The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Shuhai Xiao - One of the best experts on this subject based on the ideXlab platform.
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Palaeontology fossils come in to land
Nature, 2013Co-Authors: Shuhai Xiao, Paul L KnauthAbstract:Fossils found in rocks of the Ediacaran period in Australia have been previously characterized as early marine organisms. But a report suggests that these rocks are fossilized soils. So did some of these Ediacaran organisms in fact live on land, like lichens? A palaeontologist and a geologist weigh up the evidence. See Letter p.89 The smaller the bat, the higher the frequency of its echolocation calls. Until now this scaling has been attributed either to the bat's size or to the supposition that smaller bats seeking finer prey will need to use higher frequencies to pick out smaller objects. But that doesn't explain why small bats emit such high-pitched squeaks—up to 55 kHz, when 20 kHz would do the job, carry farther and take less effort to produce. Annemarie Surlykke and colleagues compare echolocation signals from six species of vespertilionid bat over a fivefold mass range. They show that the size–frequency relationship is governed by the need to maintain a focused, highly directional beam. As sound beams narrow with increasing emitter size and signal frequency, smaller mouths impose a constraint that forces smaller bats to use higher frequencies to achieve a sufficiently narrow beam. Exceptions prove the rule: phyllostomid bats show a much weaker correlation between size and frequency, but they emit sounds through specialized nasal structures, not through the mouth, and noseleaf dimensions do not scale with body size.
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Palaeontology undressing and redressing ediacaran embryos
Nature, 2007Co-Authors: Shuhai Xiao, Chuanming Zhou, Xunlai YuanAbstract:Arising from: J. V. Bailey, S. B. Joye, K. M. Kalanetra, B. E. Flood & F. A. Corsetti , 198–201 (2007)10.1038/nature05457 ; Bailey et al. reply Bailey et al.1 propose that the Ediacaran microfossils Megasphaera and Parapandorina, previously interpreted as animal resting eggs and blastula embryos2, represent Thiomargarita-like sulphide-oxidizing bacteria, claiming that this interpretation better explains their abundance and taphonomy. Here we highlight important observations that significantly weaken the authors' conclusions.
Xunlai Yuan - One of the best experts on this subject based on the ideXlab platform.
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Palaeontology undressing and redressing ediacaran embryos
Nature, 2007Co-Authors: Shuhai Xiao, Chuanming Zhou, Xunlai YuanAbstract:Arising from: J. V. Bailey, S. B. Joye, K. M. Kalanetra, B. E. Flood & F. A. Corsetti , 198–201 (2007)10.1038/nature05457 ; Bailey et al. reply Bailey et al.1 propose that the Ediacaran microfossils Megasphaera and Parapandorina, previously interpreted as animal resting eggs and blastula embryos2, represent Thiomargarita-like sulphide-oxidizing bacteria, claiming that this interpretation better explains their abundance and taphonomy. Here we highlight important observations that significantly weaken the authors' conclusions.
Frank A Corsetti - One of the best experts on this subject based on the ideXlab platform.
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Palaeontology undressing and redressing ediacaran embryos reply
Nature, 2007Co-Authors: Jake V Bailey, Samantha B Joye, Karen M Kalanetra, Beverly E Flood, Frank A CorsettiAbstract:Xiao et al.1 suggest that the presence of a textured capsule surrounding some Doushantuo globular microfossils calls into question the alternative interpretation of these structures as giant sulphur bacteria similar to modern Thiomargarita2. However, the outer coatings illustrated by Xiao et al.1 are similar morphologically to known bacterial features, and the texture, location and thickness change of the capsule is inconsistent with that of a fertilization envelope. We are therefore not convinced that the bacterial hypothesis has been falsified.
Imran A Rahman - One of the best experts on this subject based on the ideXlab platform.
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Computational fluid dynamics as a tool for testing functional and ecological hypotheses in fossil taxa
Palaeontology, 2017Co-Authors: Imran A RahmanAbstract:Computational fluid dynamics is a method for simulating fluid flows that has been widely used in engineering for decades, and which also has applications for studying function and ecology in fossil taxa. However, despite the possible benefits of this approach, computational fluid dynamics has been used only rarely in Palaeontology to date. The theoretical basis underlying the technique is outlined and the main steps involved in carrying out computer simulations of fluid flows are detailed. I also describe previous studies that have applied the method to fossils and discuss their potential for informing future research directions in Palaeontology. Computational fluid dynamics can enable large-scale comparative analyses, as well as exacting tests of hypotheses related to the function and ecology of ancient organisms. In this way, it could transform our understanding of many extinct fossil groups.
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virtual paleontology an overview
The Paleontological Society Papers, 2016Co-Authors: Mark D. Sutton, Imran A Rahman, Russell J GarwoodAbstract:Virtual paleontology is the study of fossils through three-dimensional digital visualizations; it represents a powerful and well-established set of tools for the analysis and dissemination of fossil data. Techniques are divisible into tomographic (i.e., slice-based) and surface-based types. Tomography has a long predigital history, but the recent explosion of virtual paleontology has resulted primarily from developments in X-ray computed tomography (CT), and of surface-based technologies (e.g., laser scanning). Destructive tomographic methods include forms of physical-optical tomography (e.g., serial grinding); these are powerful but problematic techniques. Focused Ion Beam (FIB) tomography is a modern alternative for microfossils; it is also destructive but is capable of extremely high resolutions. Nondestructive tomographic methods include the many forms of CT, which are the most widely used data-capture techniques at present, but are not universally applicable. Where CT is inappropriate, other nondestructive technologies (e.g., neutron tomography, magnetic resonance imaging, optical tomography) can prove suitable. Surface-based methods provide portable and convenient data capture for surface topography and texture, and might be appropriate when internal morphology is not of interest; technologies include laser scanning, photogrammetry, and mechanical digitization. Reconstruction methods that produce visualizations from raw data are many and various; selection of an appropriate workflow will depend on many factors, but is an important consideration that should be addressed prior to any study. The vast majority of three-dimensional fossils can now be studied using some form of virtual paleontology, and barriers to broader adaptation are being eroded. Technical issues regarding data sharing remain problematic. Technological developments continue; those promising tomographic recovery of compositional data are of particular relevance to paleontology.
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a virtual world of paleontology
Trends in Ecology and Evolution, 2014Co-Authors: John A. Cunningham, Imran A Rahman, Stephan Lautenschlager, Emily J Rayfield, Philip C J DonoghueAbstract:Computer-aided visualization and analysis of fossils has revolutionized the study of extinct organisms. Novel techniques allow fossils to be characterized in three dimensions and in unprecedented detail. This has enabled paleontologists to gain important insights into their anatomy, development, and preservation. New protocols allow more objective reconstructions of fossil organisms, including soft tissues, from incomplete remains. The resulting digital reconstructions can be used in functional analyses, rigorously testing long-standing hypotheses regarding the paleobiology of extinct organisms. These approaches are transforming our understanding of long-studied fossil groups, and of the narratives of organismal and ecological evolution that have been built upon them.
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virtual fossils a new resource for science communication in paleontology
Evolution: Education and Outreach, 2012Co-Authors: Imran A Rahman, Keith Adcock, Russell J GarwoodAbstract:Computer-aided 3-D reconstruction of fossils, or virtual paleontology, is an increasingly common and powerful technique. It is now regularly used for research in paleontology, yet to date has impacted little on public outreach and science communication; however, it is ideally suited for these purposes, being increasingly cheap and available, dynamic and exciting, and applicable to a range of topics. Here, we provide an introduction to the field, and a case study of its use for a public engagement event. The steps involved in creating such an educational resource are outlined, and include computed tomography scanning, digital visualization, and 3-D printing of fossils. We emphasize the value of virtual fossils for science communication; they allow for diverse learning styles in a variety of topics. In the future, we hope that virtual paleontology will become a mainstay of communicating the history of life, thereby promoting accurate understanding of evolution.
Philip C J Donoghue - One of the best experts on this subject based on the ideXlab platform.
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a virtual world of paleontology
Trends in Ecology and Evolution, 2014Co-Authors: John A. Cunningham, Imran A Rahman, Stephan Lautenschlager, Emily J Rayfield, Philip C J DonoghueAbstract:Computer-aided visualization and analysis of fossils has revolutionized the study of extinct organisms. Novel techniques allow fossils to be characterized in three dimensions and in unprecedented detail. This has enabled paleontologists to gain important insights into their anatomy, development, and preservation. New protocols allow more objective reconstructions of fossil organisms, including soft tissues, from incomplete remains. The resulting digital reconstructions can be used in functional analyses, rigorously testing long-standing hypotheses regarding the paleobiology of extinct organisms. These approaches are transforming our understanding of long-studied fossil groups, and of the narratives of organismal and ecological evolution that have been built upon them.
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Palaeontology embryonic identity crisis
Nature, 2007Co-Authors: Philip C J DonoghueAbstract:The oldest known animal fossils, identified as eggs and embryos, had been expected to reveal secrets from a period of great evolutionary change. Will the latest theory about the fossils' origins confound these hopes?
