Investigating Fossils. Wilson J. Wall. Читать онлайн. Newlib. NEWLIB.NET

Автор: Wilson J. Wall
Издательство: John Wiley & Sons Limited
Серия:
Жанр произведения: Биология
Год издания: 0
isbn: 9781119698487
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Strictly speaking it is a descendent of the assumed extinct lineage which was rediscovered, rather than the same species. This is, of course, the Coelacanth. This astonishing story started in December 1938 when Marjorie Courtney‐Latimer was on a trip to the dockside of East London in the Eastern Cape of South Africa, to see what the trawlers had brought up by way of specimens for the East London Museum of which she was a curator. On this particular occasion what she found was a 1.5 m, 57.7 kg fish that was already a day out of water. It had been caught at the mouth of the Chaluma river, just south of East London. Through many trials and tribulations it became apparent that this was a fish representing a lineage that had been supposed extinct for 80 million years. Identification came a few days later as a member of the Coelacanthiformes, a group previously considered extinct. Even more astonishing was that this put it into the Crossopterygii, the otherwise extinct group of lobe‐finned fish. This particular species was described and appropriately named Latimeria chalumnae (Greenwood 1988). Such a find is a very rare occurrence as it was not a rediscovery of a species, or even just a new discovery of a previously unknown species, this was finding a group of fish that were well known from the fossil record and assumed to have disappeared millions of years previously. If L. chalumnae had been discovered in the eighteenth or nineteenth century, this would have been used as a demonstration by biblical literalists and supporters, that the fossil record was of species still extant, but not yet found. There are two points to be made about this, the first is that the oxymoron ‘living fossil’ is misleading and the other is that as far as we know L. chalumnae was not represented in the fossil record, it was the lineage which had survived, rather than the species. Another such surviving ancient lineage is the Tuatara, Sphenodon punctatus, from New Zealand. This has been the subject of a quite recent debate regarding the status of a living fossil and the very concept of a ‘living fossil’ as a useful idea, rather than a confusing one (Vaux et al. 2019).

      The situation with the Coelacanth is a very unusual event, although really not so surprising when you consider the numbers involved. As there are generally regarded as being something between 1.5 and 4.5 million species extant on the planet (there are very good biological reasons for this wide range) while through the whole Phanerozoic aeon, which is approximately 541 million years, we have so far found fossils of only about 250 000 different species. This also demonstrates something else; we have no idea of the level of biodiversity for most of the past. We can only surmise what the range of animal and plant species were. There is certainly no reason to believe that the biodiversity was significantly less than it is now. The number and range of species in any ecology will determine the stability as well as the complexity of the population. It is for this reason we have to assume that in the past biological radiations have occurred to fill ecological niches adding to both the complexity and the stability of the system. The complexity and diversity present in the palaeontological ecosystem are reflected in the rate at which dinosaurs are being discovered. In 2019, there were more than 30 new species described and based on mathematical models, this is a small fraction of the potential, with anything up to 70% still to be discovered.

      With the developing interest in palaeontology among the general population and the apparently human tendency to collect things, fossils have become ever more important. They have developed an importance, from a scientific point of view, in helping us understand the way species develop and lineages change, or like the clade of Crossopterygian fish, pass through time largely unaltered. Studying fossils can even help with developing completely new ideas and lines of reasoning, such as how birds originated. As part of this they can help immensely in understanding the biggest and most important questions in biology; evolution and the development of modern species.

      At the same time, the human urge to collect and make sense of material goods, stamps, coins or fossils has meant that they have become of far greater commercial importance than would have been dreamt of 100 years ago. Wealthy collectors can pay large sums of money for rare and exotic fossils, probably far more than their scientific value merits. This can in itself generate problems, such as scientifically valuable fossils being removed from public view and scientific research. Another problem that can arise is that in the base commercial environment within which we live, it is seen as quite in order to generate chimaeric, or even just plain fraudulent, fossils for sale. Of course, this is not new or confined to fossils. Neither is it a phenomenon limited to areas where the outcome of discovery would be predominantly embarrassment, like faked paintings. When Isaac Newton joined the Royal Mint and supervised the recoinage of Britain in 1696 (there was no paper money), it was estimated that between 10 and 20% of the coins in circulation were counterfeit. Even these examples can be seen as relatively minor compared with the wholesale perversion of scientific knowledge when fraud in science takes place.

      In an era when data can be promulgated very quickly, retractions and rebuttals do not necessarily have the same weight as the original message. In these circumstances, fossil fraud can have far greater repercussions than simply questionable science or making dishonest money. Fraudulent fossils may become part of a spurious line of reasoning about creation or evolution and no amount of denial of the obvious lack of veracity of the image of, say, a fossilised giant will counter the belief systems of the ignorant.

      Knowledge of fossils cannot be given a start date, as soon as man came into contact with suitable geological areas fossils would have been seen. The cognitive recognition of them being biological in origin may well have come later, certainly as soon as writing became more than simple accountancy. It seems that in the ancient world around the Mediterranean it was easy to slot some of the large bones of fossilised mammals into the mythology, labelling them as being the skeletons of ancient giants and warriors. Because fossils are not confined to one area of the planet, it has taxed the minds of all nations to find an answer to how obviously marine species come to be found so far up mountains. It was only later that people started asking questions about the process of fossilisation itself. The process of fossilisation does take a great deal of understanding and to some extent speculation, since even for short fossilisation periods, it is still far too long when compared to a human lifetime.

      Understanding the biological, rather than mineralogical, origin of fossils was a first step in a practical attempt to explain the process of fossilisation. To turn biological material, which everyone knows decays, into a form of rock as solid and stable as any rock, was difficult to comprehend. Once this was understood,