了轟動，因為9年前，阿德萊德大學的研究生Reginald Sprigg就告訴過他的導師，自己在弗林德斯山一個叫埃迪卡拉的地方發現了前寒武紀化石。Sprigg聲稱發現了比寒武紀更早的化石，但他的導師將信將疑，認為那些巖石是寒武紀而非前寒武紀。Ford博士文章中的圖片顯示Charnia與一塊Sprigg發現的化石很像。澳大利亞地質學家都匆匆趕去埃迪卡拉，并帶回很多化石來研究。著名的科學雜志《自然》在1958年刊登了對澳大利亞化石的介紹，埃迪卡拉現在成為聯合國教科文組織世界遺產，前寒武紀化石也以埃迪卡拉生物的名字被全世界所熟知。除了南極洲，每一個大陸都發現了前寒武紀化石，包括中國的長江三峽。地理學家確信，在寒武紀之前存在一個埃迪卡拉紀，在距今6億3000萬-5億4200萬年前。“在這段漫長的時期內，世界上物種繁多。”當達爾文寫下這句的時候，他是正確的。我開始了自己作為地質學家這一生的事業。

Charles Darwin (1809-1882) was born on 12 February 1809 and 200 years after his birth he is a national hero in my country， the United Kingdom of Great Britain Northern Ireland. His anniversary is being celebrated all over the world with TV and radio programmes， books， museum exhibitions， meetings and many other activities. This year is also the 150th anniversary of the publication of his controversial book， The Origin of Species.

Celebrations were less extensive at Darwin's 100th anniversary but in 1959 I gave a talk about him to a club of my fellow middle school students that met to discuss culture and literature. I went to Cambridge University in the following year where Darwin's portrait hung in our dining hall at Christ's College because he had lived and studied there when he was a student. When I got my first job as a lecturer at University College London I regularly chatted to Dr Richard Freeman， a Darwin expert in the Biology Department， over coffee at our morning break. So I have been familiar with Darwin and his work almost all my life.

Darwin also indirectly launched me on my career as a geologist. He devoted the whole of Chapter 10 of The Origin of Species to scientific objections to his theory， and one of the most serious was the \"Cambrian explosion\". Fossilized remains of ancient life-forms suddenly become abundant in sedimentary rocks that formed in the Cambrian period about 535 million years ago， only a fraction of the Earth's total life-time of 4，560 million years. Absolute ages of rocks could not be measured when Darwin wrote the first edition in 1859 and the name Cambrian had not yet been introduced. He used it later after his former professor， Adam Sedgwick， proposed the name for ancient rocks previously included in the younger Silurian period.

Darwin wrote: \"... if the theory [of evolution] be true， it is indisputable that before the lowest Cambrian stratum was deposited long periods elapsed， as long as， or probably far longer than， the whole interval from the Cambrian age to the present day; and that during these vast periods the world swarmed with living creatures. To the question why we do not find rich fossiliferous deposits belonging to these assumed earliest periods prior to the Cambrian system， I can give no satisfactory answer. Several eminent geologists， with Sir R. Murchison at their head， were until recently convinced that we beheld in the organic remains of the lowest Silurian stratum the first dawn of life.\"Darwin argued that the question might be answered in future by the discovery of fossils in rocks that formed before the Cambrian period， in Precambrian times. Very few of the Earth's rocks had been investigated by geologists， for example almost nothing was known about Chinese geology. He noted that a possible fossil had been discovered in Precambrian rocks in Canada.

For almost a century， geologists studied more and more parts of the world and everywhere the first traces of fossilized creatures continued to crop up at the beginning of the Cambrian period. It looked as though Darwin was wrong.

Then one afternoon after school in 1957 I rode by bicycle with two classmates from Leicester， a small city in the middle of England， to a nearby hilly district called Charnwood Forest. We took a rope to go rock-climbing up the side of a disused stone quarry. I walked to the top of a small cliff to lower our rope while my friends waited below. One of them noticed a leaf-like impression in the rock and called to me to come down and take a look because I was interested in geology. My teachers had told me that the rocks were Precambrian and therefore should not contain fossils， so I told my father about it and he invited one of his friends to come and have a look. He was Dr Trevor Ford， a geology teacher at Leicester University. We walked through the trees to the rocks， and Dr Ford said， \"My God， it is [a fossil]!\"

In the next few weeks he told the head of the Geology Department about the discovery and wrote a scientific paper for a local British geological journal which was published in 1958 and named the fossil Charnia masoni. Dr Ford took the Director of the British Geological Survey to see it and news of a Precambrian fossil quickly spread round the world. It caused a stir in the city of Adelaide at the other side of the world in South Australia because nine years earlier Reginald Sprigg， a graduate of Adelaide University， had told his professors that he had found Precambrian fossils at a place called Ediacara in the Flinders Mountains. Sprigg had claimed to find ancient fossils before and his professors took his claims with a large pinch of salt， thinking that the rocks were Cambrian not Precambrian. The photograph of Charnia in Ford's paper was like one of Sprigg's fossils. The Austrilian geologists hurried to Ediacara in a lorry and brought back many fossils to study. The famous scientific journal Nature published an account of the Australian fossils in 1958 and Ediacara is now a UNESCO World Heritage geology site and the Precambrian fossils are known everywhere as the Ediacara biota. They have been found in every continent except Antarctica， including the Three Gorges of the Yangtze River in China. Geologists now recognize an Ediacaran Period at 630 to 542 million years ago， before the Cambrian Period. Darwin was right when he wrote， 揹uring these vast periods the world swarmed with living creatures.?I was launched on a lifetime as a geologist.