查尔斯·达尔文生于1809年2月12日。200年后，他在我的祖国英国成了民族英雄。全世界各地都在以各种形式纪念他的200年诞辰，比如，电视、廣播、图书、博物馆展览、研讨会，以及各种各样的活动。今年也正值达尔文的著作《物种起源》——这本备受争议的书——出版150年。
　　在达尔文诞辰100周年时，对他的纪念活动并不多。1959年，我给自己的一群中学学生作了一个关于达尔文的报告，他们相聚只是来讨论文化与文学。第二年，我去剑桥大学读书，在剑桥大学基督学院的餐厅里挂着达尔文的画像，因为学生时代的他也在剑桥学习和生活过。我的第一份工作是在伦敦大学学院做一名讲师，上午茶歇的时候，我经常和一位来自生物系的达尔文专家Richard Freeman聊天，所以我的一生都对达尔文和他的著作非常熟悉。
　　达尔文间接地为我开启了我作为地质学家的事业。《物种起源》一书的整个第10章都用来介绍他对自己理论的科学反证，其中最有力的是“寒武纪生命大爆炸”。在形成于5亿3500万年前的寒武纪的岩石中，突然发现了大量古生物的化石，这段时期对于地球整个45亿6000万年的历史而言仅仅是短暂的一页。1859年，当达尔文写《物种起源》的第一版时，人类还不能准确地判断岩石的年代，而且寒武纪这个名称也没有被使用。他曾经的导师Adam Sedgwick推荐以此命名志留纪早期的古岩石，达尔文随后采用了这个名字。
　　达尔文写道：“如果进化论的理论是正确的，在寒武纪地层沉淀之前，应该存在一个很久的时代，这是无可争论的，这段时期可能与从寒武纪到现在的时间一样长，甚至还要久。而且，在这段时期地球上物种繁多。对于为什么我们没有发现大量的属于这个比寒武纪还要早的时期的化石，我无法给出满意的答案。以R. Murchison爵士为首的一些杰出的地质学家，直到最近才证实，志留纪最底层的有机物遗留是生命的第一道曙光。”达尔文认为，也许未来在早于寒武纪或前寒武纪的地层中发现化石，才能回答这个问题。当时，地质学家只调查研究了地球上的很少的一部分岩石，比如当时中国的地质几乎丝毫不为人们所了解。他注释道，加拿大在前寒武纪地层中发现了一块可能是化石的沉积物。
　　自《物种起源》发表一个世纪过去了，地质学家研究了地球上越来越多的地层，化石生物的每一次新发现都出现在寒武纪的初期。似乎达尔文错了。
　　1957年的一天，下午放学后，我和两个同学从英国中部小城莱斯特骑车去附近的charnwood森林山区。我们带着绳子去一个废弃的采石场玩攀岩。我爬到一个小悬崖的顶上，把绳子放下去，我的朋友在下面等着。其中一个人注意到一块石头上有叶子形状的印记，就让我下来看看，因为我对地质学感兴趣。我的老师告诉我这些岩石是前寒武纪的，因此不应该还含有化石，因此我告诉了我的父亲，他邀请他的一位朋友来帮忙看看。他就是Trevor Ford，莱斯特大学的地质学老师。我们穿过树林看到了岩石，他说，“我的上帝，这是一块化石！”
　　几周后，他把发现告诉了地质系的主任，并为当地一本英国地理学杂志写了一篇科学文章，且于1958年发表，他为这种化石命名为Charnia masoni。Ford博士带领英国地质调查队考察了这块化石，发现前寒武纪化石的新闻迅速传遍全球。这在地球另一端的南澳大利亚阿德莱德市也引起了轰动，因为9年前，阿德莱德大学的研究生Reginald Sprigg就告诉过他的导师，自己在弗林德斯山一个叫埃迪卡拉的地方发现了前寒武纪化石。Sprigg声称发现了比寒武纪更早的化石，但他的导师将信将疑，认为那些岩石是寒武纪而非前寒武纪。Ford博士文章中的图片显示Charnia与一块Sprigg发现的化石很像。澳大利亚地质学家都匆匆赶去埃迪卡拉，并带回很多化石来研究。著名的科学杂志《自然》在1958年刊登了对澳大利亚化石的介绍，埃迪卡拉现在成为联合国教科文组织世界遗产，前寒武纪化石也以埃迪卡拉生物的名字被全世界所熟知。除了南极洲，每一个大陆都发现了前寒武纪化石，包括中国的长江三峡。地理学家确信，在寒武纪之前存在一个埃迪卡拉纪，在距今6亿3000万-5亿4200万年前。“在这段漫长的时期内，世界上物种繁多。”当达尔文写下这句的时候，他是正确的。我开始了自己作为地质学家这一生的事业。
　　
　　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.