"The Cambrian Fossils of China: The Flowering of early Animal Life"
Dr Derek Siveter
Tuesday, 5 September 2006
2/F Olympic House, So Kong Po, Causeway Bay
Drinks Reception 6.30 pm; Lecture 7.30 pm
We are delighted to welcome Dr Derek Siveter, Reader in Earth Sciences at Oxford and joint head of the University Museum of Natural History, and a world leading expert on the exciting new fossil findings of China, to address the Royal Geographical Society Hong Kong. The 525 million years old Cambrian biota from Yunnan Province, SW China, represents one of the world's most important fossil assemblages and its discovery one of the most important palaeontological finds ever. It is made up of exceptional fossils that are notable for showing numerous animals. The fauna is contributing fundamentally to our understanding of one of the most important events in the history of life on Earth, the socalled 'Cambrian Explosion', an event that saw the earliest abundant appearance in the fossil record of animal life. Dr. Siveter's lecture illustrates the extraordinary findings of this area of China. The fauna includes the earliest fossil representatives of many major animal groups including the vertebrates. Many of the fossils have been reported on in high profile journals such as Nature, Science, and the Proceedings of the Royal Society. In 2001, the area was established as the first National Park in China to be based on the scientific importance of its fossils. In 2007 China is applying to UNESCO for World Natural Heritage status for the fossil localities of the area. Putative fossils have been recorded from rocks of 3,500 million years. There is a more general consensus regarding the validity of life in the rock record from about 2,500 million years ago. However until about 590 million years, life consisted of relatively simple organisms such as bacteria and algae. From this point multicellular organisms started to appear at various localities globally. Shortly after the start of the Cambrian Period, some 545 million years ago, small shelly fossils appear in relative abundance for the first time. These are followed very shortly thereafter of a very rich variety of new and complex organisms. This unprecedented increase in diversity represents the socalled 'Cambrian Explosion'. It is from this point in time that the first examples are known of very many of the major animal groups that went on to dominate even presentday seas. The importance of the exceptionally preserved fossils of Yunnan is that they provide a unique window on ancient life in its evolution. The fossils are enhanced by their colour contrast against the background sediment, ironrich red, whereas the matrix can vary from grey to buff to yellow. Such contrast makes the fossils highly photogenic. There is a diverse range of organisms, including algae, sponges, sea anemonelike forms, and primitive vertebrates, together with many forms that are currently of uncertain affinity. The total number of species is more than 100. It is shown even in these seas of Early Cambrian age this was a fairly sophisticated ecosystem representing a wide variety of feeding types, including filter feeders, scavengers and predators. Derek Siveter gained his BSc and his PhD, in which he investigated Ordovician to Devonian trilobites from NW Europe, from the University of Leicester. There followed a position at the University of Hull and now the University of Oxford where he is joint head of the University Museum of Natural History and Reader in Earth Sciences. Fossil arthropods and Lower Palaeozoic (especially Silurian) geology have been his research interests. In recent years he has also been investigating the mode of palaeobiology, systematics and evolutionary significance of the animals of the Herefordshire Lagerstätte. He is a world leading expert on the exciting new fossil findings of China. Dr. Siveter is the author of numerous books and papers. Members and their guests are most welcome to attend this lecture, which is HK$50 for Members, $100 for Members' Guests and HK$150 for others.